Reorganize mdv and observe packages

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 0642db8346675bb0e63a868d6c9598f86b47abc5..d110043527aa265f8969ab7e28e17292eac5ab1b 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -9,7 +9,6 @@ import 'dart:indexed_db';
 import 'dart:isolate';
 import 'dart:json' as json;
 import 'dart:math';
-import 'dart:mdv_observe_impl';
 import 'dart:typed_data';
 import 'dart:svg' as svg;
 import 'dart:web_audio' as web_audio;
@@ -8268,21 +8267,6 @@ abstract class Element extends Node implements ElementTraversal native "Element"
     throw new UnsupportedError("Not supported on this platform");
   }
 
-  @Creates('Null') // Set from Dart code; does not instantiate a native type.
-  Map<String, StreamSubscription> _attributeBindings;
-
-  // TODO(jmesserly): I'm concerned about adding these to every element.
-  // Conceptually all of these belong on TemplateElement. They are here to
-  // support browsers that don't have <template> yet.
-  // However even in the polyfill they're restricted to certain tags
-  // (see [isTemplate]). So we can probably convert it to a (public) mixin, and
-  // only mix it in to the elements that need it.
-  @Creates('Null')  // Set from Dart code; does not instantiate a native type.
-  var _model;
-
-  @Creates('Null')  // Set from Dart code; does not instantiate a native type.
-  _TemplateIterator _templateIterator;
-
   @Creates('Null')  // Set from Dart code; does not instantiate a native type.
   Element _templateInstanceRef;
 
@@ -8292,125 +8276,6 @@ abstract class Element extends Node implements ElementTraversal native "Element"
 
   bool _templateIsDecorated;
 
-  // TODO(jmesserly): should path be optional, and default to empty path?
-  // It is used that way in at least one path in JS TemplateElement tests
-  // (see "BindImperative" test in original JS code).
-  @Experimental
-  void bind(String name, model, String path) {
-    _bindElement(this, name, model, path);
-  }
-
-  // TODO(jmesserly): this is static to work around http://dartbug.com/10166
-  // Similar issue for unbind/unbindAll below.
-  static void _bindElement(Element self, String name, model, String path) {
-    if (self._bindTemplate(name, model, path)) return;
-
-    if (self._attributeBindings == null) {
-      self._attributeBindings = new Map<String, StreamSubscription>();
-    }
-
-    self.xtag.attributes.remove(name);
-
-    var changed;
-    if (name.endsWith('?')) {
-      name = name.substring(0, name.length - 1);
-
-      changed = (value) {
-        if (_Bindings._toBoolean(value)) {
-          self.xtag.attributes[name] = '';
-        } else {
-          self.xtag.attributes.remove(name);
-        }
-      };
-    } else {
-      changed = (value) {
-        // TODO(jmesserly): escape value if needed to protect against XSS.
-        // See https://github.com/polymer-project/mdv/issues/58
-        self.xtag.attributes[name] = value == null ? '' : '$value';
-      };
-    }
-
-    self.unbind(name);
-
-    self._attributeBindings[name] =
-        new PathObserver(model, path).bindSync(changed);
-  }
-
-  @Experimental
-  void unbind(String name) {
-    _unbindElement(this, name);
-  }
-
-  static _unbindElement(Element self, String name) {
-    if (self._unbindTemplate(name)) return;
-    if (self._attributeBindings != null) {
-      var binding = self._attributeBindings.remove(name);
-      if (binding != null) binding.cancel();
-    }
-  }
-
-  @Experimental
-  void unbindAll() {
-    _unbindAllElement(this);
-  }
-
-  static void _unbindAllElement(Element self) {
-    self._unbindAllTemplate();
-
-    if (self._attributeBindings != null) {
-      for (var binding in self._attributeBindings.values) {
-        binding.cancel();
-      }
-      self._attributeBindings = null;
-    }
-  }
-
-  // TODO(jmesserly): unlike the JS polyfill, we can't mixin
-  // HTMLTemplateElement at runtime into things that are semantically template
-  // elements. So instead we implement it here with a runtime check.
-  // If the bind succeeds, we return true, otherwise we return false and let
-  // the normal Element.bind logic kick in.
-  bool _bindTemplate(String name, model, String path) {
-    if (isTemplate) {
-      switch (name) {
-        case 'bind':
-        case 'repeat':
-        case 'if':
-          _ensureTemplate();
-          if (_templateIterator == null) {
-            _templateIterator = new _TemplateIterator(this);
-          }
-          _templateIterator.inputs.bind(name, model, path);
-          return true;
-      }
-    }
-    return false;
-  }
-
-  bool _unbindTemplate(String name) {
-    if (isTemplate) {
-      switch (name) {
-        case 'bind':
-        case 'repeat':
-        case 'if':
-          _ensureTemplate();
-          if (_templateIterator != null) {
-            _templateIterator.inputs.unbind(name);
-          }
-          return true;
-      }
-    }
-    return false;
-  }
-
-  void _unbindAllTemplate() {
-    if (isTemplate) {
-      unbind('bind');
-      unbind('repeat');
-      unbind('if');
-    }
-  }
-
   /**
    * Gets the template this node refers to.
    * This is only supported if [isTemplate] is true.
@@ -8445,38 +8310,20 @@ abstract class Element extends Node implements ElementTraversal native "Element"
   @Experimental
   DocumentFragment createInstance() {
     _ensureTemplate();
-
-    var template = ref;
-    if (template == null) template = this;
-
-    var instance = _Bindings._createDeepCloneAndDecorateTemplates(
-        template.content, attributes['syntax']);
-
-    if (TemplateElement._instanceCreated != null) {
-      TemplateElement._instanceCreated.add(instance);
-    }
-    return instance;
+    return mdvPackage(this).createInstance();
   }
 
