Improve sizeviewer for Windows

tools/win/sizeviewer/codemirror.js

+// CodeMirror, copyright (c) by Marijn Haverbeke and others
+// Distributed under an MIT license: http://codemirror.net/LICENSE
+
+// This is CodeMirror (http://codemirror.net), a code editor
+// implemented in JavaScript on top of the browser's DOM.
+//
+// You can find some technical background for some of the code below
+// at http://marijnhaverbeke.nl/blog/#cm-internals .
+
+(function(mod) {
+  if (typeof exports == "object" && typeof module == "object") // CommonJS
+    module.exports = mod();
+  else if (typeof define == "function" && define.amd) // AMD
+    return define([], mod);
+  else // Plain browser env
+    this.CodeMirror = mod();
+})(function() {
+  "use strict";
+
+  // BROWSER SNIFFING
+
+  // Kludges for bugs and behavior differences that can't be feature
+  // detected are enabled based on userAgent etc sniffing.
+
+  var gecko = /gecko\/\d/i.test(navigator.userAgent);
+  // ie_uptoN means Internet Explorer version N or lower
+  var ie_upto10 = /MSIE \d/.test(navigator.userAgent);
+  var ie_11up = /Trident\/(?:[7-9]|\d{2,})\..*rv:(\d+)/.exec(navigator.userAgent);
+  var ie = ie_upto10 || ie_11up;
+  var ie_version = ie && (ie_upto10 ? document.documentMode || 6 : ie_11up[1]);
+  var webkit = /WebKit\//.test(navigator.userAgent);
+  var qtwebkit = webkit && /Qt\/\d+\.\d+/.test(navigator.userAgent);
+  var chrome = /Chrome\//.test(navigator.userAgent);
+  var presto = /Opera\//.test(navigator.userAgent);
+  var safari = /Apple Computer/.test(navigator.vendor);
+  var khtml = /KHTML\//.test(navigator.userAgent);
+  var mac_geMountainLion = /Mac OS X 1\d\D([8-9]|\d\d)\D/.test(navigator.userAgent);
+  var phantom = /PhantomJS/.test(navigator.userAgent);
+
+  var ios = /AppleWebKit/.test(navigator.userAgent) && /Mobile\/\w+/.test(navigator.userAgent);
+  // This is woefully incomplete. Suggestions for alternative methods welcome.
+  var mobile = ios || /Android|webOS|BlackBerry|Opera Mini|Opera Mobi|IEMobile/i.test(navigator.userAgent);
+  var mac = ios || /Mac/.test(navigator.platform);
+  var windows = /win/i.test(navigator.platform);
+
+  var presto_version = presto && navigator.userAgent.match(/Version\/(\d*\.\d*)/);
+  if (presto_version) presto_version = Number(presto_version[1]);
+  if (presto_version && presto_version >= 15) { presto = false; webkit = true; }
+  // Some browsers use the wrong event properties to signal cmd/ctrl on OS X
+  var flipCtrlCmd = mac && (qtwebkit || presto && (presto_version == null || presto_version < 12.11));
+  var captureRightClick = gecko || (ie && ie_version >= 9);
+
+  // Optimize some code when these features are not used.
+  var sawReadOnlySpans = false, sawCollapsedSpans = false;
+
+  // EDITOR CONSTRUCTOR
+
+  // A CodeMirror instance represents an editor. This is the object
+  // that user code is usually dealing with.
+
+  function CodeMirror(place, options) {
+    if (!(this instanceof CodeMirror)) return new CodeMirror(place, options);
+
+    this.options = options = options ? copyObj(options) : {};
+    // Determine effective options based on given values and defaults.
+    copyObj(defaults, options, false);
+    setGuttersForLineNumbers(options);
+
+    var doc = options.value;
+    if (typeof doc == "string") doc = new Doc(doc, options.mode);
+    this.doc = doc;
+
+    var display = this.display = new Display(place, doc);
+    display.wrapper.CodeMirror = this;
+    updateGutters(this);
+    themeChanged(this);
+    if (options.lineWrapping)
+      this.display.wrapper.className += " CodeMirror-wrap";
+    if (options.autofocus && !mobile) focusInput(this);
+
+    this.state = {
+      keyMaps: [],  // stores maps added by addKeyMap
+      overlays: [], // highlighting overlays, as added by addOverlay
+      modeGen: 0,   // bumped when mode/overlay changes, used to invalidate highlighting info
+      overwrite: false, focused: false,
+      suppressEdits: false, // used to disable editing during key handlers when in readOnly mode
+      pasteIncoming: false, cutIncoming: false, // help recognize paste/cut edits in readInput
+      draggingText: false,
+      highlight: new Delayed(), // stores highlight worker timeout
+      keySeq: null  // Unfinished key sequence
+    };
+
+    // Override magic textarea content restore that IE sometimes does
+    // on our hidden textarea on reload
+    if (ie && ie_version < 11) setTimeout(bind(resetInput, this, true), 20);
+
+    registerEventHandlers(this);
+    ensureGlobalHandlers();
+
+    startOperation(this);
+    this.curOp.forceUpdate = true;
+    attachDoc(this, doc);
+
+    if ((options.autofocus && !mobile) || activeElt() == display.input)
+      setTimeout(bind(onFocus, this), 20);
+    else
+      onBlur(this);
+
+    for (var opt in optionHandlers) if (optionHandlers.hasOwnProperty(opt))
+      optionHandlers[opt](this, options[opt], Init);
+    maybeUpdateLineNumberWidth(this);
+    for (var i = 0; i < initHooks.length; ++i) initHooks[i](this);
+    endOperation(this);
+  }
+
+  // DISPLAY CONSTRUCTOR
+
+  // The display handles the DOM integration, both for input reading
+  // and content drawing. It holds references to DOM nodes and
+  // display-related state.
+
+  function Display(place, doc) {
+    var d = this;
+
+    // The semihidden textarea that is focused when the editor is
+    // focused, and receives input.
+    var input = d.input = elt("textarea", null, null, "position: absolute; padding: 0; width: 1px; height: 1em; outline: none");
+    // The textarea is kept positioned near the cursor to prevent the
+    // fact that it'll be scrolled into view on input from scrolling
+    // our fake cursor out of view. On webkit, when wrap=off, paste is
+    // very slow. So make the area wide instead.
+    if (webkit) input.style.width = "1000px";
+    else input.setAttribute("wrap", "off");
+    // If border: 0; -- iOS fails to open keyboard (issue #1287)
+    if (ios) input.style.border = "1px solid black";
+    input.setAttribute("autocorrect", "off"); input.setAttribute("autocapitalize", "off"); input.setAttribute("spellcheck", "false");
+
+    // Wraps and hides input textarea
+    d.inputDiv = elt("div", [input], null, "overflow: hidden; position: relative; width: 3px; height: 0px;");
+    // The fake scrollbar elements.
+    d.scrollbarH = elt("div", [elt("div", null, null, "height: 100%; min-height: 1px")], "CodeMirror-hscrollbar");
+    d.scrollbarV = elt("div", [elt("div", null, null, "min-width: 1px")], "CodeMirror-vscrollbar");
+    // Covers bottom-right square when both scrollbars are present.
+    d.scrollbarFiller = elt("div", null, "CodeMirror-scrollbar-filler");
+    // Covers bottom of gutter when coverGutterNextToScrollbar is on
+    // and h scrollbar is present.
+    d.gutterFiller = elt("div", null, "CodeMirror-gutter-filler");
+    // Will contain the actual code, positioned to cover the viewport.
+    d.lineDiv = elt("div", null, "CodeMirror-code");
+    // Elements are added to these to represent selection and cursors.
+    d.selectionDiv = elt("div", null, null, "position: relative; z-index: 1");
+    d.cursorDiv = elt("div", null, "CodeMirror-cursors");
+    // A visibility: hidden element used to find the size of things.
+    d.measure = elt("div", null, "CodeMirror-measure");
+    // When lines outside of the viewport are measured, they are drawn in this.
+    d.lineMeasure = elt("div", null, "CodeMirror-measure");
+    // Wraps everything that needs to exist inside the vertically-padded coordinate system
+    d.lineSpace = elt("div", [d.measure, d.lineMeasure, d.selectionDiv, d.cursorDiv, d.lineDiv],
+                      null, "position: relative; outline: none");
+    // Moved around its parent to cover visible view.
+    d.mover = elt("div", [elt("div", [d.lineSpace], "CodeMirror-lines")], null, "position: relative");
+    // Set to the height of the document, allowing scrolling.
+    d.sizer = elt("div", [d.mover], "CodeMirror-sizer");
+    // Behavior of elts with overflow: auto and padding is
+    // inconsistent across browsers. This is used to ensure the
+    // scrollable area is big enough.
+    d.heightForcer = elt("div", null, null, "position: absolute; height: " + scrollerCutOff + "px; width: 1px;");
+    // Will contain the gutters, if any.
+    d.gutters = elt("div", null, "CodeMirror-gutters");
+    d.lineGutter = null;
+    // Actual scrollable element.
+    d.scroller = elt("div", [d.sizer, d.heightForcer, d.gutters], "CodeMirror-scroll");
+    d.scroller.setAttribute("tabIndex", "-1");
+    // The element in which the editor lives.
+    d.wrapper = elt("div", [d.inputDiv, d.scrollbarH, d.scrollbarV,
+                            d.scrollbarFiller, d.gutterFiller, d.scroller], "CodeMirror");
+
+    // Work around IE7 z-index bug (not perfect, hence IE7 not really being supported)
+    if (ie && ie_version < 8) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0; }
+    // Needed to hide big blue blinking cursor on Mobile Safari
+    if (ios) input.style.width = "0px";
+    if (!webkit) d.scroller.draggable = true;
+    // Needed to handle Tab key in KHTML
+    if (khtml) { d.inputDiv.style.height = "1px"; d.inputDiv.style.position = "absolute"; }
+    // Need to set a minimum width to see the scrollbar on IE7 (but must not set it on IE8).
+    if (ie && ie_version < 8) d.scrollbarH.style.minHeight = d.scrollbarV.style.minWidth = "18px";
+
+    if (place) {
+      if (place.appendChild) place.appendChild(d.wrapper);
+      else place(d.wrapper);
+    }
+
+    // Current rendered range (may be bigger than the view window).
+    d.viewFrom = d.viewTo = doc.first;
+    // Information about the rendered lines.
+    d.view = [];
+    // Holds info about a single rendered line when it was rendered
+    // for measurement, while not in view.
+    d.externalMeasured = null;
+    // Empty space (in pixels) above the view
+    d.viewOffset = 0;
+    d.lastWrapHeight = d.lastWrapWidth = 0;
+    d.updateLineNumbers = null;
+
+    // Used to only resize the line number gutter when necessary (when
+    // the amount of lines crosses a boundary that makes its width change)
+    d.lineNumWidth = d.lineNumInnerWidth = d.lineNumChars = null;
+    // See readInput and resetInput
+    d.prevInput = "";
+    // Set to true when a non-horizontal-scrolling line widget is
+    // added. As an optimization, line widget aligning is skipped when
+    // this is false.
+    d.alignWidgets = false;
+    // Flag that indicates whether we expect input to appear real soon
+    // now (after some event like 'keypress' or 'input') and are
+    // polling intensively.
+    d.pollingFast = false;
+    // Self-resetting timeout for the poller
+    d.poll = new Delayed();
+
+    d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = null;
+
+    // Tracks when resetInput has punted to just putting a short
+    // string into the textarea instead of the full selection.
+    d.inaccurateSelection = false;
+
+    // Tracks the maximum line length so that the horizontal scrollbar
+    // can be kept static when scrolling.
+    d.maxLine = null;
+    d.maxLineLength = 0;
+    d.maxLineChanged = false;
+
+    // Used for measuring wheel scrolling granularity
+    d.wheelDX = d.wheelDY = d.wheelStartX = d.wheelStartY = null;
+
+    // True when shift is held down.
+    d.shift = false;
+
+    // Used to track whether anything happened since the context menu
+    // was opened.
+    d.selForContextMenu = null;
+  }
+
+  // STATE UPDATES
+
+  // Used to get the editor into a consistent state again when options change.
+
+  function loadMode(cm) {
+    cm.doc.mode = CodeMirror.getMode(cm.options, cm.doc.modeOption);
+    resetModeState(cm);
+  }
+
+  function resetModeState(cm) {
+    cm.doc.iter(function(line) {
+      if (line.stateAfter) line.stateAfter = null;
+      if (line.styles) line.styles = null;
+    });
+    cm.doc.frontier = cm.doc.first;
+    startWorker(cm, 100);
+    cm.state.modeGen++;
+    if (cm.curOp) regChange(cm);
+  }
+
+  function wrappingChanged(cm) {
+    if (cm.options.lineWrapping) {
+      addClass(cm.display.wrapper, "CodeMirror-wrap");
+      cm.display.sizer.style.minWidth = "";
+    } else {
+      rmClass(cm.display.wrapper, "CodeMirror-wrap");
+      findMaxLine(cm);
+    }
+    estimateLineHeights(cm);
+    regChange(cm);
+    clearCaches(cm);
+    setTimeout(function(){updateScrollbars(cm);}, 100);
+  }
+
+  // Returns a function that estimates the height of a line, to use as
+  // first approximation until the line becomes visible (and is thus
+  // properly measurable).
+  function estimateHeight(cm) {
+    var th = textHeight(cm.display), wrapping = cm.options.lineWrapping;
+    var perLine = wrapping && Math.max(5, cm.display.scroller.clientWidth / charWidth(cm.display) - 3);
+    return function(line) {
+      if (lineIsHidden(cm.doc, line)) return 0;
+
+      var widgetsHeight = 0;
+      if (line.widgets) for (var i = 0; i < line.widgets.length; i++) {
+        if (line.widgets[i].height) widgetsHeight += line.widgets[i].height;
+      }
+
+      if (wrapping)
+        return widgetsHeight + (Math.ceil(line.text.length / perLine) || 1) * th;
+      else
+        return widgetsHeight + th;
+    };
+  }
+
+  function estimateLineHeights(cm) {
+    var doc = cm.doc, est = estimateHeight(cm);
+    doc.iter(function(line) {
+      var estHeight = est(line);
+      if (estHeight != line.height) updateLineHeight(line, estHeight);
+    });
+  }
+
+  function themeChanged(cm) {
+    cm.display.wrapper.className = cm.display.wrapper.className.replace(/\s*cm-s-\S+/g, "") +
+      cm.options.theme.replace(/(^|\s)\s*/g, " cm-s-");
+    clearCaches(cm);
+  }
+
+  function guttersChanged(cm) {
+    updateGutters(cm);
+    regChange(cm);
+    setTimeout(function(){alignHorizontally(cm);}, 20);
+  }
+
+  // Rebuild the gutter elements, ensure the margin to the left of the
+  // code matches their width.
+  function updateGutters(cm) {
+    var gutters = cm.display.gutters, specs = cm.options.gutters;
+    removeChildren(gutters);
+    for (var i = 0; i < specs.length; ++i) {
+      var gutterClass = specs[i];
+      var gElt = gutters.appendChild(elt("div", null, "CodeMirror-gutter " + gutterClass));
+      if (gutterClass == "CodeMirror-linenumbers") {
+        cm.display.lineGutter = gElt;
+        gElt.style.width = (cm.display.lineNumWidth || 1) + "px";
+      }
+    }
+    gutters.style.display = i ? "" : "none";
+    updateGutterSpace(cm);
+  }
+
+  function updateGutterSpace(cm) {
+    var width = cm.display.gutters.offsetWidth;
+    cm.display.sizer.style.marginLeft = width + "px";
+    cm.display.scrollbarH.style.left = cm.options.fixedGutter ? width + "px" : 0;
+  }
+
+  // Compute the character length of a line, taking into account
+  // collapsed ranges (see markText) that might hide parts, and join
+  // other lines onto it.
+  function lineLength(line) {
+    if (line.height == 0) return 0;
+    var len = line.text.length, merged, cur = line;
+    while (merged = collapsedSpanAtStart(cur)) {
+      var found = merged.find(0, true);
+      cur = found.from.line;
+      len += found.from.ch - found.to.ch;
+    }
+    cur = line;
+    while (merged = collapsedSpanAtEnd(cur)) {
+      var found = merged.find(0, true);
+      len -= cur.text.length - found.from.ch;
+      cur = found.to.line;
+      len += cur.text.length - found.to.ch;
+    }
+    return len;
+  }
+
+  // Find the longest line in the document.
+  function findMaxLine(cm) {
+    var d = cm.display, doc = cm.doc;
+    d.maxLine = getLine(doc, doc.first);
+    d.maxLineLength = lineLength(d.maxLine);
+    d.maxLineChanged = true;
+    doc.iter(function(line) {
+      var len = lineLength(line);
+      if (len > d.maxLineLength) {
+        d.maxLineLength = len;
+        d.maxLine = line;
+      }
+    });
+  }
+
+  // Make sure the gutters options contains the element
+  // "CodeMirror-linenumbers" when the lineNumbers option is true.
+  function setGuttersForLineNumbers(options) {
+    var found = indexOf(options.gutters, "CodeMirror-linenumbers");
+    if (found == -1 && options.lineNumbers) {
+      options.gutters = options.gutters.concat(["CodeMirror-linenumbers"]);
+    } else if (found > -1 && !options.lineNumbers) {
+      options.gutters = options.gutters.slice(0);
+      options.gutters.splice(found, 1);
+    }
+  }
+
+  // SCROLLBARS
+
+  function hScrollbarTakesSpace(cm) {
+    return cm.display.scroller.clientHeight - cm.display.wrapper.clientHeight < scrollerCutOff - 3;
+  }
+
+  // Prepare DOM reads needed to update the scrollbars. Done in one
+  // shot to minimize update/measure roundtrips.
+  function measureForScrollbars(cm) {
+    var scroll = cm.display.scroller;
+    return {
+      clientHeight: scroll.clientHeight,
+      barHeight: cm.display.scrollbarV.clientHeight,
+      scrollWidth: scroll.scrollWidth, clientWidth: scroll.clientWidth,
+      hScrollbarTakesSpace: hScrollbarTakesSpace(cm),
+      barWidth: cm.display.scrollbarH.clientWidth,
+      docHeight: Math.round(cm.doc.height + paddingVert(cm.display))
+    };
+  }
+
+  // Re-synchronize the fake scrollbars with the actual size of the
+  // content.
+  function updateScrollbars(cm, measure) {
+    if (!measure) measure = measureForScrollbars(cm);
+    var d = cm.display, sWidth = scrollbarWidth(d.measure);
+    var scrollHeight = measure.docHeight + scrollerCutOff;
+    var needsH = measure.scrollWidth > measure.clientWidth;
+    if (needsH && measure.scrollWidth <= measure.clientWidth + 1 &&
+        sWidth > 0 && !measure.hScrollbarTakesSpace)
+      needsH = false; // (Issue #2562)
+    var needsV = scrollHeight > measure.clientHeight;
+
+    if (needsV) {
+      d.scrollbarV.style.display = "block";
+      d.scrollbarV.style.bottom = needsH ? sWidth + "px" : "0";
+      // A bug in IE8 can cause this value to be negative, so guard it.
+      d.scrollbarV.firstChild.style.height =
+        Math.max(0, scrollHeight - measure.clientHeight + (measure.barHeight || d.scrollbarV.clientHeight)) + "px";
+    } else {
+      d.scrollbarV.style.display = "";
+      d.scrollbarV.firstChild.style.height = "0";
+    }
+    if (needsH) {
+      d.scrollbarH.style.display = "block";
+      d.scrollbarH.style.right = needsV ? sWidth + "px" : "0";
+      d.scrollbarH.firstChild.style.width =
+        (measure.scrollWidth - measure.clientWidth + (measure.barWidth || d.scrollbarH.clientWidth)) + "px";
+    } else {
+      d.scrollbarH.style.display = "";
+      d.scrollbarH.firstChild.style.width = "0";
+    }
+    if (needsH && needsV) {
+      d.scrollbarFiller.style.display = "block";
+      d.scrollbarFiller.style.height = d.scrollbarFiller.style.width = sWidth + "px";
+    } else d.scrollbarFiller.style.display = "";
+    if (needsH && cm.options.coverGutterNextToScrollbar && cm.options.fixedGutter) {
+      d.gutterFiller.style.display = "block";
+      d.gutterFiller.style.height = sWidth + "px";
+      d.gutterFiller.style.width = d.gutters.offsetWidth + "px";
+    } else d.gutterFiller.style.display = "";
+
+    if (!cm.state.checkedOverlayScrollbar && measure.clientHeight > 0) {
+      if (sWidth === 0) {
+        var w = mac && !mac_geMountainLion ? "12px" : "18px";
+        d.scrollbarV.style.minWidth = d.scrollbarH.style.minHeight = w;
+        var barMouseDown = function(e) {
+          if (e_target(e) != d.scrollbarV && e_target(e) != d.scrollbarH)
+            operation(cm, onMouseDown)(e);
+        };
+        on(d.scrollbarV, "mousedown", barMouseDown);
+        on(d.scrollbarH, "mousedown", barMouseDown);
+      }
+      cm.state.checkedOverlayScrollbar = true;
+    }
+  }
+
+  // Compute the lines that are visible in a given viewport (defaults
+  // the the current scroll position). viewport may contain top,
+  // height, and ensure (see op.scrollToPos) properties.
+  function visibleLines(display, doc, viewport) {
+    var top = viewport && viewport.top != null ? Math.max(0, viewport.top) : display.scroller.scrollTop;
+    top = Math.floor(top - paddingTop(display));
+    var bottom = viewport && viewport.bottom != null ? viewport.bottom : top + display.wrapper.clientHeight;
+
+    var from = lineAtHeight(doc, top), to = lineAtHeight(doc, bottom);
+    // Ensure is a {from: {line, ch}, to: {line, ch}} object, and
+    // forces those lines into the viewport (if possible).
+    if (viewport && viewport.ensure) {
+      var ensureFrom = viewport.ensure.from.line, ensureTo = viewport.ensure.to.line;
+      if (ensureFrom < from)
+        return {from: ensureFrom,
+                to: lineAtHeight(doc, heightAtLine(getLine(doc, ensureFrom)) + display.wrapper.clientHeight)};
+      if (Math.min(ensureTo, doc.lastLine()) >= to)
+        return {from: lineAtHeight(doc, heightAtLine(getLine(doc, ensureTo)) - display.wrapper.clientHeight),
+                to: ensureTo};
+    }
+    return {from: from, to: Math.max(to, from + 1)};
+  }
+
+  // LINE NUMBERS
+
+  // Re-align line numbers and gutter marks to compensate for
+  // horizontal scrolling.
+  function alignHorizontally(cm) {
+    var display = cm.display, view = display.view;
+    if (!display.alignWidgets && (!display.gutters.firstChild || !cm.options.fixedGutter)) return;
+    var comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.doc.scrollLeft;
+    var gutterW = display.gutters.offsetWidth, left = comp + "px";
+    for (var i = 0; i < view.length; i++) if (!view[i].hidden) {
+      if (cm.options.fixedGutter && view[i].gutter)
+        view[i].gutter.style.left = left;
+      var align = view[i].alignable;
+      if (align) for (var j = 0; j < align.length; j++)
+        align[j].style.left = left;
+    }
+    if (cm.options.fixedGutter)
+      display.gutters.style.left = (comp + gutterW) + "px";
+  }
+
+  // Used to ensure that the line number gutter is still the right
+  // size for the current document size. Returns true when an update
+  // is needed.
+  function maybeUpdateLineNumberWidth(cm) {
+    if (!cm.options.lineNumbers) return false;
+    var doc = cm.doc, last = lineNumberFor(cm.options, doc.first + doc.size - 1), display = cm.display;
+    if (last.length != display.lineNumChars) {
+      var test = display.measure.appendChild(elt("div", [elt("div", last)],
+                                                 "CodeMirror-linenumber CodeMirror-gutter-elt"));
+      var innerW = test.firstChild.offsetWidth, padding = test.offsetWidth - innerW;
+      display.lineGutter.style.width = "";
+      display.lineNumInnerWidth = Math.max(innerW, display.lineGutter.offsetWidth - padding);
+      display.lineNumWidth = display.lineNumInnerWidth + padding;
+      display.lineNumChars = display.lineNumInnerWidth ? last.length : -1;
+      display.lineGutter.style.width = display.lineNumWidth + "px";
+      updateGutterSpace(cm);
+      return true;
+    }
+    return false;
+  }
+
+  function lineNumberFor(options, i) {
+    return String(options.lineNumberFormatter(i + options.firstLineNumber));
+  }
+
+  // Computes display.scroller.scrollLeft + display.gutters.offsetWidth,
+  // but using getBoundingClientRect to get a sub-pixel-accurate
+  // result.
+  function compensateForHScroll(display) {
+    return display.scroller.getBoundingClientRect().left - display.sizer.getBoundingClientRect().left;
+  }
+
+  // DISPLAY DRAWING
+
+  function DisplayUpdate(cm, viewport, force) {
+    var display = cm.display;
+
+    this.viewport = viewport;
+    // Store some values that we'll need later (but don't want to force a relayout for)
+    this.visible = visibleLines(display, cm.doc, viewport);
+    this.editorIsHidden = !display.wrapper.offsetWidth;
+    this.wrapperHeight = display.wrapper.clientHeight;
+    this.wrapperWidth = display.wrapper.clientWidth;
+    this.oldViewFrom = display.viewFrom; this.oldViewTo = display.viewTo;
+    this.oldScrollerWidth = display.scroller.clientWidth;
+    this.force = force;
+    this.dims = getDimensions(cm);
+  }
+
+  // Does the actual updating of the line display. Bails out
+  // (returning false) when there is nothing to be done and forced is
+  // false.
+  function updateDisplayIfNeeded(cm, update) {
+    var display = cm.display, doc = cm.doc;
+    if (update.editorIsHidden) {
+      resetView(cm);
+      return false;
+    }
+
+    // Bail out if the visible area is already rendered and nothing changed.
+    if (!update.force &&
+        update.visible.from >= display.viewFrom && update.visible.to <= display.viewTo &&
+        (display.updateLineNumbers == null || display.updateLineNumbers >= display.viewTo) &&
+        countDirtyView(cm) == 0)
+      return false;
+
+    if (maybeUpdateLineNumberWidth(cm)) {
+      resetView(cm);
+      update.dims = getDimensions(cm);
+    }
+
+    // Compute a suitable new viewport (from & to)
+    var end = doc.first + doc.size;
+    var from = Math.max(update.visible.from - cm.options.viewportMargin, doc.first);
+    var to = Math.min(end, update.visible.to + cm.options.viewportMargin);
+    if (display.viewFrom < from && from - display.viewFrom < 20) from = Math.max(doc.first, display.viewFrom);
+    if (display.viewTo > to && display.viewTo - to < 20) to = Math.min(end, display.viewTo);
+    if (sawCollapsedSpans) {
+      from = visualLineNo(cm.doc, from);
+      to = visualLineEndNo(cm.doc, to);
+    }
+
+    var different = from != display.viewFrom || to != display.viewTo ||
+      display.lastWrapHeight != update.wrapperHeight || display.lastWrapWidth != update.wrapperWidth;
+    adjustView(cm, from, to);
+
+    display.viewOffset = heightAtLine(getLine(cm.doc, display.viewFrom));
+    // Position the mover div to align with the current scroll position
+    cm.display.mover.style.top = display.viewOffset + "px";
+
+    var toUpdate = countDirtyView(cm);
+    if (!different && toUpdate == 0 && !update.force &&
+        (display.updateLineNumbers == null || display.updateLineNumbers >= display.viewTo))
+      return false;
+
+    // For big changes, we hide the enclosing element during the
+    // update, since that speeds up the operations on most browsers.
+    var focused = activeElt();
+    if (toUpdate > 4) display.lineDiv.style.display = "none";
+    patchDisplay(cm, display.updateLineNumbers, update.dims);
+    if (toUpdate > 4) display.lineDiv.style.display = "";
+    // There might have been a widget with a focused element that got
+    // hidden or updated, if so re-focus it.
+    if (focused && activeElt() != focused && focused.offsetHeight) focused.focus();
+
+    // Prevent selection and cursors from interfering with the scroll
+    // width.
+    removeChildren(display.cursorDiv);
+    removeChildren(display.selectionDiv);
+
+    if (different) {
+      display.lastWrapHeight = update.wrapperHeight;
+      display.lastWrapWidth = update.wrapperWidth;
+      startWorker(cm, 400);
+    }
+
+    display.updateLineNumbers = null;
+
+    return true;
+  }
+
+  function postUpdateDisplay(cm, update) {
+    var force = update.force, viewport = update.viewport;
+    for (var first = true;; first = false) {
+      if (first && cm.options.lineWrapping && update.oldScrollerWidth != cm.display.scroller.clientWidth) {
+        force = true;
+      } else {
+        force = false;
+        // Clip forced viewport to actual scrollable area.
+        if (viewport && viewport.top != null)
+          viewport = {top: Math.min(cm.doc.height + paddingVert(cm.display) - scrollerCutOff -
+                                    cm.display.scroller.clientHeight, viewport.top)};
+        // Updated line heights might result in the drawn area not
+        // actually covering the viewport. Keep looping until it does.
+        update.visible = visibleLines(cm.display, cm.doc, viewport);
+        if (update.visible.from >= cm.display.viewFrom && update.visible.to <= cm.display.viewTo)
+          break;
+      }
+      if (!updateDisplayIfNeeded(cm, update)) break;
+      updateHeightsInViewport(cm);
+      var barMeasure = measureForScrollbars(cm);
+      updateSelection(cm);
+      setDocumentHeight(cm, barMeasure);
+      updateScrollbars(cm, barMeasure);
+    }
+
+    signalLater(cm, "update", cm);
+    if (cm.display.viewFrom != update.oldViewFrom || cm.display.viewTo != update.oldViewTo)
+      signalLater(cm, "viewportChange", cm, cm.display.viewFrom, cm.display.viewTo);
+  }
+
+  function updateDisplaySimple(cm, viewport) {
+    var update = new DisplayUpdate(cm, viewport);
+    if (updateDisplayIfNeeded(cm, update)) {
+      updateHeightsInViewport(cm);
+      postUpdateDisplay(cm, update);
+      var barMeasure = measureForScrollbars(cm);
+      updateSelection(cm);
+      setDocumentHeight(cm, barMeasure);
+      updateScrollbars(cm, barMeasure);
+    }
+  }
+
+  function setDocumentHeight(cm, measure) {
+    cm.display.sizer.style.minHeight = cm.display.heightForcer.style.top = measure.docHeight + "px";
+    cm.display.gutters.style.height = Math.max(measure.docHeight, measure.clientHeight - scrollerCutOff) + "px";
+  }
+
+  function checkForWebkitWidthBug(cm, measure) {
+    // Work around Webkit bug where it sometimes reserves space for a
+    // non-existing phantom scrollbar in the scroller (Issue #2420)
+    if (cm.display.sizer.offsetWidth + cm.display.gutters.offsetWidth < cm.display.scroller.clientWidth - 1) {
+      cm.display.sizer.style.minHeight = cm.display.heightForcer.style.top = "0px";
+      cm.display.gutters.style.height = measure.docHeight + "px";
+    }
+  }
+
+  // Read the actual heights of the rendered lines, and update their
+  // stored heights to match.
+  function updateHeightsInViewport(cm) {
+    var display = cm.display;
+    var prevBottom = display.lineDiv.offsetTop;
+    for (var i = 0; i < display.view.length; i++) {
+      var cur = display.view[i], height;
+      if (cur.hidden) continue;
+      if (ie && ie_version < 8) {
+        var bot = cur.node.offsetTop + cur.node.offsetHeight;
+        height = bot - prevBottom;
+        prevBottom = bot;
+      } else {
+        var box = cur.node.getBoundingClientRect();
+        height = box.bottom - box.top;
+      }
+      var diff = cur.line.height - height;
+      if (height < 2) height = textHeight(display);
+      if (diff > .001 || diff < -.001) {
+        updateLineHeight(cur.line, height);
+        updateWidgetHeight(cur.line);
+        if (cur.rest) for (var j = 0; j < cur.rest.length; j++)
+          updateWidgetHeight(cur.rest[j]);
+      }
+    }
+  }
+
+  // Read and store the height of line widgets associated with the
+  // given line.
+  function updateWidgetHeight(line) {
+    if (line.widgets) for (var i = 0; i < line.widgets.length; ++i)
+      line.widgets[i].height = line.widgets[i].node.offsetHeight;
+  }
+
+  // Do a bulk-read of the DOM positions and sizes needed to draw the
+  // view, so that we don't interleave reading and writing to the DOM.
+  function getDimensions(cm) {
+    var d = cm.display, left = {}, width = {};
+    var gutterLeft = d.gutters.clientLeft;
+    for (var n = d.gutters.firstChild, i = 0; n; n = n.nextSibling, ++i) {
+      left[cm.options.gutters[i]] = n.offsetLeft + n.clientLeft + gutterLeft;
+      width[cm.options.gutters[i]] = n.clientWidth;
+    }
+    return {fixedPos: compensateForHScroll(d),
+            gutterTotalWidth: d.gutters.offsetWidth,
+            gutterLeft: left,
+            gutterWidth: width,
+            wrapperWidth: d.wrapper.clientWidth};
+  }
+
+  // Sync the actual display DOM structure with display.view, removing
+  // nodes for lines that are no longer in view, and creating the ones
+  // that are not there yet, and updating the ones that are out of
+  // date.
+  function patchDisplay(cm, updateNumbersFrom, dims) {
+    var display = cm.display, lineNumbers = cm.options.lineNumbers;
+    var container = display.lineDiv, cur = container.firstChild;
+
+    function rm(node) {
+      var next = node.nextSibling;
+      // Works around a throw-scroll bug in OS X Webkit
+      if (webkit && mac && cm.display.currentWheelTarget == node)
+        node.style.display = "none";
+      else
+        node.parentNode.removeChild(node);
+      return next;
+    }
+
+    var view = display.view, lineN = display.viewFrom;
+    // Loop over the elements in the view, syncing cur (the DOM nodes
+    // in display.lineDiv) with the view as we go.
+    for (var i = 0; i < view.length; i++) {
+      var lineView = view[i];
+      if (lineView.hidden) {
+      } else if (!lineView.node) { // Not drawn yet
+        var node = buildLineElement(cm, lineView, lineN, dims);
+        container.insertBefore(node, cur);
+      } else { // Already drawn
+        while (cur != lineView.node) cur = rm(cur);
+        var updateNumber = lineNumbers && updateNumbersFrom != null &&
+          updateNumbersFrom <= lineN && lineView.lineNumber;
+        if (lineView.changes) {
+          if (indexOf(lineView.changes, "gutter") > -1) updateNumber = false;
+          updateLineForChanges(cm, lineView, lineN, dims);
+        }
+        if (updateNumber) {
+          removeChildren(lineView.lineNumber);
+          lineView.lineNumber.appendChild(document.createTextNode(lineNumberFor(cm.options, lineN)));
+        }
+        cur = lineView.node.nextSibling;
+      }
+      lineN += lineView.size;
+    }
+    while (cur) cur = rm(cur);
+  }
+
+  // When an aspect of a line changes, a string is added to
+  // lineView.changes. This updates the relevant part of the line's
+  // DOM structure.
+  function updateLineForChanges(cm, lineView, lineN, dims) {
+    for (var j = 0; j < lineView.changes.length; j++) {
+      var type = lineView.changes[j];
+      if (type == "text") updateLineText(cm, lineView);
+      else if (type == "gutter") updateLineGutter(cm, lineView, lineN, dims);
+      else if (type == "class") updateLineClasses(lineView);
+      else if (type == "widget") updateLineWidgets(lineView, dims);
+    }
+    lineView.changes = null;
+  }
+
+  // Lines with gutter elements, widgets or a background class need to
+  // be wrapped, and have the extra elements added to the wrapper div
+  function ensureLineWrapped(lineView) {
+    if (lineView.node == lineView.text) {
+      lineView.node = elt("div", null, null, "position: relative");
+      if (lineView.text.parentNode)
+        lineView.text.parentNode.replaceChild(lineView.node, lineView.text);
+      lineView.node.appendChild(lineView.text);
+      if (ie && ie_version < 8) lineView.node.style.zIndex = 2;
+    }
+    return lineView.node;
+  }
+
+  function updateLineBackground(lineView) {
+    var cls = lineView.bgClass ? lineView.bgClass + " " + (lineView.line.bgClass || "") : lineView.line.bgClass;
+    if (cls) cls += " CodeMirror-linebackground";
+    if (lineView.background) {
+      if (cls) lineView.background.className = cls;
+      else { lineView.background.parentNode.removeChild(lineView.background); lineView.background = null; }
+    } else if (cls) {
+      var wrap = ensureLineWrapped(lineView);
+      lineView.background = wrap.insertBefore(elt("div", null, cls), wrap.firstChild);
+    }
+  }
+
+  // Wrapper around buildLineContent which will reuse the structure
+  // in display.externalMeasured when possible.
+  function getLineContent(cm, lineView) {
+    var ext = cm.display.externalMeasured;
+    if (ext && ext.line == lineView.line) {
+      cm.display.externalMeasured = null;
+      lineView.measure = ext.measure;
+      return ext.built;
+    }
+    return buildLineContent(cm, lineView);
+  }
+
+  // Redraw the line's text. Interacts with the background and text
+  // classes because the mode may output tokens that influence these
+  // classes.
+  function updateLineText(cm, lineView) {
+    var cls = lineView.text.className;
+    var built = getLineContent(cm, lineView);
+    if (lineView.text == lineView.node) lineView.node = built.pre;
+    lineView.text.parentNode.replaceChild(built.pre, lineView.text);
+    lineView.text = built.pre;
+    if (built.bgClass != lineView.bgClass || built.textClass != lineView.textClass) {
+      lineView.bgClass = built.bgClass;
+      lineView.textClass = built.textClass;
+      updateLineClasses(lineView);
+    } else if (cls) {
+      lineView.text.className = cls;
+    }
+  }
+
+  function updateLineClasses(lineView) {
+    updateLineBackground(lineView);
+    if (lineView.line.wrapClass)
+      ensureLineWrapped(lineView).className = lineView.line.wrapClass;
+    else if (lineView.node != lineView.text)
+      lineView.node.className = "";
+    var textClass = lineView.textClass ? lineView.textClass + " " + (lineView.line.textClass || "") : lineView.line.textClass;
+    lineView.text.className = textClass || "";
+  }
+
+  function updateLineGutter(cm, lineView, lineN, dims) {
+    if (lineView.gutter) {
+      lineView.node.removeChild(lineView.gutter);
+      lineView.gutter = null;
+    }
+    var markers = lineView.line.gutterMarkers;
+    if (cm.options.lineNumbers || markers) {
+      var wrap = ensureLineWrapped(lineView);
+      var gutterWrap = lineView.gutter =
+        wrap.insertBefore(elt("div", null, "CodeMirror-gutter-wrapper", "left: " +
+                              (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) +
+                              "px; width: " + dims.gutterTotalWidth + "px"),
+                          lineView.text);
+      if (lineView.line.gutterClass)
+        gutterWrap.className += " " + lineView.line.gutterClass;
+      if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))
+        lineView.lineNumber = gutterWrap.appendChild(
+          elt("div", lineNumberFor(cm.options, lineN),
+              "CodeMirror-linenumber CodeMirror-gutter-elt",
+              "left: " + dims.gutterLeft["CodeMirror-linenumbers"] + "px; width: "
+              + cm.display.lineNumInnerWidth + "px"));
+      if (markers) for (var k = 0; k < cm.options.gutters.length; ++k) {
+        var id = cm.options.gutters[k], found = markers.hasOwnProperty(id) && markers[id];
+        if (found)
+          gutterWrap.appendChild(elt("div", [found], "CodeMirror-gutter-elt", "left: " +
+                                     dims.gutterLeft[id] + "px; width: " + dims.gutterWidth[id] + "px"));
+      }
+    }
+  }
+
+  function updateLineWidgets(lineView, dims) {
+    if (lineView.alignable) lineView.alignable = null;
+    for (var node = lineView.node.firstChild, next; node; node = next) {
+      var next = node.nextSibling;
+      if (node.className == "CodeMirror-linewidget")
+        lineView.node.removeChild(node);
+    }
+    insertLineWidgets(lineView, dims);
+  }
+
+  // Build a line's DOM representation from scratch
+  function buildLineElement(cm, lineView, lineN, dims) {
+    var built = getLineContent(cm, lineView);
+    lineView.text = lineView.node = built.pre;
+    if (built.bgClass) lineView.bgClass = built.bgClass;
+    if (built.textClass) lineView.textClass = built.textClass;
+
+    updateLineClasses(lineView);
+    updateLineGutter(cm, lineView, lineN, dims);
+    insertLineWidgets(lineView, dims);
+    return lineView.node;
+  }
+
+  // A lineView may contain multiple logical lines (when merged by
+  // collapsed spans). The widgets for all of them need to be drawn.
+  function insertLineWidgets(lineView, dims) {
+    insertLineWidgetsFor(lineView.line, lineView, dims, true);
+    if (lineView.rest) for (var i = 0; i < lineView.rest.length; i++)
+      insertLineWidgetsFor(lineView.rest[i], lineView, dims, false);
+  }
+
+  function insertLineWidgetsFor(line, lineView, dims, allowAbove) {
+    if (!line.widgets) return;
+    var wrap = ensureLineWrapped(lineView);
+    for (var i = 0, ws = line.widgets; i < ws.length; ++i) {
+      var widget = ws[i], node = elt("div", [widget.node], "CodeMirror-linewidget");
+      if (!widget.handleMouseEvents) node.ignoreEvents = true;
+      positionLineWidget(widget, node, lineView, dims);
+      if (allowAbove && widget.above)
+        wrap.insertBefore(node, lineView.gutter || lineView.text);
+      else
+        wrap.appendChild(node);
+      signalLater(widget, "redraw");
+    }
+  }
+
+  function positionLineWidget(widget, node, lineView, dims) {
+    if (widget.noHScroll) {
+      (lineView.alignable || (lineView.alignable = [])).push(node);
+      var width = dims.wrapperWidth;
+      node.style.left = dims.fixedPos + "px";
+      if (!widget.coverGutter) {
+        width -= dims.gutterTotalWidth;
+        node.style.paddingLeft = dims.gutterTotalWidth + "px";
+      }
+      node.style.width = width + "px";
+    }
+    if (widget.coverGutter) {
+      node.style.zIndex = 5;
+      node.style.position = "relative";
+      if (!widget.noHScroll) node.style.marginLeft = -dims.gutterTotalWidth + "px";
+    }
+  }
+
+  // POSITION OBJECT
+
+  // A Pos instance represents a position within the text.