   /**
    * The data model which is inherited through the tree.
    * This is only supported if [isTemplate] is true.
-   *
-   * Setting this will destructive propagate the value to all descendant nodes,
-   * and reinstantiate all of the nodes expanded by this template.
-   *
-   * Currently this does not support propagation through Shadow DOMs.
    */
   @Experimental
-  get model => _model;
+  get model => mdvPackage(this).model;
 
   @Experimental
   void set model(value) {
     _ensureTemplate();
-
-    var syntax = TemplateElement.syntax[attributes['syntax']];
-    _model = value;
-    _Bindings._addBindings(this, model, syntax);
+    mdvPackage(this).model = value;
   }
 
   // TODO(jmesserly): const set would be better
@@ -12512,61 +12359,6 @@ class InputElement extends _HTMLElement implements
     return e;
   }
 
-  @Creates('Null')  // Set from Dart code; does not instantiate a native type.
-  _ValueBinding _valueBinding;
-
-  @Creates('Null')  // Set from Dart code; does not instantiate a native type.
-  _CheckedBinding _checkedBinding;
-
-  @Experimental
-  void bind(String name, model, String path) {
-    switch (name) {
-      case 'value':
-        unbind('value');
-        attributes.remove('value');
-        _valueBinding = new _ValueBinding(this, model, path);
-        break;
-      case 'checked':
-        unbind('checked');
-        attributes.remove('checked');
-        _checkedBinding = new _CheckedBinding(this, model, path);
-        break;
-      default:
-        // TODO(jmesserly): this should be "super" (http://dartbug.com/10166).
-        // Similar issue for unbind/unbindAll below.
-        Element._bindElement(this, name, model, path);
-        break;
-    }
-  }
-
-  @Experimental
-  void unbind(String name) {
-    switch (name) {
-      case 'value':
-        if (_valueBinding != null) {
-          _valueBinding.unbind();
-          _valueBinding = null;
-        }
-        break;
-      case 'checked':
-        if (_checkedBinding != null) {
-          _checkedBinding.unbind();
-          _checkedBinding = null;
-        }
-        break;
-      default:
-        Element._unbindElement(this, name);
-        break;
-    }
-  }
-
-  @Experimental
-  void unbindAll() {
-    unbind('value');
-    unbind('checked');
-    Element._unbindAllElement(this);
-  }
-
 
   @DomName('HTMLInputElement.webkitSpeechChangeEvent')
   @DocsEditable
@@ -16477,6 +16269,44 @@ class _ChildNodeListLazy extends ListBase<Node> {
   Node operator[](int index) => _this.$dom_childNodes[index];
 }
 
+/**
+ * The MDV package, if available.
+ *
+ * This can be used to initialize MDV support via:
+ *
+ *     import 'dart:html';
+ *     import 'package:mdv/mdv.dart' as mdv;
+ *     main() {
+ *       mdv.initialize();
+ *     }
+ */
+Function mdvPackage = (node) {

[blois, 2013/06/26 18:39:37]

I'm a bit concerned about adding unqualified top-level members given the
post-1.0 compatibility issues of adding new ones. This one itself won't cause
issues, but we won't be able to follow the same pattern later.

Would prefer to use a pattern we can follow in the future.

[Jennifer Messerly, 2013/06/26 18:47:24]

That's fair. I feel the same way. I desperately wish we had another solution.

I'm caught between:
* the Dart language, that doesn't give libraries a way to extend HTML APIs
(unlike JavaScript)
* the dart2js implementation, that causes too much size overhead if
Node.noSuchMethod is added
  - and Dart tooling, that wouldn't autocomplete correctly if NSM used
* the web standards (MDV) effort to add native data binding capabilities
* EcmaScript embracing Object.observe
* Dart not embracing dart:observe
* Polymer choosing to be built on MDV
* Wanting to get Polymer UI to our users
* Wanting to not have less friendly APIs than JS.

... HALP!?!!

[Jennifer Messerly, 2013/06/26 22:27:10]

Chatting with Pete it sounds like the main concern here is something about
adding top level members being a breaking change. I'll just make this static on
TemplateElement...

+  throw new UnsupportedError("The MDV package is not available. "
+      "You can enable it with `import 'package:mdv/mdv.dart' as mdv;` and "
+      "`mdv.initialize()`");
+};
+
+/** Information about the instantiated template. */
+class TemplateInstance {
+  // TODO(rafaelw): firstNode & lastNode should be read-synchronous
+  // in cases where script has modified the template instance boundary.
+
+  /** The first node of this template instantiation. */
+  final Node firstNode;
+
+  /**
+   * The last node of this template instantiation.
+   * This could be identical to [firstNode] if the template only expanded to a
+   * single node.
+   */
+  final Node lastNode;
+
+  /** The model used to instantiate the template. */
+  final model;
+
+  TemplateInstance(this.firstNode, this.lastNode, this.model);
+}
+
 @DomName('Node')
 class Node extends EventTarget native "Node" {
   List<Node> get nodes {
@@ -16557,26 +16387,24 @@ class Node extends EventTarget native "Node" {
    */
   @Experimental
   void bind(String name, model, String path) {
-    // TODO(jmesserly): should we throw instead?
-    window.console.error('Unhandled binding to Node: '
-        '$this $name $model $path');
+    mdvPackage(this).bind(name, model, path);
   }
 
   /** Unbinds the attribute [name]. */
   @Experimental
-  void unbind(String name) {}
+  void unbind(String name) {
+    mdvPackage(this).unbind(name);
+  }
 
   /** Unbinds all bound attributes. */
   @Experimental
-  void unbindAll() {}
-
-  TemplateInstance _templateInstance;
+  void unbindAll() {
+    mdvPackage(this).unbindAll();
+  }
 
   /** Gets the template instance that instantiated this node, if any. */
   @Experimental
-  TemplateInstance get templateInstance =>
-      _templateInstance != null ? _templateInstance :
-      (parent != null ? parent.templateInstance : null);
+  TemplateInstance get templateInstance => mdvPackage(this).templateInstance;
 
 
   @DomName('Node.ATTRIBUTE_NODE')
@@ -21016,6 +20844,99 @@ class TableSectionElement extends _HTMLElement native "HTMLTableSectionElement"
 // WARNING: Do not edit - generated code.
 
 
+
+/**
+ * Model-Driven Views (MDV)'s native features enables a wide-range of use cases,
+ * but (by design) don't attempt to implement a wide array of specialized
+ * behaviors.
+ *
+ * Enabling these features in MDV is a matter of implementing and registering an
+ * MDV Custom Syntax. A Custom Syntax is an object which contains one or more
+ * delegation functions which implement specialized behavior. This object is
+ * registered with MDV via [TemplateElement.syntax]:
+ *
+ *
+ * HTML:
+ *     <template bind syntax="MySyntax">
+ *       {{ What!Ever('crazy')->thing^^^I+Want(data) }}
+ *     </template>
+ *
+ * Dart:
+ *     class MySyntax extends CustomBindingSyntax {
+ *       getBinding(model, path, name, node) {
+ *         // The magic happens here!
+ *       }
+ *     }
+ *
+ *     ...
+ *
+ *     TemplateElement.syntax['MySyntax'] = new MySyntax();
+ *
+ * See <https://github.com/polymer-project/mdv/blob/master/docs/syntax.md> for
+ * more information about Custom Syntax.
+ */
+// TODO(jmesserly): if this is just one method, a function type would make it
+// more Dart-friendly.
+@Experimental
+abstract class CustomBindingSyntax {
+  /**
+   * This syntax method allows for a custom interpretation of the contents of
+   * mustaches (`{{` ... `}}`).
+   *
+   * When a template is inserting an instance, it will invoke this method for
+   * each mustache which is encountered. The function is invoked with four
+   * arguments:
+   *
+   * - [model]: The data context for which this instance is being created.
+   * - [path]: The text contents (trimmed of outer whitespace) of the mustache.
+   * - [name]: The context in which the mustache occurs. Within element
+   *   attributes, this will be the name of the attribute. Within text,
+   *   this will be 'text'.
+   * - [node]: A reference to the node to which this binding will be created.
+   *
+   * If the method wishes to handle binding, it is required to return an object
+   * which has at least a `value` property that can be observed. If it does,
+   * then MDV will call [Node.bind on the node:
+   *
+   *     node.bind(name, retval, 'value');
+   *
+   * If the 'getBinding' does not wish to override the binding, it should return
+   * null.
+   */
+  // TODO(jmesserly): I had to remove type annotations from "name" and "node"
+  // Normally they are String and Node respectively. But sometimes it will pass
+  // (int name, CompoundBinding node). That seems very confusing; we may want
+  // to change this API.
+  getBinding(model, String path, name, node) => null;
+
+  /**
+   * This syntax method allows a syntax to provide an alterate model than the
+   * one the template would otherwise use when producing an instance.
+   *
+   * When a template is about to create an instance, it will invoke this method
+   * The function is invoked with two arguments:
+   *
+   * - [template]: The template element which is about to create and insert an
+   *   instance.
+   * - [model]: The data context for which this instance is being created.
+   *
+   * The template element will always use the return value of `getInstanceModel`
+   * as the model for the new instance. If the syntax does not wish to override
+   * the value, it should simply return the `model` value it was passed.
+   */
+  getInstanceModel(Element template, model) => model;
+
+  /**
+   * This syntax method allows a syntax to provide an alterate expansion of
+   * the [template] contents. When the template wants to create an instance,
+   * it will call this method with the template element.
+   *
+   * By default this will call `template.createInstance()`.
+   */
+  getInstanceFragment(Element template) => template.createInstance();
+}
+
+
 @Experimental
 @DomName('HTMLTemplateElement')
 @SupportedBrowser(SupportedBrowser.CHROME)
@@ -21041,25 +20962,6 @@ class TemplateElement extends _HTMLElement native "HTMLTemplateElement" {
   @Experimental
   DocumentFragment get content => $dom_content;
 