+  var Pos = CodeMirror.Pos = function(line, ch) {
+    if (!(this instanceof Pos)) return new Pos(line, ch);
+    this.line = line; this.ch = ch;
+  };
+
+  // Compare two positions, return 0 if they are the same, a negative
+  // number when a is less, and a positive number otherwise.
+  var cmp = CodeMirror.cmpPos = function(a, b) { return a.line - b.line || a.ch - b.ch; };
+
+  function copyPos(x) {return Pos(x.line, x.ch);}
+  function maxPos(a, b) { return cmp(a, b) < 0 ? b : a; }
+  function minPos(a, b) { return cmp(a, b) < 0 ? a : b; }
+
+  // SELECTION / CURSOR
+
+  // Selection objects are immutable. A new one is created every time
+  // the selection changes. A selection is one or more non-overlapping
+  // (and non-touching) ranges, sorted, and an integer that indicates
+  // which one is the primary selection (the one that's scrolled into
+  // view, that getCursor returns, etc).
+  function Selection(ranges, primIndex) {
+    this.ranges = ranges;
+    this.primIndex = primIndex;
+  }
+
+  Selection.prototype = {
+    primary: function() { return this.ranges[this.primIndex]; },
+    equals: function(other) {
+      if (other == this) return true;
+      if (other.primIndex != this.primIndex || other.ranges.length != this.ranges.length) return false;
+      for (var i = 0; i < this.ranges.length; i++) {
+        var here = this.ranges[i], there = other.ranges[i];
+        if (cmp(here.anchor, there.anchor) != 0 || cmp(here.head, there.head) != 0) return false;
+      }
+      return true;
+    },
+    deepCopy: function() {
+      for (var out = [], i = 0; i < this.ranges.length; i++)
+        out[i] = new Range(copyPos(this.ranges[i].anchor), copyPos(this.ranges[i].head));
+      return new Selection(out, this.primIndex);
+    },
+    somethingSelected: function() {
+      for (var i = 0; i < this.ranges.length; i++)
+        if (!this.ranges[i].empty()) return true;
+      return false;
+    },
+    contains: function(pos, end) {
+      if (!end) end = pos;
+      for (var i = 0; i < this.ranges.length; i++) {
+        var range = this.ranges[i];
+        if (cmp(end, range.from()) >= 0 && cmp(pos, range.to()) <= 0)
+          return i;
+      }
+      return -1;
+    }
+  };
+
+  function Range(anchor, head) {
+    this.anchor = anchor; this.head = head;
+  }
+
+  Range.prototype = {
+    from: function() { return minPos(this.anchor, this.head); },
+    to: function() { return maxPos(this.anchor, this.head); },
+    empty: function() {
+      return this.head.line == this.anchor.line && this.head.ch == this.anchor.ch;
+    }
+  };
+
+  // Take an unsorted, potentially overlapping set of ranges, and
+  // build a selection out of it. 'Consumes' ranges array (modifying
+  // it).
+  function normalizeSelection(ranges, primIndex) {
+    var prim = ranges[primIndex];
+    ranges.sort(function(a, b) { return cmp(a.from(), b.from()); });
+    primIndex = indexOf(ranges, prim);
+    for (var i = 1; i < ranges.length; i++) {
+      var cur = ranges[i], prev = ranges[i - 1];
+      if (cmp(prev.to(), cur.from()) >= 0) {
+        var from = minPos(prev.from(), cur.from()), to = maxPos(prev.to(), cur.to());
+        var inv = prev.empty() ? cur.from() == cur.head : prev.from() == prev.head;
+        if (i <= primIndex) --primIndex;
+        ranges.splice(--i, 2, new Range(inv ? to : from, inv ? from : to));
+      }
+    }
+    return new Selection(ranges, primIndex);
+  }
+
+  function simpleSelection(anchor, head) {
+    return new Selection([new Range(anchor, head || anchor)], 0);
+  }
+
+  // Most of the external API clips given positions to make sure they
+  // actually exist within the document.
+  function clipLine(doc, n) {return Math.max(doc.first, Math.min(n, doc.first + doc.size - 1));}
+  function clipPos(doc, pos) {
+    if (pos.line < doc.first) return Pos(doc.first, 0);
+    var last = doc.first + doc.size - 1;
+    if (pos.line > last) return Pos(last, getLine(doc, last).text.length);
+    return clipToLen(pos, getLine(doc, pos.line).text.length);
+  }
+  function clipToLen(pos, linelen) {
+    var ch = pos.ch;
+    if (ch == null || ch > linelen) return Pos(pos.line, linelen);
+    else if (ch < 0) return Pos(pos.line, 0);
+    else return pos;
+  }
+  function isLine(doc, l) {return l >= doc.first && l < doc.first + doc.size;}
+  function clipPosArray(doc, array) {
+    for (var out = [], i = 0; i < array.length; i++) out[i] = clipPos(doc, array[i]);
+    return out;
+  }
+
+  // SELECTION UPDATES
+
+  // The 'scroll' parameter given to many of these indicated whether
+  // the new cursor position should be scrolled into view after
+  // modifying the selection.
+
+  // If shift is held or the extend flag is set, extends a range to
+  // include a given position (and optionally a second position).
+  // Otherwise, simply returns the range between the given positions.
+  // Used for cursor motion and such.
+  function extendRange(doc, range, head, other) {
+    if (doc.cm && doc.cm.display.shift || doc.extend) {
+      var anchor = range.anchor;
+      if (other) {
+        var posBefore = cmp(head, anchor) < 0;
+        if (posBefore != (cmp(other, anchor) < 0)) {
+          anchor = head;
+          head = other;
+        } else if (posBefore != (cmp(head, other) < 0)) {
+          head = other;
+        }
+      }
+      return new Range(anchor, head);
+    } else {
+      return new Range(other || head, head);
+    }
+  }
+
+  // Extend the primary selection range, discard the rest.
+  function extendSelection(doc, head, other, options) {
+    setSelection(doc, new Selection([extendRange(doc, doc.sel.primary(), head, other)], 0), options);
+  }
+
+  // Extend all selections (pos is an array of selections with length
+  // equal the number of selections)
+  function extendSelections(doc, heads, options) {
+    for (var out = [], i = 0; i < doc.sel.ranges.length; i++)
+      out[i] = extendRange(doc, doc.sel.ranges[i], heads[i], null);
+    var newSel = normalizeSelection(out, doc.sel.primIndex);
+    setSelection(doc, newSel, options);
+  }
+
+  // Updates a single range in the selection.
+  function replaceOneSelection(doc, i, range, options) {
+    var ranges = doc.sel.ranges.slice(0);
+    ranges[i] = range;
+    setSelection(doc, normalizeSelection(ranges, doc.sel.primIndex), options);
+  }
+
+  // Reset the selection to a single range.
+  function setSimpleSelection(doc, anchor, head, options) {
+    setSelection(doc, simpleSelection(anchor, head), options);
+  }
+
+  // Give beforeSelectionChange handlers a change to influence a
+  // selection update.
+  function filterSelectionChange(doc, sel) {
+    var obj = {
+      ranges: sel.ranges,
+      update: function(ranges) {
+        this.ranges = [];
+        for (var i = 0; i < ranges.length; i++)
+          this.ranges[i] = new Range(clipPos(doc, ranges[i].anchor),
+                                     clipPos(doc, ranges[i].head));
+      }
+    };
+    signal(doc, "beforeSelectionChange", doc, obj);
+    if (doc.cm) signal(doc.cm, "beforeSelectionChange", doc.cm, obj);
+    if (obj.ranges != sel.ranges) return normalizeSelection(obj.ranges, obj.ranges.length - 1);
+    else return sel;
+  }
+
+  function setSelectionReplaceHistory(doc, sel, options) {
+    var done = doc.history.done, last = lst(done);
+    if (last && last.ranges) {
+      done[done.length - 1] = sel;
+      setSelectionNoUndo(doc, sel, options);
+    } else {
+      setSelection(doc, sel, options);
+    }
+  }
+
+  // Set a new selection.
+  function setSelection(doc, sel, options) {
+    setSelectionNoUndo(doc, sel, options);
+    addSelectionToHistory(doc, doc.sel, doc.cm ? doc.cm.curOp.id : NaN, options);
+  }
+
+  function setSelectionNoUndo(doc, sel, options) {
+    if (hasHandler(doc, "beforeSelectionChange") || doc.cm && hasHandler(doc.cm, "beforeSelectionChange"))
+      sel = filterSelectionChange(doc, sel);
+
+    var bias = options && options.bias ||
+      (cmp(sel.primary().head, doc.sel.primary().head) < 0 ? -1 : 1);
+    setSelectionInner(doc, skipAtomicInSelection(doc, sel, bias, true));
+
+    if (!(options && options.scroll === false) && doc.cm)
+      ensureCursorVisible(doc.cm);
+  }
+
+  function setSelectionInner(doc, sel) {
+    if (sel.equals(doc.sel)) return;
+
+    doc.sel = sel;
+
+    if (doc.cm) {
+      doc.cm.curOp.updateInput = doc.cm.curOp.selectionChanged = true;
+      signalCursorActivity(doc.cm);
+    }
+    signalLater(doc, "cursorActivity", doc);
+  }
+
+  // Verify that the selection does not partially select any atomic
+  // marked ranges.
+  function reCheckSelection(doc) {
+    setSelectionInner(doc, skipAtomicInSelection(doc, doc.sel, null, false), sel_dontScroll);
+  }
+
+  // Return a selection that does not partially select any atomic
+  // ranges.
+  function skipAtomicInSelection(doc, sel, bias, mayClear) {
+    var out;
+    for (var i = 0; i < sel.ranges.length; i++) {
+      var range = sel.ranges[i];
+      var newAnchor = skipAtomic(doc, range.anchor, bias, mayClear);
+      var newHead = skipAtomic(doc, range.head, bias, mayClear);
+      if (out || newAnchor != range.anchor || newHead != range.head) {
+        if (!out) out = sel.ranges.slice(0, i);
+        out[i] = new Range(newAnchor, newHead);
+      }
+    }
+    return out ? normalizeSelection(out, sel.primIndex) : sel;
+  }
+
+  // Ensure a given position is not inside an atomic range.
+  function skipAtomic(doc, pos, bias, mayClear) {
+    var flipped = false, curPos = pos;
+    var dir = bias || 1;
+    doc.cantEdit = false;
+    search: for (;;) {
+      var line = getLine(doc, curPos.line);
+      if (line.markedSpans) {
+        for (var i = 0; i < line.markedSpans.length; ++i) {
+          var sp = line.markedSpans[i], m = sp.marker;
+          if ((sp.from == null || (m.inclusiveLeft ? sp.from <= curPos.ch : sp.from < curPos.ch)) &&
+              (sp.to == null || (m.inclusiveRight ? sp.to >= curPos.ch : sp.to > curPos.ch))) {
+            if (mayClear) {
+              signal(m, "beforeCursorEnter");
+              if (m.explicitlyCleared) {
+                if (!line.markedSpans) break;
+                else {--i; continue;}
+              }
+            }
+            if (!m.atomic) continue;
+            var newPos = m.find(dir < 0 ? -1 : 1);
+            if (cmp(newPos, curPos) == 0) {
+              newPos.ch += dir;
+              if (newPos.ch < 0) {
+                if (newPos.line > doc.first) newPos = clipPos(doc, Pos(newPos.line - 1));
+                else newPos = null;
+              } else if (newPos.ch > line.text.length) {
+                if (newPos.line < doc.first + doc.size - 1) newPos = Pos(newPos.line + 1, 0);
+                else newPos = null;
+              }
+              if (!newPos) {
+                if (flipped) {
+                  // Driven in a corner -- no valid cursor position found at all
+                  // -- try again *with* clearing, if we didn't already
+                  if (!mayClear) return skipAtomic(doc, pos, bias, true);
+                  // Otherwise, turn off editing until further notice, and return the start of the doc
+                  doc.cantEdit = true;
+                  return Pos(doc.first, 0);
+                }
+                flipped = true; newPos = pos; dir = -dir;
+              }
+            }
+            curPos = newPos;
+            continue search;
+          }
+        }
+      }
+      return curPos;
+    }
+  }
+
+  // SELECTION DRAWING
+
+  // Redraw the selection and/or cursor
+  function drawSelection(cm) {
+    var display = cm.display, doc = cm.doc, result = {};
+    var curFragment = result.cursors = document.createDocumentFragment();
+    var selFragment = result.selection = document.createDocumentFragment();
+
+    for (var i = 0; i < doc.sel.ranges.length; i++) {
+      var range = doc.sel.ranges[i];
+      var collapsed = range.empty();
+      if (collapsed || cm.options.showCursorWhenSelecting)
+        drawSelectionCursor(cm, range, curFragment);
+      if (!collapsed)
+        drawSelectionRange(cm, range, selFragment);
+    }
+
+    // Move the hidden textarea near the cursor to prevent scrolling artifacts
+    if (cm.options.moveInputWithCursor) {
+      var headPos = cursorCoords(cm, doc.sel.primary().head, "div");
+      var wrapOff = display.wrapper.getBoundingClientRect(), lineOff = display.lineDiv.getBoundingClientRect();
+      result.teTop = Math.max(0, Math.min(display.wrapper.clientHeight - 10,
+                                          headPos.top + lineOff.top - wrapOff.top));
+      result.teLeft = Math.max(0, Math.min(display.wrapper.clientWidth - 10,
+                                           headPos.left + lineOff.left - wrapOff.left));
+    }
+
+    return result;
+  }
+
+  function showSelection(cm, drawn) {
+    removeChildrenAndAdd(cm.display.cursorDiv, drawn.cursors);
+    removeChildrenAndAdd(cm.display.selectionDiv, drawn.selection);
+    if (drawn.teTop != null) {
+      cm.display.inputDiv.style.top = drawn.teTop + "px";
+      cm.display.inputDiv.style.left = drawn.teLeft + "px";
+    }
+  }
+
+  function updateSelection(cm) {
+    showSelection(cm, drawSelection(cm));
+  }
+
+  // Draws a cursor for the given range
+  function drawSelectionCursor(cm, range, output) {
+    var pos = cursorCoords(cm, range.head, "div", null, null, !cm.options.singleCursorHeightPerLine);
+
+    var cursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor"));
+    cursor.style.left = pos.left + "px";
+    cursor.style.top = pos.top + "px";
+    cursor.style.height = Math.max(0, pos.bottom - pos.top) * cm.options.cursorHeight + "px";
+
+    if (pos.other) {
+      // Secondary cursor, shown when on a 'jump' in bi-directional text
+      var otherCursor = output.appendChild(elt("div", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor"));
+      otherCursor.style.display = "";
+      otherCursor.style.left = pos.other.left + "px";
+      otherCursor.style.top = pos.other.top + "px";
+      otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px";
+    }
+  }
+
+  // Draws the given range as a highlighted selection
+  function drawSelectionRange(cm, range, output) {
+    var display = cm.display, doc = cm.doc;
+    var fragment = document.createDocumentFragment();
+    var padding = paddingH(cm.display), leftSide = padding.left, rightSide = display.lineSpace.offsetWidth - padding.right;
+
+    function add(left, top, width, bottom) {
+      if (top < 0) top = 0;
+      top = Math.round(top);
+      bottom = Math.round(bottom);
+      fragment.appendChild(elt("div", null, "CodeMirror-selected", "position: absolute; left: " + left +
+                               "px; top: " + top + "px; width: " + (width == null ? rightSide - left : width) +
+                               "px; height: " + (bottom - top) + "px"));
+    }
+
+    function drawForLine(line, fromArg, toArg) {
+      var lineObj = getLine(doc, line);
+      var lineLen = lineObj.text.length;
+      var start, end;
+      function coords(ch, bias) {
+        return charCoords(cm, Pos(line, ch), "div", lineObj, bias);
+      }
+
+      iterateBidiSections(getOrder(lineObj), fromArg || 0, toArg == null ? lineLen : toArg, function(from, to, dir) {
+        var leftPos = coords(from, "left"), rightPos, left, right;
+        if (from == to) {
+          rightPos = leftPos;
+          left = right = leftPos.left;
+        } else {
+          rightPos = coords(to - 1, "right");
+          if (dir == "rtl") { var tmp = leftPos; leftPos = rightPos; rightPos = tmp; }
+          left = leftPos.left;
+          right = rightPos.right;
+        }
+        if (fromArg == null && from == 0) left = leftSide;
+        if (rightPos.top - leftPos.top > 3) { // Different lines, draw top part
+          add(left, leftPos.top, null, leftPos.bottom);
+          left = leftSide;
+          if (leftPos.bottom < rightPos.top) add(left, leftPos.bottom, null, rightPos.top);
+        }
+        if (toArg == null && to == lineLen) right = rightSide;
+        if (!start || leftPos.top < start.top || leftPos.top == start.top && leftPos.left < start.left)
+          start = leftPos;
+        if (!end || rightPos.bottom > end.bottom || rightPos.bottom == end.bottom && rightPos.right > end.right)
+          end = rightPos;
+        if (left < leftSide + 1) left = leftSide;
+        add(left, rightPos.top, right - left, rightPos.bottom);
+      });
+      return {start: start, end: end};
+    }
+
+    var sFrom = range.from(), sTo = range.to();
+    if (sFrom.line == sTo.line) {
+      drawForLine(sFrom.line, sFrom.ch, sTo.ch);
+    } else {
+      var fromLine = getLine(doc, sFrom.line), toLine = getLine(doc, sTo.line);
+      var singleVLine = visualLine(fromLine) == visualLine(toLine);
+      var leftEnd = drawForLine(sFrom.line, sFrom.ch, singleVLine ? fromLine.text.length + 1 : null).end;
+      var rightStart = drawForLine(sTo.line, singleVLine ? 0 : null, sTo.ch).start;
+      if (singleVLine) {
+        if (leftEnd.top < rightStart.top - 2) {
+          add(leftEnd.right, leftEnd.top, null, leftEnd.bottom);
+          add(leftSide, rightStart.top, rightStart.left, rightStart.bottom);
+        } else {
+          add(leftEnd.right, leftEnd.top, rightStart.left - leftEnd.right, leftEnd.bottom);
+        }
+      }
+      if (leftEnd.bottom < rightStart.top)
+        add(leftSide, leftEnd.bottom, null, rightStart.top);
+    }
+
+    output.appendChild(fragment);
+  }
+
+  // Cursor-blinking
+  function restartBlink(cm) {
+    if (!cm.state.focused) return;
+    var display = cm.display;
+    clearInterval(display.blinker);
+    var on = true;
+    display.cursorDiv.style.visibility = "";
+    if (cm.options.cursorBlinkRate > 0)
+      display.blinker = setInterval(function() {
+        display.cursorDiv.style.visibility = (on = !on) ? "" : "hidden";
+      }, cm.options.cursorBlinkRate);
+    else if (cm.options.cursorBlinkRate < 0)
+      display.cursorDiv.style.visibility = "hidden";
+  }
+
+  // HIGHLIGHT WORKER
+
+  function startWorker(cm, time) {
+    if (cm.doc.mode.startState && cm.doc.frontier < cm.display.viewTo)
+      cm.state.highlight.set(time, bind(highlightWorker, cm));
+  }
+
+  function highlightWorker(cm) {
+    var doc = cm.doc;
+    if (doc.frontier < doc.first) doc.frontier = doc.first;
+    if (doc.frontier >= cm.display.viewTo) return;
+    var end = +new Date + cm.options.workTime;
+    var state = copyState(doc.mode, getStateBefore(cm, doc.frontier));
+    var changedLines = [];
+
+    doc.iter(doc.frontier, Math.min(doc.first + doc.size, cm.display.viewTo + 500), function(line) {
+      if (doc.frontier >= cm.display.viewFrom) { // Visible
+        var oldStyles = line.styles;
+        var highlighted = highlightLine(cm, line, state, true);
+        line.styles = highlighted.styles;
+        var oldCls = line.styleClasses, newCls = highlighted.classes;
+        if (newCls) line.styleClasses = newCls;
+        else if (oldCls) line.styleClasses = null;
+        var ischange = !oldStyles || oldStyles.length != line.styles.length ||
+          oldCls != newCls && (!oldCls || !newCls || oldCls.bgClass != newCls.bgClass || oldCls.textClass != newCls.textClass);
+        for (var i = 0; !ischange && i < oldStyles.length; ++i) ischange = oldStyles[i] != line.styles[i];
+        if (ischange) changedLines.push(doc.frontier);
+        line.stateAfter = copyState(doc.mode, state);
+      } else {
+        processLine(cm, line.text, state);
+        line.stateAfter = doc.frontier % 5 == 0 ? copyState(doc.mode, state) : null;
+      }
+      ++doc.frontier;
+      if (+new Date > end) {
+        startWorker(cm, cm.options.workDelay);
+        return true;
+      }
+    });
+    if (changedLines.length) runInOp(cm, function() {
+      for (var i = 0; i < changedLines.length; i++)
+        regLineChange(cm, changedLines[i], "text");
+    });
+  }
+
+  // Finds the line to start with when starting a parse. Tries to
+  // find a line with a stateAfter, so that it can start with a
+  // valid state. If that fails, it returns the line with the
+  // smallest indentation, which tends to need the least context to
+  // parse correctly.
+  function findStartLine(cm, n, precise) {
+    var minindent, minline, doc = cm.doc;
+    var lim = precise ? -1 : n - (cm.doc.mode.innerMode ? 1000 : 100);
+    for (var search = n; search > lim; --search) {
+      if (search <= doc.first) return doc.first;
+      var line = getLine(doc, search - 1);
+      if (line.stateAfter && (!precise || search <= doc.frontier)) return search;
+      var indented = countColumn(line.text, null, cm.options.tabSize);
+      if (minline == null || minindent > indented) {
+        minline = search - 1;
+        minindent = indented;
+      }
+    }
+    return minline;
+  }
+
+  function getStateBefore(cm, n, precise) {
+    var doc = cm.doc, display = cm.display;
+    if (!doc.mode.startState) return true;
+    var pos = findStartLine(cm, n, precise), state = pos > doc.first && getLine(doc, pos-1).stateAfter;
+    if (!state) state = startState(doc.mode);
+    else state = copyState(doc.mode, state);
+    doc.iter(pos, n, function(line) {
+      processLine(cm, line.text, state);
+      var save = pos == n - 1 || pos % 5 == 0 || pos >= display.viewFrom && pos < display.viewTo;
+      line.stateAfter = save ? copyState(doc.mode, state) : null;
+      ++pos;
+    });
+    if (precise) doc.frontier = pos;
+    return state;
+  }
+
+  // POSITION MEASUREMENT
+
+  function paddingTop(display) {return display.lineSpace.offsetTop;}
+  function paddingVert(display) {return display.mover.offsetHeight - display.lineSpace.offsetHeight;}
+  function paddingH(display) {
+    if (display.cachedPaddingH) return display.cachedPaddingH;
+    var e = removeChildrenAndAdd(display.measure, elt("pre", "x"));
+    var style = window.getComputedStyle ? window.getComputedStyle(e) : e.currentStyle;
+    var data = {left: parseInt(style.paddingLeft), right: parseInt(style.paddingRight)};
+    if (!isNaN(data.left) && !isNaN(data.right)) display.cachedPaddingH = data;
+    return data;
+  }
+
+  // Ensure the lineView.wrapping.heights array is populated. This is
+  // an array of bottom offsets for the lines that make up a drawn
+  // line. When lineWrapping is on, there might be more than one
+  // height.
+  function ensureLineHeights(cm, lineView, rect) {
+    var wrapping = cm.options.lineWrapping;
+    var curWidth = wrapping && cm.display.scroller.clientWidth;
+    if (!lineView.measure.heights || wrapping && lineView.measure.width != curWidth) {
+      var heights = lineView.measure.heights = [];
+      if (wrapping) {
+        lineView.measure.width = curWidth;
+        var rects = lineView.text.firstChild.getClientRects();
+        for (var i = 0; i < rects.length - 1; i++) {
+          var cur = rects[i], next = rects[i + 1];
+          if (Math.abs(cur.bottom - next.bottom) > 2)
+            heights.push((cur.bottom + next.top) / 2 - rect.top);
+        }
+      }
+      heights.push(rect.bottom - rect.top);
+    }
+  }
+
+  // Find a line map (mapping character offsets to text nodes) and a
+  // measurement cache for the given line number. (A line view might
+  // contain multiple lines when collapsed ranges are present.)
+  function mapFromLineView(lineView, line, lineN) {
+    if (lineView.line == line)
+      return {map: lineView.measure.map, cache: lineView.measure.cache};
+    for (var i = 0; i < lineView.rest.length; i++)
+      if (lineView.rest[i] == line)
+        return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i]};
+    for (var i = 0; i < lineView.rest.length; i++)
+      if (lineNo(lineView.rest[i]) > lineN)
+        return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i], before: true};
+  }
+
+  // Render a line into the hidden node display.externalMeasured. Used
+  // when measurement is needed for a line that's not in the viewport.
+  function updateExternalMeasurement(cm, line) {
+    line = visualLine(line);
+    var lineN = lineNo(line);
+    var view = cm.display.externalMeasured = new LineView(cm.doc, line, lineN);
+    view.lineN = lineN;
+    var built = view.built = buildLineContent(cm, view);
+    view.text = built.pre;
+    removeChildrenAndAdd(cm.display.lineMeasure, built.pre);
+    return view;
+  }
+
+  // Get a {top, bottom, left, right} box (in line-local coordinates)
+  // for a given character.
+  function measureChar(cm, line, ch, bias) {
+    return measureCharPrepared(cm, prepareMeasureForLine(cm, line), ch, bias);
+  }
+
+  // Find a line view that corresponds to the given line number.
+  function findViewForLine(cm, lineN) {
+    if (lineN >= cm.display.viewFrom && lineN < cm.display.viewTo)
+      return cm.display.view[findViewIndex(cm, lineN)];
+    var ext = cm.display.externalMeasured;
+    if (ext && lineN >= ext.lineN && lineN < ext.lineN + ext.size)
+      return ext;
+  }
+
+  // Measurement can be split in two steps, the set-up work that
+  // applies to the whole line, and the measurement of the actual
+  // character. Functions like coordsChar, that need to do a lot of
+  // measurements in a row, can thus ensure that the set-up work is
+  // only done once.
+  function prepareMeasureForLine(cm, line) {
+    var lineN = lineNo(line);
+    var view = findViewForLine(cm, lineN);
+    if (view && !view.text)
+      view = null;
+    else if (view && view.changes)
+      updateLineForChanges(cm, view, lineN, getDimensions(cm));
+    if (!view)
+      view = updateExternalMeasurement(cm, line);
+
+    var info = mapFromLineView(view, line, lineN);
+    return {
+      line: line, view: view, rect: null,
+      map: info.map, cache: info.cache, before: info.before,
+      hasHeights: false
+    };
+  }
+
+  // Given a prepared measurement object, measures the position of an
+  // actual character (or fetches it from the cache).
+  function measureCharPrepared(cm, prepared, ch, bias, varHeight) {
+    if (prepared.before) ch = -1;
+    var key = ch + (bias || ""), found;
+    if (prepared.cache.hasOwnProperty(key)) {
+      found = prepared.cache[key];
+    } else {
+      if (!prepared.rect)
+        prepared.rect = prepared.view.text.getBoundingClientRect();
+      if (!prepared.hasHeights) {
+        ensureLineHeights(cm, prepared.view, prepared.rect);
+        prepared.hasHeights = true;
+      }
+      found = measureCharInner(cm, prepared, ch, bias);
+      if (!found.bogus) prepared.cache[key] = found;
+    }
+    return {left: found.left, right: found.right,
+            top: varHeight ? found.rtop : found.top,
+            bottom: varHeight ? found.rbottom : found.bottom};
+  }
+
+  var nullRect = {left: 0, right: 0, top: 0, bottom: 0};
+
+  function measureCharInner(cm, prepared, ch, bias) {
+    var map = prepared.map;
+
+    var node, start, end, collapse;
+    // First, search the line map for the text node corresponding to,
+    // or closest to, the target character.
+    for (var i = 0; i < map.length; i += 3) {
+      var mStart = map[i], mEnd = map[i + 1];
+      if (ch < mStart) {
+        start = 0; end = 1;
+        collapse = "left";
+      } else if (ch < mEnd) {
+        start = ch - mStart;
+        end = start + 1;
+      } else if (i == map.length - 3 || ch == mEnd && map[i + 3] > ch) {
+        end = mEnd - mStart;
+        start = end - 1;
+        if (ch >= mEnd) collapse = "right";
+      }
+      if (start != null) {
+        node = map[i + 2];
+        if (mStart == mEnd && bias == (node.insertLeft ? "left" : "right"))
+          collapse = bias;
+        if (bias == "left" && start == 0)
+          while (i && map[i - 2] == map[i - 3] && map[i - 1].insertLeft) {
+            node = map[(i -= 3) + 2];
+            collapse = "left";
+          }
+        if (bias == "right" && start == mEnd - mStart)
+          while (i < map.length - 3 && map[i + 3] == map[i + 4] && !map[i + 5].insertLeft) {
+            node = map[(i += 3) + 2];
+            collapse = "right";
+          }
+        break;
+      }
+    }
+
+    var rect;
+    if (node.nodeType == 3) { // If it is a text node, use a range to retrieve the coordinates.
+      for (var i = 0; i < 4; i++) { // Retry a maximum of 4 times when nonsense rectangles are returned
+        while (start && isExtendingChar(prepared.line.text.charAt(mStart + start))) --start;
+        while (mStart + end < mEnd && isExtendingChar(prepared.line.text.charAt(mStart + end))) ++end;
+        if (ie && ie_version < 9 && start == 0 && end == mEnd - mStart) {
+          rect = node.parentNode.getBoundingClientRect();
+        } else if (ie && cm.options.lineWrapping) {
+          var rects = range(node, start, end).getClientRects();
+          if (rects.length)
+            rect = rects[bias == "right" ? rects.length - 1 : 0];
+          else
+            rect = nullRect;
+        } else {
+          rect = range(node, start, end).getBoundingClientRect() || nullRect;
+        }
+        if (rect.left || rect.right || start == 0) break;
+        end = start;
+        start = start - 1;
+        collapse = "right";
+      }
+      if (ie && ie_version < 11) rect = maybeUpdateRectForZooming(cm.display.measure, rect);
+    } else { // If it is a widget, simply get the box for the whole widget.
+      if (start > 0) collapse = bias = "right";
+      var rects;
+      if (cm.options.lineWrapping && (rects = node.getClientRects()).length > 1)
+        rect = rects[bias == "right" ? rects.length - 1 : 0];
+      else
+        rect = node.getBoundingClientRect();
+    }
+    if (ie && ie_version < 9 && !start && (!rect || !rect.left && !rect.right)) {
+      var rSpan = node.parentNode.getClientRects()[0];
+      if (rSpan)
+        rect = {left: rSpan.left, right: rSpan.left + charWidth(cm.display), top: rSpan.top, bottom: rSpan.bottom};
+      else
+        rect = nullRect;
+    }
+
+    var rtop = rect.top - prepared.rect.top, rbot = rect.bottom - prepared.rect.top;
+    var mid = (rtop + rbot) / 2;
+    var heights = prepared.view.measure.heights;
+    for (var i = 0; i < heights.length - 1; i++)
+      if (mid < heights[i]) break;
+    var top = i ? heights[i - 1] : 0, bot = heights[i];
+    var result = {left: (collapse == "right" ? rect.right : rect.left) - prepared.rect.left,
+                  right: (collapse == "left" ? rect.left : rect.right) - prepared.rect.left,
+                  top: top, bottom: bot};
+    if (!rect.left && !rect.right) result.bogus = true;
+    if (!cm.options.singleCursorHeightPerLine) { result.rtop = rtop; result.rbottom = rbot; }
+
+    return result;
+  }
+
+  // Work around problem with bounding client rects on ranges being
+  // returned incorrectly when zoomed on IE10 and below.
+  function maybeUpdateRectForZooming(measure, rect) {
+    if (!window.screen || screen.logicalXDPI == null ||
+        screen.logicalXDPI == screen.deviceXDPI || !hasBadZoomedRects(measure))
+      return rect;
+    var scaleX = screen.logicalXDPI / screen.deviceXDPI;
+    var scaleY = screen.logicalYDPI / screen.deviceYDPI;
+    return {left: rect.left * scaleX, right: rect.right * scaleX,
+            top: rect.top * scaleY, bottom: rect.bottom * scaleY};
+  }
+
+  function clearLineMeasurementCacheFor(lineView) {
+    if (lineView.measure) {
+      lineView.measure.cache = {};
+      lineView.measure.heights = null;
+      if (lineView.rest) for (var i = 0; i < lineView.rest.length; i++)
+        lineView.measure.caches[i] = {};
+    }
+  }
+
+  function clearLineMeasurementCache(cm) {
+    cm.display.externalMeasure = null;
+    removeChildren(cm.display.lineMeasure);
+    for (var i = 0; i < cm.display.view.length; i++)
+      clearLineMeasurementCacheFor(cm.display.view[i]);
+  }
+
+  function clearCaches(cm) {
+    clearLineMeasurementCache(cm);
+    cm.display.cachedCharWidth = cm.display.cachedTextHeight = cm.display.cachedPaddingH = null;
+    if (!cm.options.lineWrapping) cm.display.maxLineChanged = true;
+    cm.display.lineNumChars = null;
+  }
+
+  function pageScrollX() { return window.pageXOffset || (document.documentElement || document.body).scrollLeft; }
+  function pageScrollY() { return window.pageYOffset || (document.documentElement || document.body).scrollTop; }
+
+  // Converts a {top, bottom, left, right} box from line-local
+  // coordinates into another coordinate system. Context may be one of
+  // "line", "div" (display.lineDiv), "local"/null (editor), or "page".
+  function intoCoordSystem(cm, lineObj, rect, context) {
+    if (lineObj.widgets) for (var i = 0; i < lineObj.widgets.length; ++i) if (lineObj.widgets[i].above) {
+      var size = widgetHeight(lineObj.widgets[i]);
+      rect.top += size; rect.bottom += size;
+    }
+    if (context == "line") return rect;
+    if (!context) context = "local";
+    var yOff = heightAtLine(lineObj);
+    if (context == "local") yOff += paddingTop(cm.display);
+    else yOff -= cm.display.viewOffset;
+    if (context == "page" || context == "window") {
+      var lOff = cm.display.lineSpace.getBoundingClientRect();
+      yOff += lOff.top + (context == "window" ? 0 : pageScrollY());
+      var xOff = lOff.left + (context == "window" ? 0 : pageScrollX());
+      rect.left += xOff; rect.right += xOff;
+    }
+    rect.top += yOff; rect.bottom += yOff;
+    return rect;
+  }
+
+  // Coverts a box from "div" coords to another coordinate system.
+  // Context may be "window", "page", "div", or "local"/null.
+  function fromCoordSystem(cm, coords, context) {
+    if (context == "div") return coords;
+    var left = coords.left, top = coords.top;
+    // First move into "page" coordinate system
+    if (context == "page") {
+      left -= pageScrollX();
+      top -= pageScrollY();
+    } else if (context == "local" || !context) {
+      var localBox = cm.display.sizer.getBoundingClientRect();
+      left += localBox.left;
+      top += localBox.top;
+    }
+
+    var lineSpaceBox = cm.display.lineSpace.getBoundingClientRect();
+    return {left: left - lineSpaceBox.left, top: top - lineSpaceBox.top};
+  }
+
+  function charCoords(cm, pos, context, lineObj, bias) {
+    if (!lineObj) lineObj = getLine(cm.doc, pos.line);
+    return intoCoordSystem(cm, lineObj, measureChar(cm, lineObj, pos.ch, bias), context);
+  }
+
+  // Returns a box for a given cursor position, which may have an
+  // 'other' property containing the position of the secondary cursor
+  // on a bidi boundary.
+  function cursorCoords(cm, pos, context, lineObj, preparedMeasure, varHeight) {
+    lineObj = lineObj || getLine(cm.doc, pos.line);
+    if (!preparedMeasure) preparedMeasure = prepareMeasureForLine(cm, lineObj);
+    function get(ch, right) {
+      var m = measureCharPrepared(cm, preparedMeasure, ch, right ? "right" : "left", varHeight);
+      if (right) m.left = m.right; else m.right = m.left;
+      return intoCoordSystem(cm, lineObj, m, context);
+    }
+    function getBidi(ch, partPos) {
+      var part = order[partPos], right = part.level % 2;
+      if (ch == bidiLeft(part) && partPos && part.level < order[partPos - 1].level) {
+        part = order[--partPos];
+        ch = bidiRight(part) - (part.level % 2 ? 0 : 1);
+        right = true;
+      } else if (ch == bidiRight(part) && partPos < order.length - 1 && part.level < order[partPos + 1].level) {
+        part = order[++partPos];
+        ch = bidiLeft(part) - part.level % 2;
+        right = false;
+      }
+      if (right && ch == part.to && ch > part.from) return get(ch - 1);
+      return get(ch, right);
+    }
+    var order = getOrder(lineObj), ch = pos.ch;
+    if (!order) return get(ch);
+    var partPos = getBidiPartAt(order, ch);
+    var val = getBidi(ch, partPos);
+    if (bidiOther != null) val.other = getBidi(ch, bidiOther);
+    return val;
+  }
+
+  // Used to cheaply estimate the coordinates for a position. Used for
+  // intermediate scroll updates.
+  function estimateCoords(cm, pos) {
+    var left = 0, pos = clipPos(cm.doc, pos);
+    if (!cm.options.lineWrapping) left = charWidth(cm.display) * pos.ch;
+    var lineObj = getLine(cm.doc, pos.line);
+    var top = heightAtLine(lineObj) + paddingTop(cm.display);
+    return {left: left, right: left, top: top, bottom: top + lineObj.height};
+  }
+
+  // Positions returned by coordsChar contain some extra information.
+  // xRel is the relative x position of the input coordinates compared
+  // to the found position (so xRel > 0 means the coordinates are to
+  // the right of the character position, for example). When outside
+  // is true, that means the coordinates lie outside the line's
+  // vertical range.
+  function PosWithInfo(line, ch, outside, xRel) {
+    var pos = Pos(line, ch);
+    pos.xRel = xRel;
+    if (outside) pos.outside = true;
+    return pos;
+  }
+
+  // Compute the character position closest to the given coordinates.
+  // Input must be lineSpace-local ("div" coordinate system).
+  function coordsChar(cm, x, y) {
+    var doc = cm.doc;
+    y += cm.display.viewOffset;
+    if (y < 0) return PosWithInfo(doc.first, 0, true, -1);
+    var lineN = lineAtHeight(doc, y), last = doc.first + doc.size - 1;
+    if (lineN > last)
+      return PosWithInfo(doc.first + doc.size - 1, getLine(doc, last).text.length, true, 1);
+    if (x < 0) x = 0;
+
+    var lineObj = getLine(doc, lineN);
+    for (;;) {
+      var found = coordsCharInner(cm, lineObj, lineN, x, y);
+      var merged = collapsedSpanAtEnd(lineObj);
+      var mergedPos = merged && merged.find(0, true);
+      if (merged && (found.ch > mergedPos.from.ch || found.ch == mergedPos.from.ch && found.xRel > 0))
+        lineN = lineNo(lineObj = mergedPos.to.line);
+      else
+        return found;
+    }
+  }
+
+  function coordsCharInner(cm, lineObj, lineNo, x, y) {
+    var innerOff = y - heightAtLine(lineObj);
+    var wrongLine = false, adjust = 2 * cm.display.wrapper.clientWidth;
+    var preparedMeasure = prepareMeasureForLine(cm, lineObj);
+
+    function getX(ch) {
+      var sp = cursorCoords(cm, Pos(lineNo, ch), "line", lineObj, preparedMeasure);
+      wrongLine = true;
+      if (innerOff > sp.bottom) return sp.left - adjust;
+      else if (innerOff < sp.top) return sp.left + adjust;
+      else wrongLine = false;
+      return sp.left;
+    }
+
+    var bidi = getOrder(lineObj), dist = lineObj.text.length;
+    var from = lineLeft(lineObj), to = lineRight(lineObj);
+    var fromX = getX(from), fromOutside = wrongLine, toX = getX(to), toOutside = wrongLine;
+
+    if (x > toX) return PosWithInfo(lineNo, to, toOutside, 1);
+    // Do a binary search between these bounds.
+    for (;;) {
+      if (bidi ? to == from || to == moveVisually(lineObj, from, 1) : to - from <= 1) {
+        var ch = x < fromX || x - fromX <= toX - x ? from : to;
+        var xDiff = x - (ch == from ? fromX : toX);
+        while (isExtendingChar(lineObj.text.charAt(ch))) ++ch;
+        var pos = PosWithInfo(lineNo, ch, ch == from ? fromOutside : toOutside,
+                              xDiff < -1 ? -1 : xDiff > 1 ? 1 : 0);
+        return pos;
+      }
+      var step = Math.ceil(dist / 2), middle = from + step;
+      if (bidi) {
+        middle = from;
+        for (var i = 0; i < step; ++i) middle = moveVisually(lineObj, middle, 1);
+      }
+      var middleX = getX(middle);
+      if (middleX > x) {to = middle; toX = middleX; if (toOutside = wrongLine) toX += 1000; dist = step;}
+      else {from = middle; fromX = middleX; fromOutside = wrongLine; dist -= step;}
+    }
+  }
+
+  var measureText;
+  // Compute the default text height.
+  function textHeight(display) {
+    if (display.cachedTextHeight != null) return display.cachedTextHeight;
+    if (measureText == null) {
+      measureText = elt("pre");
+      // Measure a bunch of lines, for browsers that compute
+      // fractional heights.
+      for (var i = 0; i < 49; ++i) {
+        measureText.appendChild(document.createTextNode("x"));
+        measureText.appendChild(elt("br"));
+      }
+      measureText.appendChild(document.createTextNode("x"));
+    }
+    removeChildrenAndAdd(display.measure, measureText);
+    var height = measureText.offsetHeight / 50;
+    if (height > 3) display.cachedTextHeight = height;
+    removeChildren(display.measure);
+    return height || 1;
+  }
+
+  // Compute the default character width.