-  static StreamController<DocumentFragment> _instanceCreated;
-
-  /**
-   * *Warning*: This is an implementation helper for Model-Driven Views and
-   * should not be used in your code.
-   *
-   * This event is fired whenever a template is instantiated via
-   * [createInstance].
-   */
-  // TODO(rafaelw): This is a hack, and is neccesary for the polyfill
-  // because custom elements are not upgraded during clone()
-  @Experimental
-  static Stream<DocumentFragment> get instanceCreated {
-    if (_instanceCreated == null) {
-      _instanceCreated = new StreamController<DocumentFragment>(sync: true);
-    }
-    return _instanceCreated.stream;
-  }
-
   /**
    * Ensures proper API and content model for template elements.
    *
@@ -21081,7 +20983,7 @@ class TemplateElement extends _HTMLElement native "HTMLTemplateElement" {
 
     // Create content
     if (template is! TemplateElement) {
-      var doc = _Bindings._getTemplateContentsOwner(template.document);
+      var doc = _getTemplateContentsOwner(template.document);
       template._templateContent = doc.createDocumentFragment();
     }
 
@@ -21093,43 +20995,112 @@ class TemplateElement extends _HTMLElement native "HTMLTemplateElement" {
     if (template is TemplateElement) {
       bootstrap(template.content);
     } else {
-      _Bindings._liftNonNativeChildrenIntoContent(template);
+      _liftNonNativeChildrenIntoContent(template);
     }
 
     return true;
   }
 
-  /**
-   * This used to decorate recursively all templates from a given node.
-   *
-   * By default [decorate] will be called on templates lazily when certain
-   * properties such as [model] are accessed, but it can be run eagerly to
-   * decorate an entire tree recursively.
-   */
-  // TODO(rafaelw): Review whether this is the right public API.
-  @Experimental
-  static void bootstrap(Node content) {
-    _Bindings._bootstrapTemplatesRecursivelyFrom(content);
-  }
-
-  /**
-   * Binds all mustaches recursively starting from the [root] node.
-   *
-   * Note: this is not an official Model-Driven-Views API; it is intended to
-   * support binding the [ShadowRoot]'s content to a model.
-   */
-  // TODO(jmesserly): this is needed to avoid two <template> nodes when using
-  // bindings in a custom element's template. See also:
-  // https://github.com/polymer-project/polymer/blob/master/src/bindMDV.js#L68
-  // Called from:
-  // https://github.com/polymer-project/polymer/blob/master/src/register.js#L99
-  @Experimental
-  static void bindModel(Node root, model, [CustomBindingSyntax syntax]) {
-    _Bindings._addBindings(root, model, syntax);
+  // http://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/templates/index.html#dfn-template-contents-owner
+  static Document _getTemplateContentsOwner(HtmlDocument doc) {
+    if (doc.window == null) {
+      return doc;
+    }
+    var d = doc._templateContentsOwner;
+    if (d == null) {
+      // TODO(arv): This should either be a Document or HTMLDocument depending
+      // on doc.
+      d = doc.implementation.createHtmlDocument('');
+      while (d.$dom_lastChild != null) {
+        d.$dom_lastChild.remove();
+      }
+      doc._templateContentsOwner = d;
+    }
+    return d;
   }
 
-  static bool _initStyles;
-
+  static Element _cloneAndSeperateAttributeTemplate(Element templateElement) {
+    var clone = templateElement.clone(false);
+    var attributes = templateElement.attributes;
+    for (var name in attributes.keys.toList()) {
+      switch (name) {
+        case 'template':
+        case 'repeat':
+        case 'bind':
+        case 'ref':
+          clone.attributes.remove(name);
+          break;
+        default:
+          attributes.remove(name);
+          break;
+      }
+    }
+
+    return clone;
+  }
+
+  static void _liftNonNativeChildrenIntoContent(Element templateElement) {
+    var content = templateElement.content;
+
+    if (!templateElement._isAttributeTemplate) {
+      var child;
+      while ((child = templateElement.$dom_firstChild) != null) {
+        content.append(child);
+      }
+      return;
+    }
+
+    // For attribute templates we copy the whole thing into the content and
+    // we move the non template attributes into the content.
+    //
+    //   <tr foo template>
+    //
+    // becomes
+    //
+    //   <tr template>
+    //   + #document-fragment
+    //     + <tr foo>
+    //
+    var newRoot = _cloneAndSeperateAttributeTemplate(templateElement);
+    var child;
+    while ((child = templateElement.$dom_firstChild) != null) {
+      newRoot.append(child);
+    }
+    content.append(newRoot);
+  }
+
+  /**
+   * This used to decorate recursively all templates from a given node.
+   *
+   * By default [decorate] will be called on templates lazily when certain
+   * properties such as [model] are accessed, but it can be run eagerly to
+   * decorate an entire tree recursively.
+   */
+  // TODO(rafaelw): Review whether this is the right public API.
+  @Experimental
+  static void bootstrap(Node content) {
+    void _bootstrap(template) {
+      if (!TemplateElement.decorate(template)) {
+        bootstrap(template.content);
+      }
+    }
+
+    // Need to do this first as the contents may get lifted if |node| is
+    // template.
+    // TODO(jmesserly): content is DocumentFragment or Element
+    var descendents = (content as dynamic).queryAll(_allTemplatesSelectors);
+    if (content is Element && (content as Element).isTemplate) {
+      _bootstrap(content);
+    }
+
+    descendents.forEach(_bootstrap);
+  }
+
+  static final String _allTemplatesSelectors = 'template, option[template], ' +
+      Element._TABLE_TAGS.keys.map((k) => "$k[template]").join(", ");
+
+  static bool _initStyles;
+
   static void _injectStylesheet() {
     if (_initStyles == true) return;
     _initStyles = true;
@@ -21184,42 +21155,6 @@ class Text extends CharacterData native "Text" {
   @DocsEditable
   Text splitText(int offset) native;
 