+  function charWidth(display) {
+    if (display.cachedCharWidth != null) return display.cachedCharWidth;
+    var anchor = elt("span", "xxxxxxxxxx");
+    var pre = elt("pre", [anchor]);
+    removeChildrenAndAdd(display.measure, pre);
+    var rect = anchor.getBoundingClientRect(), width = (rect.right - rect.left) / 10;
+    if (width > 2) display.cachedCharWidth = width;
+    return width || 10;
+  }
+
+  // OPERATIONS
+
+  // Operations are used to wrap a series of changes to the editor
+  // state in such a way that each change won't have to update the
+  // cursor and display (which would be awkward, slow, and
+  // error-prone). Instead, display updates are batched and then all
+  // combined and executed at once.
+
+  var operationGroup = null;
+
+  var nextOpId = 0;
+  // Start a new operation.
+  function startOperation(cm) {
+    cm.curOp = {
+      cm: cm,
+      viewChanged: false,      // Flag that indicates that lines might need to be redrawn
+      startHeight: cm.doc.height, // Used to detect need to update scrollbar
+      forceUpdate: false,      // Used to force a redraw
+      updateInput: null,       // Whether to reset the input textarea
+      typing: false,           // Whether this reset should be careful to leave existing text (for compositing)
+      changeObjs: null,        // Accumulated changes, for firing change events
+      cursorActivityHandlers: null, // Set of handlers to fire cursorActivity on
+      cursorActivityCalled: 0, // Tracks which cursorActivity handlers have been called already
+      selectionChanged: false, // Whether the selection needs to be redrawn
+      updateMaxLine: false,    // Set when the widest line needs to be determined anew
+      scrollLeft: null, scrollTop: null, // Intermediate scroll position, not pushed to DOM yet
+      scrollToPos: null,       // Used to scroll to a specific position
+      id: ++nextOpId           // Unique ID
+    };
+    if (operationGroup) {
+      operationGroup.ops.push(cm.curOp);
+    } else {
+      cm.curOp.ownsGroup = operationGroup = {
+        ops: [cm.curOp],
+        delayedCallbacks: []
+      };
+    }
+  }
+
+  function fireCallbacksForOps(group) {
+    // Calls delayed callbacks and cursorActivity handlers until no
+    // new ones appear
+    var callbacks = group.delayedCallbacks, i = 0;
+    do {
+      for (; i < callbacks.length; i++)
+        callbacks[i]();
+      for (var j = 0; j < group.ops.length; j++) {
+        var op = group.ops[j];
+        if (op.cursorActivityHandlers)
+          while (op.cursorActivityCalled < op.cursorActivityHandlers.length)
+            op.cursorActivityHandlers[op.cursorActivityCalled++](op.cm);
+      }
+    } while (i < callbacks.length);
+  }
+
+  // Finish an operation, updating the display and signalling delayed events
+  function endOperation(cm) {
+    var op = cm.curOp, group = op.ownsGroup;
+    if (!group) return;
+
+    try { fireCallbacksForOps(group); }
+    finally {
+      operationGroup = null;
+      for (var i = 0; i < group.ops.length; i++)
+        group.ops[i].cm.curOp = null;
+      endOperations(group);
+    }
+  }
+
+  // The DOM updates done when an operation finishes are batched so
+  // that the minimum number of relayouts are required.
+  function endOperations(group) {
+    var ops = group.ops;
+    for (var i = 0; i < ops.length; i++) // Read DOM
+      endOperation_R1(ops[i]);
+    for (var i = 0; i < ops.length; i++) // Write DOM (maybe)
+      endOperation_W1(ops[i]);
+    for (var i = 0; i < ops.length; i++) // Read DOM
+      endOperation_R2(ops[i]);
+    for (var i = 0; i < ops.length; i++) // Write DOM (maybe)
+      endOperation_W2(ops[i]);
+    for (var i = 0; i < ops.length; i++) // Read DOM
+      endOperation_finish(ops[i]);
+  }
+
+  function endOperation_R1(op) {
+    var cm = op.cm, display = cm.display;
+    if (op.updateMaxLine) findMaxLine(cm);
+
+    op.mustUpdate = op.viewChanged || op.forceUpdate || op.scrollTop != null ||
+      op.scrollToPos && (op.scrollToPos.from.line < display.viewFrom ||
+                         op.scrollToPos.to.line >= display.viewTo) ||
+      display.maxLineChanged && cm.options.lineWrapping;
+    op.update = op.mustUpdate &&
+      new DisplayUpdate(cm, op.mustUpdate && {top: op.scrollTop, ensure: op.scrollToPos}, op.forceUpdate);
+  }
+
+  function endOperation_W1(op) {
+    op.updatedDisplay = op.mustUpdate && updateDisplayIfNeeded(op.cm, op.update);
+  }
+
+  function endOperation_R2(op) {
+    var cm = op.cm, display = cm.display;
+    if (op.updatedDisplay) updateHeightsInViewport(cm);
+
+    op.barMeasure = measureForScrollbars(cm);
+
+    // If the max line changed since it was last measured, measure it,
+    // and ensure the document's width matches it.
+    // updateDisplay_W2 will use these properties to do the actual resizing
+    if (display.maxLineChanged && !cm.options.lineWrapping) {
+      op.adjustWidthTo = measureChar(cm, display.maxLine, display.maxLine.text.length).left + 3;
+      op.maxScrollLeft = Math.max(0, display.sizer.offsetLeft + op.adjustWidthTo +
+                                  scrollerCutOff - display.scroller.clientWidth);
+    }
+
+    if (op.updatedDisplay || op.selectionChanged)
+      op.newSelectionNodes = drawSelection(cm);
+  }
+
+  function endOperation_W2(op) {
+    var cm = op.cm;
+
+    if (op.adjustWidthTo != null) {
+      cm.display.sizer.style.minWidth = op.adjustWidthTo + "px";
+      if (op.maxScrollLeft < cm.doc.scrollLeft)
+        setScrollLeft(cm, Math.min(cm.display.scroller.scrollLeft, op.maxScrollLeft), true);
+      cm.display.maxLineChanged = false;
+    }
+
+    if (op.newSelectionNodes)
+      showSelection(cm, op.newSelectionNodes);
+    if (op.updatedDisplay)
+      setDocumentHeight(cm, op.barMeasure);
+    if (op.updatedDisplay || op.startHeight != cm.doc.height)
+      updateScrollbars(cm, op.barMeasure);
+
+    if (op.selectionChanged) restartBlink(cm);
+
+    if (cm.state.focused && op.updateInput)
+      resetInput(cm, op.typing);
+  }
+
+  function endOperation_finish(op) {
+    var cm = op.cm, display = cm.display, doc = cm.doc;
+
+    if (op.adjustWidthTo != null && Math.abs(op.barMeasure.scrollWidth - cm.display.scroller.scrollWidth) > 1)
+      updateScrollbars(cm);
+
+    if (op.updatedDisplay) postUpdateDisplay(cm, op.update);
+
+    // Abort mouse wheel delta measurement, when scrolling explicitly
+    if (display.wheelStartX != null && (op.scrollTop != null || op.scrollLeft != null || op.scrollToPos))
+      display.wheelStartX = display.wheelStartY = null;
+
+    // Propagate the scroll position to the actual DOM scroller
+    if (op.scrollTop != null && (display.scroller.scrollTop != op.scrollTop || op.forceScroll)) {
+      var top = Math.max(0, Math.min(display.scroller.scrollHeight - display.scroller.clientHeight, op.scrollTop));
+      display.scroller.scrollTop = display.scrollbarV.scrollTop = doc.scrollTop = top;
+    }
+    if (op.scrollLeft != null && (display.scroller.scrollLeft != op.scrollLeft || op.forceScroll)) {
+      var left = Math.max(0, Math.min(display.scroller.scrollWidth - display.scroller.clientWidth, op.scrollLeft));
+      display.scroller.scrollLeft = display.scrollbarH.scrollLeft = doc.scrollLeft = left;
+      alignHorizontally(cm);
+    }
+    // If we need to scroll a specific position into view, do so.
+    if (op.scrollToPos) {
+      var coords = scrollPosIntoView(cm, clipPos(doc, op.scrollToPos.from),
+                                     clipPos(doc, op.scrollToPos.to), op.scrollToPos.margin);
+      if (op.scrollToPos.isCursor && cm.state.focused) maybeScrollWindow(cm, coords);
+    }
+
+    // Fire events for markers that are hidden/unidden by editing or
+    // undoing
+    var hidden = op.maybeHiddenMarkers, unhidden = op.maybeUnhiddenMarkers;
+    if (hidden) for (var i = 0; i < hidden.length; ++i)
+      if (!hidden[i].lines.length) signal(hidden[i], "hide");
+    if (unhidden) for (var i = 0; i < unhidden.length; ++i)
+      if (unhidden[i].lines.length) signal(unhidden[i], "unhide");
+
+    if (display.wrapper.offsetHeight)
+      doc.scrollTop = cm.display.scroller.scrollTop;
+
+    // Apply workaround for two webkit bugs
+    if (op.updatedDisplay && webkit) {
+      if (cm.options.lineWrapping)
+        checkForWebkitWidthBug(cm, op.barMeasure); // (Issue #2420)
+      if (op.barMeasure.scrollWidth > op.barMeasure.clientWidth &&
+          op.barMeasure.scrollWidth < op.barMeasure.clientWidth + 1 &&
+          !hScrollbarTakesSpace(cm))
+        updateScrollbars(cm); // (Issue #2562)
+    }
+
+    // Fire change events, and delayed event handlers
+    if (op.changeObjs)
+      signal(cm, "changes", cm, op.changeObjs);
+  }
+
+  // Run the given function in an operation
+  function runInOp(cm, f) {
+    if (cm.curOp) return f();
+    startOperation(cm);
+    try { return f(); }
+    finally { endOperation(cm); }
+  }
+  // Wraps a function in an operation. Returns the wrapped function.
+  function operation(cm, f) {
+    return function() {
+      if (cm.curOp) return f.apply(cm, arguments);
+      startOperation(cm);
+      try { return f.apply(cm, arguments); }
+      finally { endOperation(cm); }
+    };
+  }
+  // Used to add methods to editor and doc instances, wrapping them in
+  // operations.
+  function methodOp(f) {
+    return function() {
+      if (this.curOp) return f.apply(this, arguments);
+      startOperation(this);
+      try { return f.apply(this, arguments); }
+      finally { endOperation(this); }
+    };
+  }
+  function docMethodOp(f) {
+    return function() {
+      var cm = this.cm;
+      if (!cm || cm.curOp) return f.apply(this, arguments);
+      startOperation(cm);
+      try { return f.apply(this, arguments); }
+      finally { endOperation(cm); }
+    };
+  }
+
+  // VIEW TRACKING
+
+  // These objects are used to represent the visible (currently drawn)
+  // part of the document. A LineView may correspond to multiple
+  // logical lines, if those are connected by collapsed ranges.
+  function LineView(doc, line, lineN) {
+    // The starting line
+    this.line = line;
+    // Continuing lines, if any
+    this.rest = visualLineContinued(line);
+    // Number of logical lines in this visual line
+    this.size = this.rest ? lineNo(lst(this.rest)) - lineN + 1 : 1;
+    this.node = this.text = null;
+    this.hidden = lineIsHidden(doc, line);
+  }
+
+  // Create a range of LineView objects for the given lines.
+  function buildViewArray(cm, from, to) {
+    var array = [], nextPos;
+    for (var pos = from; pos < to; pos = nextPos) {
+      var view = new LineView(cm.doc, getLine(cm.doc, pos), pos);
+      nextPos = pos + view.size;
+      array.push(view);
+    }
+    return array;
+  }
+
+  // Updates the display.view data structure for a given change to the
+  // document. From and to are in pre-change coordinates. Lendiff is
+  // the amount of lines added or subtracted by the change. This is
+  // used for changes that span multiple lines, or change the way
+  // lines are divided into visual lines. regLineChange (below)
+  // registers single-line changes.
+  function regChange(cm, from, to, lendiff) {
+    if (from == null) from = cm.doc.first;
+    if (to == null) to = cm.doc.first + cm.doc.size;
+    if (!lendiff) lendiff = 0;
+
+    var display = cm.display;
+    if (lendiff && to < display.viewTo &&
+        (display.updateLineNumbers == null || display.updateLineNumbers > from))
+      display.updateLineNumbers = from;
+
+    cm.curOp.viewChanged = true;
+
+    if (from >= display.viewTo) { // Change after
+      if (sawCollapsedSpans && visualLineNo(cm.doc, from) < display.viewTo)
+        resetView(cm);
+    } else if (to <= display.viewFrom) { // Change before
+      if (sawCollapsedSpans && visualLineEndNo(cm.doc, to + lendiff) > display.viewFrom) {
+        resetView(cm);
+      } else {
+        display.viewFrom += lendiff;
+        display.viewTo += lendiff;
+      }
+    } else if (from <= display.viewFrom && to >= display.viewTo) { // Full overlap
+      resetView(cm);
+    } else if (from <= display.viewFrom) { // Top overlap
+      var cut = viewCuttingPoint(cm, to, to + lendiff, 1);
+      if (cut) {
+        display.view = display.view.slice(cut.index);
+        display.viewFrom = cut.lineN;
+        display.viewTo += lendiff;
+      } else {
+        resetView(cm);
+      }
+    } else if (to >= display.viewTo) { // Bottom overlap
+      var cut = viewCuttingPoint(cm, from, from, -1);
+      if (cut) {
+        display.view = display.view.slice(0, cut.index);
+        display.viewTo = cut.lineN;
+      } else {
+        resetView(cm);
+      }
+    } else { // Gap in the middle
+      var cutTop = viewCuttingPoint(cm, from, from, -1);
+      var cutBot = viewCuttingPoint(cm, to, to + lendiff, 1);
+      if (cutTop && cutBot) {
+        display.view = display.view.slice(0, cutTop.index)
+          .concat(buildViewArray(cm, cutTop.lineN, cutBot.lineN))
+          .concat(display.view.slice(cutBot.index));
+        display.viewTo += lendiff;
+      } else {
+        resetView(cm);
+      }
+    }
+
+    var ext = display.externalMeasured;
+    if (ext) {
+      if (to < ext.lineN)
+        ext.lineN += lendiff;
+      else if (from < ext.lineN + ext.size)
+        display.externalMeasured = null;
+    }
+  }
+
+  // Register a change to a single line. Type must be one of "text",
+  // "gutter", "class", "widget"
+  function regLineChange(cm, line, type) {
+    cm.curOp.viewChanged = true;
+    var display = cm.display, ext = cm.display.externalMeasured;
+    if (ext && line >= ext.lineN && line < ext.lineN + ext.size)
+      display.externalMeasured = null;
+
+    if (line < display.viewFrom || line >= display.viewTo) return;
+    var lineView = display.view[findViewIndex(cm, line)];
+    if (lineView.node == null) return;
+    var arr = lineView.changes || (lineView.changes = []);
+    if (indexOf(arr, type) == -1) arr.push(type);
+  }
+
+  // Clear the view.
+  function resetView(cm) {
+    cm.display.viewFrom = cm.display.viewTo = cm.doc.first;
+    cm.display.view = [];
+    cm.display.viewOffset = 0;
+  }
+
+  // Find the view element corresponding to a given line. Return null
+  // when the line isn't visible.
+  function findViewIndex(cm, n) {
+    if (n >= cm.display.viewTo) return null;
+    n -= cm.display.viewFrom;
+    if (n < 0) return null;
+    var view = cm.display.view;
+    for (var i = 0; i < view.length; i++) {
+      n -= view[i].size;
+      if (n < 0) return i;
+    }
+  }
+
+  function viewCuttingPoint(cm, oldN, newN, dir) {
+    var index = findViewIndex(cm, oldN), diff, view = cm.display.view;
+    if (!sawCollapsedSpans || newN == cm.doc.first + cm.doc.size)
+      return {index: index, lineN: newN};
+    for (var i = 0, n = cm.display.viewFrom; i < index; i++)
+      n += view[i].size;
+    if (n != oldN) {
+      if (dir > 0) {
+        if (index == view.length - 1) return null;
+        diff = (n + view[index].size) - oldN;
+        index++;
+      } else {
+        diff = n - oldN;
+      }
+      oldN += diff; newN += diff;
+    }
+    while (visualLineNo(cm.doc, newN) != newN) {
+      if (index == (dir < 0 ? 0 : view.length - 1)) return null;
+      newN += dir * view[index - (dir < 0 ? 1 : 0)].size;
+      index += dir;
+    }
+    return {index: index, lineN: newN};
+  }
+
+  // Force the view to cover a given range, adding empty view element
+  // or clipping off existing ones as needed.
+  function adjustView(cm, from, to) {
+    var display = cm.display, view = display.view;
+    if (view.length == 0 || from >= display.viewTo || to <= display.viewFrom) {
+      display.view = buildViewArray(cm, from, to);
+      display.viewFrom = from;
+    } else {
+      if (display.viewFrom > from)
+        display.view = buildViewArray(cm, from, display.viewFrom).concat(display.view);
+      else if (display.viewFrom < from)
+        display.view = display.view.slice(findViewIndex(cm, from));
+      display.viewFrom = from;
+      if (display.viewTo < to)
+        display.view = display.view.concat(buildViewArray(cm, display.viewTo, to));
+      else if (display.viewTo > to)
+        display.view = display.view.slice(0, findViewIndex(cm, to));
+    }
+    display.viewTo = to;
+  }
+
+  // Count the number of lines in the view whose DOM representation is
+  // out of date (or nonexistent).
+  function countDirtyView(cm) {
+    var view = cm.display.view, dirty = 0;
+    for (var i = 0; i < view.length; i++) {
+      var lineView = view[i];
+      if (!lineView.hidden && (!lineView.node || lineView.changes)) ++dirty;
+    }
+    return dirty;
+  }
+
+  // INPUT HANDLING
+
+  // Poll for input changes, using the normal rate of polling. This
+  // runs as long as the editor is focused.
+  function slowPoll(cm) {
+    if (cm.display.pollingFast) return;
+    cm.display.poll.set(cm.options.pollInterval, function() {
+      readInput(cm);
+      if (cm.state.focused) slowPoll(cm);
+    });
+  }
+
+  // When an event has just come in that is likely to add or change
+  // something in the input textarea, we poll faster, to ensure that
+  // the change appears on the screen quickly.
+  function fastPoll(cm) {
+    var missed = false;
+    cm.display.pollingFast = true;
+    function p() {
+      var changed = readInput(cm);
+      if (!changed && !missed) {missed = true; cm.display.poll.set(60, p);}
+      else {cm.display.pollingFast = false; slowPoll(cm);}
+    }
+    cm.display.poll.set(20, p);
+  }
+
+  // This will be set to an array of strings when copying, so that,
+  // when pasting, we know what kind of selections the copied text
+  // was made out of.
+  var lastCopied = null;
+
+  // Read input from the textarea, and update the document to match.
+  // When something is selected, it is present in the textarea, and
+  // selected (unless it is huge, in which case a placeholder is
+  // used). When nothing is selected, the cursor sits after previously
+  // seen text (can be empty), which is stored in prevInput (we must
+  // not reset the textarea when typing, because that breaks IME).
+  function readInput(cm) {
+    var input = cm.display.input, prevInput = cm.display.prevInput, doc = cm.doc;
+    // Since this is called a *lot*, try to bail out as cheaply as
+    // possible when it is clear that nothing happened. hasSelection
+    // will be the case when there is a lot of text in the textarea,
+    // in which case reading its value would be expensive.
+    if (!cm.state.focused || (hasSelection(input) && !prevInput) || isReadOnly(cm) || cm.options.disableInput || cm.state.keySeq)
+      return false;
+    // See paste handler for more on the fakedLastChar kludge
+    if (cm.state.pasteIncoming && cm.state.fakedLastChar) {
+      input.value = input.value.substring(0, input.value.length - 1);
+      cm.state.fakedLastChar = false;
+    }
+    var text = input.value;
+    // If nothing changed, bail.
+    if (text == prevInput && !cm.somethingSelected()) return false;
+    // Work around nonsensical selection resetting in IE9/10, and
+    // inexplicable appearance of private area unicode characters on
+    // some key combos in Mac (#2689).
+    if (ie && ie_version >= 9 && cm.display.inputHasSelection === text ||
+        mac && /[\uf700-\uf7ff]/.test(text)) {
+      resetInput(cm);
+      return false;
+    }
+
+    var withOp = !cm.curOp;
+    if (withOp) startOperation(cm);
+    cm.display.shift = false;
+
+    if (text.charCodeAt(0) == 0x200b && doc.sel == cm.display.selForContextMenu && !prevInput)
+      prevInput = "\u200b";
+    // Find the part of the input that is actually new
+    var same = 0, l = Math.min(prevInput.length, text.length);
+    while (same < l && prevInput.charCodeAt(same) == text.charCodeAt(same)) ++same;
+    var inserted = text.slice(same), textLines = splitLines(inserted);
+
+    // When pasing N lines into N selections, insert one line per selection
+    var multiPaste = null;
+    if (cm.state.pasteIncoming && doc.sel.ranges.length > 1) {
+      if (lastCopied && lastCopied.join("\n") == inserted)
+        multiPaste = doc.sel.ranges.length % lastCopied.length == 0 && map(lastCopied, splitLines);
+      else if (textLines.length == doc.sel.ranges.length)
+        multiPaste = map(textLines, function(l) { return [l]; });
+    }
+
+    // Normal behavior is to insert the new text into every selection
+    for (var i = doc.sel.ranges.length - 1; i >= 0; i--) {
+      var range = doc.sel.ranges[i];
+      var from = range.from(), to = range.to();
+      // Handle deletion
+      if (same < prevInput.length)
+        from = Pos(from.line, from.ch - (prevInput.length - same));
+      // Handle overwrite
+      else if (cm.state.overwrite && range.empty() && !cm.state.pasteIncoming)
+        to = Pos(to.line, Math.min(getLine(doc, to.line).text.length, to.ch + lst(textLines).length));
+      var updateInput = cm.curOp.updateInput;
+      var changeEvent = {from: from, to: to, text: multiPaste ? multiPaste[i % multiPaste.length] : textLines,
+                         origin: cm.state.pasteIncoming ? "paste" : cm.state.cutIncoming ? "cut" : "+input"};
+      makeChange(cm.doc, changeEvent);
+      signalLater(cm, "inputRead", cm, changeEvent);
+      // When an 'electric' character is inserted, immediately trigger a reindent
+      if (inserted && !cm.state.pasteIncoming && cm.options.electricChars &&
+          cm.options.smartIndent && range.head.ch < 100 &&
+          (!i || doc.sel.ranges[i - 1].head.line != range.head.line)) {
+        var mode = cm.getModeAt(range.head);
+        var end = changeEnd(changeEvent);
+        if (mode.electricChars) {
+          for (var j = 0; j < mode.electricChars.length; j++)
+            if (inserted.indexOf(mode.electricChars.charAt(j)) > -1) {
+              indentLine(cm, end.line, "smart");
+              break;
+            }
+        } else if (mode.electricInput) {
+          if (mode.electricInput.test(getLine(doc, end.line).text.slice(0, end.ch)))
+            indentLine(cm, end.line, "smart");
+        }
+      }
+    }
+    ensureCursorVisible(cm);
+    cm.curOp.updateInput = updateInput;
+    cm.curOp.typing = true;
+
+    // Don't leave long text in the textarea, since it makes further polling slow
+    if (text.length > 1000 || text.indexOf("\n") > -1) input.value = cm.display.prevInput = "";
+    else cm.display.prevInput = text;
+    if (withOp) endOperation(cm);
+    cm.state.pasteIncoming = cm.state.cutIncoming = false;
+    return true;
+  }
+
+  // Reset the input to correspond to the selection (or to be empty,
+  // when not typing and nothing is selected)
+  function resetInput(cm, typing) {
+    var minimal, selected, doc = cm.doc;
+    if (cm.somethingSelected()) {
+      cm.display.prevInput = "";
+      var range = doc.sel.primary();
+      minimal = hasCopyEvent &&
+        (range.to().line - range.from().line > 100 || (selected = cm.getSelection()).length > 1000);
+      var content = minimal ? "-" : selected || cm.getSelection();
+      cm.display.input.value = content;
+      if (cm.state.focused) selectInput(cm.display.input);
+      if (ie && ie_version >= 9) cm.display.inputHasSelection = content;
+    } else if (!typing) {
+      cm.display.prevInput = cm.display.input.value = "";
+      if (ie && ie_version >= 9) cm.display.inputHasSelection = null;
+    }
+    cm.display.inaccurateSelection = minimal;
+  }
+
+  function focusInput(cm) {
+    if (cm.options.readOnly != "nocursor" && (!mobile || activeElt() != cm.display.input))
+      cm.display.input.focus();
+  }
+
+  function ensureFocus(cm) {
+    if (!cm.state.focused) { focusInput(cm); onFocus(cm); }
+  }
+
+  function isReadOnly(cm) {
+    return cm.options.readOnly || cm.doc.cantEdit;
+  }
+
+  // EVENT HANDLERS
+
+  // Attach the necessary event handlers when initializing the editor
+  function registerEventHandlers(cm) {
+    var d = cm.display;
+    on(d.scroller, "mousedown", operation(cm, onMouseDown));
+    // Older IE's will not fire a second mousedown for a double click
+    if (ie && ie_version < 11)
+      on(d.scroller, "dblclick", operation(cm, function(e) {
+        if (signalDOMEvent(cm, e)) return;
+        var pos = posFromMouse(cm, e);
+        if (!pos || clickInGutter(cm, e) || eventInWidget(cm.display, e)) return;
+        e_preventDefault(e);
+        var word = cm.findWordAt(pos);
+        extendSelection(cm.doc, word.anchor, word.head);
+      }));
+    else
+      on(d.scroller, "dblclick", function(e) { signalDOMEvent(cm, e) || e_preventDefault(e); });
+    // Prevent normal selection in the editor (we handle our own)
+    on(d.lineSpace, "selectstart", function(e) {
+      if (!eventInWidget(d, e)) e_preventDefault(e);
+    });
+    // Some browsers fire contextmenu *after* opening the menu, at
+    // which point we can't mess with it anymore. Context menu is
+    // handled in onMouseDown for these browsers.
+    if (!captureRightClick) on(d.scroller, "contextmenu", function(e) {onContextMenu(cm, e);});
+
+    // Sync scrolling between fake scrollbars and real scrollable
+    // area, ensure viewport is updated when scrolling.
+    on(d.scroller, "scroll", function() {
+      if (d.scroller.clientHeight) {
+        setScrollTop(cm, d.scroller.scrollTop);
+        setScrollLeft(cm, d.scroller.scrollLeft, true);
+        signal(cm, "scroll", cm);
+      }
+    });
+    on(d.scrollbarV, "scroll", function() {
+      if (d.scroller.clientHeight) setScrollTop(cm, d.scrollbarV.scrollTop);
+    });
+    on(d.scrollbarH, "scroll", function() {
+      if (d.scroller.clientHeight) setScrollLeft(cm, d.scrollbarH.scrollLeft);
+    });
+
+    // Listen to wheel events in order to try and update the viewport on time.
+    on(d.scroller, "mousewheel", function(e){onScrollWheel(cm, e);});
+    on(d.scroller, "DOMMouseScroll", function(e){onScrollWheel(cm, e);});
+
+    // Prevent clicks in the scrollbars from killing focus
+    function reFocus() { if (cm.state.focused) setTimeout(bind(focusInput, cm), 0); }
+    on(d.scrollbarH, "mousedown", reFocus);
+    on(d.scrollbarV, "mousedown", reFocus);
+    // Prevent wrapper from ever scrolling
+    on(d.wrapper, "scroll", function() { d.wrapper.scrollTop = d.wrapper.scrollLeft = 0; });
+
+    on(d.input, "keyup", function(e) { onKeyUp.call(cm, e); });
+    on(d.input, "input", function() {
+      if (ie && ie_version >= 9 && cm.display.inputHasSelection) cm.display.inputHasSelection = null;
+      fastPoll(cm);
+    });
+    on(d.input, "keydown", operation(cm, onKeyDown));
+    on(d.input, "keypress", operation(cm, onKeyPress));
+    on(d.input, "focus", bind(onFocus, cm));
+    on(d.input, "blur", bind(onBlur, cm));
+
+    function drag_(e) {
+      if (!signalDOMEvent(cm, e)) e_stop(e);
+    }
+    if (cm.options.dragDrop) {
+      on(d.scroller, "dragstart", function(e){onDragStart(cm, e);});
+      on(d.scroller, "dragenter", drag_);
+      on(d.scroller, "dragover", drag_);
+      on(d.scroller, "drop", operation(cm, onDrop));
+    }
+    on(d.scroller, "paste", function(e) {
+      if (eventInWidget(d, e)) return;
+      cm.state.pasteIncoming = true;
+      focusInput(cm);
+      fastPoll(cm);
+    });
+    on(d.input, "paste", function() {
+      // Workaround for webkit bug https://bugs.webkit.org/show_bug.cgi?id=90206
+      // Add a char to the end of textarea before paste occur so that
+      // selection doesn't span to the end of textarea.
+      if (webkit && !cm.state.fakedLastChar && !(new Date - cm.state.lastMiddleDown < 200)) {
+        var start = d.input.selectionStart, end = d.input.selectionEnd;
+        d.input.value += "$";
+        // The selection end needs to be set before the start, otherwise there
+        // can be an intermediate non-empty selection between the two, which
+        // can override the middle-click paste buffer on linux and cause the
+        // wrong thing to get pasted.
+        d.input.selectionEnd = end;
+        d.input.selectionStart = start;
+        cm.state.fakedLastChar = true;
+      }
+      cm.state.pasteIncoming = true;
+      fastPoll(cm);
+    });
+
+    function prepareCopyCut(e) {
+      if (cm.somethingSelected()) {
+        lastCopied = cm.getSelections();
+        if (d.inaccurateSelection) {
+          d.prevInput = "";
+          d.inaccurateSelection = false;
+          d.input.value = lastCopied.join("\n");
+          selectInput(d.input);
+        }
+      } else {
+        var text = [], ranges = [];
+        for (var i = 0; i < cm.doc.sel.ranges.length; i++) {
+          var line = cm.doc.sel.ranges[i].head.line;
+          var lineRange = {anchor: Pos(line, 0), head: Pos(line + 1, 0)};
+          ranges.push(lineRange);
+          text.push(cm.getRange(lineRange.anchor, lineRange.head));
+        }
+        if (e.type == "cut") {
+          cm.setSelections(ranges, null, sel_dontScroll);
+        } else {
+          d.prevInput = "";
+          d.input.value = text.join("\n");
+          selectInput(d.input);
+        }
+        lastCopied = text;
+      }
+      if (e.type == "cut") cm.state.cutIncoming = true;
+    }
+    on(d.input, "cut", prepareCopyCut);
+    on(d.input, "copy", prepareCopyCut);
+
+    // Needed to handle Tab key in KHTML
+    if (khtml) on(d.sizer, "mouseup", function() {
+      if (activeElt() == d.input) d.input.blur();
+      focusInput(cm);
+    });
+  }
+
+  // Called when the window resizes
+  function onResize(cm) {
+    var d = cm.display;
+    if (d.lastWrapHeight == d.wrapper.clientHeight && d.lastWrapWidth == d.wrapper.clientWidth)
+      return;
+    // Might be a text scaling operation, clear size caches.
+    d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = null;
+    cm.setSize();
+  }
+
+  // MOUSE EVENTS
+
+  // Return true when the given mouse event happened in a widget
+  function eventInWidget(display, e) {
+    for (var n = e_target(e); n != display.wrapper; n = n.parentNode) {
+      if (!n || n.ignoreEvents || n.parentNode == display.sizer && n != display.mover) return true;
+    }
+  }
+
+  // Given a mouse event, find the corresponding position. If liberal
+  // is false, it checks whether a gutter or scrollbar was clicked,
+  // and returns null if it was. forRect is used by rectangular
+  // selections, and tries to estimate a character position even for
+  // coordinates beyond the right of the text.
+  function posFromMouse(cm, e, liberal, forRect) {
+    var display = cm.display;
+    if (!liberal) {
+      var target = e_target(e);
+      if (target == display.scrollbarH || target == display.scrollbarV ||
+          target == display.scrollbarFiller || target == display.gutterFiller) return null;
+    }
+    var x, y, space = display.lineSpace.getBoundingClientRect();
+    // Fails unpredictably on IE[67] when mouse is dragged around quickly.
+    try { x = e.clientX - space.left; y = e.clientY - space.top; }
+    catch (e) { return null; }
+    var coords = coordsChar(cm, x, y), line;
+    if (forRect && coords.xRel == 1 && (line = getLine(cm.doc, coords.line).text).length == coords.ch) {
+      var colDiff = countColumn(line, line.length, cm.options.tabSize) - line.length;
+      coords = Pos(coords.line, Math.max(0, Math.round((x - paddingH(cm.display).left) / charWidth(cm.display)) - colDiff));
+    }
+    return coords;
+  }
+
+  // A mouse down can be a single click, double click, triple click,
+  // start of selection drag, start of text drag, new cursor
+  // (ctrl-click), rectangle drag (alt-drag), or xwin
+  // middle-click-paste. Or it might be a click on something we should
+  // not interfere with, such as a scrollbar or widget.
+  function onMouseDown(e) {
+    if (signalDOMEvent(this, e)) return;
+    var cm = this, display = cm.display;
+    display.shift = e.shiftKey;
+
+    if (eventInWidget(display, e)) {
+      if (!webkit) {
+        // Briefly turn off draggability, to allow widgets to do
+        // normal dragging things.
+        display.scroller.draggable = false;
+        setTimeout(function(){display.scroller.draggable = true;}, 100);
+      }
+      return;
+    }
+    if (clickInGutter(cm, e)) return;
+    var start = posFromMouse(cm, e);
+    window.focus();
+
+    switch (e_button(e)) {
+    case 1:
+      if (start)
+        leftButtonDown(cm, e, start);
+      else if (e_target(e) == display.scroller)
+        e_preventDefault(e);
+      break;
+    case 2:
+      if (webkit) cm.state.lastMiddleDown = +new Date;
+      if (start) extendSelection(cm.doc, start);
+      setTimeout(bind(focusInput, cm), 20);
+      e_preventDefault(e);
+      break;
+    case 3:
+      if (captureRightClick) onContextMenu(cm, e);
+      break;
+    }
+  }
+
+  var lastClick, lastDoubleClick;
+  function leftButtonDown(cm, e, start) {
+    setTimeout(bind(ensureFocus, cm), 0);
+
+    var now = +new Date, type;
+    if (lastDoubleClick && lastDoubleClick.time > now - 400 && cmp(lastDoubleClick.pos, start) == 0) {
+      type = "triple";
+    } else if (lastClick && lastClick.time > now - 400 && cmp(lastClick.pos, start) == 0) {
+      type = "double";
+      lastDoubleClick = {time: now, pos: start};
+    } else {
+      type = "single";
+      lastClick = {time: now, pos: start};
+    }
+
+    var sel = cm.doc.sel, modifier = mac ? e.metaKey : e.ctrlKey;
+    if (cm.options.dragDrop && dragAndDrop && !isReadOnly(cm) &&
+        type == "single" && sel.contains(start) > -1 && sel.somethingSelected())
+      leftButtonStartDrag(cm, e, start, modifier);
+    else
+      leftButtonSelect(cm, e, start, type, modifier);
+  }
+
+  // Start a text drag. When it ends, see if any dragging actually
+  // happen, and treat as a click if it didn't.
+  function leftButtonStartDrag(cm, e, start, modifier) {
+    var display = cm.display;
+    var dragEnd = operation(cm, function(e2) {
+      if (webkit) display.scroller.draggable = false;
+      cm.state.draggingText = false;
+      off(document, "mouseup", dragEnd);
+      off(display.scroller, "drop", dragEnd);
+      if (Math.abs(e.clientX - e2.clientX) + Math.abs(e.clientY - e2.clientY) < 10) {
+        e_preventDefault(e2);
+        if (!modifier)
+          extendSelection(cm.doc, start);
+        focusInput(cm);
+        // Work around unexplainable focus problem in IE9 (#2127)
+        if (ie && ie_version == 9)
+          setTimeout(function() {document.body.focus(); focusInput(cm);}, 20);
+      }
+    });
+    // Let the drag handler handle this.
+    if (webkit) display.scroller.draggable = true;
+    cm.state.draggingText = dragEnd;
+    // IE's approach to draggable
+    if (display.scroller.dragDrop) display.scroller.dragDrop();
+    on(document, "mouseup", dragEnd);
+    on(display.scroller, "drop", dragEnd);
+  }
+
+  // Normal selection, as opposed to text dragging.
+  function leftButtonSelect(cm, e, start, type, addNew) {
+    var display = cm.display, doc = cm.doc;
+    e_preventDefault(e);
+
+    var ourRange, ourIndex, startSel = doc.sel;
+    if (addNew && !e.shiftKey) {
+      ourIndex = doc.sel.contains(start);
+      if (ourIndex > -1)
+        ourRange = doc.sel.ranges[ourIndex];
+      else
+        ourRange = new Range(start, start);
+    } else {
+      ourRange = doc.sel.primary();
+    }
+
+    if (e.altKey) {
+      type = "rect";
+      if (!addNew) ourRange = new Range(start, start);
+      start = posFromMouse(cm, e, true, true);
+      ourIndex = -1;
+    } else if (type == "double") {
+      var word = cm.findWordAt(start);
+      if (cm.display.shift || doc.extend)
+        ourRange = extendRange(doc, ourRange, word.anchor, word.head);
+      else
+        ourRange = word;
+    } else if (type == "triple") {
+      var line = new Range(Pos(start.line, 0), clipPos(doc, Pos(start.line + 1, 0)));
+      if (cm.display.shift || doc.extend)
+        ourRange = extendRange(doc, ourRange, line.anchor, line.head);
+      else
+        ourRange = line;
+    } else {
+      ourRange = extendRange(doc, ourRange, start);
+    }
+
+    if (!addNew) {
+      ourIndex = 0;
+      setSelection(doc, new Selection([ourRange], 0), sel_mouse);
+      startSel = doc.sel;
+    } else if (ourIndex > -1) {
+      replaceOneSelection(doc, ourIndex, ourRange, sel_mouse);
+    } else {
+      ourIndex = doc.sel.ranges.length;
+      setSelection(doc, normalizeSelection(doc.sel.ranges.concat([ourRange]), ourIndex),
+                   {scroll: false, origin: "*mouse"});
+    }
+
+    var lastPos = start;
+    function extendTo(pos) {
+      if (cmp(lastPos, pos) == 0) return;
+      lastPos = pos;
+
+      if (type == "rect") {
+        var ranges = [], tabSize = cm.options.tabSize;
+        var startCol = countColumn(getLine(doc, start.line).text, start.ch, tabSize);
+        var posCol = countColumn(getLine(doc, pos.line).text, pos.ch, tabSize);
+        var left = Math.min(startCol, posCol), right = Math.max(startCol, posCol);
+        for (var line = Math.min(start.line, pos.line), end = Math.min(cm.lastLine(), Math.max(start.line, pos.line));
+             line <= end; line++) {
+          var text = getLine(doc, line).text, leftPos = findColumn(text, left, tabSize);
+          if (left == right)
+            ranges.push(new Range(Pos(line, leftPos), Pos(line, leftPos)));
+          else if (text.length > leftPos)
+            ranges.push(new Range(Pos(line, leftPos), Pos(line, findColumn(text, right, tabSize))));
+        }
+        if (!ranges.length) ranges.push(new Range(start, start));
+        setSelection(doc, normalizeSelection(startSel.ranges.slice(0, ourIndex).concat(ranges), ourIndex),
+                     {origin: "*mouse", scroll: false});
+        cm.scrollIntoView(pos);
+      } else {
+        var oldRange = ourRange;
+        var anchor = oldRange.anchor, head = pos;
+        if (type != "single") {
+          if (type == "double")
+            var range = cm.findWordAt(pos);
+          else
+            var range = new Range(Pos(pos.line, 0), clipPos(doc, Pos(pos.line + 1, 0)));
+          if (cmp(range.anchor, anchor) > 0) {
+            head = range.head;
+            anchor = minPos(oldRange.from(), range.anchor);
+          } else {
+            head = range.anchor;
+            anchor = maxPos(oldRange.to(), range.head);
+          }
+        }
+        var ranges = startSel.ranges.slice(0);
+        ranges[ourIndex] = new Range(clipPos(doc, anchor), head);
+        setSelection(doc, normalizeSelection(ranges, ourIndex), sel_mouse);
+      }
+    }
+
+    var editorSize = display.wrapper.getBoundingClientRect();
+    // Used to ensure timeout re-tries don't fire when another extend
+    // happened in the meantime (clearTimeout isn't reliable -- at
+    // least on Chrome, the timeouts still happen even when cleared,
+    // if the clear happens after their scheduled firing time).
+    var counter = 0;
+
+    function extend(e) {
+      var curCount = ++counter;
+      var cur = posFromMouse(cm, e, true, type == "rect");
+      if (!cur) return;
+      if (cmp(cur, lastPos) != 0) {
+        ensureFocus(cm);
+        extendTo(cur);
+        var visible = visibleLines(display, doc);
+        if (cur.line >= visible.to || cur.line < visible.from)
+          setTimeout(operation(cm, function(){if (counter == curCount) extend(e);}), 150);
+      } else {
+        var outside = e.clientY < editorSize.top ? -20 : e.clientY > editorSize.bottom ? 20 : 0;
+        if (outside) setTimeout(operation(cm, function() {
+          if (counter != curCount) return;
+          display.scroller.scrollTop += outside;
+          extend(e);
+        }), 50);
+      }
+    }
+
+    function done(e) {
+      counter = Infinity;
+      e_preventDefault(e);
+      focusInput(cm);
+      off(document, "mousemove", move);
+      off(document, "mouseup", up);
+      doc.history.lastSelOrigin = null;
+    }
+
+    var move = operation(cm, function(e) {
+      if (!e_button(e)) done(e);
+      else extend(e);
+    });
+    var up = operation(cm, done);
+    on(document, "mousemove", move);
+    on(document, "mouseup", up);
+  }
+
+  // Determines whether an event happened in the gutter, and fires the
+  // handlers for the corresponding event.
+  function gutterEvent(cm, e, type, prevent, signalfn) {
+    try { var mX = e.clientX, mY = e.clientY; }
+    catch(e) { return false; }
+    if (mX >= Math.floor(cm.display.gutters.getBoundingClientRect().right)) return false;
+    if (prevent) e_preventDefault(e);
+
+    var display = cm.display;
+    var lineBox = display.lineDiv.getBoundingClientRect();
+
+    if (mY > lineBox.bottom || !hasHandler(cm, type)) return e_defaultPrevented(e);
+    mY -= lineBox.top - display.viewOffset;
+
+    for (var i = 0; i < cm.options.gutters.length; ++i) {
+      var g = display.gutters.childNodes[i];
+      if (g && g.getBoundingClientRect().right >= mX) {
+        var line = lineAtHeight(cm.doc, mY);
+        var gutter = cm.options.gutters[i];
+        signalfn(cm, type, cm, line, gutter, e);
+        return e_defaultPrevented(e);
+      }
+    }
+  }
+
+  function clickInGutter(cm, e) {
+    return gutterEvent(cm, e, "gutterClick", true, signalLater);
+  }
+
+  // Kludge to work around strange IE behavior where it'll sometimes
+  // re-fire a series of drag-related events right after the drop (#1551)
+  var lastDrop = 0;
+
+  function onDrop(e) {
+    var cm = this;
+    if (signalDOMEvent(cm, e) || eventInWidget(cm.display, e))
+      return;
+    e_preventDefault(e);
+    if (ie) lastDrop = +new Date;
+    var pos = posFromMouse(cm, e, true), files = e.dataTransfer.files;
+    if (!pos || isReadOnly(cm)) return;
+    // Might be a file drop, in which case we simply extract the text
+    // and insert it.
+    if (files && files.length && window.FileReader && window.File) {
+      var n = files.length, text = Array(n), read = 0;
+      var loadFile = function(file, i) {
+        var reader = new FileReader;
+        reader.onload = operation(cm, function() {
+          text[i] = reader.result;
+          if (++read == n) {
+            pos = clipPos(cm.doc, pos);
+            var change = {from: pos, to: pos, text: splitLines(text.join("\n")), origin: "paste"};
+            makeChange(cm.doc, change);
+            setSelectionReplaceHistory(cm.doc, simpleSelection(pos, changeEnd(change)));
+          }
+        });
+        reader.readAsText(file);
+      };
+      for (var i = 0; i < n; ++i) loadFile(files[i], i);
+    } else { // Normal drop
+      // Don't do a replace if the drop happened inside of the selected text.
+      if (cm.state.draggingText && cm.doc.sel.contains(pos) > -1) {
+        cm.state.draggingText(e);
+        // Ensure the editor is re-focused
+        setTimeout(bind(focusInput, cm), 20);
+        return;
+      }
+      try {
+        var text = e.dataTransfer.getData("Text");
+        if (text) {
+          if (cm.state.draggingText && !(mac ? e.metaKey : e.ctrlKey))
+            var selected = cm.listSelections();
+          setSelectionNoUndo(cm.doc, simpleSelection(pos, pos));
+          if (selected) for (var i = 0; i < selected.length; ++i)
+            replaceRange(cm.doc, "", selected[i].anchor, selected[i].head, "drag");
+          cm.replaceSelection(text, "around", "paste");
+          focusInput(cm);
+        }
+      }
+      catch(e){}
+    }
+  }
+
+  function onDragStart(cm, e) {
+    if (ie && (!cm.state.draggingText || +new Date - lastDrop < 100)) { e_stop(e); return; }
+    if (signalDOMEvent(cm, e) || eventInWidget(cm.display, e)) return;
+
+    e.dataTransfer.setData("Text", cm.getSelection());
+
+    // Use dummy image instead of default browsers image.
+    // Recent Safari (~6.0.2) have a tendency to segfault when this happens, so we don't do it there.
+    if (e.dataTransfer.setDragImage && !safari) {
+      var img = elt("img", null, null, "position: fixed; left: 0; top: 0;");
+      img.src = "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==";
+      if (presto) {
+        img.width = img.height = 1;
+        cm.display.wrapper.appendChild(img);
+        // Force a relayout, or Opera won't use our image for some obscure reason
+        img._top = img.offsetTop;
+      }
+      e.dataTransfer.setDragImage(img, 0, 0);
+      if (presto) img.parentNode.removeChild(img);
+    }
+  }
+
+  // SCROLL EVENTS
+
+  // Sync the scrollable area and scrollbars, ensure the viewport
+  // covers the visible area.
+  function setScrollTop(cm, val) {
+    if (Math.abs(cm.doc.scrollTop - val) < 2) return;
+    cm.doc.scrollTop = val;
+    if (!gecko) updateDisplaySimple(cm, {top: val});
+    if (cm.display.scroller.scrollTop != val) cm.display.scroller.scrollTop = val;
+    if (cm.display.scrollbarV.scrollTop != val) cm.display.scrollbarV.scrollTop = val;
+    if (gecko) updateDisplaySimple(cm);
+    startWorker(cm, 100);
+  }
+  // Sync scroller and scrollbar, ensure the gutter elements are
+  // aligned.
+  function setScrollLeft(cm, val, isScroller) {
+    if (isScroller ? val == cm.doc.scrollLeft : Math.abs(cm.doc.scrollLeft - val) < 2) return;
+    val = Math.min(val, cm.display.scroller.scrollWidth - cm.display.scroller.clientWidth);
+    cm.doc.scrollLeft = val;
+    alignHorizontally(cm);
+    if (cm.display.scroller.scrollLeft != val) cm.display.scroller.scrollLeft = val;
+    if (cm.display.scrollbarH.scrollLeft != val) cm.display.scrollbarH.scrollLeft = val;
+  }
+
+  // Since the delta values reported on mouse wheel events are
+  // unstandardized between browsers and even browser versions, and
+  // generally horribly unpredictable, this code starts by measuring
+  // the scroll effect that the first few mouse wheel events have,
+  // and, from that, detects the way it can convert deltas to pixel
+  // offsets afterwards.
+  //
+  // The reason we want to know the amount a wheel event will scroll
+  // is that it gives us a chance to update the display before the
+  // actual scrolling happens, reducing flickering.
+
+  var wheelSamples = 0, wheelPixelsPerUnit = null;
+  // Fill in a browser-detected starting value on browsers where we
+  // know one. These don't have to be accurate -- the result of them
+  // being wrong would just be a slight flicker on the first wheel
+  // scroll (if it is large enough).
+  if (ie) wheelPixelsPerUnit = -.53;
+  else if (gecko) wheelPixelsPerUnit = 15;
+  else if (chrome) wheelPixelsPerUnit = -.7;
+  else if (safari) wheelPixelsPerUnit = -1/3;
+
+  function onScrollWheel(cm, e) {
+    var dx = e.wheelDeltaX, dy = e.wheelDeltaY;
+    if (dx == null && e.detail && e.axis == e.HORIZONTAL_AXIS) dx = e.detail;
+    if (dy == null && e.detail && e.axis == e.VERTICAL_AXIS) dy = e.detail;
+    else if (dy == null) dy = e.wheelDelta;
+
+    var display = cm.display, scroll = display.scroller;
+    // Quit if there's nothing to scroll here
+    if (!(dx && scroll.scrollWidth > scroll.clientWidth ||
+          dy && scroll.scrollHeight > scroll.clientHeight)) return;
+
+    // Webkit browsers on OS X abort momentum scrolls when the target
+    // of the scroll event is removed from the scrollable element.
+    // This hack (see related code in patchDisplay) makes sure the
+    // element is kept around.
+    if (dy && mac && webkit) {
+      outer: for (var cur = e.target, view = display.view; cur != scroll; cur = cur.parentNode) {
+        for (var i = 0; i < view.length; i++) {
+          if (view[i].node == cur) {
+            cm.display.currentWheelTarget = cur;
+            break outer;
+          }
+        }
+      }
+    }
+
+    // On some browsers, horizontal scrolling will cause redraws to
+    // happen before the gutter has been realigned, causing it to
+    // wriggle around in a most unseemly way. When we have an
+    // estimated pixels/delta value, we just handle horizontal
+    // scrolling entirely here. It'll be slightly off from native, but
+    // better than glitching out.
+    if (dx && !gecko && !presto && wheelPixelsPerUnit != null) {
+      if (dy)
+        setScrollTop(cm, Math.max(0, Math.min(scroll.scrollTop + dy * wheelPixelsPerUnit, scroll.scrollHeight - scroll.clientHeight)));
+      setScrollLeft(cm, Math.max(0, Math.min(scroll.scrollLeft + dx * wheelPixelsPerUnit, scroll.scrollWidth - scroll.clientWidth)));
+      e_preventDefault(e);
+      display.wheelStartX = null; // Abort measurement, if in progress
+      return;
+    }
+
+    // 'Project' the visible viewport to cover the area that is being
+    // scrolled into view (if we know enough to estimate it).
+    if (dy && wheelPixelsPerUnit != null) {
+      var pixels = dy * wheelPixelsPerUnit;
+      var top = cm.doc.scrollTop, bot = top + display.wrapper.clientHeight;
+      if (pixels < 0) top = Math.max(0, top + pixels - 50);
+      else bot = Math.min(cm.doc.height, bot + pixels + 50);
+      updateDisplaySimple(cm, {top: top, bottom: bot});
+    }
+
+    if (wheelSamples < 20) {
+      if (display.wheelStartX == null) {
+        display.wheelStartX = scroll.scrollLeft; display.wheelStartY = scroll.scrollTop;
+        display.wheelDX = dx; display.wheelDY = dy;
+        setTimeout(function() {
+          if (display.wheelStartX == null) return;
+          var movedX = scroll.scrollLeft - display.wheelStartX;
+          var movedY = scroll.scrollTop - display.wheelStartY;
+          var sample = (movedY && display.wheelDY && movedY / display.wheelDY) ||
+            (movedX && display.wheelDX && movedX / display.wheelDX);
+          display.wheelStartX = display.wheelStartY = null;
+          if (!sample) return;
+          wheelPixelsPerUnit = (wheelPixelsPerUnit * wheelSamples + sample) / (wheelSamples + 1);
+          ++wheelSamples;
+        }, 200);
+      } else {
+        display.wheelDX += dx; display.wheelDY += dy;
+      }
+    }
+  }
+
+  // KEY EVENTS
+
+  // Run a handler that was bound to a key.
+  function doHandleBinding(cm, bound, dropShift) {
+    if (typeof bound == "string") {
+      bound = commands[bound];
+      if (!bound) return false;
+    }
+    // Ensure previous input has been read, so that the handler sees a
+    // consistent view of the document
+    if (cm.display.pollingFast && readInput(cm)) cm.display.pollingFast = false;
+    var prevShift = cm.display.shift, done = false;
+    try {
+      if (isReadOnly(cm)) cm.state.suppressEdits = true;
+      if (dropShift) cm.display.shift = false;
+      done = bound(cm) != Pass;
+    } finally {
+      cm.display.shift = prevShift;
+      cm.state.suppressEdits = false;
+    }
+    return done;
+  }
+
+  function lookupKeyForEditor(cm, name, handle) {
+    for (var i = 0; i < cm.state.keyMaps.length; i++) {
+      var result = lookupKey(name, cm.state.keyMaps[i], handle);
+      if (result) return result;
+    }
+    return (cm.options.extraKeys && lookupKey(name, cm.options.extraKeys, handle))
+      || lookupKey(name, cm.options.keyMap, handle);
+  }
+
+  var stopSeq = new Delayed;
+  function dispatchKey(cm, name, e, handle) {
+    var seq = cm.state.keySeq;
+    if (seq) {
+      if (isModifierKey(name)) return "handled";
+      stopSeq.set(50, function() {
+        if (cm.state.keySeq == seq) {
+          cm.state.keySeq = null;
+          resetInput(cm);
+        }
+      });
+      name = seq + " " + name;
+    }
+    var result = lookupKeyForEditor(cm, name, handle);
+
+    if (result == "multi")
+      cm.state.keySeq = name;
+    if (result == "handled")
+      signalLater(cm, "keyHandled", cm, name, e);
+
+    if (result == "handled" || result == "multi") {
+      e_preventDefault(e);
+      restartBlink(cm);
+    }
+
+    if (seq && !result && /\'$/.test(name)) {
+      e_preventDefault(e);
+      return true;
+    }
+    return !!result;
+  }
+
+  // Handle a key from the keydown event.
+  function handleKeyBinding(cm, e) {
+    var name = keyName(e, true);
+    if (!name) return false;
+
+    if (e.shiftKey && !cm.state.keySeq) {
+      // First try to resolve full name (including 'Shift-'). Failing
+      // that, see if there is a cursor-motion command (starting with
+      // 'go') bound to the keyname without 'Shift-'.
+      return dispatchKey(cm, "Shift-" + name, e, function(b) {return doHandleBinding(cm, b, true);})
+          || dispatchKey(cm, name, e, function(b) {
+               if (typeof b == "string" ? /^go[A-Z]/.test(b) : b.motion)
+                 return doHandleBinding(cm, b);
+             });
+    } else {
+      return dispatchKey(cm, name, e, function(b) { return doHandleBinding(cm, b); });
+    }
+  }
+
+  // Handle a key from the keypress event
+  function handleCharBinding(cm, e, ch) {
+    return dispatchKey(cm, "'" + ch + "'", e,
+                       function(b) { return doHandleBinding(cm, b, true); });
+  }
+
+  var lastStoppedKey = null;
+  function onKeyDown(e) {
+    var cm = this;
+    ensureFocus(cm);
+    if (signalDOMEvent(cm, e)) return;
+    // IE does strange things with escape.
+    if (ie && ie_version < 11 && e.keyCode == 27) e.returnValue = false;
+    var code = e.keyCode;
+    cm.display.shift = code == 16 || e.shiftKey;
+    var handled = handleKeyBinding(cm, e);
+    if (presto) {
+      lastStoppedKey = handled ? code : null;
+      // Opera has no cut event... we try to at least catch the key combo
+      if (!handled && code == 88 && !hasCopyEvent && (mac ? e.metaKey : e.ctrlKey))
+        cm.replaceSelection("", null, "cut");
+    }
+
+    // Turn mouse into crosshair when Alt is held on Mac.
+    if (code == 18 && !/\bCodeMirror-crosshair\b/.test(cm.display.lineDiv.className))
+      showCrossHair(cm);
+  }
+
+  function showCrossHair(cm) {
+    var lineDiv = cm.display.lineDiv;
+    addClass(lineDiv, "CodeMirror-crosshair");
+
+    function up(e) {
+      if (e.keyCode == 18 || !e.altKey) {
+        rmClass(lineDiv, "CodeMirror-crosshair");
+        off(document, "keyup", up);
+        off(document, "mouseover", up);
+      }
+    }
+    on(document, "keyup", up);
+    on(document, "mouseover", up);
+  }
+
+  function onKeyUp(e) {
+    if (e.keyCode == 16) this.doc.sel.shift = false;
+    signalDOMEvent(this, e);
+  }
+
+  function onKeyPress(e) {
+    var cm = this;
+    if (signalDOMEvent(cm, e) || e.ctrlKey && !e.altKey || mac && e.metaKey) return;
+    var keyCode = e.keyCode, charCode = e.charCode;
+    if (presto && keyCode == lastStoppedKey) {lastStoppedKey = null; e_preventDefault(e); return;}
+    if (((presto && (!e.which || e.which < 10)) || khtml) && handleKeyBinding(cm, e)) return;
+    var ch = String.fromCharCode(charCode == null ? keyCode : charCode);
+    if (handleCharBinding(cm, e, ch)) return;
+    if (ie && ie_version >= 9) cm.display.inputHasSelection = null;
+    fastPoll(cm);
+  }
+
+  // FOCUS/BLUR EVENTS
+
+  function onFocus(cm) {
+    if (cm.options.readOnly == "nocursor") return;
+    if (!cm.state.focused) {
+      signal(cm, "focus", cm);
+      cm.state.focused = true;
+      addClass(cm.display.wrapper, "CodeMirror-focused");
+      // The prevInput test prevents this from firing when a context
+      // menu is closed (since the resetInput would kill the
+      // select-all detection hack)
+      if (!cm.curOp && cm.display.selForContextMenu != cm.doc.sel) {
+        resetInput(cm);
+        if (webkit) setTimeout(bind(resetInput, cm, true), 0); // Issue #1730
+      }
+    }
+    slowPoll(cm);
+    restartBlink(cm);
+  }
+  function onBlur(cm) {
+    if (cm.state.focused) {
+      signal(cm, "blur", cm);
+      cm.state.focused = false;
+      rmClass(cm.display.wrapper, "CodeMirror-focused");
+    }
+    clearInterval(cm.display.blinker);
+    setTimeout(function() {if (!cm.state.focused) cm.display.shift = false;}, 150);
+  }
+
+  // CONTEXT MENU HANDLING
+
+  // To make the context menu work, we need to briefly unhide the
+  // textarea (making it as unobtrusive as possible) to let the
+  // right-click take effect on it.
+  function onContextMenu(cm, e) {
+    if (signalDOMEvent(cm, e, "contextmenu")) return;
+    var display = cm.display;
+    if (eventInWidget(display, e) || contextMenuInGutter(cm, e)) return;
+
+    var pos = posFromMouse(cm, e), scrollPos = display.scroller.scrollTop;
+    if (!pos || presto) return; // Opera is difficult.
+
+    // Reset the current text selection only if the click is done outside of the selection
+    // and 'resetSelectionOnContextMenu' option is true.
+    var reset = cm.options.resetSelectionOnContextMenu;
+    if (reset && cm.doc.sel.contains(pos) == -1)
+      operation(cm, setSelection)(cm.doc, simpleSelection(pos), sel_dontScroll);
+
+    var oldCSS = display.input.style.cssText;
+    display.inputDiv.style.position = "absolute";
+    display.input.style.cssText = "position: fixed; width: 30px; height: 30px; top: " + (e.clientY - 5) +
+      "px; left: " + (e.clientX - 5) + "px; z-index: 1000; background: " +
+      (ie ? "rgba(255, 255, 255, .05)" : "transparent") +
+      "; outline: none; border-width: 0; outline: none; overflow: hidden; opacity: .05; filter: alpha(opacity=5);";
+    if (webkit) var oldScrollY = window.scrollY; // Work around Chrome issue (#2712)
+    focusInput(cm);
+    if (webkit) window.scrollTo(null, oldScrollY);
+    resetInput(cm);
+    // Adds "Select all" to context menu in FF
+    if (!cm.somethingSelected()) display.input.value = display.prevInput = " ";
+    display.selForContextMenu = cm.doc.sel;
+    clearTimeout(display.detectingSelectAll);
+
+    // Select-all will be greyed out if there's nothing to select, so
+    // this adds a zero-width space so that we can later check whether
+    // it got selected.
+    function prepareSelectAllHack() {
+      if (display.input.selectionStart != null) {
+        var selected = cm.somethingSelected();
+        var extval = display.input.value = "\u200b" + (selected ? display.input.value : "");
+        display.prevInput = selected ? "" : "\u200b";
+        display.input.selectionStart = 1; display.input.selectionEnd = extval.length;
+        // Re-set this, in case some other handler touched the
+        // selection in the meantime.
+        display.selForContextMenu = cm.doc.sel;
+      }
+    }
+    function rehide() {
+      display.inputDiv.style.position = "relative";
+      display.input.style.cssText = oldCSS;
+      if (ie && ie_version < 9) display.scrollbarV.scrollTop = display.scroller.scrollTop = scrollPos;
+      slowPoll(cm);
+
+      // Try to detect the user choosing select-all
+      if (display.input.selectionStart != null) {
+        if (!ie || (ie && ie_version < 9)) prepareSelectAllHack();
+        var i = 0, poll = function() {
+          if (display.selForContextMenu == cm.doc.sel && display.input.selectionStart == 0)
+            operation(cm, commands.selectAll)(cm);
+          else if (i++ < 10) display.detectingSelectAll = setTimeout(poll, 500);
+          else resetInput(cm);
+        };
+        display.detectingSelectAll = setTimeout(poll, 200);
+      }
+    }
+
+    if (ie && ie_version >= 9) prepareSelectAllHack();
+    if (captureRightClick) {
+      e_stop(e);
+      var mouseup = function() {
+        off(window, "mouseup", mouseup);
+        setTimeout(rehide, 20);
+      };
+      on(window, "mouseup", mouseup);
+    } else {
+      setTimeout(rehide, 50);
+    }
+  }
+
+  function contextMenuInGutter(cm, e) {
+    if (!hasHandler(cm, "gutterContextMenu")) return false;
+    return gutterEvent(cm, e, "gutterContextMenu", false, signal);
+  }
+
+  // UPDATING
+
+  // Compute the position of the end of a change (its 'to' property
+  // refers to the pre-change end).
+  var changeEnd = CodeMirror.changeEnd = function(change) {
+    if (!change.text) return change.to;
+    return Pos(change.from.line + change.text.length - 1,
+               lst(change.text).length + (change.text.length == 1 ? change.from.ch : 0));
+  };
+
+  // Adjust a position to refer to the post-change position of the
+  // same text, or the end of the change if the change covers it.
+  function adjustForChange(pos, change) {
+    if (cmp(pos, change.from) < 0) return pos;
+    if (cmp(pos, change.to) <= 0) return changeEnd(change);
+
+    var line = pos.line + change.text.length - (change.to.line - change.from.line) - 1, ch = pos.ch;
+    if (pos.line == change.to.line) ch += changeEnd(change).ch - change.to.ch;
+    return Pos(line, ch);
+  }
+
+  function computeSelAfterChange(doc, change) {
+    var out = [];
+    for (var i = 0; i < doc.sel.ranges.length; i++) {
+      var range = doc.sel.ranges[i];
+      out.push(new Range(adjustForChange(range.anchor, change),
+                         adjustForChange(range.head, change)));
+    }
+    return normalizeSelection(out, doc.sel.primIndex);
+  }
+
+  function offsetPos(pos, old, nw) {
+    if (pos.line == old.line)
+      return Pos(nw.line, pos.ch - old.ch + nw.ch);
+    else
+      return Pos(nw.line + (pos.line - old.line), pos.ch);
+  }
+
+  // Used by replaceSelections to allow moving the selection to the
+  // start or around the replaced test. Hint may be "start" or "around".
+  function computeReplacedSel(doc, changes, hint) {
+    var out = [];
+    var oldPrev = Pos(doc.first, 0), newPrev = oldPrev;
+    for (var i = 0; i < changes.length; i++) {
+      var change = changes[i];
+      var from = offsetPos(change.from, oldPrev, newPrev);
+      var to = offsetPos(changeEnd(change), oldPrev, newPrev);
+      oldPrev = change.to;
+      newPrev = to;
+      if (hint == "around") {
+        var range = doc.sel.ranges[i], inv = cmp(range.head, range.anchor) < 0;
+        out[i] = new Range(inv ? to : from, inv ? from : to);
+      } else {
+        out[i] = new Range(from, from);
+      }
+    }
+    return new Selection(out, doc.sel.primIndex);
+  }
+
+  // Allow "beforeChange" event handlers to influence a change
+  function filterChange(doc, change, update) {
+    var obj = {
+      canceled: false,
+      from: change.from,
+      to: change.to,
+      text: change.text,
+      origin: change.origin,
+      cancel: function() { this.canceled = true; }
+    };
+    if (update) obj.update = function(from, to, text, origin) {
+      if (from) this.from = clipPos(doc, from);
+      if (to) this.to = clipPos(doc, to);
+      if (text) this.text = text;
+      if (origin !== undefined) this.origin = origin;
+    };
+    signal(doc, "beforeChange", doc, obj);
+    if (doc.cm) signal(doc.cm, "beforeChange", doc.cm, obj);
+
+    if (obj.canceled) return null;
+    return {from: obj.from, to: obj.to, text: obj.text, origin: obj.origin};
+  }
+
+  // Apply a change to a document, and add it to the document's
+  // history, and propagating it to all linked documents.
+  function makeChange(doc, change, ignoreReadOnly) {
+    if (doc.cm) {
+      if (!doc.cm.curOp) return operation(doc.cm, makeChange)(doc, change, ignoreReadOnly);
+      if (doc.cm.state.suppressEdits) return;
+    }
+
+    if (hasHandler(doc, "beforeChange") || doc.cm && hasHandler(doc.cm, "beforeChange")) {
+      change = filterChange(doc, change, true);
+      if (!change) return;
+    }
+
+    // Possibly split or suppress the update based on the presence
+    // of read-only spans in its range.
+    var split = sawReadOnlySpans && !ignoreReadOnly && removeReadOnlyRanges(doc, change.from, change.to);
+    if (split) {
+      for (var i = split.length - 1; i >= 0; --i)
+        makeChangeInner(doc, {from: split[i].from, to: split[i].to, text: i ? [""] : change.text});
+    } else {
+      makeChangeInner(doc, change);
+    }
+  }
+
+  function makeChangeInner(doc, change) {
+    if (change.text.length == 1 && change.text[0] == "" && cmp(change.from, change.to) == 0) return;
+    var selAfter = computeSelAfterChange(doc, change);
+    addChangeToHistory(doc, change, selAfter, doc.cm ? doc.cm.curOp.id : NaN);
+
+    makeChangeSingleDoc(doc, change, selAfter, stretchSpansOverChange(doc, change));
+    var rebased = [];
+
+    linkedDocs(doc, function(doc, sharedHist) {
+      if (!sharedHist && indexOf(rebased, doc.history) == -1) {
+        rebaseHist(doc.history, change);
+        rebased.push(doc.history);
+      }
+      makeChangeSingleDoc(doc, change, null, stretchSpansOverChange(doc, change));
+    });
+  }
+
+  // Revert a change stored in a document's history.
+  function makeChangeFromHistory(doc, type, allowSelectionOnly) {
+    if (doc.cm && doc.cm.state.suppressEdits) return;
+
+    var hist = doc.history, event, selAfter = doc.sel;
+    var source = type == "undo" ? hist.done : hist.undone, dest = type == "undo" ? hist.undone : hist.done;
+
+    // Verify that there is a useable event (so that ctrl-z won't
+    // needlessly clear selection events)
+    for (var i = 0; i < source.length; i++) {
+      event = source[i];
+      if (allowSelectionOnly ? event.ranges && !event.equals(doc.sel) : !event.ranges)
+        break;
+    }
+    if (i == source.length) return;
+    hist.lastOrigin = hist.lastSelOrigin = null;
+
+    for (;;) {
+      event = source.pop();
+      if (event.ranges) {
+        pushSelectionToHistory(event, dest);
+        if (allowSelectionOnly && !event.equals(doc.sel)) {
+          setSelection(doc, event, {clearRedo: false});
+          return;
+        }
+        selAfter = event;
+      }
+      else break;
+    }
+
+    // Build up a reverse change object to add to the opposite history
+    // stack (redo when undoing, and vice versa).
+    var antiChanges = [];
+    pushSelectionToHistory(selAfter, dest);
+    dest.push({changes: antiChanges, generation: hist.generation});
+    hist.generation = event.generation || ++hist.maxGeneration;
+
+    var filter = hasHandler(doc, "beforeChange") || doc.cm && hasHandler(doc.cm, "beforeChange");
+
+    for (var i = event.changes.length - 1; i >= 0; --i) {
+      var change = event.changes[i];
+      change.origin = type;
+      if (filter && !filterChange(doc, change, false)) {
+        source.length = 0;
+        return;
+      }
+
+      antiChanges.push(historyChangeFromChange(doc, change));
+
+      var after = i ? computeSelAfterChange(doc, change) : lst(source);
+      makeChangeSingleDoc(doc, change, after, mergeOldSpans(doc, change));
+      if (!i && doc.cm) doc.cm.scrollIntoView({from: change.from, to: changeEnd(change)});
+      var rebased = [];
+
+      // Propagate to the linked documents
+      linkedDocs(doc, function(doc, sharedHist) {
+        if (!sharedHist && indexOf(rebased, doc.history) == -1) {
+          rebaseHist(doc.history, change);
+          rebased.push(doc.history);
+        }
+        makeChangeSingleDoc(doc, change, null, mergeOldSpans(doc, change));
+      });
+    }
+  }
+
+  // Sub-views need their line numbers shifted when text is added
+  // above or below them in the parent document.
+  function shiftDoc(doc, distance) {
+    if (distance == 0) return;
+    doc.first += distance;
+    doc.sel = new Selection(map(doc.sel.ranges, function(range) {
+      return new Range(Pos(range.anchor.line + distance, range.anchor.ch),
+                       Pos(range.head.line + distance, range.head.ch));
+    }), doc.sel.primIndex);
+    if (doc.cm) {
+      regChange(doc.cm, doc.first, doc.first - distance, distance);
+      for (var d = doc.cm.display, l = d.viewFrom; l < d.viewTo; l++)
+        regLineChange(doc.cm, l, "gutter");
+    }
+  }
+
+  // More lower-level change function, handling only a single document
+  // (not linked ones).
+  function makeChangeSingleDoc(doc, change, selAfter, spans) {
+    if (doc.cm && !doc.cm.curOp)
+      return operation(doc.cm, makeChangeSingleDoc)(doc, change, selAfter, spans);
+
+    if (change.to.line < doc.first) {
+      shiftDoc(doc, change.text.length - 1 - (change.to.line - change.from.line));
+      return;
+    }
+    if (change.from.line > doc.lastLine()) return;
+
+    // Clip the change to the size of this doc
+    if (change.from.line < doc.first) {
+      var shift = change.text.length - 1 - (doc.first - change.from.line);
+      shiftDoc(doc, shift);
+      change = {from: Pos(doc.first, 0), to: Pos(change.to.line + shift, change.to.ch),
+                text: [lst(change.text)], origin: change.origin};
+    }
+    var last = doc.lastLine();
+    if (change.to.line > last) {
+      change = {from: change.from, to: Pos(last, getLine(doc, last).text.length),
+                text: [change.text[0]], origin: change.origin};
+    }
+
+    change.removed = getBetween(doc, change.from, change.to);
+
+    if (!selAfter) selAfter = computeSelAfterChange(doc, change);
+    if (doc.cm) makeChangeSingleDocInEditor(doc.cm, change, spans);
+    else updateDoc(doc, change, spans);
+    setSelectionNoUndo(doc, selAfter, sel_dontScroll);
+  }
+
+  // Handle the interaction of a change to a document with the editor
+  // that this document is part of.
+  function makeChangeSingleDocInEditor(cm, change, spans) {
+    var doc = cm.doc, display = cm.display, from = change.from, to = change.to;
+
+    var recomputeMaxLength = false, checkWidthStart = from.line;
+    if (!cm.options.lineWrapping) {
+      checkWidthStart = lineNo(visualLine(getLine(doc, from.line)));
+      doc.iter(checkWidthStart, to.line + 1, function(line) {
+        if (line == display.maxLine) {
+          recomputeMaxLength = true;
+          return true;
+        }
+      });
+    }
+
+    if (doc.sel.contains(change.from, change.to) > -1)
+      signalCursorActivity(cm);
+
+    updateDoc(doc, change, spans, estimateHeight(cm));
+
+    if (!cm.options.lineWrapping) {
+      doc.iter(checkWidthStart, from.line + change.text.length, function(line) {
+        var len = lineLength(line);
+        if (len > display.maxLineLength) {
+          display.maxLine = line;
+          display.maxLineLength = len;
+          display.maxLineChanged = true;
+          recomputeMaxLength = false;
+        }
+      });
+      if (recomputeMaxLength) cm.curOp.updateMaxLine = true;
+    }
+
+    // Adjust frontier, schedule worker
+    doc.frontier = Math.min(doc.frontier, from.line);
+    startWorker(cm, 400);
+
+    var lendiff = change.text.length - (to.line - from.line) - 1;
+    // Remember that these lines changed, for updating the display
+    if (from.line == to.line && change.text.length == 1 && !isWholeLineUpdate(cm.doc, change))
+      regLineChange(cm, from.line, "text");
+    else
+      regChange(cm, from.line, to.line + 1, lendiff);
+
+    var changesHandler = hasHandler(cm, "changes"), changeHandler = hasHandler(cm, "change");
+    if (changeHandler || changesHandler) {
+      var obj = {
+        from: from, to: to,
+        text: change.text,
+        removed: change.removed,
+        origin: change.origin
+      };
+      if (changeHandler) signalLater(cm, "change", cm, obj);
+      if (changesHandler) (cm.curOp.changeObjs || (cm.curOp.changeObjs = [])).push(obj);
+    }
+    cm.display.selForContextMenu = null;
+  }
+
+  function replaceRange(doc, code, from, to, origin) {
+    if (!to) to = from;
+    if (cmp(to, from) < 0) { var tmp = to; to = from; from = tmp; }
+    if (typeof code == "string") code = splitLines(code);
+    makeChange(doc, {from: from, to: to, text: code, origin: origin});
+  }
+
+  // SCROLLING THINGS INTO VIEW
+
+  // If an editor sits on the top or bottom of the window, partially
+  // scrolled out of view, this ensures that the cursor is visible.
+  function maybeScrollWindow(cm, coords) {
+    if (signalDOMEvent(cm, "scrollCursorIntoView")) return;
+
+    var display = cm.display, box = display.sizer.getBoundingClientRect(), doScroll = null;
+    if (coords.top + box.top < 0) doScroll = true;
+    else if (coords.bottom + box.top > (window.innerHeight || document.documentElement.clientHeight)) doScroll = false;
+    if (doScroll != null && !phantom) {
+      var scrollNode = elt("div", "\u200b", null, "position: absolute; top: " +
+                           (coords.top - display.viewOffset - paddingTop(cm.display)) + "px; height: " +
+                           (coords.bottom - coords.top + scrollerCutOff) + "px; left: " +
+                           coords.left + "px; width: 2px;");
+      cm.display.lineSpace.appendChild(scrollNode);
+      scrollNode.scrollIntoView(doScroll);
+      cm.display.lineSpace.removeChild(scrollNode);
+    }
+  }
+
+  // Scroll a given position into view (immediately), verifying that
+  // it actually became visible (as line heights are accurately
+  // measured, the position of something may 'drift' during drawing).
+  function scrollPosIntoView(cm, pos, end, margin) {
+    if (margin == null) margin = 0;
+    for (var limit = 0; limit < 5; limit++) {
+      var changed = false, coords = cursorCoords(cm, pos);
+      var endCoords = !end || end == pos ? coords : cursorCoords(cm, end);
+      var scrollPos = calculateScrollPos(cm, Math.min(coords.left, endCoords.left),
+                                         Math.min(coords.top, endCoords.top) - margin,
+                                         Math.max(coords.left, endCoords.left),
+                                         Math.max(coords.bottom, endCoords.bottom) + margin);
+      var startTop = cm.doc.scrollTop, startLeft = cm.doc.scrollLeft;
+      if (scrollPos.scrollTop != null) {
+        setScrollTop(cm, scrollPos.scrollTop);
+        if (Math.abs(cm.doc.scrollTop - startTop) > 1) changed = true;
+      }
+      if (scrollPos.scrollLeft != null) {
+        setScrollLeft(cm, scrollPos.scrollLeft);
+        if (Math.abs(cm.doc.scrollLeft - startLeft) > 1) changed = true;
+      }
+      if (!changed) return coords;
+    }
+  }
+
+  // Scroll a given set of coordinates into view (immediately).
+  function scrollIntoView(cm, x1, y1, x2, y2) {
+    var scrollPos = calculateScrollPos(cm, x1, y1, x2, y2);
+    if (scrollPos.scrollTop != null) setScrollTop(cm, scrollPos.scrollTop);
+    if (scrollPos.scrollLeft != null) setScrollLeft(cm, scrollPos.scrollLeft);
+  }
+
+  // Calculate a new scroll position needed to scroll the given
+  // rectangle into view. Returns an object with scrollTop and
+  // scrollLeft properties. When these are undefined, the
+  // vertical/horizontal position does not need to be adjusted.
+  function calculateScrollPos(cm, x1, y1, x2, y2) {
+    var display = cm.display, snapMargin = textHeight(cm.display);
+    if (y1 < 0) y1 = 0;
+    var screentop = cm.curOp && cm.curOp.scrollTop != null ? cm.curOp.scrollTop : display.scroller.scrollTop;
+    var screen = display.scroller.clientHeight - scrollerCutOff, result = {};
+    if (y2 - y1 > screen) y2 = y1 + screen;
+    var docBottom = cm.doc.height + paddingVert(display);
+    var atTop = y1 < snapMargin, atBottom = y2 > docBottom - snapMargin;
+    if (y1 < screentop) {
+      result.scrollTop = atTop ? 0 : y1;
+    } else if (y2 > screentop + screen) {
+      var newTop = Math.min(y1, (atBottom ? docBottom : y2) - screen);
+      if (newTop != screentop) result.scrollTop = newTop;
+    }
+
+    var screenleft = cm.curOp && cm.curOp.scrollLeft != null ? cm.curOp.scrollLeft : display.scroller.scrollLeft;
+    var screenw = display.scroller.clientWidth - scrollerCutOff - display.gutters.offsetWidth;
+    var tooWide = x2 - x1 > screenw;
+    if (tooWide) x2 = x1 + screenw;
+    if (x1 < 10)
+      result.scrollLeft = 0;
+    else if (x1 < screenleft)
+      result.scrollLeft = Math.max(0, x1 - (tooWide ? 0 : 10));
+    else if (x2 > screenw + screenleft - 3)
+      result.scrollLeft = x2 + (tooWide ? 0 : 10) - screenw;
+
+    return result;
+  }
+
+  // Store a relative adjustment to the scroll position in the current
+  // operation (to be applied when the operation finishes).
+  function addToScrollPos(cm, left, top) {
+    if (left != null || top != null) resolveScrollToPos(cm);
+    if (left != null)
+      cm.curOp.scrollLeft = (cm.curOp.scrollLeft == null ? cm.doc.scrollLeft : cm.curOp.scrollLeft) + left;
+    if (top != null)
+      cm.curOp.scrollTop = (cm.curOp.scrollTop == null ? cm.doc.scrollTop : cm.curOp.scrollTop) + top;
+  }
+
+  // Make sure that at the end of the operation the current cursor is
+  // shown.
+  function ensureCursorVisible(cm) {
+    resolveScrollToPos(cm);
+    var cur = cm.getCursor(), from = cur, to = cur;
+    if (!cm.options.lineWrapping) {
+      from = cur.ch ? Pos(cur.line, cur.ch - 1) : cur;
+      to = Pos(cur.line, cur.ch + 1);
+    }
+    cm.curOp.scrollToPos = {from: from, to: to, margin: cm.options.cursorScrollMargin, isCursor: true};
+  }
+
+  // When an operation has its scrollToPos property set, and another
+  // scroll action is applied before the end of the operation, this
+  // 'simulates' scrolling that position into view in a cheap way, so
+  // that the effect of intermediate scroll commands is not ignored.
+  function resolveScrollToPos(cm) {
+    var range = cm.curOp.scrollToPos;
+    if (range) {
+      cm.curOp.scrollToPos = null;
+      var from = estimateCoords(cm, range.from), to = estimateCoords(cm, range.to);
+      var sPos = calculateScrollPos(cm, Math.min(from.left, to.left),
+                                    Math.min(from.top, to.top) - range.margin,
+                                    Math.max(from.right, to.right),
+                                    Math.max(from.bottom, to.bottom) + range.margin);
+      cm.scrollTo(sPos.scrollLeft, sPos.scrollTop);
+    }
+  }
+
+  // API UTILITIES
+
+  // Indent the given line. The how parameter can be "smart",
+  // "add"/null, "subtract", or "prev". When aggressive is false
+  // (typically set to true for forced single-line indents), empty
+  // lines are not indented, and places where the mode returns Pass
+  // are left alone.
+  function indentLine(cm, n, how, aggressive) {
+    var doc = cm.doc, state;
+    if (how == null) how = "add";
+    if (how == "smart") {
+      // Fall back to "prev" when the mode doesn't have an indentation
+      // method.
+      if (!doc.mode.indent) how = "prev";
+      else state = getStateBefore(cm, n);
+    }
+
+    var tabSize = cm.options.tabSize;
+    var line = getLine(doc, n), curSpace = countColumn(line.text, null, tabSize);
+    if (line.stateAfter) line.stateAfter = null;
+    var curSpaceString = line.text.match(/^\s*/)[0], indentation;
+    if (!aggressive && !/\S/.test(line.text)) {
+      indentation = 0;
+      how = "not";
+    } else if (how == "smart") {
+      indentation = doc.mode.indent(state, line.text.slice(curSpaceString.length), line.text);
+      if (indentation == Pass || indentation > 150) {
+        if (!aggressive) return;
+        how = "prev";
+      }
+    }
+    if (how == "prev") {
+      if (n > doc.first) indentation = countColumn(getLine(doc, n-1).text, null, tabSize);
+      else indentation = 0;
+    } else if (how == "add") {
+      indentation = curSpace + cm.options.indentUnit;
+    } else if (how == "subtract") {
+      indentation = curSpace - cm.options.indentUnit;
+    } else if (typeof how == "number") {
+      indentation = curSpace + how;
+    }
+    indentation = Math.max(0, indentation);
+
+    var indentString = "", pos = 0;
+    if (cm.options.indentWithTabs)
+      for (var i = Math.floor(indentation / tabSize); i; --i) {pos += tabSize; indentString += "\t";}
+    if (pos < indentation) indentString += spaceStr(indentation - pos);
+
+    if (indentString != curSpaceString) {
+      replaceRange(doc, indentString, Pos(n, 0), Pos(n, curSpaceString.length), "+input");
+    } else {
+      // Ensure that, if the cursor was in the whitespace at the start
+      // of the line, it is moved to the end of that space.
+      for (var i = 0; i < doc.sel.ranges.length; i++) {
+        var range = doc.sel.ranges[i];
+        if (range.head.line == n && range.head.ch < curSpaceString.length) {
+          var pos = Pos(n, curSpaceString.length);
+          replaceOneSelection(doc, i, new Range(pos, pos));
+          break;
+        }
+      }
+    }
+    line.stateAfter = null;
+  }
+
+  // Utility for applying a change to a line by handle or number,
+  // returning the number and optionally registering the line as
+  // changed.
+  function changeLine(doc, handle, changeType, op) {
+    var no = handle, line = handle;
+    if (typeof handle == "number") line = getLine(doc, clipLine(doc, handle));
+    else no = lineNo(handle);
+    if (no == null) return null;
+    if (op(line, no) && doc.cm) regLineChange(doc.cm, no, changeType);
+    return line;
+  }
+
+  // Helper for deleting text near the selection(s), used to implement
+  // backspace, delete, and similar functionality.