-
-  @Creates('Null')  // Set from Dart code; does not instantiate a native type.
-  StreamSubscription _textBinding;
-
-  @Experimental
-  void bind(String name, model, String path) {
-    if (name != 'text') {
-      super.bind(name, model, path);
-      return;
-    }
-
-    unbind('text');
-
-    _textBinding = new PathObserver(model, path).bindSync((value) {
-      text = value == null ? '' : '$value';
-    });
-  }
-
-  @Experimental
-  void unbind(String name) {
-    if (name != 'text') {
-      super.unbind(name);
-      return;
-    }
-
-    if (_textBinding == null) return;
-
-    _textBinding.cancel();
-    _textBinding = null;
-  }
-
-  @Experimental
-  void unbindAll() {
-    unbind('text');
-    super.unbindAll();
-  }
 }
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
@@ -27685,794 +27620,6 @@ class Rect {
   Point get bottomRight => new Point(this.left + this.width,
       this.top + this.height);
 }
-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-
-// This code is a port of Model-Driven-Views:
-// https://github.com/polymer-project/mdv
-// The code mostly comes from src/template_element.js
-
-typedef void _ChangeHandler(value);
-
-/**
- * Model-Driven Views (MDV)'s native features enables a wide-range of use cases,
- * but (by design) don't attempt to implement a wide array of specialized
- * behaviors.
- *
- * Enabling these features in MDV is a matter of implementing and registering an
- * MDV Custom Syntax. A Custom Syntax is an object which contains one or more
- * delegation functions which implement specialized behavior. This object is
- * registered with MDV via [TemplateElement.syntax]:
- *
- *
- * HTML:
- *     <template bind syntax="MySyntax">
- *       {{ What!Ever('crazy')->thing^^^I+Want(data) }}
- *     </template>
- *
- * Dart:
- *     class MySyntax extends CustomBindingSyntax {
- *       getBinding(model, path, name, node) {
- *         // The magic happens here!
- *       }
- *     }
- *
- *     ...
- *
- *     TemplateElement.syntax['MySyntax'] = new MySyntax();
- *
- * See <https://github.com/polymer-project/mdv/blob/master/docs/syntax.md> for more
- * information about Custom Syntax.
- */
-// TODO(jmesserly): if this is just one method, a function type would make it
-// more Dart-friendly.
-@Experimental
-abstract class CustomBindingSyntax {
-  /**
-   * This syntax method allows for a custom interpretation of the contents of
-   * mustaches (`{{` ... `}}`).
-   *
-   * When a template is inserting an instance, it will invoke this method for
-   * each mustache which is encountered. The function is invoked with four
-   * arguments:
-   *
-   * - [model]: The data context for which this instance is being created.
-   * - [path]: The text contents (trimmed of outer whitespace) of the mustache.
-   * - [name]: The context in which the mustache occurs. Within element
-   *   attributes, this will be the name of the attribute. Within text,
-   *   this will be 'text'.
-   * - [node]: A reference to the node to which this binding will be created.
-   *
-   * If the method wishes to handle binding, it is required to return an object
-   * which has at least a `value` property that can be observed. If it does,
-   * then MDV will call [Node.bind on the node:
-   *
-   *     node.bind(name, retval, 'value');
-   *
-   * If the 'getBinding' does not wish to override the binding, it should return
-   * null.
-   */
-  // TODO(jmesserly): I had to remove type annotations from "name" and "node"
-  // Normally they are String and Node respectively. But sometimes it will pass
-  // (int name, CompoundBinding node). That seems very confusing; we may want
-  // to change this API.
-  getBinding(model, String path, name, node) => null;
-
-  /**
-   * This syntax method allows a syntax to provide an alterate model than the
-   * one the template would otherwise use when producing an instance.
-   *
-   * When a template is about to create an instance, it will invoke this method
-   * The function is invoked with two arguments:
-   *
-   * - [template]: The template element which is about to create and insert an
-   *   instance.
-   * - [model]: The data context for which this instance is being created.
-   *
-   * The template element will always use the return value of `getInstanceModel`
-   * as the model for the new instance. If the syntax does not wish to override
-   * the value, it should simply return the `model` value it was passed.
-   */
-  getInstanceModel(Element template, model) => model;
-
-  /**
-   * This syntax method allows a syntax to provide an alterate expansion of
-   * the [template] contents. When the template wants to create an instance,
-   * it will call this method with the template element.
-   *
-   * By default this will call `template.createInstance()`.
-   */
-  getInstanceFragment(Element template) => template.createInstance();
-}
-
-/** The callback used in the [CompoundBinding.combinator] field. */
-@Experimental
-typedef Object CompoundBindingCombinator(Map objects);
-
-/** Information about the instantiated template. */
-@Experimental
-class TemplateInstance {
-  // TODO(rafaelw): firstNode & lastNode should be read-synchronous
-  // in cases where script has modified the template instance boundary.
-
-  /** The first node of this template instantiation. */
-  final Node firstNode;