+  function deleteNearSelection(cm, compute) {
+    var ranges = cm.doc.sel.ranges, kill = [];
+    // Build up a set of ranges to kill first, merging overlapping
+    // ranges.
+    for (var i = 0; i < ranges.length; i++) {
+      var toKill = compute(ranges[i]);
+      while (kill.length && cmp(toKill.from, lst(kill).to) <= 0) {
+        var replaced = kill.pop();
+        if (cmp(replaced.from, toKill.from) < 0) {
+          toKill.from = replaced.from;
+          break;
+        }
+      }
+      kill.push(toKill);
+    }
+    // Next, remove those actual ranges.
+    runInOp(cm, function() {
+      for (var i = kill.length - 1; i >= 0; i--)
+        replaceRange(cm.doc, "", kill[i].from, kill[i].to, "+delete");
+      ensureCursorVisible(cm);
+    });
+  }
+
+  // Used for horizontal relative motion. Dir is -1 or 1 (left or
+  // right), unit can be "char", "column" (like char, but doesn't
+  // cross line boundaries), "word" (across next word), or "group" (to
+  // the start of next group of word or non-word-non-whitespace
+  // chars). The visually param controls whether, in right-to-left
+  // text, direction 1 means to move towards the next index in the
+  // string, or towards the character to the right of the current
+  // position. The resulting position will have a hitSide=true
+  // property if it reached the end of the document.
+  function findPosH(doc, pos, dir, unit, visually) {
+    var line = pos.line, ch = pos.ch, origDir = dir;
+    var lineObj = getLine(doc, line);
+    var possible = true;
+    function findNextLine() {
+      var l = line + dir;
+      if (l < doc.first || l >= doc.first + doc.size) return (possible = false);
+      line = l;
+      return lineObj = getLine(doc, l);
+    }
+    function moveOnce(boundToLine) {
+      var next = (visually ? moveVisually : moveLogically)(lineObj, ch, dir, true);
+      if (next == null) {
+        if (!boundToLine && findNextLine()) {
+          if (visually) ch = (dir < 0 ? lineRight : lineLeft)(lineObj);
+          else ch = dir < 0 ? lineObj.text.length : 0;
+        } else return (possible = false);
+      } else ch = next;
+      return true;
+    }
+
+    if (unit == "char") moveOnce();
+    else if (unit == "column") moveOnce(true);
+    else if (unit == "word" || unit == "group") {
+      var sawType = null, group = unit == "group";
+      var helper = doc.cm && doc.cm.getHelper(pos, "wordChars");
+      for (var first = true;; first = false) {
+        if (dir < 0 && !moveOnce(!first)) break;
+        var cur = lineObj.text.charAt(ch) || "\n";
+        var type = isWordChar(cur, helper) ? "w"
+          : group && cur == "\n" ? "n"
+          : !group || /\s/.test(cur) ? null
+          : "p";
+        if (group && !first && !type) type = "s";
+        if (sawType && sawType != type) {
+          if (dir < 0) {dir = 1; moveOnce();}
+          break;
+        }
+
+        if (type) sawType = type;
+        if (dir > 0 && !moveOnce(!first)) break;
+      }
+    }
+    var result = skipAtomic(doc, Pos(line, ch), origDir, true);
+    if (!possible) result.hitSide = true;
+    return result;
+  }
+
+  // For relative vertical movement. Dir may be -1 or 1. Unit can be
+  // "page" or "line". The resulting position will have a hitSide=true
+  // property if it reached the end of the document.
+  function findPosV(cm, pos, dir, unit) {
+    var doc = cm.doc, x = pos.left, y;
+    if (unit == "page") {
+      var pageSize = Math.min(cm.display.wrapper.clientHeight, window.innerHeight || document.documentElement.clientHeight);
+      y = pos.top + dir * (pageSize - (dir < 0 ? 1.5 : .5) * textHeight(cm.display));
+    } else if (unit == "line") {
+      y = dir > 0 ? pos.bottom + 3 : pos.top - 3;
+    }
+    for (;;) {
+      var target = coordsChar(cm, x, y);
+      if (!target.outside) break;
+      if (dir < 0 ? y <= 0 : y >= doc.height) { target.hitSide = true; break; }
+      y += dir * 5;
+    }
+    return target;
+  }
+
+  // EDITOR METHODS
+
+  // The publicly visible API. Note that methodOp(f) means
+  // 'wrap f in an operation, performed on its `this` parameter'.
+
+  // This is not the complete set of editor methods. Most of the
+  // methods defined on the Doc type are also injected into
+  // CodeMirror.prototype, for backwards compatibility and
+  // convenience.
+
+  CodeMirror.prototype = {
+    constructor: CodeMirror,
+    focus: function(){window.focus(); focusInput(this); fastPoll(this);},
+
+    setOption: function(option, value) {
+      var options = this.options, old = options[option];
+      if (options[option] == value && option != "mode") return;
+      options[option] = value;
+      if (optionHandlers.hasOwnProperty(option))
+        operation(this, optionHandlers[option])(this, value, old);
+    },
+
+    getOption: function(option) {return this.options[option];},
+    getDoc: function() {return this.doc;},
+
+    addKeyMap: function(map, bottom) {
+      this.state.keyMaps[bottom ? "push" : "unshift"](getKeyMap(map));
+    },
+    removeKeyMap: function(map) {
+      var maps = this.state.keyMaps;
+      for (var i = 0; i < maps.length; ++i)
+        if (maps[i] == map || maps[i].name == map) {
+          maps.splice(i, 1);
+          return true;
+        }
+    },
+
+    addOverlay: methodOp(function(spec, options) {
+      var mode = spec.token ? spec : CodeMirror.getMode(this.options, spec);
+      if (mode.startState) throw new Error("Overlays may not be stateful.");
+      this.state.overlays.push({mode: mode, modeSpec: spec, opaque: options && options.opaque});
+      this.state.modeGen++;
+      regChange(this);
+    }),
+    removeOverlay: methodOp(function(spec) {
+      var overlays = this.state.overlays;
+      for (var i = 0; i < overlays.length; ++i) {
+        var cur = overlays[i].modeSpec;
+        if (cur == spec || typeof spec == "string" && cur.name == spec) {
+          overlays.splice(i, 1);
+          this.state.modeGen++;
+          regChange(this);
+          return;
+        }
+      }
+    }),
+
+    indentLine: methodOp(function(n, dir, aggressive) {
+      if (typeof dir != "string" && typeof dir != "number") {
+        if (dir == null) dir = this.options.smartIndent ? "smart" : "prev";
+        else dir = dir ? "add" : "subtract";
+      }
+      if (isLine(this.doc, n)) indentLine(this, n, dir, aggressive);
+    }),
+    indentSelection: methodOp(function(how) {
+      var ranges = this.doc.sel.ranges, end = -1;
+      for (var i = 0; i < ranges.length; i++) {
+        var range = ranges[i];
+        if (!range.empty()) {
+          var from = range.from(), to = range.to();
+          var start = Math.max(end, from.line);
+          end = Math.min(this.lastLine(), to.line - (to.ch ? 0 : 1)) + 1;
+          for (var j = start; j < end; ++j)
+            indentLine(this, j, how);
+          var newRanges = this.doc.sel.ranges;
+          if (from.ch == 0 && ranges.length == newRanges.length && newRanges[i].from().ch > 0)
+            replaceOneSelection(this.doc, i, new Range(from, newRanges[i].to()), sel_dontScroll);
+        } else if (range.head.line > end) {
+          indentLine(this, range.head.line, how, true);
+          end = range.head.line;
+          if (i == this.doc.sel.primIndex) ensureCursorVisible(this);
+        }
+      }
+    }),
+
+    // Fetch the parser token for a given character. Useful for hacks
+    // that want to inspect the mode state (say, for completion).
+    getTokenAt: function(pos, precise) {
+      return takeToken(this, pos, precise);
+    },
+
+    getLineTokens: function(line, precise) {
+      return takeToken(this, Pos(line), precise, true);
+    },
+
+    getTokenTypeAt: function(pos) {
+      pos = clipPos(this.doc, pos);
+      var styles = getLineStyles(this, getLine(this.doc, pos.line));
+      var before = 0, after = (styles.length - 1) / 2, ch = pos.ch;
+      var type;
+      if (ch == 0) type = styles[2];
+      else for (;;) {
+        var mid = (before + after) >> 1;
+        if ((mid ? styles[mid * 2 - 1] : 0) >= ch) after = mid;
+        else if (styles[mid * 2 + 1] < ch) before = mid + 1;
+        else { type = styles[mid * 2 + 2]; break; }
+      }
+      var cut = type ? type.indexOf("cm-overlay ") : -1;
+      return cut < 0 ? type : cut == 0 ? null : type.slice(0, cut - 1);
+    },
+
+    getModeAt: function(pos) {
+      var mode = this.doc.mode;
+      if (!mode.innerMode) return mode;
+      return CodeMirror.innerMode(mode, this.getTokenAt(pos).state).mode;
+    },
+
+    getHelper: function(pos, type) {
+      return this.getHelpers(pos, type)[0];
+    },
+
+    getHelpers: function(pos, type) {
+      var found = [];
+      if (!helpers.hasOwnProperty(type)) return helpers;
+      var help = helpers[type], mode = this.getModeAt(pos);
+      if (typeof mode[type] == "string") {
+        if (help[mode[type]]) found.push(help[mode[type]]);
+      } else if (mode[type]) {
+        for (var i = 0; i < mode[type].length; i++) {
+          var val = help[mode[type][i]];
+          if (val) found.push(val);
+        }
+      } else if (mode.helperType && help[mode.helperType]) {
+        found.push(help[mode.helperType]);
+      } else if (help[mode.name]) {
+        found.push(help[mode.name]);
+      }
+      for (var i = 0; i < help._global.length; i++) {
+        var cur = help._global[i];
+        if (cur.pred(mode, this) && indexOf(found, cur.val) == -1)
+          found.push(cur.val);
+      }
+      return found;
+    },
+
+    getStateAfter: function(line, precise) {
+      var doc = this.doc;
+      line = clipLine(doc, line == null ? doc.first + doc.size - 1: line);
+      return getStateBefore(this, line + 1, precise);
+    },
+
+    cursorCoords: function(start, mode) {
+      var pos, range = this.doc.sel.primary();
+      if (start == null) pos = range.head;
+      else if (typeof start == "object") pos = clipPos(this.doc, start);
+      else pos = start ? range.from() : range.to();
+      return cursorCoords(this, pos, mode || "page");
+    },
+
+    charCoords: function(pos, mode) {
+      return charCoords(this, clipPos(this.doc, pos), mode || "page");
+    },
+
+    coordsChar: function(coords, mode) {
+      coords = fromCoordSystem(this, coords, mode || "page");
+      return coordsChar(this, coords.left, coords.top);
+    },
+
+    lineAtHeight: function(height, mode) {
+      height = fromCoordSystem(this, {top: height, left: 0}, mode || "page").top;
+      return lineAtHeight(this.doc, height + this.display.viewOffset);
+    },
+    heightAtLine: function(line, mode) {
+      var end = false, last = this.doc.first + this.doc.size - 1;
+      if (line < this.doc.first) line = this.doc.first;
+      else if (line > last) { line = last; end = true; }
+      var lineObj = getLine(this.doc, line);
+      return intoCoordSystem(this, lineObj, {top: 0, left: 0}, mode || "page").top +
+        (end ? this.doc.height - heightAtLine(lineObj) : 0);
+    },
+
+    defaultTextHeight: function() { return textHeight(this.display); },
+    defaultCharWidth: function() { return charWidth(this.display); },
+
+    setGutterMarker: methodOp(function(line, gutterID, value) {
+      return changeLine(this.doc, line, "gutter", function(line) {
+        var markers = line.gutterMarkers || (line.gutterMarkers = {});
+        markers[gutterID] = value;
+        if (!value && isEmpty(markers)) line.gutterMarkers = null;
+        return true;
+      });
+    }),
+
+    clearGutter: methodOp(function(gutterID) {
+      var cm = this, doc = cm.doc, i = doc.first;
+      doc.iter(function(line) {
+        if (line.gutterMarkers && line.gutterMarkers[gutterID]) {
+          line.gutterMarkers[gutterID] = null;
+          regLineChange(cm, i, "gutter");
+          if (isEmpty(line.gutterMarkers)) line.gutterMarkers = null;
+        }
+        ++i;
+      });
+    }),
+
+    addLineWidget: methodOp(function(handle, node, options) {
+      return addLineWidget(this, handle, node, options);
+    }),
+
+    removeLineWidget: function(widget) { widget.clear(); },
+
+    lineInfo: function(line) {
+      if (typeof line == "number") {
+        if (!isLine(this.doc, line)) return null;
+        var n = line;
+        line = getLine(this.doc, line);
+        if (!line) return null;
+      } else {
+        var n = lineNo(line);
+        if (n == null) return null;
+      }
+      return {line: n, handle: line, text: line.text, gutterMarkers: line.gutterMarkers,
+              textClass: line.textClass, bgClass: line.bgClass, wrapClass: line.wrapClass,
+              widgets: line.widgets};
+    },
+
+    getViewport: function() { return {from: this.display.viewFrom, to: this.display.viewTo};},
+
+    addWidget: function(pos, node, scroll, vert, horiz) {
+      var display = this.display;
+      pos = cursorCoords(this, clipPos(this.doc, pos));
+      var top = pos.bottom, left = pos.left;
+      node.style.position = "absolute";
+      display.sizer.appendChild(node);
+      if (vert == "over") {
+        top = pos.top;
+      } else if (vert == "above" || vert == "near") {
+        var vspace = Math.max(display.wrapper.clientHeight, this.doc.height),
+        hspace = Math.max(display.sizer.clientWidth, display.lineSpace.clientWidth);
+        // Default to positioning above (if specified and possible); otherwise default to positioning below
+        if ((vert == 'above' || pos.bottom + node.offsetHeight > vspace) && pos.top > node.offsetHeight)
+          top = pos.top - node.offsetHeight;
+        else if (pos.bottom + node.offsetHeight <= vspace)
+          top = pos.bottom;
+        if (left + node.offsetWidth > hspace)
+          left = hspace - node.offsetWidth;
+      }
+      node.style.top = top + "px";
+      node.style.left = node.style.right = "";
+      if (horiz == "right") {
+        left = display.sizer.clientWidth - node.offsetWidth;
+        node.style.right = "0px";
+      } else {
+        if (horiz == "left") left = 0;
+        else if (horiz == "middle") left = (display.sizer.clientWidth - node.offsetWidth) / 2;
+        node.style.left = left + "px";
+      }
+      if (scroll)
+        scrollIntoView(this, left, top, left + node.offsetWidth, top + node.offsetHeight);
+    },
+
+    triggerOnKeyDown: methodOp(onKeyDown),
+    triggerOnKeyPress: methodOp(onKeyPress),
+    triggerOnKeyUp: onKeyUp,
+
+    execCommand: function(cmd) {
+      if (commands.hasOwnProperty(cmd))
+        return commands[cmd](this);
+    },
+
+    findPosH: function(from, amount, unit, visually) {
+      var dir = 1;
+      if (amount < 0) { dir = -1; amount = -amount; }
+      for (var i = 0, cur = clipPos(this.doc, from); i < amount; ++i) {
+        cur = findPosH(this.doc, cur, dir, unit, visually);
+        if (cur.hitSide) break;
+      }
+      return cur;
+    },
+
+    moveH: methodOp(function(dir, unit) {
+      var cm = this;
+      cm.extendSelectionsBy(function(range) {
+        if (cm.display.shift || cm.doc.extend || range.empty())
+          return findPosH(cm.doc, range.head, dir, unit, cm.options.rtlMoveVisually);
+        else
+          return dir < 0 ? range.from() : range.to();
+      }, sel_move);
+    }),
+
+    deleteH: methodOp(function(dir, unit) {
+      var sel = this.doc.sel, doc = this.doc;
+      if (sel.somethingSelected())
+        doc.replaceSelection("", null, "+delete");
+      else
+        deleteNearSelection(this, function(range) {
+          var other = findPosH(doc, range.head, dir, unit, false);
+          return dir < 0 ? {from: other, to: range.head} : {from: range.head, to: other};
+        });
+    }),
+
+    findPosV: function(from, amount, unit, goalColumn) {
+      var dir = 1, x = goalColumn;
+      if (amount < 0) { dir = -1; amount = -amount; }
+      for (var i = 0, cur = clipPos(this.doc, from); i < amount; ++i) {
+        var coords = cursorCoords(this, cur, "div");
+        if (x == null) x = coords.left;
+        else coords.left = x;
+        cur = findPosV(this, coords, dir, unit);
+        if (cur.hitSide) break;
+      }
+      return cur;
+    },
+
+    moveV: methodOp(function(dir, unit) {
+      var cm = this, doc = this.doc, goals = [];
+      var collapse = !cm.display.shift && !doc.extend && doc.sel.somethingSelected();
+      doc.extendSelectionsBy(function(range) {
+        if (collapse)
+          return dir < 0 ? range.from() : range.to();
+        var headPos = cursorCoords(cm, range.head, "div");
+        if (range.goalColumn != null) headPos.left = range.goalColumn;
+        goals.push(headPos.left);
+        var pos = findPosV(cm, headPos, dir, unit);
+        if (unit == "page" && range == doc.sel.primary())
+          addToScrollPos(cm, null, charCoords(cm, pos, "div").top - headPos.top);
+        return pos;
+      }, sel_move);
+      if (goals.length) for (var i = 0; i < doc.sel.ranges.length; i++)
+        doc.sel.ranges[i].goalColumn = goals[i];
+    }),
+
+    // Find the word at the given position (as returned by coordsChar).
+    findWordAt: function(pos) {
+      var doc = this.doc, line = getLine(doc, pos.line).text;
+      var start = pos.ch, end = pos.ch;
+      if (line) {
+        var helper = this.getHelper(pos, "wordChars");
+        if ((pos.xRel < 0 || end == line.length) && start) --start; else ++end;
+        var startChar = line.charAt(start);
+        var check = isWordChar(startChar, helper)
+          ? function(ch) { return isWordChar(ch, helper); }
+          : /\s/.test(startChar) ? function(ch) {return /\s/.test(ch);}
+          : function(ch) {return !/\s/.test(ch) && !isWordChar(ch);};
+        while (start > 0 && check(line.charAt(start - 1))) --start;
+        while (end < line.length && check(line.charAt(end))) ++end;
+      }
+      return new Range(Pos(pos.line, start), Pos(pos.line, end));
+    },
+
+    toggleOverwrite: function(value) {
+      if (value != null && value == this.state.overwrite) return;
+      if (this.state.overwrite = !this.state.overwrite)
+        addClass(this.display.cursorDiv, "CodeMirror-overwrite");
+      else
+        rmClass(this.display.cursorDiv, "CodeMirror-overwrite");
+
+      signal(this, "overwriteToggle", this, this.state.overwrite);
+    },
+    hasFocus: function() { return activeElt() == this.display.input; },
+
+    scrollTo: methodOp(function(x, y) {
+      if (x != null || y != null) resolveScrollToPos(this);
+      if (x != null) this.curOp.scrollLeft = x;
+      if (y != null) this.curOp.scrollTop = y;
+    }),
+    getScrollInfo: function() {
+      var scroller = this.display.scroller, co = scrollerCutOff;
+      return {left: scroller.scrollLeft, top: scroller.scrollTop,
+              height: scroller.scrollHeight - co, width: scroller.scrollWidth - co,
+              clientHeight: scroller.clientHeight - co, clientWidth: scroller.clientWidth - co};
+    },
+
+    scrollIntoView: methodOp(function(range, margin) {
+      if (range == null) {
+        range = {from: this.doc.sel.primary().head, to: null};
+        if (margin == null) margin = this.options.cursorScrollMargin;
+      } else if (typeof range == "number") {
+        range = {from: Pos(range, 0), to: null};
+      } else if (range.from == null) {
+        range = {from: range, to: null};
+      }
+      if (!range.to) range.to = range.from;
+      range.margin = margin || 0;
+
+      if (range.from.line != null) {
+        resolveScrollToPos(this);
+        this.curOp.scrollToPos = range;
+      } else {
+        var sPos = calculateScrollPos(this, Math.min(range.from.left, range.to.left),
+                                      Math.min(range.from.top, range.to.top) - range.margin,
+                                      Math.max(range.from.right, range.to.right),
+                                      Math.max(range.from.bottom, range.to.bottom) + range.margin);
+        this.scrollTo(sPos.scrollLeft, sPos.scrollTop);
+      }
+    }),
+
+    setSize: methodOp(function(width, height) {
+      var cm = this;
+      function interpret(val) {
+        return typeof val == "number" || /^\d+$/.test(String(val)) ? val + "px" : val;
+      }
+      if (width != null) cm.display.wrapper.style.width = interpret(width);
+      if (height != null) cm.display.wrapper.style.height = interpret(height);
+      if (cm.options.lineWrapping) clearLineMeasurementCache(this);
+      var lineNo = cm.display.viewFrom;
+      cm.doc.iter(lineNo, cm.display.viewTo, function(line) {
+        if (line.widgets) for (var i = 0; i < line.widgets.length; i++)
+          if (line.widgets[i].noHScroll) { regLineChange(cm, lineNo, "widget"); break; }
+        ++lineNo;
+      });
+      cm.curOp.forceUpdate = true;
+      signal(cm, "refresh", this);
+    }),
+
+    operation: function(f){return runInOp(this, f);},
+
+    refresh: methodOp(function() {
+      var oldHeight = this.display.cachedTextHeight;
+      regChange(this);
+      this.curOp.forceUpdate = true;
+      clearCaches(this);
+      this.scrollTo(this.doc.scrollLeft, this.doc.scrollTop);
+      updateGutterSpace(this);
+      if (oldHeight == null || Math.abs(oldHeight - textHeight(this.display)) > .5)
+        estimateLineHeights(this);
+      signal(this, "refresh", this);
+    }),
+
+    swapDoc: methodOp(function(doc) {
+      var old = this.doc;
+      old.cm = null;
+      attachDoc(this, doc);
+      clearCaches(this);
+      resetInput(this);
+      this.scrollTo(doc.scrollLeft, doc.scrollTop);
+      this.curOp.forceScroll = true;
+      signalLater(this, "swapDoc", this, old);
+      return old;
+    }),
+
+    getInputField: function(){return this.display.input;},
+    getWrapperElement: function(){return this.display.wrapper;},
+    getScrollerElement: function(){return this.display.scroller;},
+    getGutterElement: function(){return this.display.gutters;}
+  };
+  eventMixin(CodeMirror);
+
+  // OPTION DEFAULTS
+
+  // The default configuration options.
+  var defaults = CodeMirror.defaults = {};
+  // Functions to run when options are changed.
+  var optionHandlers = CodeMirror.optionHandlers = {};
+
+  function option(name, deflt, handle, notOnInit) {
+    CodeMirror.defaults[name] = deflt;
+    if (handle) optionHandlers[name] =
+      notOnInit ? function(cm, val, old) {if (old != Init) handle(cm, val, old);} : handle;
+  }
+
+  // Passed to option handlers when there is no old value.
+  var Init = CodeMirror.Init = {toString: function(){return "CodeMirror.Init";}};
+
+  // These two are, on init, called from the constructor because they
+  // have to be initialized before the editor can start at all.
+  option("value", "", function(cm, val) {
+    cm.setValue(val);
+  }, true);
+  option("mode", null, function(cm, val) {
+    cm.doc.modeOption = val;
+    loadMode(cm);
+  }, true);
+
+  option("indentUnit", 2, loadMode, true);
+  option("indentWithTabs", false);
+  option("smartIndent", true);
+  option("tabSize", 4, function(cm) {
+    resetModeState(cm);
+    clearCaches(cm);
+    regChange(cm);
+  }, true);
+  option("specialChars", /[\t\u0000-\u0019\u00ad\u200b-\u200f\u2028\u2029\ufeff]/g, function(cm, val) {
+    cm.options.specialChars = new RegExp(val.source + (val.test("\t") ? "" : "|\t"), "g");
+    cm.refresh();
+  }, true);
+  option("specialCharPlaceholder", defaultSpecialCharPlaceholder, function(cm) {cm.refresh();}, true);
+  option("electricChars", true);
+  option("rtlMoveVisually", !windows);
+  option("wholeLineUpdateBefore", true);
+
+  option("theme", "default", function(cm) {
+    themeChanged(cm);
+    guttersChanged(cm);
+  }, true);
+  option("keyMap", "default", function(cm, val, old) {
+    var next = getKeyMap(val);
+    var prev = old != CodeMirror.Init && getKeyMap(old);
+    if (prev && prev.detach) prev.detach(cm, next);
+    if (next.attach) next.attach(cm, prev || null);
+  });
+  option("extraKeys", null);
+
+  option("lineWrapping", false, wrappingChanged, true);
+  option("gutters", [], function(cm) {
+    setGuttersForLineNumbers(cm.options);
+    guttersChanged(cm);
+  }, true);
+  option("fixedGutter", true, function(cm, val) {
+    cm.display.gutters.style.left = val ? compensateForHScroll(cm.display) + "px" : "0";
+    cm.refresh();
+  }, true);
+  option("coverGutterNextToScrollbar", false, updateScrollbars, true);
+  option("lineNumbers", false, function(cm) {
+    setGuttersForLineNumbers(cm.options);
+    guttersChanged(cm);
+  }, true);
+  option("firstLineNumber", 1, guttersChanged, true);
+  option("lineNumberFormatter", function(integer) {return integer;}, guttersChanged, true);
+  option("showCursorWhenSelecting", false, updateSelection, true);
+
+  option("resetSelectionOnContextMenu", true);
+
+  option("readOnly", false, function(cm, val) {
+    if (val == "nocursor") {
+      onBlur(cm);
+      cm.display.input.blur();
+      cm.display.disabled = true;
+    } else {
+      cm.display.disabled = false;
+      if (!val) resetInput(cm);
+    }
+  });
+  option("disableInput", false, function(cm, val) {if (!val) resetInput(cm);}, true);
+  option("dragDrop", true);
+
+  option("cursorBlinkRate", 530);
+  option("cursorScrollMargin", 0);
+  option("cursorHeight", 1, updateSelection, true);
+  option("singleCursorHeightPerLine", true, updateSelection, true);
+  option("workTime", 100);
+  option("workDelay", 100);
+  option("flattenSpans", true, resetModeState, true);
+  option("addModeClass", false, resetModeState, true);
+  option("pollInterval", 100);
+  option("undoDepth", 200, function(cm, val){cm.doc.history.undoDepth = val;});
+  option("historyEventDelay", 1250);
+  option("viewportMargin", 10, function(cm){cm.refresh();}, true);
+  option("maxHighlightLength", 10000, resetModeState, true);
+  option("moveInputWithCursor", true, function(cm, val) {
+    if (!val) cm.display.inputDiv.style.top = cm.display.inputDiv.style.left = 0;
+  });
+
+  option("tabindex", null, function(cm, val) {
+    cm.display.input.tabIndex = val || "";
+  });
+  option("autofocus", null);
+
+  // MODE DEFINITION AND QUERYING
+
+  // Known modes, by name and by MIME
+  var modes = CodeMirror.modes = {}, mimeModes = CodeMirror.mimeModes = {};
+
+  // Extra arguments are stored as the mode's dependencies, which is
+  // used by (legacy) mechanisms like loadmode.js to automatically
+  // load a mode. (Preferred mechanism is the require/define calls.)
+  CodeMirror.defineMode = function(name, mode) {
+    if (!CodeMirror.defaults.mode && name != "null") CodeMirror.defaults.mode = name;
+    if (arguments.length > 2)
+      mode.dependencies = Array.prototype.slice.call(arguments, 2);
+    modes[name] = mode;
+  };
+
+  CodeMirror.defineMIME = function(mime, spec) {
+    mimeModes[mime] = spec;
+  };
+
+  // Given a MIME type, a {name, ...options} config object, or a name
+  // string, return a mode config object.
+  CodeMirror.resolveMode = function(spec) {
+    if (typeof spec == "string" && mimeModes.hasOwnProperty(spec)) {
+      spec = mimeModes[spec];
+    } else if (spec && typeof spec.name == "string" && mimeModes.hasOwnProperty(spec.name)) {
+      var found = mimeModes[spec.name];
+      if (typeof found == "string") found = {name: found};
+      spec = createObj(found, spec);
+      spec.name = found.name;
+    } else if (typeof spec == "string" && /^[\w\-]+\/[\w\-]+\+xml$/.test(spec)) {
+      return CodeMirror.resolveMode("application/xml");
+    }
+    if (typeof spec == "string") return {name: spec};
+    else return spec || {name: "null"};
+  };
+
+  // Given a mode spec (anything that resolveMode accepts), find and
+  // initialize an actual mode object.
+  CodeMirror.getMode = function(options, spec) {
+    var spec = CodeMirror.resolveMode(spec);
+    var mfactory = modes[spec.name];
+    if (!mfactory) return CodeMirror.getMode(options, "text/plain");
+    var modeObj = mfactory(options, spec);
+    if (modeExtensions.hasOwnProperty(spec.name)) {
+      var exts = modeExtensions[spec.name];
+      for (var prop in exts) {
+        if (!exts.hasOwnProperty(prop)) continue;
+        if (modeObj.hasOwnProperty(prop)) modeObj["_" + prop] = modeObj[prop];
+        modeObj[prop] = exts[prop];
+      }
+    }
+    modeObj.name = spec.name;
+    if (spec.helperType) modeObj.helperType = spec.helperType;
+    if (spec.modeProps) for (var prop in spec.modeProps)
+      modeObj[prop] = spec.modeProps[prop];
+
+    return modeObj;
+  };
+
+  // Minimal default mode.
+  CodeMirror.defineMode("null", function() {
+    return {token: function(stream) {stream.skipToEnd();}};
+  });
+  CodeMirror.defineMIME("text/plain", "null");
+
+  // This can be used to attach properties to mode objects from
+  // outside the actual mode definition.
+  var modeExtensions = CodeMirror.modeExtensions = {};
+  CodeMirror.extendMode = function(mode, properties) {
+    var exts = modeExtensions.hasOwnProperty(mode) ? modeExtensions[mode] : (modeExtensions[mode] = {});
+    copyObj(properties, exts);
+  };
+
+  // EXTENSIONS
+
+  CodeMirror.defineExtension = function(name, func) {
+    CodeMirror.prototype[name] = func;
+  };
+  CodeMirror.defineDocExtension = function(name, func) {
+    Doc.prototype[name] = func;
+  };
+  CodeMirror.defineOption = option;
+
+  var initHooks = [];
+  CodeMirror.defineInitHook = function(f) {initHooks.push(f);};
+
+  var helpers = CodeMirror.helpers = {};
+  CodeMirror.registerHelper = function(type, name, value) {
+    if (!helpers.hasOwnProperty(type)) helpers[type] = CodeMirror[type] = {_global: []};
+    helpers[type][name] = value;
+  };
+  CodeMirror.registerGlobalHelper = function(type, name, predicate, value) {
+    CodeMirror.registerHelper(type, name, value);
+    helpers[type]._global.push({pred: predicate, val: value});
+  };
+
+  // MODE STATE HANDLING
+
+  // Utility functions for working with state. Exported because nested
+  // modes need to do this for their inner modes.
+
+  var copyState = CodeMirror.copyState = function(mode, state) {
+    if (state === true) return state;
+    if (mode.copyState) return mode.copyState(state);
+    var nstate = {};
+    for (var n in state) {
+      var val = state[n];
+      if (val instanceof Array) val = val.concat([]);
+      nstate[n] = val;
+    }
+    return nstate;
+  };
+
+  var startState = CodeMirror.startState = function(mode, a1, a2) {
+    return mode.startState ? mode.startState(a1, a2) : true;
+  };
+
+  // Given a mode and a state (for that mode), find the inner mode and
+  // state at the position that the state refers to.
+  CodeMirror.innerMode = function(mode, state) {
+    while (mode.innerMode) {
+      var info = mode.innerMode(state);
+      if (!info || info.mode == mode) break;
+      state = info.state;
+      mode = info.mode;
+    }
+    return info || {mode: mode, state: state};
+  };
+
+  // STANDARD COMMANDS
+
+  // Commands are parameter-less actions that can be performed on an
+  // editor, mostly used for keybindings.
+  var commands = CodeMirror.commands = {
+    selectAll: function(cm) {cm.setSelection(Pos(cm.firstLine(), 0), Pos(cm.lastLine()), sel_dontScroll);},
+    singleSelection: function(cm) {
+      cm.setSelection(cm.getCursor("anchor"), cm.getCursor("head"), sel_dontScroll);
+    },
+    killLine: function(cm) {
+      deleteNearSelection(cm, function(range) {
+        if (range.empty()) {
+          var len = getLine(cm.doc, range.head.line).text.length;
+          if (range.head.ch == len && range.head.line < cm.lastLine())
+            return {from: range.head, to: Pos(range.head.line + 1, 0)};
+          else
+            return {from: range.head, to: Pos(range.head.line, len)};
+        } else {
+          return {from: range.from(), to: range.to()};
+        }
+      });
+    },
+    deleteLine: function(cm) {
+      deleteNearSelection(cm, function(range) {
+        return {from: Pos(range.from().line, 0),
+                to: clipPos(cm.doc, Pos(range.to().line + 1, 0))};
+      });
+    },
+    delLineLeft: function(cm) {
+      deleteNearSelection(cm, function(range) {
+        return {from: Pos(range.from().line, 0), to: range.from()};
+      });
+    },
+    delWrappedLineLeft: function(cm) {
+      deleteNearSelection(cm, function(range) {
+        var top = cm.charCoords(range.head, "div").top + 5;
+        var leftPos = cm.coordsChar({left: 0, top: top}, "div");
+        return {from: leftPos, to: range.from()};
+      });
+    },
+    delWrappedLineRight: function(cm) {
+      deleteNearSelection(cm, function(range) {
+        var top = cm.charCoords(range.head, "div").top + 5;
+        var rightPos = cm.coordsChar({left: cm.display.lineDiv.offsetWidth + 100, top: top}, "div");
+        return {from: range.from(), to: rightPos };
+      });
+    },
+    undo: function(cm) {cm.undo();},
+    redo: function(cm) {cm.redo();},
+    undoSelection: function(cm) {cm.undoSelection();},
+    redoSelection: function(cm) {cm.redoSelection();},
+    goDocStart: function(cm) {cm.extendSelection(Pos(cm.firstLine(), 0));},
+    goDocEnd: function(cm) {cm.extendSelection(Pos(cm.lastLine()));},
+    goLineStart: function(cm) {
+      cm.extendSelectionsBy(function(range) { return lineStart(cm, range.head.line); },
+                            {origin: "+move", bias: 1});
+    },
+    goLineStartSmart: function(cm) {
+      cm.extendSelectionsBy(function(range) {
+        return lineStartSmart(cm, range.head);
+      }, {origin: "+move", bias: 1});
+    },
+    goLineEnd: function(cm) {
+      cm.extendSelectionsBy(function(range) { return lineEnd(cm, range.head.line); },
+                            {origin: "+move", bias: -1});
+    },
+    goLineRight: function(cm) {
+      cm.extendSelectionsBy(function(range) {
+        var top = cm.charCoords(range.head, "div").top + 5;
+        return cm.coordsChar({left: cm.display.lineDiv.offsetWidth + 100, top: top}, "div");
+      }, sel_move);
+    },
+    goLineLeft: function(cm) {
+      cm.extendSelectionsBy(function(range) {
+        var top = cm.charCoords(range.head, "div").top + 5;
+        return cm.coordsChar({left: 0, top: top}, "div");
+      }, sel_move);
+    },
+    goLineLeftSmart: function(cm) {
+      cm.extendSelectionsBy(function(range) {
+        var top = cm.charCoords(range.head, "div").top + 5;
+        var pos = cm.coordsChar({left: 0, top: top}, "div");
+        if (pos.ch < cm.getLine(pos.line).search(/\S/)) return lineStartSmart(cm, range.head);
+        return pos;
+      }, sel_move);
+    },
+    goLineUp: function(cm) {cm.moveV(-1, "line");},
+    goLineDown: function(cm) {cm.moveV(1, "line");},
+    goPageUp: function(cm) {cm.moveV(-1, "page");},
+    goPageDown: function(cm) {cm.moveV(1, "page");},
+    goCharLeft: function(cm) {cm.moveH(-1, "char");},
+    goCharRight: function(cm) {cm.moveH(1, "char");},
+    goColumnLeft: function(cm) {cm.moveH(-1, "column");},
+    goColumnRight: function(cm) {cm.moveH(1, "column");},
+    goWordLeft: function(cm) {cm.moveH(-1, "word");},
+    goGroupRight: function(cm) {cm.moveH(1, "group");},
+    goGroupLeft: function(cm) {cm.moveH(-1, "group");},
+    goWordRight: function(cm) {cm.moveH(1, "word");},
+    delCharBefore: function(cm) {cm.deleteH(-1, "char");},
+    delCharAfter: function(cm) {cm.deleteH(1, "char");},
+    delWordBefore: function(cm) {cm.deleteH(-1, "word");},
+    delWordAfter: function(cm) {cm.deleteH(1, "word");},
+    delGroupBefore: function(cm) {cm.deleteH(-1, "group");},
+    delGroupAfter: function(cm) {cm.deleteH(1, "group");},
+    indentAuto: function(cm) {cm.indentSelection("smart");},
+    indentMore: function(cm) {cm.indentSelection("add");},
+    indentLess: function(cm) {cm.indentSelection("subtract");},
+    insertTab: function(cm) {cm.replaceSelection("\t");},
+    insertSoftTab: function(cm) {
+      var spaces = [], ranges = cm.listSelections(), tabSize = cm.options.tabSize;
+      for (var i = 0; i < ranges.length; i++) {
+        var pos = ranges[i].from();
+        var col = countColumn(cm.getLine(pos.line), pos.ch, tabSize);
+        spaces.push(new Array(tabSize - col % tabSize + 1).join(" "));
+      }
+      cm.replaceSelections(spaces);
+    },
+    defaultTab: function(cm) {
+      if (cm.somethingSelected()) cm.indentSelection("add");
+      else cm.execCommand("insertTab");
+    },
+    transposeChars: function(cm) {
+      runInOp(cm, function() {
+        var ranges = cm.listSelections(), newSel = [];
+        for (var i = 0; i < ranges.length; i++) {
+          var cur = ranges[i].head, line = getLine(cm.doc, cur.line).text;
+          if (line) {
+            if (cur.ch == line.length) cur = new Pos(cur.line, cur.ch - 1);
+            if (cur.ch > 0) {
+              cur = new Pos(cur.line, cur.ch + 1);
+              cm.replaceRange(line.charAt(cur.ch - 1) + line.charAt(cur.ch - 2),
+                              Pos(cur.line, cur.ch - 2), cur, "+transpose");
+            } else if (cur.line > cm.doc.first) {
+              var prev = getLine(cm.doc, cur.line - 1).text;
+              if (prev)
+                cm.replaceRange(line.charAt(0) + "\n" + prev.charAt(prev.length - 1),
+                                Pos(cur.line - 1, prev.length - 1), Pos(cur.line, 1), "+transpose");
+            }
+          }
+          newSel.push(new Range(cur, cur));
+        }
+        cm.setSelections(newSel);
+      });
+    },
+    newlineAndIndent: function(cm) {
+      runInOp(cm, function() {
+        var len = cm.listSelections().length;
+        for (var i = 0; i < len; i++) {
+          var range = cm.listSelections()[i];
+          cm.replaceRange("\n", range.anchor, range.head, "+input");
+          cm.indentLine(range.from().line + 1, null, true);
+          ensureCursorVisible(cm);
+        }
+      });
+    },
+    toggleOverwrite: function(cm) {cm.toggleOverwrite();}
+  };
+
+
+  // STANDARD KEYMAPS
+
+  var keyMap = CodeMirror.keyMap = {};
+
+  keyMap.basic = {
+    "Left": "goCharLeft", "Right": "goCharRight", "Up": "goLineUp", "Down": "goLineDown",
+    "End": "goLineEnd", "Home": "goLineStartSmart", "PageUp": "goPageUp", "PageDown": "goPageDown",
+    "Delete": "delCharAfter", "Backspace": "delCharBefore", "Shift-Backspace": "delCharBefore",
+    "Tab": "defaultTab", "Shift-Tab": "indentAuto",
+    "Enter": "newlineAndIndent", "Insert": "toggleOverwrite",
+    "Esc": "singleSelection"
+  };
+  // Note that the save and find-related commands aren't defined by
+  // default. User code or addons can define them. Unknown commands
+  // are simply ignored.
+  keyMap.pcDefault = {
+    "Ctrl-A": "selectAll", "Ctrl-D": "deleteLine", "Ctrl-Z": "undo", "Shift-Ctrl-Z": "redo", "Ctrl-Y": "redo",
+    "Ctrl-Home": "goDocStart", "Ctrl-End": "goDocEnd", "Ctrl-Up": "goLineUp", "Ctrl-Down": "goLineDown",
+    "Ctrl-Left": "goGroupLeft", "Ctrl-Right": "goGroupRight", "Alt-Left": "goLineStart", "Alt-Right": "goLineEnd",
+    "Ctrl-Backspace": "delGroupBefore", "Ctrl-Delete": "delGroupAfter", "Ctrl-S": "save", "Ctrl-F": "find",
+    "Ctrl-G": "findNext", "Shift-Ctrl-G": "findPrev", "Shift-Ctrl-F": "replace", "Shift-Ctrl-R": "replaceAll",
+    "Ctrl-[": "indentLess", "Ctrl-]": "indentMore",
+    "Ctrl-U": "undoSelection", "Shift-Ctrl-U": "redoSelection", "Alt-U": "redoSelection",
+    fallthrough: "basic"
+  };
+  // Very basic readline/emacs-style bindings, which are standard on Mac.
+  keyMap.emacsy = {
+    "Ctrl-F": "goCharRight", "Ctrl-B": "goCharLeft", "Ctrl-P": "goLineUp", "Ctrl-N": "goLineDown",
+    "Alt-F": "goWordRight", "Alt-B": "goWordLeft", "Ctrl-A": "goLineStart", "Ctrl-E": "goLineEnd",
+    "Ctrl-V": "goPageDown", "Shift-Ctrl-V": "goPageUp", "Ctrl-D": "delCharAfter", "Ctrl-H": "delCharBefore",
+    "Alt-D": "delWordAfter", "Alt-Backspace": "delWordBefore", "Ctrl-K": "killLine", "Ctrl-T": "transposeChars"
+  };
+  keyMap.macDefault = {
+    "Cmd-A": "selectAll", "Cmd-D": "deleteLine", "Cmd-Z": "undo", "Shift-Cmd-Z": "redo", "Cmd-Y": "redo",
+    "Cmd-Home": "goDocStart", "Cmd-Up": "goDocStart", "Cmd-End": "goDocEnd", "Cmd-Down": "goDocEnd", "Alt-Left": "goGroupLeft",
+    "Alt-Right": "goGroupRight", "Cmd-Left": "goLineLeft", "Cmd-Right": "goLineRight", "Alt-Backspace": "delGroupBefore",
+    "Ctrl-Alt-Backspace": "delGroupAfter", "Alt-Delete": "delGroupAfter", "Cmd-S": "save", "Cmd-F": "find",
+    "Cmd-G": "findNext", "Shift-Cmd-G": "findPrev", "Cmd-Alt-F": "replace", "Shift-Cmd-Alt-F": "replaceAll",
+    "Cmd-[": "indentLess", "Cmd-]": "indentMore", "Cmd-Backspace": "delWrappedLineLeft", "Cmd-Delete": "delWrappedLineRight",
+    "Cmd-U": "undoSelection", "Shift-Cmd-U": "redoSelection", "Ctrl-Up": "goDocStart", "Ctrl-Down": "goDocEnd",
+    fallthrough: ["basic", "emacsy"]
+  };
+  keyMap["default"] = mac ? keyMap.macDefault : keyMap.pcDefault;
+
+  // KEYMAP DISPATCH
+
+  function normalizeKeyName(name) {
+    var parts = name.split(/-(?!$)/), name = parts[parts.length - 1];
+    var alt, ctrl, shift, cmd;
+    for (var i = 0; i < parts.length - 1; i++) {
+      var mod = parts[i];
+      if (/^(cmd|meta|m)$/i.test(mod)) cmd = true;
+      else if (/^a(lt)?$/i.test(mod)) alt = true;
+      else if (/^(c|ctrl|control)$/i.test(mod)) ctrl = true;
+      else if (/^s(hift)$/i.test(mod)) shift = true;
+      else throw new Error("Unrecognized modifier name: " + mod);
+    }
+    if (alt) name = "Alt-" + name;
+    if (ctrl) name = "Ctrl-" + name;
+    if (cmd) name = "Cmd-" + name;
+    if (shift) name = "Shift-" + name;
+    return name;
+  }
+
+  // This is a kludge to keep keymaps mostly working as raw objects
+  // (backwards compatibility) while at the same time support features
+  // like normalization and multi-stroke key bindings. It compiles a
+  // new normalized keymap, and then updates the old object to reflect
+  // this.
+  CodeMirror.normalizeKeyMap = function(keymap) {
+    var copy = {};
+    for (var keyname in keymap) if (keymap.hasOwnProperty(keyname)) {
+      var value = keymap[keyname];
+      if (/^(name|fallthrough|(de|at)tach)$/.test(keyname)) continue;
+      if (value == "...") { delete keymap[keyname]; continue; }
+
+      var keys = map(keyname.split(" "), normalizeKeyName);
+      for (var i = 0; i < keys.length; i++) {
+        var val, name;
+        if (i == keys.length - 1) {
+          name = keyname;
+          val = value;
+        } else {
+          name = keys.slice(0, i + 1).join(" ");
+          val = "...";
+        }
+        var prev = copy[name];
+        if (!prev) copy[name] = val;
+        else if (prev != val) throw new Error("Inconsistent bindings for " + name);
+      }
+      delete keymap[keyname];
+    }
+    for (var prop in copy) keymap[prop] = copy[prop];
+    return keymap;
+  };
+
+  var lookupKey = CodeMirror.lookupKey = function(key, map, handle) {
+    map = getKeyMap(map);
+    var found = map.call ? map.call(key) : map[key];
+    if (found === false) return "nothing";
+    if (found === "...") return "multi";
+    if (found != null && handle(found)) return "handled";
+
+    if (map.fallthrough) {
+      if (Object.prototype.toString.call(map.fallthrough) != "[object Array]")
+        return lookupKey(key, map.fallthrough, handle);
+      for (var i = 0; i < map.fallthrough.length; i++) {
+        var result = lookupKey(key, map.fallthrough[i], handle);
+        if (result) return result;
+      }
+    }
+  };
+
+  // Modifier key presses don't count as 'real' key presses for the
+  // purpose of keymap fallthrough.
+  var isModifierKey = CodeMirror.isModifierKey = function(value) {
+    var name = typeof value == "string" ? value : keyNames[value.keyCode];
+    return name == "Ctrl" || name == "Alt" || name == "Shift" || name == "Mod";
+  };
+
+  // Look up the name of a key as indicated by an event object.
+  var keyName = CodeMirror.keyName = function(event, noShift) {
+    if (presto && event.keyCode == 34 && event["char"]) return false;
+    var base = keyNames[event.keyCode], name = base;
+    if (name == null || event.altGraphKey) return false;
+    if (event.altKey && base != "Alt") name = "Alt-" + name;
+    if ((flipCtrlCmd ? event.metaKey : event.ctrlKey) && base != "Ctrl") name = "Ctrl-" + name;
+    if ((flipCtrlCmd ? event.ctrlKey : event.metaKey) && base != "Cmd") name = "Cmd-" + name;
+    if (!noShift && event.shiftKey && base != "Shift") name = "Shift-" + name;
+    return name;
+  };
+
+  function getKeyMap(val) {
+    return typeof val == "string" ? keyMap[val] : val;
+  }
+
+  // FROMTEXTAREA
+
+  CodeMirror.fromTextArea = function(textarea, options) {
+    if (!options) options = {};
+    options.value = textarea.value;
+    if (!options.tabindex && textarea.tabindex)
+      options.tabindex = textarea.tabindex;
+    if (!options.placeholder && textarea.placeholder)
+      options.placeholder = textarea.placeholder;
+    // Set autofocus to true if this textarea is focused, or if it has
+    // autofocus and no other element is focused.
+    if (options.autofocus == null) {
+      var hasFocus = activeElt();
+      options.autofocus = hasFocus == textarea ||
+        textarea.getAttribute("autofocus") != null && hasFocus == document.body;
+    }
+
+    function save() {textarea.value = cm.getValue();}
+    if (textarea.form) {
+      on(textarea.form, "submit", save);
+      // Deplorable hack to make the submit method do the right thing.
+      if (!options.leaveSubmitMethodAlone) {
+        var form = textarea.form, realSubmit = form.submit;
+        try {
+          var wrappedSubmit = form.submit = function() {
+            save();
+            form.submit = realSubmit;
+            form.submit();
+            form.submit = wrappedSubmit;
+          };
+        } catch(e) {}
+      }
+    }
+
+    textarea.style.display = "none";
+    var cm = CodeMirror(function(node) {
+      textarea.parentNode.insertBefore(node, textarea.nextSibling);
+    }, options);
+    cm.save = save;
+    cm.getTextArea = function() { return textarea; };
+    cm.toTextArea = function() {
+      cm.toTextArea = isNaN; // Prevent this from being ran twice
+      save();
+      textarea.parentNode.removeChild(cm.getWrapperElement());
+      textarea.style.display = "";
+      if (textarea.form) {
+        off(textarea.form, "submit", save);
+        if (typeof textarea.form.submit == "function")
+          textarea.form.submit = realSubmit;
+      }
+    };
+    return cm;
+  };
+
+  // STRING STREAM
+
+  // Fed to the mode parsers, provides helper functions to make
+  // parsers more succinct.
+
+  var StringStream = CodeMirror.StringStream = function(string, tabSize) {
+    this.pos = this.start = 0;
+    this.string = string;
+    this.tabSize = tabSize || 8;
+    this.lastColumnPos = this.lastColumnValue = 0;
+    this.lineStart = 0;
+  };
+
+  StringStream.prototype = {
+    eol: function() {return this.pos >= this.string.length;},
+    sol: function() {return this.pos == this.lineStart;},
+    peek: function() {return this.string.charAt(this.pos) || undefined;},
+    next: function() {
+      if (this.pos < this.string.length)
+        return this.string.charAt(this.pos++);
+    },
+    eat: function(match) {
+      var ch = this.string.charAt(this.pos);
+      if (typeof match == "string") var ok = ch == match;
+      else var ok = ch && (match.test ? match.test(ch) : match(ch));
+      if (ok) {++this.pos; return ch;}
+    },
+    eatWhile: function(match) {
+      var start = this.pos;
+      while (this.eat(match)){}
+      return this.pos > start;
+    },
+    eatSpace: function() {
+      var start = this.pos;
+      while (/[\s\u00a0]/.test(this.string.charAt(this.pos))) ++this.pos;
+      return this.pos > start;
+    },
+    skipToEnd: function() {this.pos = this.string.length;},
+    skipTo: function(ch) {
+      var found = this.string.indexOf(ch, this.pos);
+      if (found > -1) {this.pos = found; return true;}
+    },
+    backUp: function(n) {this.pos -= n;},
+    column: function() {
+      if (this.lastColumnPos < this.start) {
+        this.lastColumnValue = countColumn(this.string, this.start, this.tabSize, this.lastColumnPos, this.lastColumnValue);
+        this.lastColumnPos = this.start;
+      }
+      return this.lastColumnValue - (this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0);
+    },
+    indentation: function() {
+      return countColumn(this.string, null, this.tabSize) -
+        (this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0);
+    },
+    match: function(pattern, consume, caseInsensitive) {
+      if (typeof pattern == "string") {
+        var cased = function(str) {return caseInsensitive ? str.toLowerCase() : str;};
+        var substr = this.string.substr(this.pos, pattern.length);
+        if (cased(substr) == cased(pattern)) {
+          if (consume !== false) this.pos += pattern.length;
+          return true;
+        }
+      } else {
+        var match = this.string.slice(this.pos).match(pattern);
+        if (match && match.index > 0) return null;
+        if (match && consume !== false) this.pos += match[0].length;
+        return match;
+      }
+    },
+    current: function(){return this.string.slice(this.start, this.pos);},
+    hideFirstChars: function(n, inner) {
+      this.lineStart += n;
+      try { return inner(); }
+      finally { this.lineStart -= n; }
+    }
+  };
+
+  // TEXTMARKERS
+
+  // Created with markText and setBookmark methods. A TextMarker is a
+  // handle that can be used to clear or find a marked position in the
+  // document. Line objects hold arrays (markedSpans) containing
+  // {from, to, marker} object pointing to such marker objects, and
+  // indicating that such a marker is present on that line. Multiple
+  // lines may point to the same marker when it spans across lines.
+  // The spans will have null for their from/to properties when the
+  // marker continues beyond the start/end of the line. Markers have
+  // links back to the lines they currently touch.
+
+  var TextMarker = CodeMirror.TextMarker = function(doc, type) {
+    this.lines = [];
+    this.type = type;
+    this.doc = doc;
+  };
+  eventMixin(TextMarker);
+
+  // Clear the marker.
+  TextMarker.prototype.clear = function() {
+    if (this.explicitlyCleared) return;
+    var cm = this.doc.cm, withOp = cm && !cm.curOp;
+    if (withOp) startOperation(cm);
+    if (hasHandler(this, "clear")) {
+      var found = this.find();
+      if (found) signalLater(this, "clear", found.from, found.to);
+    }
+    var min = null, max = null;
+    for (var i = 0; i < this.lines.length; ++i) {
+      var line = this.lines[i];
+      var span = getMarkedSpanFor(line.markedSpans, this);
+      if (cm && !this.collapsed) regLineChange(cm, lineNo(line), "text");
+      else if (cm) {
+        if (span.to != null) max = lineNo(line);
+        if (span.from != null) min = lineNo(line);
+      }
+      line.markedSpans = removeMarkedSpan(line.markedSpans, span);
+      if (span.from == null && this.collapsed && !lineIsHidden(this.doc, line) && cm)
+        updateLineHeight(line, textHeight(cm.display));
+    }
+    if (cm && this.collapsed && !cm.options.lineWrapping) for (var i = 0; i < this.lines.length; ++i) {
+      var visual = visualLine(this.lines[i]), len = lineLength(visual);
+      if (len > cm.display.maxLineLength) {
+        cm.display.maxLine = visual;
+        cm.display.maxLineLength = len;
+        cm.display.maxLineChanged = true;
+      }
+    }
+
+    if (min != null && cm && this.collapsed) regChange(cm, min, max + 1);
+    this.lines.length = 0;
+    this.explicitlyCleared = true;
+    if (this.atomic && this.doc.cantEdit) {
+      this.doc.cantEdit = false;
+      if (cm) reCheckSelection(cm.doc);
+    }
+    if (cm) signalLater(cm, "markerCleared", cm, this);
+    if (withOp) endOperation(cm);
+    if (this.parent) this.parent.clear();
+  };
+
+  // Find the position of the marker in the document. Returns a {from,
+  // to} object by default. Side can be passed to get a specific side
+  // -- 0 (both), -1 (left), or 1 (right). When lineObj is true, the
+  // Pos objects returned contain a line object, rather than a line
+  // number (used to prevent looking up the same line twice).
+  TextMarker.prototype.find = function(side, lineObj) {
+    if (side == null && this.type == "bookmark") side = 1;
+    var from, to;
+    for (var i = 0; i < this.lines.length; ++i) {
+      var line = this.lines[i];
+      var span = getMarkedSpanFor(line.markedSpans, this);
+      if (span.from != null) {
+        from = Pos(lineObj ? line : lineNo(line), span.from);
+        if (side == -1) return from;
+      }
+      if (span.to != null) {
+        to = Pos(lineObj ? line : lineNo(line), span.to);
+        if (side == 1) return to;
+      }
+    }
+    return from && {from: from, to: to};
+  };
+
+  // Signals that the marker's widget changed, and surrounding layout
+  // should be recomputed.
+  TextMarker.prototype.changed = function() {
+    var pos = this.find(-1, true), widget = this, cm = this.doc.cm;
+    if (!pos || !cm) return;
+    runInOp(cm, function() {
+      var line = pos.line, lineN = lineNo(pos.line);
+      var view = findViewForLine(cm, lineN);
+      if (view) {
+        clearLineMeasurementCacheFor(view);
+        cm.curOp.selectionChanged = cm.curOp.forceUpdate = true;
+      }
+      cm.curOp.updateMaxLine = true;
+      if (!lineIsHidden(widget.doc, line) && widget.height != null) {
+        var oldHeight = widget.height;
+        widget.height = null;
+        var dHeight = widgetHeight(widget) - oldHeight;
+        if (dHeight)
+          updateLineHeight(line, line.height + dHeight);
+      }
+    });
+  };
+
+  TextMarker.prototype.attachLine = function(line) {
+    if (!this.lines.length && this.doc.cm) {
+      var op = this.doc.cm.curOp;
+      if (!op.maybeHiddenMarkers || indexOf(op.maybeHiddenMarkers, this) == -1)
+        (op.maybeUnhiddenMarkers || (op.maybeUnhiddenMarkers = [])).push(this);
+    }
+    this.lines.push(line);
+  };
+  TextMarker.prototype.detachLine = function(line) {
+    this.lines.splice(indexOf(this.lines, line), 1);
+    if (!this.lines.length && this.doc.cm) {
+      var op = this.doc.cm.curOp;
+      (op.maybeHiddenMarkers || (op.maybeHiddenMarkers = [])).push(this);
+    }
+  };
+
+  // Collapsed markers have unique ids, in order to be able to order
+  // them, which is needed for uniquely determining an outer marker
+  // when they overlap (they may nest, but not partially overlap).
+  var nextMarkerId = 0;
+
+  // Create a marker, wire it up to the right lines, and
+  function markText(doc, from, to, options, type) {
+    // Shared markers (across linked documents) are handled separately
+    // (markTextShared will call out to this again, once per
+    // document).
+    if (options && options.shared) return markTextShared(doc, from, to, options, type);
+    // Ensure we are in an operation.
+    if (doc.cm && !doc.cm.curOp) return operation(doc.cm, markText)(doc, from, to, options, type);
+
+    var marker = new TextMarker(doc, type), diff = cmp(from, to);
+    if (options) copyObj(options, marker, false);
+    // Don't connect empty markers unless clearWhenEmpty is false
+    if (diff > 0 || diff == 0 && marker.clearWhenEmpty !== false)
+      return marker;
+    if (marker.replacedWith) {
+      // Showing up as a widget implies collapsed (widget replaces text)
+      marker.collapsed = true;
+      marker.widgetNode = elt("span", [marker.replacedWith], "CodeMirror-widget");
+      if (!options.handleMouseEvents) marker.widgetNode.ignoreEvents = true;
+      if (options.insertLeft) marker.widgetNode.insertLeft = true;
+    }
+    if (marker.collapsed) {
+      if (conflictingCollapsedRange(doc, from.line, from, to, marker) ||
+          from.line != to.line && conflictingCollapsedRange(doc, to.line, from, to, marker))
+        throw new Error("Inserting collapsed marker partially overlapping an existing one");
+      sawCollapsedSpans = true;
+    }
+
+    if (marker.addToHistory)
+      addChangeToHistory(doc, {from: from, to: to, origin: "markText"}, doc.sel, NaN);
+
+    var curLine = from.line, cm = doc.cm, updateMaxLine;
+    doc.iter(curLine, to.line + 1, function(line) {
+      if (cm && marker.collapsed && !cm.options.lineWrapping && visualLine(line) == cm.display.maxLine)
+        updateMaxLine = true;
+      if (marker.collapsed && curLine != from.line) updateLineHeight(line, 0);
+      addMarkedSpan(line, new MarkedSpan(marker,
+                                         curLine == from.line ? from.ch : null,
+                                         curLine == to.line ? to.ch : null));
+      ++curLine;
+    });
+    // lineIsHidden depends on the presence of the spans, so needs a second pass
+    if (marker.collapsed) doc.iter(from.line, to.line + 1, function(line) {
+      if (lineIsHidden(doc, line)) updateLineHeight(line, 0);
+    });
+
+    if (marker.clearOnEnter) on(marker, "beforeCursorEnter", function() { marker.clear(); });
+
+    if (marker.readOnly) {
+      sawReadOnlySpans = true;
+      if (doc.history.done.length || doc.history.undone.length)
+        doc.clearHistory();
+    }
+    if (marker.collapsed) {
+      marker.id = ++nextMarkerId;
+      marker.atomic = true;
+    }
+    if (cm) {
+      // Sync editor state
+      if (updateMaxLine) cm.curOp.updateMaxLine = true;
+      if (marker.collapsed)
+        regChange(cm, from.line, to.line + 1);
+      else if (marker.className || marker.title || marker.startStyle || marker.endStyle)
+        for (var i = from.line; i <= to.line; i++) regLineChange(cm, i, "text");
+      if (marker.atomic) reCheckSelection(cm.doc);
+      signalLater(cm, "markerAdded", cm, marker);
+    }
+    return marker;
+  }
+
+  // SHARED TEXTMARKERS
+
+  // A shared marker spans multiple linked documents. It is
+  // implemented as a meta-marker-object controlling multiple normal
+  // markers.
+  var SharedTextMarker = CodeMirror.SharedTextMarker = function(markers, primary) {
+    this.markers = markers;
+    this.primary = primary;
+    for (var i = 0; i < markers.length; ++i)
+      markers[i].parent = this;
+  };
+  eventMixin(SharedTextMarker);
+
+  SharedTextMarker.prototype.clear = function() {
+    if (this.explicitlyCleared) return;
+    this.explicitlyCleared = true;
+    for (var i = 0; i < this.markers.length; ++i)
+      this.markers[i].clear();
+    signalLater(this, "clear");
+  };
+  SharedTextMarker.prototype.find = function(side, lineObj) {
+    return this.primary.find(side, lineObj);
+  };
+
+  function markTextShared(doc, from, to, options, type) {
+    options = copyObj(options);
+    options.shared = false;
+    var markers = [markText(doc, from, to, options, type)], primary = markers[0];
+    var widget = options.widgetNode;
+    linkedDocs(doc, function(doc) {
+      if (widget) options.widgetNode = widget.cloneNode(true);
+      markers.push(markText(doc, clipPos(doc, from), clipPos(doc, to), options, type));
+      for (var i = 0; i < doc.linked.length; ++i)
+        if (doc.linked[i].isParent) return;
+      primary = lst(markers);
+    });
+    return new SharedTextMarker(markers, primary);
+  }
+
+  function findSharedMarkers(doc) {
+    return doc.findMarks(Pos(doc.first, 0), doc.clipPos(Pos(doc.lastLine())),
+                         function(m) { return m.parent; });
+  }
+
+  function copySharedMarkers(doc, markers) {
+    for (var i = 0; i < markers.length; i++) {
+      var marker = markers[i], pos = marker.find();
+      var mFrom = doc.clipPos(pos.from), mTo = doc.clipPos(pos.to);
+      if (cmp(mFrom, mTo)) {
+        var subMark = markText(doc, mFrom, mTo, marker.primary, marker.primary.type);
+        marker.markers.push(subMark);
+        subMark.parent = marker;
+      }
+    }
+  }
+
+  function detachSharedMarkers(markers) {
+    for (var i = 0; i < markers.length; i++) {
+      var marker = markers[i], linked = [marker.primary.doc];;
+      linkedDocs(marker.primary.doc, function(d) { linked.push(d); });
+      for (var j = 0; j < marker.markers.length; j++) {
+        var subMarker = marker.markers[j];
+        if (indexOf(linked, subMarker.doc) == -1) {
+          subMarker.parent = null;
+          marker.markers.splice(j--, 1);
+        }
+      }
+    }
+  }
+
+  // TEXTMARKER SPANS
+
+  function MarkedSpan(marker, from, to) {
+    this.marker = marker;
+    this.from = from; this.to = to;
+  }
+
+  // Search an array of spans for a span matching the given marker.
+  function getMarkedSpanFor(spans, marker) {
+    if (spans) for (var i = 0; i < spans.length; ++i) {
+      var span = spans[i];
+      if (span.marker == marker) return span;
+    }
+  }
+  // Remove a span from an array, returning undefined if no spans are
+  // left (we don't store arrays for lines without spans).
+  function removeMarkedSpan(spans, span) {
+    for (var r, i = 0; i < spans.length; ++i)
+      if (spans[i] != span) (r || (r = [])).push(spans[i]);
+    return r;
+  }
+  // Add a span to a line.
+  function addMarkedSpan(line, span) {
+    line.markedSpans = line.markedSpans ? line.markedSpans.concat([span]) : [span];
+    span.marker.attachLine(line);
+  }
+
+  // Used for the algorithm that adjusts markers for a change in the
+  // document. These functions cut an array of spans at a given
+  // character position, returning an array of remaining chunks (or
+  // undefined if nothing remains).
+  function markedSpansBefore(old, startCh, isInsert) {
+    if (old) for (var i = 0, nw; i < old.length; ++i) {
+      var span = old[i], marker = span.marker;
+      var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= startCh : span.from < startCh);
+      if (startsBefore || span.from == startCh && marker.type == "bookmark" && (!isInsert || !span.marker.insertLeft)) {
+        var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= startCh : span.to > startCh);
+        (nw || (nw = [])).push(new MarkedSpan(marker, span.from, endsAfter ? null : span.to));
+      }
+    }
+    return nw;
+  }
+  function markedSpansAfter(old, endCh, isInsert) {
+    if (old) for (var i = 0, nw; i < old.length; ++i) {
+      var span = old[i], marker = span.marker;
+      var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= endCh : span.to > endCh);
+      if (endsAfter || span.from == endCh && marker.type == "bookmark" && (!isInsert || span.marker.insertLeft)) {
+        var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= endCh : span.from < endCh);
+        (nw || (nw = [])).push(new MarkedSpan(marker, startsBefore ? null : span.from - endCh,
+                                              span.to == null ? null : span.to - endCh));
+      }
+    }
+    return nw;
+  }
+
+  // Given a change object, compute the new set of marker spans that
+  // cover the line in which the change took place. Removes spans
+  // entirely within the change, reconnects spans belonging to the
+  // same marker that appear on both sides of the change, and cuts off
+  // spans partially within the change. Returns an array of span
+  // arrays with one element for each line in (after) the change.
+  function stretchSpansOverChange(doc, change) {
+    var oldFirst = isLine(doc, change.from.line) && getLine(doc, change.from.line).markedSpans;
+    var oldLast = isLine(doc, change.to.line) && getLine(doc, change.to.line).markedSpans;
+    if (!oldFirst && !oldLast) return null;
+
+    var startCh = change.from.ch, endCh = change.to.ch, isInsert = cmp(change.from, change.to) == 0;
+    // Get the spans that 'stick out' on both sides
+    var first = markedSpansBefore(oldFirst, startCh, isInsert);
+    var last = markedSpansAfter(oldLast, endCh, isInsert);
+
+    // Next, merge those two ends
+    var sameLine = change.text.length == 1, offset = lst(change.text).length + (sameLine ? startCh : 0);
+    if (first) {
+      // Fix up .to properties of first
+      for (var i = 0; i < first.length; ++i) {
+        var span = first[i];
+        if (span.to == null) {
+          var found = getMarkedSpanFor(last, span.marker);
+          if (!found) span.to = startCh;
+          else if (sameLine) span.to = found.to == null ? null : found.to + offset;
+        }
+      }
+    }
+    if (last) {
+      // Fix up .from in last (or move them into first in case of sameLine)
+      for (var i = 0; i < last.length; ++i) {
+        var span = last[i];
+        if (span.to != null) span.to += offset;
+        if (span.from == null) {
+          var found = getMarkedSpanFor(first, span.marker);
+          if (!found) {
+            span.from = offset;
+            if (sameLine) (first || (first = [])).push(span);
+          }
+        } else {
+          span.from += offset;
+          if (sameLine) (first || (first = [])).push(span);
+        }
+      }
+    }
+    // Make sure we didn't create any zero-length spans
+    if (first) first = clearEmptySpans(first);
+    if (last && last != first) last = clearEmptySpans(last);
+
+    var newMarkers = [first];
+    if (!sameLine) {
+      // Fill gap with whole-line-spans
+      var gap = change.text.length - 2, gapMarkers;
+      if (gap > 0 && first)
+        for (var i = 0; i < first.length; ++i)
+          if (first[i].to == null)
+            (gapMarkers || (gapMarkers = [])).push(new MarkedSpan(first[i].marker, null, null));
+      for (var i = 0; i < gap; ++i)
+        newMarkers.push(gapMarkers);
+      newMarkers.push(last);
+    }
+    return newMarkers;
+  }
+
+  // Remove spans that are empty and don't have a clearWhenEmpty
+  // option of false.
+  function clearEmptySpans(spans) {
+    for (var i = 0; i < spans.length; ++i) {
+      var span = spans[i];
+      if (span.from != null && span.from == span.to && span.marker.clearWhenEmpty !== false)
+        spans.splice(i--, 1);
+    }
+    if (!spans.length) return null;
+    return spans;
+  }
+
+  // Used for un/re-doing changes from the history. Combines the
+  // result of computing the existing spans with the set of spans that
+  // existed in the history (so that deleting around a span and then
+  // undoing brings back the span).
+  function mergeOldSpans(doc, change) {
+    var old = getOldSpans(doc, change);
+    var stretched = stretchSpansOverChange(doc, change);
+    if (!old) return stretched;
+    if (!stretched) return old;
+
+    for (var i = 0; i < old.length; ++i) {
+      var oldCur = old[i], stretchCur = stretched[i];
+      if (oldCur && stretchCur) {
+        spans: for (var j = 0; j < stretchCur.length; ++j) {
+          var span = stretchCur[j];
+          for (var k = 0; k < oldCur.length; ++k)
+            if (oldCur[k].marker == span.marker) continue spans;
+          oldCur.push(span);
+        }
+      } else if (stretchCur) {
+        old[i] = stretchCur;
+      }
+    }
+    return old;
+  }
+
+  // Used to 'clip' out readOnly ranges when making a change.
+  function removeReadOnlyRanges(doc, from, to) {
+    var markers = null;
+    doc.iter(from.line, to.line + 1, function(line) {
+      if (line.markedSpans) for (var i = 0; i < line.markedSpans.length; ++i) {
+        var mark = line.markedSpans[i].marker;
+        if (mark.readOnly && (!markers || indexOf(markers, mark) == -1))
+          (markers || (markers = [])).push(mark);
+      }
+    });
+    if (!markers) return null;
+    var parts = [{from: from, to: to}];
+    for (var i = 0; i < markers.length; ++i) {
+      var mk = markers[i], m = mk.find(0);
+      for (var j = 0; j < parts.length; ++j) {
+        var p = parts[j];
+        if (cmp(p.to, m.from) < 0 || cmp(p.from, m.to) > 0) continue;
+        var newParts = [j, 1], dfrom = cmp(p.from, m.from), dto = cmp(p.to, m.to);
+        if (dfrom < 0 || !mk.inclusiveLeft && !dfrom)
+          newParts.push({from: p.from, to: m.from});
+        if (dto > 0 || !mk.inclusiveRight && !dto)
+          newParts.push({from: m.to, to: p.to});
+        parts.splice.apply(parts, newParts);
+        j += newParts.length - 1;
+      }
+    }
+    return parts;
+  }
+
+  // Connect or disconnect spans from a line.
+  function detachMarkedSpans(line) {
+    var spans = line.markedSpans;
+    if (!spans) return;
+    for (var i = 0; i < spans.length; ++i)
+      spans[i].marker.detachLine(line);
+    line.markedSpans = null;
+  }
+  function attachMarkedSpans(line, spans) {
+    if (!spans) return;
+    for (var i = 0; i < spans.length; ++i)
+      spans[i].marker.attachLine(line);
+    line.markedSpans = spans;
+  }
+
+  // Helpers used when computing which overlapping collapsed span
+  // counts as the larger one.
+  function extraLeft(marker) { return marker.inclusiveLeft ? -1 : 0; }
+  function extraRight(marker) { return marker.inclusiveRight ? 1 : 0; }
+
+  // Returns a number indicating which of two overlapping collapsed
+  // spans is larger (and thus includes the other). Falls back to
+  // comparing ids when the spans cover exactly the same range.
+  function compareCollapsedMarkers(a, b) {
+    var lenDiff = a.lines.length - b.lines.length;
+    if (lenDiff != 0) return lenDiff;
+    var aPos = a.find(), bPos = b.find();
+    var fromCmp = cmp(aPos.from, bPos.from) || extraLeft(a) - extraLeft(b);
+    if (fromCmp) return -fromCmp;
+    var toCmp = cmp(aPos.to, bPos.to) || extraRight(a) - extraRight(b);
+    if (toCmp) return toCmp;
+    return b.id - a.id;
+  }
+
+  // Find out whether a line ends or starts in a collapsed span. If
+  // so, return the marker for that span.
+  function collapsedSpanAtSide(line, start) {
+    var sps = sawCollapsedSpans && line.markedSpans, found;
+    if (sps) for (var sp, i = 0; i < sps.length; ++i) {
+      sp = sps[i];
+      if (sp.marker.collapsed && (start ? sp.from : sp.to) == null &&
+          (!found || compareCollapsedMarkers(found, sp.marker) < 0))
+        found = sp.marker;
+    }
+    return found;
+  }
+  function collapsedSpanAtStart(line) { return collapsedSpanAtSide(line, true); }
+  function collapsedSpanAtEnd(line) { return collapsedSpanAtSide(line, false); }
+
+  // Test whether there exists a collapsed span that partially
+  // overlaps (covers the start or end, but not both) of a new span.
+  // Such overlap is not allowed.
+  function conflictingCollapsedRange(doc, lineNo, from, to, marker) {
+    var line = getLine(doc, lineNo);
+    var sps = sawCollapsedSpans && line.markedSpans;
+    if (sps) for (var i = 0; i < sps.length; ++i) {
+      var sp = sps[i];
+      if (!sp.marker.collapsed) continue;
+      var found = sp.marker.find(0);
+      var fromCmp = cmp(found.from, from) || extraLeft(sp.marker) - extraLeft(marker);
+      var toCmp = cmp(found.to, to) || extraRight(sp.marker) - extraRight(marker);
+      if (fromCmp >= 0 && toCmp <= 0 || fromCmp <= 0 && toCmp >= 0) continue;
+      if (fromCmp <= 0 && (cmp(found.to, from) > 0 || (sp.marker.inclusiveRight && marker.inclusiveLeft)) ||
+          fromCmp >= 0 && (cmp(found.from, to) < 0 || (sp.marker.inclusiveLeft && marker.inclusiveRight)))
+        return true;
+    }
+  }
+
+  // A visual line is a line as drawn on the screen. Folding, for
+  // example, can cause multiple logical lines to appear on the same
+  // visual line. This finds the start of the visual line that the
+  // given line is part of (usually that is the line itself).
+  function visualLine(line) {
+    var merged;
+    while (merged = collapsedSpanAtStart(line))
+      line = merged.find(-1, true).line;
+    return line;
+  }
+
+  // Returns an array of logical lines that continue the visual line
+  // started by the argument, or undefined if there are no such lines.
+  function visualLineContinued(line) {
+    var merged, lines;
+    while (merged = collapsedSpanAtEnd(line)) {
+      line = merged.find(1, true).line;
+      (lines || (lines = [])).push(line);
+    }
+    return lines;
+  }
+
+  // Get the line number of the start of the visual line that the
+  // given line number is part of.
+  function visualLineNo(doc, lineN) {
+    var line = getLine(doc, lineN), vis = visualLine(line);
+    if (line == vis) return lineN;
+    return lineNo(vis);
+  }
+  // Get the line number of the start of the next visual line after
+  // the given line.
+  function visualLineEndNo(doc, lineN) {
+    if (lineN > doc.lastLine()) return lineN;
+    var line = getLine(doc, lineN), merged;
+    if (!lineIsHidden(doc, line)) return lineN;
+    while (merged = collapsedSpanAtEnd(line))
+      line = merged.find(1, true).line;
+    return lineNo(line) + 1;
+  }
+
+  // Compute whether a line is hidden. Lines count as hidden when they
+  // are part of a visual line that starts with another line, or when
+  // they are entirely covered by collapsed, non-widget span.
+  function lineIsHidden(doc, line) {
+    var sps = sawCollapsedSpans && line.markedSpans;
+    if (sps) for (var sp, i = 0; i < sps.length; ++i) {
+      sp = sps[i];
+      if (!sp.marker.collapsed) continue;
+      if (sp.from == null) return true;
+      if (sp.marker.widgetNode) continue;
+      if (sp.from == 0 && sp.marker.inclusiveLeft && lineIsHiddenInner(doc, line, sp))
+        return true;
+    }
+  }
+  function lineIsHiddenInner(doc, line, span) {
+    if (span.to == null) {
+      var end = span.marker.find(1, true);
+      return lineIsHiddenInner(doc, end.line, getMarkedSpanFor(end.line.markedSpans, span.marker));
+    }
+    if (span.marker.inclusiveRight && span.to == line.text.length)
+      return true;
+    for (var sp, i = 0; i < line.markedSpans.length; ++i) {
+      sp = line.markedSpans[i];
+      if (sp.marker.collapsed && !sp.marker.widgetNode && sp.from == span.to &&
+          (sp.to == null || sp.to != span.from) &&
+          (sp.marker.inclusiveLeft || span.marker.inclusiveRight) &&
+          lineIsHiddenInner(doc, line, sp)) return true;
+    }
+  }
+
+  // LINE WIDGETS
+
+  // Line widgets are block elements displayed above or below a line.
+
+  var LineWidget = CodeMirror.LineWidget = function(cm, node, options) {
+    if (options) for (var opt in options) if (options.hasOwnProperty(opt))
+      this[opt] = options[opt];
+    this.cm = cm;
+    this.node = node;
+  };
+  eventMixin(LineWidget);
+
+  function adjustScrollWhenAboveVisible(cm, line, diff) {
+    if (heightAtLine(line) < ((cm.curOp && cm.curOp.scrollTop) || cm.doc.scrollTop))
+      addToScrollPos(cm, null, diff);
+  }
+
+  LineWidget.prototype.clear = function() {
+    var cm = this.cm, ws = this.line.widgets, line = this.line, no = lineNo(line);
+    if (no == null || !ws) return;
+    for (var i = 0; i < ws.length; ++i) if (ws[i] == this) ws.splice(i--, 1);
+    if (!ws.length) line.widgets = null;
+    var height = widgetHeight(this);
+    runInOp(cm, function() {
+      adjustScrollWhenAboveVisible(cm, line, -height);
+      regLineChange(cm, no, "widget");
+      updateLineHeight(line, Math.max(0, line.height - height));
+    });
+  };
+  LineWidget.prototype.changed = function() {
+    var oldH = this.height, cm = this.cm, line = this.line;
+    this.height = null;
+    var diff = widgetHeight(this) - oldH;
+    if (!diff) return;
+    runInOp(cm, function() {
+      cm.curOp.forceUpdate = true;
+      adjustScrollWhenAboveVisible(cm, line, diff);
+      updateLineHeight(line, line.height + diff);
+    });
+  };
+
+  function widgetHeight(widget) {
+    if (widget.height != null) return widget.height;
+    if (!contains(document.body, widget.node)) {
+      var parentStyle = "position: relative;";
+      if (widget.coverGutter)
+        parentStyle += "margin-left: -" + widget.cm.getGutterElement().offsetWidth + "px;";
+      removeChildrenAndAdd(widget.cm.display.measure, elt("div", [widget.node], null, parentStyle));
+    }
+    return widget.height = widget.node.offsetHeight;
+  }
+
+  function addLineWidget(cm, handle, node, options) {
+    var widget = new LineWidget(cm, node, options);
+    if (widget.noHScroll) cm.display.alignWidgets = true;
+    changeLine(cm.doc, handle, "widget", function(line) {
+      var widgets = line.widgets || (line.widgets = []);
+      if (widget.insertAt == null) widgets.push(widget);
+      else widgets.splice(Math.min(widgets.length - 1, Math.max(0, widget.insertAt)), 0, widget);
+      widget.line = line;
+      if (!lineIsHidden(cm.doc, line)) {
+        var aboveVisible = heightAtLine(line) < cm.doc.scrollTop;
+        updateLineHeight(line, line.height + widgetHeight(widget));
+        if (aboveVisible) addToScrollPos(cm, null, widget.height);
+        cm.curOp.forceUpdate = true;
+      }
+      return true;
+    });
+    return widget;
+  }
+
+  // LINE DATA STRUCTURE
+
+  // Line objects. These hold state related to a line, including
+  // highlighting info (the styles array).
+  var Line = CodeMirror.Line = function(text, markedSpans, estimateHeight) {
+    this.text = text;
+    attachMarkedSpans(this, markedSpans);
+    this.height = estimateHeight ? estimateHeight(this) : 1;
+  };
+  eventMixin(Line);
+  Line.prototype.lineNo = function() { return lineNo(this); };
+
+  // Change the content (text, markers) of a line. Automatically
+  // invalidates cached information and tries to re-estimate the
+  // line's height.
+  function updateLine(line, text, markedSpans, estimateHeight) {
+    line.text = text;
+    if (line.stateAfter) line.stateAfter = null;
+    if (line.styles) line.styles = null;
+    if (line.order != null) line.order = null;
+    detachMarkedSpans(line);
+    attachMarkedSpans(line, markedSpans);
+    var estHeight = estimateHeight ? estimateHeight(line) : 1;
+    if (estHeight != line.height) updateLineHeight(line, estHeight);
+  }
+
+  // Detach a line from the document tree and its markers.
+  function cleanUpLine(line) {
+    line.parent = null;
+    detachMarkedSpans(line);
+  }
+
+  function extractLineClasses(type, output) {
+    if (type) for (;;) {
+      var lineClass = type.match(/(?:^|\s+)line-(background-)?(\S+)/);
+      if (!lineClass) break;
+      type = type.slice(0, lineClass.index) + type.slice(lineClass.index + lineClass[0].length);
+      var prop = lineClass[1] ? "bgClass" : "textClass";
+      if (output[prop] == null)
+        output[prop] = lineClass[2];
+      else if (!(new RegExp("(?:^|\s)" + lineClass[2] + "(?:$|\s)")).test(output[prop]))
+        output[prop] += " " + lineClass[2];
+    }
+    return type;
+  }
+
+  function callBlankLine(mode, state) {
+    if (mode.blankLine) return mode.blankLine(state);
+    if (!mode.innerMode) return;
+    var inner = CodeMirror.innerMode(mode, state);
+    if (inner.mode.blankLine) return inner.mode.blankLine(inner.state);
+  }
+
+  function readToken(mode, stream, state, inner) {
+    for (var i = 0; i < 10; i++) {
+      if (inner) inner[0] = CodeMirror.innerMode(mode, state).mode;
+      var style = mode.token(stream, state);
+      if (stream.pos > stream.start) return style;
+    }
+    throw new Error("Mode " + mode.name + " failed to advance stream.");
+  }
+
+  // Utility for getTokenAt and getLineTokens
+  function takeToken(cm, pos, precise, asArray) {
+    function getObj(copy) {
+      return {start: stream.start, end: stream.pos,
+              string: stream.current(),
+              type: style || null,
+              state: copy ? copyState(doc.mode, state) : state};
+    }
+
+    var doc = cm.doc, mode = doc.mode, style;
+    pos = clipPos(doc, pos);
+    var line = getLine(doc, pos.line), state = getStateBefore(cm, pos.line, precise);
+    var stream = new StringStream(line.text, cm.options.tabSize), tokens;
+    if (asArray) tokens = [];
+    while ((asArray || stream.pos < pos.ch) && !stream.eol()) {
+      stream.start = stream.pos;
+      style = readToken(mode, stream, state);
+      if (asArray) tokens.push(getObj(true));
+    }
+    return asArray ? tokens : getObj();
+  }
+
+  // Run the given mode's parser over a line, calling f for each token.