-
-  /**
-   * The last node of this template instantiation.
-   * This could be identical to [firstNode] if the template only expanded to a
-   * single node.
-   */
-  final Node lastNode;
-
-  /** The model used to instantiate the template. */
-  final model;
-
-  TemplateInstance(this.firstNode, this.lastNode, this.model);
-}
-
-/**
- * Model-Driven Views contains a helper object which is useful for the
- * implementation of a Custom Syntax.
- *
- *     var binding = new CompoundBinding((values) {
- *       var combinedValue;
- *       // compute combinedValue based on the current values which are provided
- *       return combinedValue;
- *     });
- *     binding.bind('name1', obj1, path1);
- *     binding.bind('name2', obj2, path2);
- *     //...
- *     binding.bind('nameN', objN, pathN);
- *
- * CompoundBinding is an object which knows how to listen to multiple path
- * values (registered via [bind]) and invoke its [combinator] when one or more
- * of the values have changed and set its [value] property to the return value
- * of the function. When any value has changed, all current values are provided
- * to the [combinator] in the single `values` argument.
- *
- * See [CustomBindingSyntax] for more information.
- */
-// TODO(jmesserly): what is the public API surface here? I just guessed;
-// most of it seemed non-public.
-@Experimental
-class CompoundBinding extends ObservableBase {
-  CompoundBindingCombinator _combinator;
-
-  // TODO(jmesserly): ideally these would be String keys, but sometimes we
-  // use integers.
-  Map<dynamic, StreamSubscription> _bindings = new Map();
-  Map _values = new Map();
-  bool _scheduled = false;
-  bool _disposed = false;
-  Object _value;
-
-  CompoundBinding([CompoundBindingCombinator combinator]) {
-    // TODO(jmesserly): this is a tweak to the original code, it seemed to me
-    // that passing the combinator to the constructor should be equivalent to
-    // setting it via the property.
-    // I also added a null check to the combinator setter.
-    this.combinator = combinator;
-  }
-
-  CompoundBindingCombinator get combinator => _combinator;
-
-  set combinator(CompoundBindingCombinator combinator) {
-    _combinator = combinator;
-    if (combinator != null) _scheduleResolve();
-  }
-
-  static const _VALUE = const Symbol('value');
-
-  get value => _value;
-
-  void set value(newValue) {
-    _value = notifyPropertyChange(_VALUE, _value, newValue);
-  }
-
-  // TODO(jmesserly): remove these workarounds when dart2js supports mirrors!
-  getValueWorkaround(key) {
-    if (key == _VALUE) return value;
-    return null;
-  }
-  setValueWorkaround(key, val) {
-    if (key == _VALUE) value = val;
-  }
-
-  void bind(name, model, String path) {
-    unbind(name);
-
-    _bindings[name] = new PathObserver(model, path).bindSync((value) {
-      _values[name] = value;
-      _scheduleResolve();
-    });
-  }
-
-  void unbind(name, {bool suppressResolve: false}) {
-    var binding = _bindings.remove(name);
-    if (binding == null) return;
-
-    binding.cancel();
-    _values.remove(name);
-    if (!suppressResolve) _scheduleResolve();
-  }
-
-  // TODO(rafaelw): Is this the right processing model?
-  // TODO(rafaelw): Consider having a seperate ChangeSummary for
-  // CompoundBindings so to excess dirtyChecks.
-  void _scheduleResolve() {
-    if (_scheduled) return;
-    _scheduled = true;
-    queueChangeRecords(resolve);
-  }
-
-  void resolve() {
-    if (_disposed) return;
-    _scheduled = false;
-
-    if (_combinator == null) {
-      throw new StateError(
-          'CompoundBinding attempted to resolve without a combinator');
-    }
-
-    value = _combinator(_values);
-  }
-
-  void dispose() {
-    for (var binding in _bindings.values) {
-      binding.cancel();
-    }
-    _bindings.clear();
-    _values.clear();
-
-    _disposed = true;
-    value = null;
-  }
-}
-
-abstract class _InputBinding {
-  final InputElement element;
-  PathObserver binding;
-  StreamSubscription _pathSub;
-  StreamSubscription _eventSub;
-
-  _InputBinding(this.element, model, String path) {
-    binding = new PathObserver(model, path);
-    _pathSub = binding.bindSync(valueChanged);
-    _eventSub = _getStreamForInputType(element).listen(updateBinding);
-  }
-
-  void valueChanged(newValue);
-
-  void updateBinding(e);
-
-  void unbind() {
-    binding = null;
-    _pathSub.cancel();
-    _eventSub.cancel();
-  }
-
-
-  static Stream<Event> _getStreamForInputType(InputElement element) {
-    switch (element.type) {
-      case 'checkbox':
-        return element.onClick;
-      case 'radio':
-      case 'select-multiple':
-      case 'select-one':
-        return element.onChange;
-      default:
-        return element.onInput;
-    }
-  }
-}
-
-class _ValueBinding extends _InputBinding {
-  _ValueBinding(element, model, path) : super(element, model, path);
-
-  void valueChanged(value) {
-    element.value = value == null ? '' : '$value';
-  }
-
-  void updateBinding(e) {
-    binding.value = element.value;
-  }
-}
-
-class _CheckedBinding extends _InputBinding {
-  _CheckedBinding(element, model, path) : super(element, model, path);
-
-  void valueChanged(value) {
-    element.checked = _Bindings._toBoolean(value);
-  }
-
-  void updateBinding(e) {
-    binding.value = element.checked;
-