+  function runMode(cm, text, mode, state, f, lineClasses, forceToEnd) {
+    var flattenSpans = mode.flattenSpans;
+    if (flattenSpans == null) flattenSpans = cm.options.flattenSpans;
+    var curStart = 0, curStyle = null;
+    var stream = new StringStream(text, cm.options.tabSize), style;
+    var inner = cm.options.addModeClass && [null];
+    if (text == "") extractLineClasses(callBlankLine(mode, state), lineClasses);
+    while (!stream.eol()) {
+      if (stream.pos > cm.options.maxHighlightLength) {
+        flattenSpans = false;
+        if (forceToEnd) processLine(cm, text, state, stream.pos);
+        stream.pos = text.length;
+        style = null;
+      } else {
+        style = extractLineClasses(readToken(mode, stream, state, inner), lineClasses);
+      }
+      if (inner) {
+        var mName = inner[0].name;
+        if (mName) style = "m-" + (style ? mName + " " + style : mName);
+      }
+      if (!flattenSpans || curStyle != style) {
+        if (curStart < stream.start) f(stream.start, curStyle);
+        curStart = stream.start; curStyle = style;
+      }
+      stream.start = stream.pos;
+    }
+    while (curStart < stream.pos) {
+      // Webkit seems to refuse to render text nodes longer than 57444 characters
+      var pos = Math.min(stream.pos, curStart + 50000);
+      f(pos, curStyle);
+      curStart = pos;
+    }
+  }
+
+  // Compute a style array (an array starting with a mode generation
+  // -- for invalidation -- followed by pairs of end positions and
+  // style strings), which is used to highlight the tokens on the
+  // line.
+  function highlightLine(cm, line, state, forceToEnd) {
+    // A styles array always starts with a number identifying the
+    // mode/overlays that it is based on (for easy invalidation).
+    var st = [cm.state.modeGen], lineClasses = {};
+    // Compute the base array of styles
+    runMode(cm, line.text, cm.doc.mode, state, function(end, style) {
+      st.push(end, style);
+    }, lineClasses, forceToEnd);
+
+    // Run overlays, adjust style array.
+    for (var o = 0; o < cm.state.overlays.length; ++o) {
+      var overlay = cm.state.overlays[o], i = 1, at = 0;
+      runMode(cm, line.text, overlay.mode, true, function(end, style) {
+        var start = i;
+        // Ensure there's a token end at the current position, and that i points at it
+        while (at < end) {
+          var i_end = st[i];
+          if (i_end > end)
+            st.splice(i, 1, end, st[i+1], i_end);
+          i += 2;
+          at = Math.min(end, i_end);
+        }
+        if (!style) return;
+        if (overlay.opaque) {
+          st.splice(start, i - start, end, "cm-overlay " + style);
+          i = start + 2;
+        } else {
+          for (; start < i; start += 2) {
+            var cur = st[start+1];
+            st[start+1] = (cur ? cur + " " : "") + "cm-overlay " + style;
+          }
+        }
+      }, lineClasses);
+    }
+
+    return {styles: st, classes: lineClasses.bgClass || lineClasses.textClass ? lineClasses : null};
+  }
+
+  function getLineStyles(cm, line, updateFrontier) {
+    if (!line.styles || line.styles[0] != cm.state.modeGen) {
+      var result = highlightLine(cm, line, line.stateAfter = getStateBefore(cm, lineNo(line)));
+      line.styles = result.styles;
+      if (result.classes) line.styleClasses = result.classes;
+      else if (line.styleClasses) line.styleClasses = null;
+      if (updateFrontier === cm.doc.frontier) cm.doc.frontier++;
+    }
+    return line.styles;
+  }
+
+  // Lightweight form of highlight -- proceed over this line and
+  // update state, but don't save a style array. Used for lines that
+  // aren't currently visible.
+  function processLine(cm, text, state, startAt) {
+    var mode = cm.doc.mode;
+    var stream = new StringStream(text, cm.options.tabSize);
+    stream.start = stream.pos = startAt || 0;
+    if (text == "") callBlankLine(mode, state);
+    while (!stream.eol() && stream.pos <= cm.options.maxHighlightLength) {
+      readToken(mode, stream, state);
+      stream.start = stream.pos;
+    }
+  }
+
+  // Convert a style as returned by a mode (either null, or a string
+  // containing one or more styles) to a CSS style. This is cached,
+  // and also looks for line-wide styles.
+  var styleToClassCache = {}, styleToClassCacheWithMode = {};
+  function interpretTokenStyle(style, options) {
+    if (!style || /^\s*$/.test(style)) return null;
+    var cache = options.addModeClass ? styleToClassCacheWithMode : styleToClassCache;
+    return cache[style] ||
+      (cache[style] = style.replace(/\S+/g, "cm-$&"));
+  }
+
+  // Render the DOM representation of the text of a line. Also builds
+  // up a 'line map', which points at the DOM nodes that represent
+  // specific stretches of text, and is used by the measuring code.
+  // The returned object contains the DOM node, this map, and
+  // information about line-wide styles that were set by the mode.
+  function buildLineContent(cm, lineView) {
+    // The padding-right forces the element to have a 'border', which
+    // is needed on Webkit to be able to get line-level bounding
+    // rectangles for it (in measureChar).
+    var content = elt("span", null, null, webkit ? "padding-right: .1px" : null);
+    var builder = {pre: elt("pre", [content]), content: content, col: 0, pos: 0, cm: cm};
+    lineView.measure = {};
+
+    // Iterate over the logical lines that make up this visual line.
+    for (var i = 0; i <= (lineView.rest ? lineView.rest.length : 0); i++) {
+      var line = i ? lineView.rest[i - 1] : lineView.line, order;
+      builder.pos = 0;
+      builder.addToken = buildToken;
+      // Optionally wire in some hacks into the token-rendering
+      // algorithm, to deal with browser quirks.
+      if ((ie || webkit) && cm.getOption("lineWrapping"))
+        builder.addToken = buildTokenSplitSpaces(builder.addToken);
+      if (hasBadBidiRects(cm.display.measure) && (order = getOrder(line)))
+        builder.addToken = buildTokenBadBidi(builder.addToken, order);
+      builder.map = [];
+      var allowFrontierUpdate = lineView != cm.display.externalMeasured && lineNo(line);
+      insertLineContent(line, builder, getLineStyles(cm, line, allowFrontierUpdate));
+      if (line.styleClasses) {
+        if (line.styleClasses.bgClass)
+          builder.bgClass = joinClasses(line.styleClasses.bgClass, builder.bgClass || "");
+        if (line.styleClasses.textClass)
+          builder.textClass = joinClasses(line.styleClasses.textClass, builder.textClass || "");
+      }
+
+      // Ensure at least a single node is present, for measuring.
+      if (builder.map.length == 0)
+        builder.map.push(0, 0, builder.content.appendChild(zeroWidthElement(cm.display.measure)));
+
+      // Store the map and a cache object for the current logical line
+      if (i == 0) {
+        lineView.measure.map = builder.map;
+        lineView.measure.cache = {};
+      } else {
+        (lineView.measure.maps || (lineView.measure.maps = [])).push(builder.map);
+        (lineView.measure.caches || (lineView.measure.caches = [])).push({});
+      }
+    }
+
+    // See issue #2901
+    if (webkit && /\bcm-tab\b/.test(builder.content.lastChild.className))
+      builder.content.className = "cm-tab-wrap-hack";
+
+    signal(cm, "renderLine", cm, lineView.line, builder.pre);
+    if (builder.pre.className)
+      builder.textClass = joinClasses(builder.pre.className, builder.textClass || "");
+
+    return builder;
+  }
+
+  function defaultSpecialCharPlaceholder(ch) {
+    var token = elt("span", "\u2022", "cm-invalidchar");
+    token.title = "\\u" + ch.charCodeAt(0).toString(16);
+    return token;
+  }
+
+  // Build up the DOM representation for a single token, and add it to
+  // the line map. Takes care to render special characters separately.
+  function buildToken(builder, text, style, startStyle, endStyle, title) {
+    if (!text) return;
+    var special = builder.cm.options.specialChars, mustWrap = false;
+    if (!special.test(text)) {
+      builder.col += text.length;
+      var content = document.createTextNode(text);
+      builder.map.push(builder.pos, builder.pos + text.length, content);
+      if (ie && ie_version < 9) mustWrap = true;
+      builder.pos += text.length;
+    } else {
+      var content = document.createDocumentFragment(), pos = 0;
+      while (true) {
+        special.lastIndex = pos;
+        var m = special.exec(text);
+        var skipped = m ? m.index - pos : text.length - pos;
+        if (skipped) {
+          var txt = document.createTextNode(text.slice(pos, pos + skipped));
+          if (ie && ie_version < 9) content.appendChild(elt("span", [txt]));
+          else content.appendChild(txt);
+          builder.map.push(builder.pos, builder.pos + skipped, txt);
+          builder.col += skipped;
+          builder.pos += skipped;
+        }
+        if (!m) break;
+        pos += skipped + 1;
+        if (m[0] == "\t") {
+          var tabSize = builder.cm.options.tabSize, tabWidth = tabSize - builder.col % tabSize;
+          var txt = content.appendChild(elt("span", spaceStr(tabWidth), "cm-tab"));
+          builder.col += tabWidth;
+        } else {
+          var txt = builder.cm.options.specialCharPlaceholder(m[0]);
+          if (ie && ie_version < 9) content.appendChild(elt("span", [txt]));
+          else content.appendChild(txt);
+          builder.col += 1;
+        }
+        builder.map.push(builder.pos, builder.pos + 1, txt);
+        builder.pos++;
+      }
+    }
+    if (style || startStyle || endStyle || mustWrap) {
+      var fullStyle = style || "";
+      if (startStyle) fullStyle += startStyle;
+      if (endStyle) fullStyle += endStyle;
+      var token = elt("span", [content], fullStyle);
+      if (title) token.title = title;
+      return builder.content.appendChild(token);
+    }
+    builder.content.appendChild(content);
+  }
+
+  function buildTokenSplitSpaces(inner) {
+    function split(old) {
+      var out = " ";
+      for (var i = 0; i < old.length - 2; ++i) out += i % 2 ? " " : "\u00a0";
+      out += " ";
+      return out;
+    }
+    return function(builder, text, style, startStyle, endStyle, title) {
+      inner(builder, text.replace(/ {3,}/g, split), style, startStyle, endStyle, title);
+    };
+  }
+
+  // Work around nonsense dimensions being reported for stretches of
+  // right-to-left text.
+  function buildTokenBadBidi(inner, order) {
+    return function(builder, text, style, startStyle, endStyle, title) {
+      style = style ? style + " cm-force-border" : "cm-force-border";
+      var start = builder.pos, end = start + text.length;
+      for (;;) {
+        // Find the part that overlaps with the start of this text
+        for (var i = 0; i < order.length; i++) {
+          var part = order[i];
+          if (part.to > start && part.from <= start) break;
+        }
+        if (part.to >= end) return inner(builder, text, style, startStyle, endStyle, title);
+        inner(builder, text.slice(0, part.to - start), style, startStyle, null, title);
+        startStyle = null;
+        text = text.slice(part.to - start);
+        start = part.to;
+      }
+    };
+  }
+
+  function buildCollapsedSpan(builder, size, marker, ignoreWidget) {
+    var widget = !ignoreWidget && marker.widgetNode;
+    if (widget) {
+      builder.map.push(builder.pos, builder.pos + size, widget);
+      builder.content.appendChild(widget);
+    }
+    builder.pos += size;
+  }
+
+  // Outputs a number of spans to make up a line, taking highlighting
+  // and marked text into account.
+  function insertLineContent(line, builder, styles) {
+    var spans = line.markedSpans, allText = line.text, at = 0;
+    if (!spans) {
+      for (var i = 1; i < styles.length; i+=2)
+        builder.addToken(builder, allText.slice(at, at = styles[i]), interpretTokenStyle(styles[i+1], builder.cm.options));
+      return;
+    }
+
+    var len = allText.length, pos = 0, i = 1, text = "", style;
+    var nextChange = 0, spanStyle, spanEndStyle, spanStartStyle, title, collapsed;
+    for (;;) {
+      if (nextChange == pos) { // Update current marker set
+        spanStyle = spanEndStyle = spanStartStyle = title = "";
+        collapsed = null; nextChange = Infinity;
+        var foundBookmarks = [];
+        for (var j = 0; j < spans.length; ++j) {
+          var sp = spans[j], m = sp.marker;
+          if (sp.from <= pos && (sp.to == null || sp.to > pos)) {
+            if (sp.to != null && nextChange > sp.to) { nextChange = sp.to; spanEndStyle = ""; }
+            if (m.className) spanStyle += " " + m.className;
+            if (m.startStyle && sp.from == pos) spanStartStyle += " " + m.startStyle;
+            if (m.endStyle && sp.to == nextChange) spanEndStyle += " " + m.endStyle;
+            if (m.title && !title) title = m.title;
+            if (m.collapsed && (!collapsed || compareCollapsedMarkers(collapsed.marker, m) < 0))
+              collapsed = sp;
+          } else if (sp.from > pos && nextChange > sp.from) {
+            nextChange = sp.from;
+          }
+          if (m.type == "bookmark" && sp.from == pos && m.widgetNode) foundBookmarks.push(m);
+        }
+        if (collapsed && (collapsed.from || 0) == pos) {
+          buildCollapsedSpan(builder, (collapsed.to == null ? len + 1 : collapsed.to) - pos,
+                             collapsed.marker, collapsed.from == null);
+          if (collapsed.to == null) return;
+        }
+        if (!collapsed && foundBookmarks.length) for (var j = 0; j < foundBookmarks.length; ++j)
+          buildCollapsedSpan(builder, 0, foundBookmarks[j]);
+      }
+      if (pos >= len) break;
+
+      var upto = Math.min(len, nextChange);
+      while (true) {
+        if (text) {
+          var end = pos + text.length;
+          if (!collapsed) {
+            var tokenText = end > upto ? text.slice(0, upto - pos) : text;
+            builder.addToken(builder, tokenText, style ? style + spanStyle : spanStyle,
+                             spanStartStyle, pos + tokenText.length == nextChange ? spanEndStyle : "", title);
+          }
+          if (end >= upto) {text = text.slice(upto - pos); pos = upto; break;}
+          pos = end;
+          spanStartStyle = "";
+        }
+        text = allText.slice(at, at = styles[i++]);
+        style = interpretTokenStyle(styles[i++], builder.cm.options);
+      }
+    }
+  }
+
+  // DOCUMENT DATA STRUCTURE
+
+  // By default, updates that start and end at the beginning of a line
+  // are treated specially, in order to make the association of line
+  // widgets and marker elements with the text behave more intuitive.
+  function isWholeLineUpdate(doc, change) {
+    return change.from.ch == 0 && change.to.ch == 0 && lst(change.text) == "" &&
+      (!doc.cm || doc.cm.options.wholeLineUpdateBefore);
+  }
+
+  // Perform a change on the document data structure.
+  function updateDoc(doc, change, markedSpans, estimateHeight) {
+    function spansFor(n) {return markedSpans ? markedSpans[n] : null;}
+    function update(line, text, spans) {
+      updateLine(line, text, spans, estimateHeight);
+      signalLater(line, "change", line, change);
+    }
+
+    var from = change.from, to = change.to, text = change.text;
+    var firstLine = getLine(doc, from.line), lastLine = getLine(doc, to.line);
+    var lastText = lst(text), lastSpans = spansFor(text.length - 1), nlines = to.line - from.line;
+
+    // Adjust the line structure
+    if (isWholeLineUpdate(doc, change)) {
+      // This is a whole-line replace. Treated specially to make
+      // sure line objects move the way they are supposed to.
+      for (var i = 0, added = []; i < text.length - 1; ++i)
+        added.push(new Line(text[i], spansFor(i), estimateHeight));
+      update(lastLine, lastLine.text, lastSpans);
+      if (nlines) doc.remove(from.line, nlines);
+      if (added.length) doc.insert(from.line, added);
+    } else if (firstLine == lastLine) {
+      if (text.length == 1) {
+        update(firstLine, firstLine.text.slice(0, from.ch) + lastText + firstLine.text.slice(to.ch), lastSpans);
+      } else {
+        for (var added = [], i = 1; i < text.length - 1; ++i)
+          added.push(new Line(text[i], spansFor(i), estimateHeight));
+        added.push(new Line(lastText + firstLine.text.slice(to.ch), lastSpans, estimateHeight));
+        update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0));
+        doc.insert(from.line + 1, added);
+      }
+    } else if (text.length == 1) {
+      update(firstLine, firstLine.text.slice(0, from.ch) + text[0] + lastLine.text.slice(to.ch), spansFor(0));
+      doc.remove(from.line + 1, nlines);
+    } else {
+      update(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0));
+      update(lastLine, lastText + lastLine.text.slice(to.ch), lastSpans);
+      for (var i = 1, added = []; i < text.length - 1; ++i)
+        added.push(new Line(text[i], spansFor(i), estimateHeight));
+      if (nlines > 1) doc.remove(from.line + 1, nlines - 1);
+      doc.insert(from.line + 1, added);
+    }
+
+    signalLater(doc, "change", doc, change);
+  }
+
+  // The document is represented as a BTree consisting of leaves, with
+  // chunk of lines in them, and branches, with up to ten leaves or
+  // other branch nodes below them. The top node is always a branch
+  // node, and is the document object itself (meaning it has
+  // additional methods and properties).
+  //
+  // All nodes have parent links. The tree is used both to go from
+  // line numbers to line objects, and to go from objects to numbers.
+  // It also indexes by height, and is used to convert between height
+  // and line object, and to find the total height of the document.
+  //
+  // See also http://marijnhaverbeke.nl/blog/codemirror-line-tree.html
+
+  function LeafChunk(lines) {
+    this.lines = lines;
+    this.parent = null;
+    for (var i = 0, height = 0; i < lines.length; ++i) {
+      lines[i].parent = this;
+      height += lines[i].height;
+    }
+    this.height = height;
+  }
+
+  LeafChunk.prototype = {
+    chunkSize: function() { return this.lines.length; },
+    // Remove the n lines at offset 'at'.
+    removeInner: function(at, n) {
+      for (var i = at, e = at + n; i < e; ++i) {
+        var line = this.lines[i];
+        this.height -= line.height;
+        cleanUpLine(line);
+        signalLater(line, "delete");
+      }
+      this.lines.splice(at, n);
+    },
+    // Helper used to collapse a small branch into a single leaf.
+    collapse: function(lines) {
+      lines.push.apply(lines, this.lines);
+    },
+    // Insert the given array of lines at offset 'at', count them as
+    // having the given height.
+    insertInner: function(at, lines, height) {
+      this.height += height;
+      this.lines = this.lines.slice(0, at).concat(lines).concat(this.lines.slice(at));
+      for (var i = 0; i < lines.length; ++i) lines[i].parent = this;
+    },
+    // Used to iterate over a part of the tree.
+    iterN: function(at, n, op) {
+      for (var e = at + n; at < e; ++at)
+        if (op(this.lines[at])) return true;
+    }
+  };
+
+  function BranchChunk(children) {
+    this.children = children;
+    var size = 0, height = 0;
+    for (var i = 0; i < children.length; ++i) {
+      var ch = children[i];
+      size += ch.chunkSize(); height += ch.height;
+      ch.parent = this;
+    }
+    this.size = size;
+    this.height = height;
+    this.parent = null;
+  }
+
+  BranchChunk.prototype = {
+    chunkSize: function() { return this.size; },
+    removeInner: function(at, n) {
+      this.size -= n;
+      for (var i = 0; i < this.children.length; ++i) {
+        var child = this.children[i], sz = child.chunkSize();
+        if (at < sz) {
+          var rm = Math.min(n, sz - at), oldHeight = child.height;
+          child.removeInner(at, rm);
+          this.height -= oldHeight - child.height;
+          if (sz == rm) { this.children.splice(i--, 1); child.parent = null; }
+          if ((n -= rm) == 0) break;
+          at = 0;
+        } else at -= sz;
+      }
+      // If the result is smaller than 25 lines, ensure that it is a
+      // single leaf node.
+      if (this.size - n < 25 &&
+          (this.children.length > 1 || !(this.children[0] instanceof LeafChunk))) {
+        var lines = [];
+        this.collapse(lines);
+        this.children = [new LeafChunk(lines)];
+        this.children[0].parent = this;
+      }
+    },
+    collapse: function(lines) {
+      for (var i = 0; i < this.children.length; ++i) this.children[i].collapse(lines);
+    },
+    insertInner: function(at, lines, height) {
+      this.size += lines.length;
+      this.height += height;
+      for (var i = 0; i < this.children.length; ++i) {
+        var child = this.children[i], sz = child.chunkSize();
+        if (at <= sz) {
+          child.insertInner(at, lines, height);
+          if (child.lines && child.lines.length > 50) {
+            while (child.lines.length > 50) {
+              var spilled = child.lines.splice(child.lines.length - 25, 25);
+              var newleaf = new LeafChunk(spilled);
+              child.height -= newleaf.height;
+              this.children.splice(i + 1, 0, newleaf);
+              newleaf.parent = this;
+            }
+            this.maybeSpill();
+          }
+          break;
+        }
+        at -= sz;
+      }
+    },
+    // When a node has grown, check whether it should be split.
+    maybeSpill: function() {
+      if (this.children.length <= 10) return;
+      var me = this;
+      do {
+        var spilled = me.children.splice(me.children.length - 5, 5);
+        var sibling = new BranchChunk(spilled);
+        if (!me.parent) { // Become the parent node
+          var copy = new BranchChunk(me.children);
+          copy.parent = me;
+          me.children = [copy, sibling];
+          me = copy;
+        } else {
+          me.size -= sibling.size;
+          me.height -= sibling.height;
+          var myIndex = indexOf(me.parent.children, me);
+          me.parent.children.splice(myIndex + 1, 0, sibling);
+        }
+        sibling.parent = me.parent;
+      } while (me.children.length > 10);
+      me.parent.maybeSpill();
+    },
+    iterN: function(at, n, op) {
+      for (var i = 0; i < this.children.length; ++i) {
+        var child = this.children[i], sz = child.chunkSize();
+        if (at < sz) {
+          var used = Math.min(n, sz - at);
+          if (child.iterN(at, used, op)) return true;
+          if ((n -= used) == 0) break;
+          at = 0;
+        } else at -= sz;
+      }
+    }
+  };
+
+  var nextDocId = 0;
+  var Doc = CodeMirror.Doc = function(text, mode, firstLine) {
+    if (!(this instanceof Doc)) return new Doc(text, mode, firstLine);
+    if (firstLine == null) firstLine = 0;
+
+    BranchChunk.call(this, [new LeafChunk([new Line("", null)])]);
+    this.first = firstLine;
+    this.scrollTop = this.scrollLeft = 0;
+    this.cantEdit = false;
+    this.cleanGeneration = 1;
+    this.frontier = firstLine;
+    var start = Pos(firstLine, 0);
+    this.sel = simpleSelection(start);
+    this.history = new History(null);
+    this.id = ++nextDocId;
+    this.modeOption = mode;
+
+    if (typeof text == "string") text = splitLines(text);
+    updateDoc(this, {from: start, to: start, text: text});
+    setSelection(this, simpleSelection(start), sel_dontScroll);
+  };
+
+  Doc.prototype = createObj(BranchChunk.prototype, {
+    constructor: Doc,
+    // Iterate over the document. Supports two forms -- with only one
+    // argument, it calls that for each line in the document. With
+    // three, it iterates over the range given by the first two (with
+    // the second being non-inclusive).
+    iter: function(from, to, op) {
+      if (op) this.iterN(from - this.first, to - from, op);
+      else this.iterN(this.first, this.first + this.size, from);
+    },
+
+    // Non-public interface for adding and removing lines.
+    insert: function(at, lines) {
+      var height = 0;
+      for (var i = 0; i < lines.length; ++i) height += lines[i].height;
+      this.insertInner(at - this.first, lines, height);
+    },
+    remove: function(at, n) { this.removeInner(at - this.first, n); },
+
+    // From here, the methods are part of the public interface. Most
+    // are also available from CodeMirror (editor) instances.
+
+    getValue: function(lineSep) {
+      var lines = getLines(this, this.first, this.first + this.size);
+      if (lineSep === false) return lines;
+      return lines.join(lineSep || "\n");
+    },
+    setValue: docMethodOp(function(code) {
+      var top = Pos(this.first, 0), last = this.first + this.size - 1;
+      makeChange(this, {from: top, to: Pos(last, getLine(this, last).text.length),
+                        text: splitLines(code), origin: "setValue"}, true);
+      setSelection(this, simpleSelection(top));
+    }),
+    replaceRange: function(code, from, to, origin) {
+      from = clipPos(this, from);
+      to = to ? clipPos(this, to) : from;
+      replaceRange(this, code, from, to, origin);
+    },
+    getRange: function(from, to, lineSep) {
+      var lines = getBetween(this, clipPos(this, from), clipPos(this, to));
+      if (lineSep === false) return lines;
+      return lines.join(lineSep || "\n");
+    },
+
+    getLine: function(line) {var l = this.getLineHandle(line); return l && l.text;},
+
+    getLineHandle: function(line) {if (isLine(this, line)) return getLine(this, line);},
+    getLineNumber: function(line) {return lineNo(line);},
+
+    getLineHandleVisualStart: function(line) {
+      if (typeof line == "number") line = getLine(this, line);
+      return visualLine(line);
+    },
+
+    lineCount: function() {return this.size;},
+    firstLine: function() {return this.first;},
+    lastLine: function() {return this.first + this.size - 1;},
+
+    clipPos: function(pos) {return clipPos(this, pos);},
+
+    getCursor: function(start) {
+      var range = this.sel.primary(), pos;
+      if (start == null || start == "head") pos = range.head;
+      else if (start == "anchor") pos = range.anchor;
+      else if (start == "end" || start == "to" || start === false) pos = range.to();
+      else pos = range.from();
+      return pos;
+    },
+    listSelections: function() { return this.sel.ranges; },
+    somethingSelected: function() {return this.sel.somethingSelected();},
+
+    setCursor: docMethodOp(function(line, ch, options) {
+      setSimpleSelection(this, clipPos(this, typeof line == "number" ? Pos(line, ch || 0) : line), null, options);
+    }),
+    setSelection: docMethodOp(function(anchor, head, options) {
+      setSimpleSelection(this, clipPos(this, anchor), clipPos(this, head || anchor), options);
+    }),
+    extendSelection: docMethodOp(function(head, other, options) {
+      extendSelection(this, clipPos(this, head), other && clipPos(this, other), options);
+    }),
+    extendSelections: docMethodOp(function(heads, options) {
+      extendSelections(this, clipPosArray(this, heads, options));
+    }),
+    extendSelectionsBy: docMethodOp(function(f, options) {
+      extendSelections(this, map(this.sel.ranges, f), options);
+    }),
+    setSelections: docMethodOp(function(ranges, primary, options) {
+      if (!ranges.length) return;
+      for (var i = 0, out = []; i < ranges.length; i++)
+        out[i] = new Range(clipPos(this, ranges[i].anchor),
+                           clipPos(this, ranges[i].head));
+      if (primary == null) primary = Math.min(ranges.length - 1, this.sel.primIndex);
+      setSelection(this, normalizeSelection(out, primary), options);
+    }),
+    addSelection: docMethodOp(function(anchor, head, options) {
+      var ranges = this.sel.ranges.slice(0);
+      ranges.push(new Range(clipPos(this, anchor), clipPos(this, head || anchor)));
+      setSelection(this, normalizeSelection(ranges, ranges.length - 1), options);
+    }),
+
+    getSelection: function(lineSep) {
+      var ranges = this.sel.ranges, lines;
+      for (var i = 0; i < ranges.length; i++) {
+        var sel = getBetween(this, ranges[i].from(), ranges[i].to());
+        lines = lines ? lines.concat(sel) : sel;
+      }
+      if (lineSep === false) return lines;
+      else return lines.join(lineSep || "\n");
+    },
+    getSelections: function(lineSep) {
+      var parts = [], ranges = this.sel.ranges;
+      for (var i = 0; i < ranges.length; i++) {
+        var sel = getBetween(this, ranges[i].from(), ranges[i].to());
+        if (lineSep !== false) sel = sel.join(lineSep || "\n");
+        parts[i] = sel;
+      }
+      return parts;
+    },
+    replaceSelection: function(code, collapse, origin) {
+      var dup = [];
+      for (var i = 0; i < this.sel.ranges.length; i++)
+        dup[i] = code;
+      this.replaceSelections(dup, collapse, origin || "+input");
+    },
+    replaceSelections: docMethodOp(function(code, collapse, origin) {
+      var changes = [], sel = this.sel;
+      for (var i = 0; i < sel.ranges.length; i++) {
+        var range = sel.ranges[i];
+        changes[i] = {from: range.from(), to: range.to(), text: splitLines(code[i]), origin: origin};
+      }
+      var newSel = collapse && collapse != "end" && computeReplacedSel(this, changes, collapse);
+      for (var i = changes.length - 1; i >= 0; i--)
+        makeChange(this, changes[i]);
+      if (newSel) setSelectionReplaceHistory(this, newSel);
+      else if (this.cm) ensureCursorVisible(this.cm);
+    }),
+    undo: docMethodOp(function() {makeChangeFromHistory(this, "undo");}),
+    redo: docMethodOp(function() {makeChangeFromHistory(this, "redo");}),
+    undoSelection: docMethodOp(function() {makeChangeFromHistory(this, "undo", true);}),
+    redoSelection: docMethodOp(function() {makeChangeFromHistory(this, "redo", true);}),
+
+    setExtending: function(val) {this.extend = val;},
+    getExtending: function() {return this.extend;},
+
+    historySize: function() {
+      var hist = this.history, done = 0, undone = 0;
+      for (var i = 0; i < hist.done.length; i++) if (!hist.done[i].ranges) ++done;
+      for (var i = 0; i < hist.undone.length; i++) if (!hist.undone[i].ranges) ++undone;
+      return {undo: done, redo: undone};
+    },
+    clearHistory: function() {this.history = new History(this.history.maxGeneration);},
+
+    markClean: function() {
+      this.cleanGeneration = this.changeGeneration(true);
+    },
+    changeGeneration: function(forceSplit) {
+      if (forceSplit)
+        this.history.lastOp = this.history.lastSelOp = this.history.lastOrigin = null;
+      return this.history.generation;
+    },
+    isClean: function (gen) {
+      return this.history.generation == (gen || this.cleanGeneration);
+    },
+
+    getHistory: function() {
+      return {done: copyHistoryArray(this.history.done),
+              undone: copyHistoryArray(this.history.undone)};
+    },
+    setHistory: function(histData) {
+      var hist = this.history = new History(this.history.maxGeneration);
+      hist.done = copyHistoryArray(histData.done.slice(0), null, true);
+      hist.undone = copyHistoryArray(histData.undone.slice(0), null, true);
+    },
+
+    addLineClass: docMethodOp(function(handle, where, cls) {
+      return changeLine(this, handle, where == "gutter" ? "gutter" : "class", function(line) {
+        var prop = where == "text" ? "textClass"
+                 : where == "background" ? "bgClass"
+                 : where == "gutter" ? "gutterClass" : "wrapClass";
+        if (!line[prop]) line[prop] = cls;
+        else if (classTest(cls).test(line[prop])) return false;
+        else line[prop] += " " + cls;
+        return true;
+      });
+    }),
+    removeLineClass: docMethodOp(function(handle, where, cls) {
+      return changeLine(this, handle, "class", function(line) {
+        var prop = where == "text" ? "textClass"
+                 : where == "background" ? "bgClass"
+                 : where == "gutter" ? "gutterClass" : "wrapClass";
+        var cur = line[prop];
+        if (!cur) return false;
+        else if (cls == null) line[prop] = null;
+        else {
+          var found = cur.match(classTest(cls));
+          if (!found) return false;
+          var end = found.index + found[0].length;
+          line[prop] = cur.slice(0, found.index) + (!found.index || end == cur.length ? "" : " ") + cur.slice(end) || null;
+        }
+        return true;
+      });
+    }),
+
+    markText: function(from, to, options) {
+      return markText(this, clipPos(this, from), clipPos(this, to), options, "range");
+    },
+    setBookmark: function(pos, options) {
+      var realOpts = {replacedWith: options && (options.nodeType == null ? options.widget : options),
+                      insertLeft: options && options.insertLeft,
+                      clearWhenEmpty: false, shared: options && options.shared};
+      pos = clipPos(this, pos);
+      return markText(this, pos, pos, realOpts, "bookmark");
+    },
+    findMarksAt: function(pos) {
+      pos = clipPos(this, pos);
+      var markers = [], spans = getLine(this, pos.line).markedSpans;
+      if (spans) for (var i = 0; i < spans.length; ++i) {
+        var span = spans[i];
+        if ((span.from == null || span.from <= pos.ch) &&
+            (span.to == null || span.to >= pos.ch))
+          markers.push(span.marker.parent || span.marker);
+      }
+      return markers;
+    },
+    findMarks: function(from, to, filter) {
+      from = clipPos(this, from); to = clipPos(this, to);
+      var found = [], lineNo = from.line;
+      this.iter(from.line, to.line + 1, function(line) {
+        var spans = line.markedSpans;
+        if (spans) for (var i = 0; i < spans.length; i++) {
+          var span = spans[i];
+          if (!(lineNo == from.line && from.ch > span.to ||
+                span.from == null && lineNo != from.line||
+                lineNo == to.line && span.from > to.ch) &&
+              (!filter || filter(span.marker)))
+            found.push(span.marker.parent || span.marker);
+        }
+        ++lineNo;
+      });
+      return found;
+    },
+    getAllMarks: function() {
+      var markers = [];
+      this.iter(function(line) {
+        var sps = line.markedSpans;
+        if (sps) for (var i = 0; i < sps.length; ++i)
+          if (sps[i].from != null) markers.push(sps[i].marker);
+      });
+      return markers;
+    },
+
+    posFromIndex: function(off) {
+      var ch, lineNo = this.first;
+      this.iter(function(line) {
+        var sz = line.text.length + 1;
+        if (sz > off) { ch = off; return true; }
+        off -= sz;
+        ++lineNo;
+      });
+      return clipPos(this, Pos(lineNo, ch));
+    },
+    indexFromPos: function (coords) {
+      coords = clipPos(this, coords);
+      var index = coords.ch;
+      if (coords.line < this.first || coords.ch < 0) return 0;
+      this.iter(this.first, coords.line, function (line) {
+        index += line.text.length + 1;
+      });
+      return index;
+    },
+
+    copy: function(copyHistory) {
+      var doc = new Doc(getLines(this, this.first, this.first + this.size), this.modeOption, this.first);
+      doc.scrollTop = this.scrollTop; doc.scrollLeft = this.scrollLeft;
+      doc.sel = this.sel;
+      doc.extend = false;
+      if (copyHistory) {
+        doc.history.undoDepth = this.history.undoDepth;
+        doc.setHistory(this.getHistory());
+      }
+      return doc;
+    },
+
+    linkedDoc: function(options) {
+      if (!options) options = {};
+      var from = this.first, to = this.first + this.size;
+      if (options.from != null && options.from > from) from = options.from;
+      if (options.to != null && options.to < to) to = options.to;
+      var copy = new Doc(getLines(this, from, to), options.mode || this.modeOption, from);
+      if (options.sharedHist) copy.history = this.history;
+      (this.linked || (this.linked = [])).push({doc: copy, sharedHist: options.sharedHist});
+      copy.linked = [{doc: this, isParent: true, sharedHist: options.sharedHist}];
+      copySharedMarkers(copy, findSharedMarkers(this));
+      return copy;
+    },
+    unlinkDoc: function(other) {
+      if (other instanceof CodeMirror) other = other.doc;
+      if (this.linked) for (var i = 0; i < this.linked.length; ++i) {
+        var link = this.linked[i];
+        if (link.doc != other) continue;
+        this.linked.splice(i, 1);
+        other.unlinkDoc(this);
+        detachSharedMarkers(findSharedMarkers(this));
+        break;
+      }
+      // If the histories were shared, split them again
+      if (other.history == this.history) {
+        var splitIds = [other.id];
+        linkedDocs(other, function(doc) {splitIds.push(doc.id);}, true);
+        other.history = new History(null);
+        other.history.done = copyHistoryArray(this.history.done, splitIds);
+        other.history.undone = copyHistoryArray(this.history.undone, splitIds);
+      }
+    },
+    iterLinkedDocs: function(f) {linkedDocs(this, f);},
+
+    getMode: function() {return this.mode;},
+    getEditor: function() {return this.cm;}
+  });
+
+  // Public alias.
+  Doc.prototype.eachLine = Doc.prototype.iter;
+
+  // Set up methods on CodeMirror's prototype to redirect to the editor's document.
+  var dontDelegate = "iter insert remove copy getEditor".split(" ");
+  for (var prop in Doc.prototype) if (Doc.prototype.hasOwnProperty(prop) && indexOf(dontDelegate, prop) < 0)
+    CodeMirror.prototype[prop] = (function(method) {
+      return function() {return method.apply(this.doc, arguments);};
+    })(Doc.prototype[prop]);
+
+  eventMixin(Doc);
+
+  // Call f for all linked documents.
+  function linkedDocs(doc, f, sharedHistOnly) {
+    function propagate(doc, skip, sharedHist) {
+      if (doc.linked) for (var i = 0; i < doc.linked.length; ++i) {
+        var rel = doc.linked[i];
+        if (rel.doc == skip) continue;
+        var shared = sharedHist && rel.sharedHist;
+        if (sharedHistOnly && !shared) continue;
+        f(rel.doc, shared);
+        propagate(rel.doc, doc, shared);
+      }
+    }
+    propagate(doc, null, true);
+  }
+
+  // Attach a document to an editor.
+  function attachDoc(cm, doc) {
+    if (doc.cm) throw new Error("This document is already in use.");
+    cm.doc = doc;
+    doc.cm = cm;
+    estimateLineHeights(cm);
+    loadMode(cm);
+    if (!cm.options.lineWrapping) findMaxLine(cm);
+    cm.options.mode = doc.modeOption;
+    regChange(cm);
+  }
+
+  // LINE UTILITIES
+
+  // Find the line object corresponding to the given line number.
+  function getLine(doc, n) {
+    n -= doc.first;
+    if (n < 0 || n >= doc.size) throw new Error("There is no line " + (n + doc.first) + " in the document.");
+    for (var chunk = doc; !chunk.lines;) {
+      for (var i = 0;; ++i) {
+        var child = chunk.children[i], sz = child.chunkSize();
+        if (n < sz) { chunk = child; break; }
+        n -= sz;
+      }
+    }
+    return chunk.lines[n];
+  }
+
+  // Get the part of a document between two positions, as an array of
+  // strings.
+  function getBetween(doc, start, end) {
+    var out = [], n = start.line;
+    doc.iter(start.line, end.line + 1, function(line) {
+      var text = line.text;
+      if (n == end.line) text = text.slice(0, end.ch);
+      if (n == start.line) text = text.slice(start.ch);
+      out.push(text);
+      ++n;
+    });
+    return out;
+  }
+  // Get the lines between from and to, as array of strings.
+  function getLines(doc, from, to) {
+    var out = [];
+    doc.iter(from, to, function(line) { out.push(line.text); });
+    return out;
+  }
+
+  // Update the height of a line, propagating the height change
+  // upwards to parent nodes.
+  function updateLineHeight(line, height) {
+    var diff = height - line.height;
+    if (diff) for (var n = line; n; n = n.parent) n.height += diff;
+  }
+
+  // Given a line object, find its line number by walking up through
+  // its parent links.
+  function lineNo(line) {
+    if (line.parent == null) return null;
+    var cur = line.parent, no = indexOf(cur.lines, line);
+    for (var chunk = cur.parent; chunk; cur = chunk, chunk = chunk.parent) {
+      for (var i = 0;; ++i) {
+        if (chunk.children[i] == cur) break;
+        no += chunk.children[i].chunkSize();
+      }
+    }
+    return no + cur.first;
+  }
+
+  // Find the line at the given vertical position, using the height
+  // information in the document tree.
+  function lineAtHeight(chunk, h) {
+    var n = chunk.first;
+    outer: do {
+      for (var i = 0; i < chunk.children.length; ++i) {
+        var child = chunk.children[i], ch = child.height;
+        if (h < ch) { chunk = child; continue outer; }
+        h -= ch;
+        n += child.chunkSize();
+      }
+      return n;
+    } while (!chunk.lines);
+    for (var i = 0; i < chunk.lines.length; ++i) {
+      var line = chunk.lines[i], lh = line.height;
+      if (h < lh) break;
+      h -= lh;
+    }
+    return n + i;
+  }
+
+
+  // Find the height above the given line.
+  function heightAtLine(lineObj) {
+    lineObj = visualLine(lineObj);
+
+    var h = 0, chunk = lineObj.parent;
+    for (var i = 0; i < chunk.lines.length; ++i) {
+      var line = chunk.lines[i];
+      if (line == lineObj) break;
+      else h += line.height;
+    }
+    for (var p = chunk.parent; p; chunk = p, p = chunk.parent) {
+      for (var i = 0; i < p.children.length; ++i) {
+        var cur = p.children[i];
+        if (cur == chunk) break;
+        else h += cur.height;
+      }
+    }
+    return h;
+  }
+
+  // Get the bidi ordering for the given line (and cache it). Returns
+  // false for lines that are fully left-to-right, and an array of
+  // BidiSpan objects otherwise.
+  function getOrder(line) {
+    var order = line.order;
+    if (order == null) order = line.order = bidiOrdering(line.text);
+    return order;
+  }
+
+  // HISTORY
+
+  function History(startGen) {
+    // Arrays of change events and selections. Doing something adds an
+    // event to done and clears undo. Undoing moves events from done
+    // to undone, redoing moves them in the other direction.
+    this.done = []; this.undone = [];
+    this.undoDepth = Infinity;
+    // Used to track when changes can be merged into a single undo
+    // event
+    this.lastModTime = this.lastSelTime = 0;
+    this.lastOp = this.lastSelOp = null;
+    this.lastOrigin = this.lastSelOrigin = null;
+    // Used by the isClean() method
+    this.generation = this.maxGeneration = startGen || 1;
+  }
+
+  // Create a history change event from an updateDoc-style change
+  // object.
+  function historyChangeFromChange(doc, change) {
+    var histChange = {from: copyPos(change.from), to: changeEnd(change), text: getBetween(doc, change.from, change.to)};
+    attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1);
+    linkedDocs(doc, function(doc) {attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1);}, true);
+    return histChange;
+  }
+
+  // Pop all selection events off the end of a history array. Stop at
+  // a change event.
+  function clearSelectionEvents(array) {
+    while (array.length) {
+      var last = lst(array);
+      if (last.ranges) array.pop();
+      else break;
+    }
+  }
+
+  // Find the top change event in the history. Pop off selection
+  // events that are in the way.