-    // Only the radio button that is getting checked gets an event. We
-    // therefore find all the associated radio buttons and update their
-    // CheckedBinding manually.
-    if (element is InputElement && element.type == 'radio') {
-      for (var r in _getAssociatedRadioButtons(element)) {
-        var checkedBinding = r._checkedBinding;
-        if (checkedBinding != null) {
-          // Set the value directly to avoid an infinite call stack.
-          checkedBinding.binding.value = false;
-        }
-      }
-    }
-  }
-
-  // |element| is assumed to be an HTMLInputElement with |type| == 'radio'.
-  // Returns an array containing all radio buttons other than |element| that
-  // have the same |name|, either in the form that |element| belongs to or,
-  // if no form, in the document tree to which |element| belongs.
-  //
-  // This implementation is based upon the HTML spec definition of a
-  // "radio button group":
-  //   http://www.whatwg.org/specs/web-apps/current-work/multipage/number-state.html#radio-button-group
-  //
-  static Iterable _getAssociatedRadioButtons(element) {
-    if (!_isNodeInDocument(element)) return [];
-    if (element.form != null) {
-      return element.form.nodes.where((el) {
-        return el != element &&
-            el is InputElement &&
-            el.type == 'radio' &&
-            el.name == element.name;
-      });
-    } else {
-      var radios = element.document.queryAll(
-          'input[type="radio"][name="${element.name}"]');
-      return radios.where((el) => el != element && el.form == null);
-    }
-  }
-
-  // TODO(jmesserly): polyfill document.contains API instead of doing it here
-  static bool _isNodeInDocument(Node node) {
-    // On non-IE this works:
-    // return node.document.contains(node);
-    var document = node.document;
-    if (node == document || node.parentNode == document) return true;
-    return document.documentElement.contains(node);
-  }
-}
-
-class _Bindings {
-  // TODO(jmesserly): not sure what kind of boolean conversion rules to
-  // apply for template data-binding. HTML attributes are true if they're
-  // present. However Dart only treats "true" as true. Since this is HTML we'll
-  // use something closer to the HTML rules: null (missing) and false are false,
-  // everything else is true. See: https://github.com/polymer-project/mdv/issues/59
-  static bool _toBoolean(value) => null != value && false != value;
-
-  static Node _createDeepCloneAndDecorateTemplates(Node node, String syntax) {
-    var clone = node.clone(false); // Shallow clone.
-    if (clone is Element && clone.isTemplate) {
-      TemplateElement.decorate(clone, node);
-      if (syntax != null) {
-        clone.attributes.putIfAbsent('syntax', () => syntax);
-      }
-    }
-
-    for (var c = node.$dom_firstChild; c != null; c = c.nextNode) {
-      clone.append(_createDeepCloneAndDecorateTemplates(c, syntax));
-    }
-    return clone;
-  }
-
-  // http://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/templates/index.html#dfn-template-contents-owner
-  static Document _getTemplateContentsOwner(HtmlDocument doc) {
-    if (doc.window == null) {
-      return doc;
-    }
-    var d = doc._templateContentsOwner;
-    if (d == null) {
-      // TODO(arv): This should either be a Document or HTMLDocument depending
-      // on doc.
-      d = doc.implementation.createHtmlDocument('');
-      while (d.$dom_lastChild != null) {
-        d.$dom_lastChild.remove();
-      }
-      doc._templateContentsOwner = d;
-    }
-    return d;
-  }
-
-  static Element _cloneAndSeperateAttributeTemplate(Element templateElement) {
-    var clone = templateElement.clone(false);
-    var attributes = templateElement.attributes;
-    for (var name in attributes.keys.toList()) {
-      switch (name) {
-        case 'template':
-        case 'repeat':
-        case 'bind':
-        case 'ref':
-          clone.attributes.remove(name);
-          break;
-        default:
-          attributes.remove(name);
-          break;
-      }
-    }
-
-    return clone;
-  }
-
-  static void _liftNonNativeChildrenIntoContent(Element templateElement) {
-    var content = templateElement.content;
-
-    if (!templateElement._isAttributeTemplate) {
-      var child;
-      while ((child = templateElement.$dom_firstChild) != null) {
-        content.append(child);
-      }
-      return;
-    }
-
-    // For attribute templates we copy the whole thing into the content and
-    // we move the non template attributes into the content.
-    //
-    //   <tr foo template>
-    //
-    // becomes
-    //
-    //   <tr template>
-    //   + #document-fragment
-    //     + <tr foo>
-    //
-    var newRoot = _cloneAndSeperateAttributeTemplate(templateElement);
-    var child;
-    while ((child = templateElement.$dom_firstChild) != null) {
-      newRoot.append(child);
-    }
-    content.append(newRoot);
-  }
-
-  static void _bootstrapTemplatesRecursivelyFrom(Node node) {
-    void bootstrap(template) {
-      if (!TemplateElement.decorate(template)) {
-        _bootstrapTemplatesRecursivelyFrom(template.content);
-      }
-    }
-
-    // Need to do this first as the contents may get lifted if |node| is
-    // template.
-    // TODO(jmesserly): node is DocumentFragment or Element
-    var descendents = (node as dynamic).queryAll(_allTemplatesSelectors);