+  function lastChangeEvent(hist, force) {
+    if (force) {
+      clearSelectionEvents(hist.done);
+      return lst(hist.done);
+    } else if (hist.done.length && !lst(hist.done).ranges) {
+      return lst(hist.done);
+    } else if (hist.done.length > 1 && !hist.done[hist.done.length - 2].ranges) {
+      hist.done.pop();
+      return lst(hist.done);
+    }
+  }
+
+  // Register a change in the history. Merges changes that are within
+  // a single operation, ore are close together with an origin that
+  // allows merging (starting with "+") into a single event.
+  function addChangeToHistory(doc, change, selAfter, opId) {
+    var hist = doc.history;
+    hist.undone.length = 0;
+    var time = +new Date, cur;
+
+    if ((hist.lastOp == opId ||
+         hist.lastOrigin == change.origin && change.origin &&
+         ((change.origin.charAt(0) == "+" && doc.cm && hist.lastModTime > time - doc.cm.options.historyEventDelay) ||
+          change.origin.charAt(0) == "*")) &&
+        (cur = lastChangeEvent(hist, hist.lastOp == opId))) {
+      // Merge this change into the last event
+      var last = lst(cur.changes);
+      if (cmp(change.from, change.to) == 0 && cmp(change.from, last.to) == 0) {
+        // Optimized case for simple insertion -- don't want to add
+        // new changesets for every character typed
+        last.to = changeEnd(change);
+      } else {
+        // Add new sub-event
+        cur.changes.push(historyChangeFromChange(doc, change));
+      }
+    } else {
+      // Can not be merged, start a new event.
+      var before = lst(hist.done);
+      if (!before || !before.ranges)
+        pushSelectionToHistory(doc.sel, hist.done);
+      cur = {changes: [historyChangeFromChange(doc, change)],
+             generation: hist.generation};
+      hist.done.push(cur);
+      while (hist.done.length > hist.undoDepth) {
+        hist.done.shift();
+        if (!hist.done[0].ranges) hist.done.shift();
+      }
+    }
+    hist.done.push(selAfter);
+    hist.generation = ++hist.maxGeneration;
+    hist.lastModTime = hist.lastSelTime = time;
+    hist.lastOp = hist.lastSelOp = opId;
+    hist.lastOrigin = hist.lastSelOrigin = change.origin;
+
+    if (!last) signal(doc, "historyAdded");
+  }
+
+  function selectionEventCanBeMerged(doc, origin, prev, sel) {
+    var ch = origin.charAt(0);
+    return ch == "*" ||
+      ch == "+" &&
+      prev.ranges.length == sel.ranges.length &&
+      prev.somethingSelected() == sel.somethingSelected() &&
+      new Date - doc.history.lastSelTime <= (doc.cm ? doc.cm.options.historyEventDelay : 500);
+  }
+
+  // Called whenever the selection changes, sets the new selection as
+  // the pending selection in the history, and pushes the old pending
+  // selection into the 'done' array when it was significantly
+  // different (in number of selected ranges, emptiness, or time).
+  function addSelectionToHistory(doc, sel, opId, options) {
+    var hist = doc.history, origin = options && options.origin;
+
+    // A new event is started when the previous origin does not match
+    // the current, or the origins don't allow matching. Origins
+    // starting with * are always merged, those starting with + are
+    // merged when similar and close together in time.
+    if (opId == hist.lastSelOp ||
+        (origin && hist.lastSelOrigin == origin &&
+         (hist.lastModTime == hist.lastSelTime && hist.lastOrigin == origin ||
+          selectionEventCanBeMerged(doc, origin, lst(hist.done), sel))))
+      hist.done[hist.done.length - 1] = sel;
+    else
+      pushSelectionToHistory(sel, hist.done);
+
+    hist.lastSelTime = +new Date;
+    hist.lastSelOrigin = origin;
+    hist.lastSelOp = opId;
+    if (options && options.clearRedo !== false)
+      clearSelectionEvents(hist.undone);
+  }
+
+  function pushSelectionToHistory(sel, dest) {
+    var top = lst(dest);
+    if (!(top && top.ranges && top.equals(sel)))
+      dest.push(sel);
+  }
+
+  // Used to store marked span information in the history.
+  function attachLocalSpans(doc, change, from, to) {
+    var existing = change["spans_" + doc.id], n = 0;
+    doc.iter(Math.max(doc.first, from), Math.min(doc.first + doc.size, to), function(line) {
+      if (line.markedSpans)
+        (existing || (existing = change["spans_" + doc.id] = {}))[n] = line.markedSpans;
+      ++n;
+    });
+  }
+
+  // When un/re-doing restores text containing marked spans, those
+  // that have been explicitly cleared should not be restored.
+  function removeClearedSpans(spans) {
+    if (!spans) return null;
+    for (var i = 0, out; i < spans.length; ++i) {
+      if (spans[i].marker.explicitlyCleared) { if (!out) out = spans.slice(0, i); }
+      else if (out) out.push(spans[i]);
+    }
+    return !out ? spans : out.length ? out : null;
+  }
+
+  // Retrieve and filter the old marked spans stored in a change event.
+  function getOldSpans(doc, change) {
+    var found = change["spans_" + doc.id];
+    if (!found) return null;
+    for (var i = 0, nw = []; i < change.text.length; ++i)
+      nw.push(removeClearedSpans(found[i]));
+    return nw;
+  }
+
+  // Used both to provide a JSON-safe object in .getHistory, and, when
+  // detaching a document, to split the history in two
+  function copyHistoryArray(events, newGroup, instantiateSel) {
+    for (var i = 0, copy = []; i < events.length; ++i) {
+      var event = events[i];
+      if (event.ranges) {
+        copy.push(instantiateSel ? Selection.prototype.deepCopy.call(event) : event);
+        continue;
+      }
+      var changes = event.changes, newChanges = [];
+      copy.push({changes: newChanges});
+      for (var j = 0; j < changes.length; ++j) {
+        var change = changes[j], m;
+        newChanges.push({from: change.from, to: change.to, text: change.text});
+        if (newGroup) for (var prop in change) if (m = prop.match(/^spans_(\d+)$/)) {
+          if (indexOf(newGroup, Number(m[1])) > -1) {
+            lst(newChanges)[prop] = change[prop];
+            delete change[prop];
+          }
+        }
+      }
+    }
+    return copy;
+  }
+
+  // Rebasing/resetting history to deal with externally-sourced changes
+
+  function rebaseHistSelSingle(pos, from, to, diff) {
+    if (to < pos.line) {
+      pos.line += diff;
+    } else if (from < pos.line) {
+      pos.line = from;
+      pos.ch = 0;
+    }
+  }
+
+  // Tries to rebase an array of history events given a change in the
+  // document. If the change touches the same lines as the event, the
+  // event, and everything 'behind' it, is discarded. If the change is
+  // before the event, the event's positions are updated. Uses a
+  // copy-on-write scheme for the positions, to avoid having to
+  // reallocate them all on every rebase, but also avoid problems with
+  // shared position objects being unsafely updated.
+  function rebaseHistArray(array, from, to, diff) {
+    for (var i = 0; i < array.length; ++i) {
+      var sub = array[i], ok = true;
+      if (sub.ranges) {
+        if (!sub.copied) { sub = array[i] = sub.deepCopy(); sub.copied = true; }
+        for (var j = 0; j < sub.ranges.length; j++) {
+          rebaseHistSelSingle(sub.ranges[j].anchor, from, to, diff);
+          rebaseHistSelSingle(sub.ranges[j].head, from, to, diff);
+        }
+        continue;
+      }
+      for (var j = 0; j < sub.changes.length; ++j) {
+        var cur = sub.changes[j];
+        if (to < cur.from.line) {
+          cur.from = Pos(cur.from.line + diff, cur.from.ch);
+          cur.to = Pos(cur.to.line + diff, cur.to.ch);
+        } else if (from <= cur.to.line) {
+          ok = false;
+          break;
+        }
+      }
+      if (!ok) {
+        array.splice(0, i + 1);
+        i = 0;
+      }
+    }
+  }
+
+  function rebaseHist(hist, change) {
+    var from = change.from.line, to = change.to.line, diff = change.text.length - (to - from) - 1;
+    rebaseHistArray(hist.done, from, to, diff);
+    rebaseHistArray(hist.undone, from, to, diff);
+  }
+
+  // EVENT UTILITIES
+
+  // Due to the fact that we still support jurassic IE versions, some
+  // compatibility wrappers are needed.
+
+  var e_preventDefault = CodeMirror.e_preventDefault = function(e) {
+    if (e.preventDefault) e.preventDefault();
+    else e.returnValue = false;
+  };
+  var e_stopPropagation = CodeMirror.e_stopPropagation = function(e) {
+    if (e.stopPropagation) e.stopPropagation();
+    else e.cancelBubble = true;
+  };
+  function e_defaultPrevented(e) {
+    return e.defaultPrevented != null ? e.defaultPrevented : e.returnValue == false;
+  }
+  var e_stop = CodeMirror.e_stop = function(e) {e_preventDefault(e); e_stopPropagation(e);};
+
+  function e_target(e) {return e.target || e.srcElement;}
+  function e_button(e) {
+    var b = e.which;
+    if (b == null) {
+      if (e.button & 1) b = 1;
+      else if (e.button & 2) b = 3;
+      else if (e.button & 4) b = 2;
+    }
+    if (mac && e.ctrlKey && b == 1) b = 3;
+    return b;
+  }
+
+  // EVENT HANDLING
+
+  // Lightweight event framework. on/off also work on DOM nodes,
+  // registering native DOM handlers.
+
+  var on = CodeMirror.on = function(emitter, type, f) {
+    if (emitter.addEventListener)
+      emitter.addEventListener(type, f, false);
+    else if (emitter.attachEvent)
+      emitter.attachEvent("on" + type, f);
+    else {
+      var map = emitter._handlers || (emitter._handlers = {});
+      var arr = map[type] || (map[type] = []);
+      arr.push(f);
+    }
+  };
+
+  var off = CodeMirror.off = function(emitter, type, f) {
+    if (emitter.removeEventListener)
+      emitter.removeEventListener(type, f, false);
+    else if (emitter.detachEvent)
+      emitter.detachEvent("on" + type, f);
+    else {
+      var arr = emitter._handlers && emitter._handlers[type];
+      if (!arr) return;
+      for (var i = 0; i < arr.length; ++i)
+        if (arr[i] == f) { arr.splice(i, 1); break; }
+    }
+  };
+
+  var signal = CodeMirror.signal = function(emitter, type /*, values...*/) {
+    var arr = emitter._handlers && emitter._handlers[type];
+    if (!arr) return;
+    var args = Array.prototype.slice.call(arguments, 2);
+    for (var i = 0; i < arr.length; ++i) arr[i].apply(null, args);
+  };
+
+  var orphanDelayedCallbacks = null;
+
+  // Often, we want to signal events at a point where we are in the
+  // middle of some work, but don't want the handler to start calling
+  // other methods on the editor, which might be in an inconsistent
+  // state or simply not expect any other events to happen.
+  // signalLater looks whether there are any handlers, and schedules
+  // them to be executed when the last operation ends, or, if no
+  // operation is active, when a timeout fires.
+  function signalLater(emitter, type /*, values...*/) {
+    var arr = emitter._handlers && emitter._handlers[type];
+    if (!arr) return;
+    var args = Array.prototype.slice.call(arguments, 2), list;
+    if (operationGroup) {
+      list = operationGroup.delayedCallbacks;
+    } else if (orphanDelayedCallbacks) {
+      list = orphanDelayedCallbacks;
+    } else {
+      list = orphanDelayedCallbacks = [];
+      setTimeout(fireOrphanDelayed, 0);
+    }
+    function bnd(f) {return function(){f.apply(null, args);};};
+    for (var i = 0; i < arr.length; ++i)
+      list.push(bnd(arr[i]));
+  }
+
+  function fireOrphanDelayed() {
+    var delayed = orphanDelayedCallbacks;
+    orphanDelayedCallbacks = null;
+    for (var i = 0; i < delayed.length; ++i) delayed[i]();
+  }
+
+  // The DOM events that CodeMirror handles can be overridden by
+  // registering a (non-DOM) handler on the editor for the event name,
+  // and preventDefault-ing the event in that handler.
+  function signalDOMEvent(cm, e, override) {
+    if (typeof e == "string")
+      e = {type: e, preventDefault: function() { this.defaultPrevented = true; }};
+    signal(cm, override || e.type, cm, e);
+    return e_defaultPrevented(e) || e.codemirrorIgnore;
+  }
+
+  function signalCursorActivity(cm) {
+    var arr = cm._handlers && cm._handlers.cursorActivity;
+    if (!arr) return;
+    var set = cm.curOp.cursorActivityHandlers || (cm.curOp.cursorActivityHandlers = []);
+    for (var i = 0; i < arr.length; ++i) if (indexOf(set, arr[i]) == -1)
+      set.push(arr[i]);
+  }
+
+  function hasHandler(emitter, type) {
+    var arr = emitter._handlers && emitter._handlers[type];
+    return arr && arr.length > 0;
+  }
+
+  // Add on and off methods to a constructor's prototype, to make
+  // registering events on such objects more convenient.
+  function eventMixin(ctor) {
+    ctor.prototype.on = function(type, f) {on(this, type, f);};
+    ctor.prototype.off = function(type, f) {off(this, type, f);};
+  }
+
+  // MISC UTILITIES
+
+  // Number of pixels added to scroller and sizer to hide scrollbar
+  var scrollerCutOff = 30;
+
+  // Returned or thrown by various protocols to signal 'I'm not
+  // handling this'.
+  var Pass = CodeMirror.Pass = {toString: function(){return "CodeMirror.Pass";}};
+
+  // Reused option objects for setSelection & friends
+  var sel_dontScroll = {scroll: false}, sel_mouse = {origin: "*mouse"}, sel_move = {origin: "+move"};
+
+  function Delayed() {this.id = null;}
+  Delayed.prototype.set = function(ms, f) {
+    clearTimeout(this.id);
+    this.id = setTimeout(f, ms);
+  };
+
+  // Counts the column offset in a string, taking tabs into account.
+  // Used mostly to find indentation.
+  var countColumn = CodeMirror.countColumn = function(string, end, tabSize, startIndex, startValue) {
+    if (end == null) {
+      end = string.search(/[^\s\u00a0]/);
+      if (end == -1) end = string.length;
+    }
+    for (var i = startIndex || 0, n = startValue || 0;;) {
+      var nextTab = string.indexOf("\t", i);
+      if (nextTab < 0 || nextTab >= end)
+        return n + (end - i);
+      n += nextTab - i;
+      n += tabSize - (n % tabSize);
+      i = nextTab + 1;
+    }
+  };
+
+  // The inverse of countColumn -- find the offset that corresponds to
+  // a particular column.
+  function findColumn(string, goal, tabSize) {
+    for (var pos = 0, col = 0;;) {
+      var nextTab = string.indexOf("\t", pos);
+      if (nextTab == -1) nextTab = string.length;
+      var skipped = nextTab - pos;
+      if (nextTab == string.length || col + skipped >= goal)
+        return pos + Math.min(skipped, goal - col);
+      col += nextTab - pos;
+      col += tabSize - (col % tabSize);
+      pos = nextTab + 1;
+      if (col >= goal) return pos;
+    }
+  }
+
+  var spaceStrs = [""];
+  function spaceStr(n) {
+    while (spaceStrs.length <= n)
+      spaceStrs.push(lst(spaceStrs) + " ");
+    return spaceStrs[n];
+  }
+
+  function lst(arr) { return arr[arr.length-1]; }
+
+  var selectInput = function(node) { node.select(); };
+  if (ios) // Mobile Safari apparently has a bug where select() is broken.
+    selectInput = function(node) { node.selectionStart = 0; node.selectionEnd = node.value.length; };
+  else if (ie) // Suppress mysterious IE10 errors
+    selectInput = function(node) { try { node.select(); } catch(_e) {} };
+
+  function indexOf(array, elt) {
+    for (var i = 0; i < array.length; ++i)
+      if (array[i] == elt) return i;
+    return -1;
+  }
+  if ([].indexOf) indexOf = function(array, elt) { return array.indexOf(elt); };
+  function map(array, f) {
+    var out = [];
+    for (var i = 0; i < array.length; i++) out[i] = f(array[i], i);
+    return out;
+  }
+  if ([].map) map = function(array, f) { return array.map(f); };
+
+  function createObj(base, props) {
+    var inst;
+    if (Object.create) {
+      inst = Object.create(base);
+    } else {
+      var ctor = function() {};
+      ctor.prototype = base;
+      inst = new ctor();
+    }
+    if (props) copyObj(props, inst);
+    return inst;
+  };
+
+  function copyObj(obj, target, overwrite) {
+    if (!target) target = {};
+    for (var prop in obj)
+      if (obj.hasOwnProperty(prop) && (overwrite !== false || !target.hasOwnProperty(prop)))
+        target[prop] = obj[prop];
+    return target;
+  }
+
+  function bind(f) {
+    var args = Array.prototype.slice.call(arguments, 1);
+    return function(){return f.apply(null, args);};
+  }
+
+  var nonASCIISingleCaseWordChar = /[\u00df\u0590-\u05f4\u0600-\u06ff\u3040-\u309f\u30a0-\u30ff\u3400-\u4db5\u4e00-\u9fcc\uac00-\ud7af]/;
+  var isWordCharBasic = CodeMirror.isWordChar = function(ch) {
+    return /\w/.test(ch) || ch > "\x80" &&
+      (ch.toUpperCase() != ch.toLowerCase() || nonASCIISingleCaseWordChar.test(ch));
+  };
+  function isWordChar(ch, helper) {
+    if (!helper) return isWordCharBasic(ch);
+    if (helper.source.indexOf("\\w") > -1 && isWordCharBasic(ch)) return true;
+    return helper.test(ch);
+  }
+
+  function isEmpty(obj) {
+    for (var n in obj) if (obj.hasOwnProperty(n) && obj[n]) return false;
+    return true;
+  }
+
+  // Extending unicode characters. A series of a non-extending char +
+  // any number of extending chars is treated as a single unit as far
+  // as editing and measuring is concerned. This is not fully correct,
+  // since some scripts/fonts/browsers also treat other configurations
+  // of code points as a group.
+  var extendingChars = /[\u0300-\u036f\u0483-\u0489\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u065e\u0670\u06d6-\u06dc\u06de-\u06e4\u06e7\u06e8\u06ea-\u06ed\u0711\u0730-\u074a\u07a6-\u07b0\u07eb-\u07f3\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0900-\u0902\u093c\u0941-\u0948\u094d\u0951-\u0955\u0962\u0963\u0981\u09bc\u09be\u09c1-\u09c4\u09cd\u09d7\u09e2\u09e3\u0a01\u0a02\u0a3c\u0a41\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a70\u0a71\u0a75\u0a81\u0a82\u0abc\u0ac1-\u0ac5\u0ac7\u0ac8\u0acd\u0ae2\u0ae3\u0b01\u0b3c\u0b3e\u0b3f\u0b41-\u0b44\u0b4d\u0b56\u0b57\u0b62\u0b63\u0b82\u0bbe\u0bc0\u0bcd\u0bd7\u0c3e-\u0c40\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0cbc\u0cbf\u0cc2\u0cc6\u0ccc\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0d3e\u0d41-\u0d44\u0d4d\u0d57\u0d62\u0d63\u0dca\u0dcf\u0dd2-\u0dd4\u0dd6\u0ddf\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0eb1\u0eb4-\u0eb9\u0ebb\u0ebc\u0ec8-\u0ecd\u0f18\u0f19\u0f35\u0f37\u0f39\u0f71-\u0f7e\u0f80-\u0f84\u0f86\u0f87\u0f90-\u0f97\u0f99-\u0fbc\u0fc6\u102d-\u1030\u1032-\u1037\u1039\u103a\u103d\u103e\u1058\u1059\u105e-\u1060\u1071-\u1074\u1082\u1085\u1086\u108d\u109d\u135f\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b7-\u17bd\u17c6\u17c9-\u17d3\u17dd\u180b-\u180d\u18a9\u1920-\u1922\u1927\u1928\u1932\u1939-\u193b\u1a17\u1a18\u1a56\u1a58-\u1a5e\u1a60\u1a62\u1a65-\u1a6c\u1a73-\u1a7c\u1a7f\u1b00-\u1b03\u1b34\u1b36-\u1b3a\u1b3c\u1b42\u1b6b-\u1b73\u1b80\u1b81\u1ba2-\u1ba5\u1ba8\u1ba9\u1c2c-\u1c33\u1c36\u1c37\u1cd0-\u1cd2\u1cd4-\u1ce0\u1ce2-\u1ce8\u1ced\u1dc0-\u1de6\u1dfd-\u1dff\u200c\u200d\u20d0-\u20f0\u2cef-\u2cf1\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua66f-\ua672\ua67c\ua67d\ua6f0\ua6f1\ua802\ua806\ua80b\ua825\ua826\ua8c4\ua8e0-\ua8f1\ua926-\ua92d\ua947-\ua951\ua980-\ua982\ua9b3\ua9b6-\ua9b9\ua9bc\uaa29-\uaa2e\uaa31\uaa32\uaa35\uaa36\uaa43\uaa4c\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uabe5\uabe8\uabed\udc00-\udfff\ufb1e\ufe00-\ufe0f\ufe20-\ufe26\uff9e\uff9f]/;
+  function isExtendingChar(ch) { return ch.charCodeAt(0) >= 768 && extendingChars.test(ch); }
+
+  // DOM UTILITIES
+
+  function elt(tag, content, className, style) {
+    var e = document.createElement(tag);
+    if (className) e.className = className;
+    if (style) e.style.cssText = style;
+    if (typeof content == "string") e.appendChild(document.createTextNode(content));
+    else if (content) for (var i = 0; i < content.length; ++i) e.appendChild(content[i]);
+    return e;
+  }
+
+  var range;
+  if (document.createRange) range = function(node, start, end) {
+    var r = document.createRange();
+    r.setEnd(node, end);
+    r.setStart(node, start);
+    return r;
+  };
+  else range = function(node, start, end) {
+    var r = document.body.createTextRange();
+    try { r.moveToElementText(node.parentNode); }
+    catch(e) { return r; }
+    r.collapse(true);
+    r.moveEnd("character", end);
+    r.moveStart("character", start);
+    return r;
+  };
+
+  function removeChildren(e) {
+    for (var count = e.childNodes.length; count > 0; --count)
+      e.removeChild(e.firstChild);
+    return e;
+  }
+
+  function removeChildrenAndAdd(parent, e) {
+    return removeChildren(parent).appendChild(e);
+  }
+
+  function contains(parent, child) {
+    if (parent.contains)
+      return parent.contains(child);
+    while (child = child.parentNode)
+      if (child == parent) return true;
+  }
+
+  function activeElt() { return document.activeElement; }
+  // Older versions of IE throws unspecified error when touching
+  // document.activeElement in some cases (during loading, in iframe)
+  if (ie && ie_version < 11) activeElt = function() {
+    try { return document.activeElement; }
+    catch(e) { return document.body; }
+  };
+
+  function classTest(cls) { return new RegExp("(^|\\s)" + cls + "(?:$|\\s)\\s*"); }
+  var rmClass = CodeMirror.rmClass = function(node, cls) {
+    var current = node.className;
+    var match = classTest(cls).exec(current);
+    if (match) {
+      var after = current.slice(match.index + match[0].length);
+      node.className = current.slice(0, match.index) + (after ? match[1] + after : "");
+    }
+  };
+  var addClass = CodeMirror.addClass = function(node, cls) {
+    var current = node.className;
+    if (!classTest(cls).test(current)) node.className += (current ? " " : "") + cls;
+  };
+  function joinClasses(a, b) {
+    var as = a.split(" ");
+    for (var i = 0; i < as.length; i++)
+      if (as[i] && !classTest(as[i]).test(b)) b += " " + as[i];
+    return b;
+  }
+
+  // WINDOW-WIDE EVENTS
+
+  // These must be handled carefully, because naively registering a
+  // handler for each editor will cause the editors to never be
+  // garbage collected.
+
+  function forEachCodeMirror(f) {
+    if (!document.body.getElementsByClassName) return;
+    var byClass = document.body.getElementsByClassName("CodeMirror");
+    for (var i = 0; i < byClass.length; i++) {
+      var cm = byClass[i].CodeMirror;
+      if (cm) f(cm);
+    }
+  }
+
+  var globalsRegistered = false;
+  function ensureGlobalHandlers() {
+    if (globalsRegistered) return;
+    registerGlobalHandlers();
+    globalsRegistered = true;
+  }
+  function registerGlobalHandlers() {
+    // When the window resizes, we need to refresh active editors.
+    var resizeTimer;
+    on(window, "resize", function() {
+      if (resizeTimer == null) resizeTimer = setTimeout(function() {
+        resizeTimer = null;
+        knownScrollbarWidth = null;
+        forEachCodeMirror(onResize);
+      }, 100);
+    });
+    // When the window loses focus, we want to show the editor as blurred
+    on(window, "blur", function() {
+      forEachCodeMirror(onBlur);
+    });
+  }
+
+  // FEATURE DETECTION
+
+  // Detect drag-and-drop
+  var dragAndDrop = function() {
+    // There is *some* kind of drag-and-drop support in IE6-8, but I
+    // couldn't get it to work yet.
+    if (ie && ie_version < 9) return false;
+    var div = elt('div');
+    return "draggable" in div || "dragDrop" in div;
+  }();
+
+  var knownScrollbarWidth;
+  function scrollbarWidth(measure) {
+    if (knownScrollbarWidth != null) return knownScrollbarWidth;
+    var test = elt("div", null, null, "width: 50px; height: 50px; overflow-x: scroll");
+    removeChildrenAndAdd(measure, test);
+    if (test.offsetWidth)
+      knownScrollbarWidth = test.offsetHeight - test.clientHeight;
+    return knownScrollbarWidth || 0;
+  }
+
+  var zwspSupported;
+  function zeroWidthElement(measure) {
+    if (zwspSupported == null) {
+      var test = elt("span", "\u200b");
+      removeChildrenAndAdd(measure, elt("span", [test, document.createTextNode("x")]));
+      if (measure.firstChild.offsetHeight != 0)
+        zwspSupported = test.offsetWidth <= 1 && test.offsetHeight > 2 && !(ie && ie_version < 8);
+    }
+    if (zwspSupported) return elt("span", "\u200b");
+    else return elt("span", "\u00a0", null, "display: inline-block; width: 1px; margin-right: -1px");
+  }
+
+  // Feature-detect IE's crummy client rect reporting for bidi text
+  var badBidiRects;
+  function hasBadBidiRects(measure) {
+    if (badBidiRects != null) return badBidiRects;
+    var txt = removeChildrenAndAdd(measure, document.createTextNode("A\u062eA"));
+    var r0 = range(txt, 0, 1).getBoundingClientRect();
+    if (!r0 || r0.left == r0.right) return false; // Safari returns null in some cases (#2780)
+    var r1 = range(txt, 1, 2).getBoundingClientRect();
+    return badBidiRects = (r1.right - r0.right < 3);
+  }
+
+  // See if "".split is the broken IE version, if so, provide an
+  // alternative way to split lines.
+  var splitLines = CodeMirror.splitLines = "\n\nb".split(/\n/).length != 3 ? function(string) {
+    var pos = 0, result = [], l = string.length;
+    while (pos <= l) {
+      var nl = string.indexOf("\n", pos);
+      if (nl == -1) nl = string.length;
+      var line = string.slice(pos, string.charAt(nl - 1) == "\r" ? nl - 1 : nl);
+      var rt = line.indexOf("\r");
+      if (rt != -1) {
+        result.push(line.slice(0, rt));
+        pos += rt + 1;
+      } else {
+        result.push(line);
+        pos = nl + 1;
+      }
+    }
+    return result;
+  } : function(string){return string.split(/\r\n?|\n/);};
+
+  var hasSelection = window.getSelection ? function(te) {
+    try { return te.selectionStart != te.selectionEnd; }
+    catch(e) { return false; }
+  } : function(te) {
+    try {var range = te.ownerDocument.selection.createRange();}
+    catch(e) {}
+    if (!range || range.parentElement() != te) return false;
+    return range.compareEndPoints("StartToEnd", range) != 0;
+  };
+
+  var hasCopyEvent = (function() {
+    var e = elt("div");
+    if ("oncopy" in e) return true;
+    e.setAttribute("oncopy", "return;");
+    return typeof e.oncopy == "function";
+  })();
+
+  var badZoomedRects = null;
+  function hasBadZoomedRects(measure) {
+    if (badZoomedRects != null) return badZoomedRects;
+    var node = removeChildrenAndAdd(measure, elt("span", "x"));
+    var normal = node.getBoundingClientRect();
+    var fromRange = range(node, 0, 1).getBoundingClientRect();
+    return badZoomedRects = Math.abs(normal.left - fromRange.left) > 1;
+  }
+
+  // KEY NAMES
+
+  var keyNames = {3: "Enter", 8: "Backspace", 9: "Tab", 13: "Enter", 16: "Shift", 17: "Ctrl", 18: "Alt",
+                  19: "Pause", 20: "CapsLock", 27: "Esc", 32: "Space", 33: "PageUp", 34: "PageDown", 35: "End",
+                  36: "Home", 37: "Left", 38: "Up", 39: "Right", 40: "Down", 44: "PrintScrn", 45: "Insert",
+                  46: "Delete", 59: ";", 61: "=", 91: "Mod", 92: "Mod", 93: "Mod", 107: "=", 109: "-", 127: "Delete",
+                  173: "-", 186: ";", 187: "=", 188: ",", 189: "-", 190: ".", 191: "/", 192: "`", 219: "[", 220: "\\",
+                  221: "]", 222: "'", 63232: "Up", 63233: "Down", 63234: "Left", 63235: "Right", 63272: "Delete",
+                  63273: "Home", 63275: "End", 63276: "PageUp", 63277: "PageDown", 63302: "Insert"};
+  CodeMirror.keyNames = keyNames;
+  (function() {
+    // Number keys
+    for (var i = 0; i < 10; i++) keyNames[i + 48] = keyNames[i + 96] = String(i);
+    // Alphabetic keys
+    for (var i = 65; i <= 90; i++) keyNames[i] = String.fromCharCode(i);
+    // Function keys
+    for (var i = 1; i <= 12; i++) keyNames[i + 111] = keyNames[i + 63235] = "F" + i;
+  })();
+
+  // BIDI HELPERS
+
+  function iterateBidiSections(order, from, to, f) {
+    if (!order) return f(from, to, "ltr");
+    var found = false;
+    for (var i = 0; i < order.length; ++i) {
+      var part = order[i];
+      if (part.from < to && part.to > from || from == to && part.to == from) {
+        f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr");
+        found = true;
+      }
+    }
+    if (!found) f(from, to, "ltr");
+  }
+
+  function bidiLeft(part) { return part.level % 2 ? part.to : part.from; }
+  function bidiRight(part) { return part.level % 2 ? part.from : part.to; }
+
+  function lineLeft(line) { var order = getOrder(line); return order ? bidiLeft(order[0]) : 0; }
+  function lineRight(line) {
+    var order = getOrder(line);
+    if (!order) return line.text.length;
+    return bidiRight(lst(order));
+  }
+
+  function lineStart(cm, lineN) {
+    var line = getLine(cm.doc, lineN);
+    var visual = visualLine(line);
+    if (visual != line) lineN = lineNo(visual);
+    var order = getOrder(visual);
+    var ch = !order ? 0 : order[0].level % 2 ? lineRight(visual) : lineLeft(visual);
+    return Pos(lineN, ch);
+  }
+  function lineEnd(cm, lineN) {
+    var merged, line = getLine(cm.doc, lineN);
+    while (merged = collapsedSpanAtEnd(line)) {
+      line = merged.find(1, true).line;
+      lineN = null;
+    }
+    var order = getOrder(line);
+    var ch = !order ? line.text.length : order[0].level % 2 ? lineLeft(line) : lineRight(line);
+    return Pos(lineN == null ? lineNo(line) : lineN, ch);
+  }
+  function lineStartSmart(cm, pos) {
+    var start = lineStart(cm, pos.line);
+    var line = getLine(cm.doc, start.line);
+    var order = getOrder(line);
+    if (!order || order[0].level == 0) {
+      var firstNonWS = Math.max(0, line.text.search(/\S/));
+      var inWS = pos.line == start.line && pos.ch <= firstNonWS && pos.ch;
+      return Pos(start.line, inWS ? 0 : firstNonWS);
+    }
+    return start;
+  }
+
+  function compareBidiLevel(order, a, b) {
+    var linedir = order[0].level;
+    if (a == linedir) return true;
+    if (b == linedir) return false;
+    return a < b;
+  }
+  var bidiOther;
+  function getBidiPartAt(order, pos) {
+    bidiOther = null;
+    for (var i = 0, found; i < order.length; ++i) {
+      var cur = order[i];
+      if (cur.from < pos && cur.to > pos) return i;
+      if ((cur.from == pos || cur.to == pos)) {
+        if (found == null) {
+          found = i;
+        } else if (compareBidiLevel(order, cur.level, order[found].level)) {
+          if (cur.from != cur.to) bidiOther = found;
+          return i;
+        } else {
+          if (cur.from != cur.to) bidiOther = i;
+          return found;
+        }
+      }
+    }
+    return found;
+  }
+
+  function moveInLine(line, pos, dir, byUnit) {
+    if (!byUnit) return pos + dir;
+    do pos += dir;
+    while (pos > 0 && isExtendingChar(line.text.charAt(pos)));
+    return pos;
+  }
+
+  // This is needed in order to move 'visually' through bi-directional
+  // text -- i.e., pressing left should make the cursor go left, even
+  // when in RTL text. The tricky part is the 'jumps', where RTL and
+  // LTR text touch each other. This often requires the cursor offset
+  // to move more than one unit, in order to visually move one unit.
+  function moveVisually(line, start, dir, byUnit) {
+    var bidi = getOrder(line);
+    if (!bidi) return moveLogically(line, start, dir, byUnit);
+    var pos = getBidiPartAt(bidi, start), part = bidi[pos];
+    var target = moveInLine(line, start, part.level % 2 ? -dir : dir, byUnit);
+
+    for (;;) {
+      if (target > part.from && target < part.to) return target;
+      if (target == part.from || target == part.to) {
+        if (getBidiPartAt(bidi, target) == pos) return target;
+        part = bidi[pos += dir];
+        return (dir > 0) == part.level % 2 ? part.to : part.from;
+      } else {
+        part = bidi[pos += dir];
+        if (!part) return null;
+        if ((dir > 0) == part.level % 2)
+          target = moveInLine(line, part.to, -1, byUnit);
+        else
+          target = moveInLine(line, part.from, 1, byUnit);
+      }
+    }
+  }
+
+  function moveLogically(line, start, dir, byUnit) {
+    var target = start + dir;
+    if (byUnit) while (target > 0 && isExtendingChar(line.text.charAt(target))) target += dir;
+    return target < 0 || target > line.text.length ? null : target;
+  }
+
+  // Bidirectional ordering algorithm
+  // See http://unicode.org/reports/tr9/tr9-13.html for the algorithm
+  // that this (partially) implements.
+
+  // One-char codes used for character types:
+  // L (L):   Left-to-Right
+  // R (R):   Right-to-Left
+  // r (AL):  Right-to-Left Arabic
+  // 1 (EN):  European Number
+  // + (ES):  European Number Separator
+  // % (ET):  European Number Terminator
+  // n (AN):  Arabic Number
+  // , (CS):  Common Number Separator
+  // m (NSM): Non-Spacing Mark
+  // b (BN):  Boundary Neutral
+  // s (B):   Paragraph Separator
+  // t (S):   Segment Separator
+  // w (WS):  Whitespace
+  // N (ON):  Other Neutrals
+
+  // Returns null if characters are ordered as they appear
+  // (left-to-right), or an array of sections ({from, to, level}
+  // objects) in the order in which they occur visually.
+  var bidiOrdering = (function() {
+    // Character types for codepoints 0 to 0xff
+    var lowTypes = "bbbbbbbbbtstwsbbbbbbbbbbbbbbssstwNN%%%NNNNNN,N,N1111111111NNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNbbbbbbsbbbbbbbbbbbbbbbbbbbbbbbbbb,N%%%%NNNNLNNNNN%%11NLNNN1LNNNNNLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLN";
+    // Character types for codepoints 0x600 to 0x6ff
+    var arabicTypes = "rrrrrrrrrrrr,rNNmmmmmmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmrrrrrrrnnnnnnnnnn%nnrrrmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmNmmmm";
+    function charType(code) {
+      if (code <= 0xf7) return lowTypes.charAt(code);
+      else if (0x590 <= code && code <= 0x5f4) return "R";
+      else if (0x600 <= code && code <= 0x6ed) return arabicTypes.charAt(code - 0x600);
+      else if (0x6ee <= code && code <= 0x8ac) return "r";
+      else if (0x2000 <= code && code <= 0x200b) return "w";
+      else if (code == 0x200c) return "b";
+      else return "L";
+    }
+
+    var bidiRE = /[\u0590-\u05f4\u0600-\u06ff\u0700-\u08ac]/;
+    var isNeutral = /[stwN]/, isStrong = /[LRr]/, countsAsLeft = /[Lb1n]/, countsAsNum = /[1n]/;
+    // Browsers seem to always treat the boundaries of block elements as being L.
+    var outerType = "L";
+
+    function BidiSpan(level, from, to) {
+      this.level = level;
+      this.from = from; this.to = to;
+    }
+
+    return function(str) {
+      if (!bidiRE.test(str)) return false;
+      var len = str.length, types = [];
+      for (var i = 0, type; i < len; ++i)
+        types.push(type = charType(str.charCodeAt(i)));
+
+      // W1. Examine each non-spacing mark (NSM) in the level run, and
+      // change the type of the NSM to the type of the previous
+      // character. If the NSM is at the start of the level run, it will
+      // get the type of sor.
+      for (var i = 0, prev = outerType; i < len; ++i) {
+        var type = types[i];
+        if (type == "m") types[i] = prev;
+        else prev = type;
+      }
+
+      // W2. Search backwards from each instance of a European number
+      // until the first strong type (R, L, AL, or sor) is found. If an
+      // AL is found, change the type of the European number to Arabic
+      // number.
+      // W3. Change all ALs to R.
+      for (var i = 0, cur = outerType; i < len; ++i) {
+        var type = types[i];
+        if (type == "1" && cur == "r") types[i] = "n";
+        else if (isStrong.test(type)) { cur = type; if (type == "r") types[i] = "R"; }
+      }
+
+      // W4. A single European separator between two European numbers
+      // changes to a European number. A single common separator between
+      // two numbers of the same type changes to that type.
+      for (var i = 1, prev = types[0]; i < len - 1; ++i) {
+        var type = types[i];
+        if (type == "+" && prev == "1" && types[i+1] == "1") types[i] = "1";
+        else if (type == "," && prev == types[i+1] &&
+                 (prev == "1" || prev == "n")) types[i] = prev;
+        prev = type;
+      }
+
+      // W5. A sequence of European terminators adjacent to European
+      // numbers changes to all European numbers.
+      // W6. Otherwise, separators and terminators change to Other
+      // Neutral.
+      for (var i = 0; i < len; ++i) {
+        var type = types[i];
+        if (type == ",") types[i] = "N";
+        else if (type == "%") {
+          for (var end = i + 1; end < len && types[end] == "%"; ++end) {}
+          var replace = (i && types[i-1] == "!") || (end < len && types[end] == "1") ? "1" : "N";
+          for (var j = i; j < end; ++j) types[j] = replace;
+          i = end - 1;
+        }
+      }
+
+      // W7. Search backwards from each instance of a European number
+      // until the first strong type (R, L, or sor) is found. If an L is
+      // found, then change the type of the European number to L.
+      for (var i = 0, cur = outerType; i < len; ++i) {
+        var type = types[i];
+        if (cur == "L" && type == "1") types[i] = "L";
+        else if (isStrong.test(type)) cur = type;
+      }
+
+      // N1. A sequence of neutrals takes the direction of the
+      // surrounding strong text if the text on both sides has the same
+      // direction. European and Arabic numbers act as if they were R in
+      // terms of their influence on neutrals. Start-of-level-run (sor)
+      // and end-of-level-run (eor) are used at level run boundaries.
+      // N2. Any remaining neutrals take the embedding direction.
+      for (var i = 0; i < len; ++i) {
+        if (isNeutral.test(types[i])) {
+          for (var end = i + 1; end < len && isNeutral.test(types[end]); ++end) {}
+          var before = (i ? types[i-1] : outerType) == "L";
+          var after = (end < len ? types[end] : outerType) == "L";
+          var replace = before || after ? "L" : "R";
+          for (var j = i; j < end; ++j) types[j] = replace;
+          i = end - 1;
+        }
+      }
+
+      // Here we depart from the documented algorithm, in order to avoid
+      // building up an actual levels array. Since there are only three
+      // levels (0, 1, 2) in an implementation that doesn't take
+      // explicit embedding into account, we can build up the order on
+      // the fly, without following the level-based algorithm.
+      var order = [], m;
+      for (var i = 0; i < len;) {
+        if (countsAsLeft.test(types[i])) {
+          var start = i;
+          for (++i; i < len && countsAsLeft.test(types[i]); ++i) {}
+          order.push(new BidiSpan(0, start, i));
+        } else {
+          var pos = i, at = order.length;
+          for (++i; i < len && types[i] != "L"; ++i) {}
+          for (var j = pos; j < i;) {
+            if (countsAsNum.test(types[j])) {
+              if (pos < j) order.splice(at, 0, new BidiSpan(1, pos, j));
+              var nstart = j;
+              for (++j; j < i && countsAsNum.test(types[j]); ++j) {}
+              order.splice(at, 0, new BidiSpan(2, nstart, j));
+              pos = j;
+            } else ++j;
+          }
+          if (pos < i) order.splice(at, 0, new BidiSpan(1, pos, i));
+        }
+      }
+      if (order[0].level == 1 && (m = str.match(/^\s+/))) {
+        order[0].from = m[0].length;
+        order.unshift(new BidiSpan(0, 0, m[0].length));
+      }
+      if (lst(order).level == 1 && (m = str.match(/\s+$/))) {
+        lst(order).to -= m[0].length;
+        order.push(new BidiSpan(0, len - m[0].length, len));
+      }
+      if (order[0].level != lst(order).level)
+        order.push(new BidiSpan(order[0].level, len, len));
+
+      return order;
+    };
+  })();
+
+  // THE END
+
+  CodeMirror.version = "4.8.0";
+
+  return CodeMirror;
+});