-    if (node is Element && (node as Element).isTemplate) bootstrap(node);
-
-    descendents.forEach(bootstrap);
-  }
-
-  static final String _allTemplatesSelectors = 'template, option[template], ' +
-      Element._TABLE_TAGS.keys.map((k) => "$k[template]").join(", ");
-
-  static void _addBindings(Node node, model, [CustomBindingSyntax syntax]) {
-    if (node is Element) {
-      _addAttributeBindings(node, model, syntax);
-    } else if (node is Text) {
-      _parseAndBind(node, 'text', node.text, model, syntax);
-    }
-
-    for (var c = node.$dom_firstChild; c != null; c = c.nextNode) {
-      _addBindings(c, model, syntax);
-    }
-  }
-
-  static void _addAttributeBindings(Element element, model, syntax) {
-    element.attributes.forEach((name, value) {
-      if (value == '' && (name == 'bind' || name == 'repeat')) {
-        value = '{{}}';
-      }
-      _parseAndBind(element, name, value, model, syntax);
-    });
-  }
-
-  static void _parseAndBind(Node node, String name, String text, model,
-      CustomBindingSyntax syntax) {
-
-    var tokens = _parseMustacheTokens(text);
-    if (tokens.length == 0 || (tokens.length == 1 && tokens[0].isText)) {
-      return;
-    }
-
-    // If this is a custom element, give the .xtag a change to bind.
-    node = _nodeOrCustom(node);
-
-    if (tokens.length == 1 && tokens[0].isBinding) {
-      _bindOrDelegate(node, name, model, tokens[0].value, syntax);
-      return;
-    }
-
-    var replacementBinding = new CompoundBinding();
-    for (var i = 0; i < tokens.length; i++) {
-      var token = tokens[i];
-      if (token.isBinding) {
-        _bindOrDelegate(replacementBinding, i, model, token.value, syntax);
-      }
-    }
-
-    replacementBinding.combinator = (values) {
-      var newValue = new StringBuffer();
-
-      for (var i = 0; i < tokens.length; i++) {
-        var token = tokens[i];
-        if (token.isText) {
-          newValue.write(token.value);
-        } else {
-          var value = values[i];
-          if (value != null) {
-            newValue.write(value);
-          }
-        }
-      }
-
-      return newValue.toString();
-    };
-
-    node.bind(name, replacementBinding, 'value');
-  }
-
-  static void _bindOrDelegate(node, name, model, String path,
-      CustomBindingSyntax syntax) {
-
-    if (syntax != null) {
-      var delegateBinding = syntax.getBinding(model, path, name, node);
-      if (delegateBinding != null) {
-        model = delegateBinding;
-        path = 'value';
-      }
-    }
-
-    node.bind(name, model, path);
-  }
-
-  /**
-   * Gets the [node]'s custom [Element.xtag] if present, otherwise returns
-   * the node. This is used so nodes can override [Node.bind], [Node.unbind],
-   * and [Node.unbindAll] like InputElement does.
-   */
-  // TODO(jmesserly): remove this when we can extend Element for real.
-  static _nodeOrCustom(node) => node is Element ? node.xtag : node;
-
-  static List<_BindingToken> _parseMustacheTokens(String s) {
-    var result = [];
-    var length = s.length;
-    var index = 0, lastIndex = 0;
-    while (lastIndex < length) {
-      index = s.indexOf('{{', lastIndex);
-      if (index < 0) {
-        result.add(new _BindingToken(s.substring(lastIndex)));
-        break;
-      } else {
-        // There is a non-empty text run before the next path token.
-        if (index > 0 && lastIndex < index) {
-          result.add(new _BindingToken(s.substring(lastIndex, index)));
-        }
-        lastIndex = index + 2;
-        index = s.indexOf('}}', lastIndex);
-        if (index < 0) {
-          var text = s.substring(lastIndex - 2);
-          if (result.length > 0 && result.last.isText) {
-            result.last.value += text;
-          } else {
-            result.add(new _BindingToken(text));
-          }
-          break;
-        }
-
-        var value = s.substring(lastIndex, index).trim();
-        result.add(new _BindingToken(value, isBinding: true));
-        lastIndex = index + 2;
-      }
-    }
-    return result;
-  }
-
-  static void _addTemplateInstanceRecord(fragment, model) {
-    if (fragment.$dom_firstChild == null) {
-      return;
-    }
-
-    var instanceRecord = new TemplateInstance(
-        fragment.$dom_firstChild, fragment.$dom_lastChild, model);
-
-    var node = instanceRecord.firstNode;
-    while (node != null) {
-      node._templateInstance = instanceRecord;
-      node = node.nextNode;
-    }
-  }
-
-  static void _removeAllBindingsRecursively(Node node) {
-    _nodeOrCustom(node).unbindAll();
-    for (var c = node.$dom_firstChild; c != null; c = c.nextNode) {
-      _removeAllBindingsRecursively(c);
-    }
-  }
-
-  static void _removeChild(Node parent, Node child) {
-    child._templateInstance = null;
-    if (child is Element && (child as Element).isTemplate) {
-      Element childElement = child;
-      // Make sure we stop observing when we remove an element.
-      var templateIterator = childElement._templateIterator;
-      if (templateIterator != null) {
-        templateIterator.abandon();
-        childElement._templateIterator = null;
-      }
-    }
-    child.remove();
-    _removeAllBindingsRecursively(child);
-  }
-}
-
-class _BindingToken {
-  final String value;
-  final bool isBinding;
-
-  _BindingToken(this.value, {this.isBinding: false});
-
-  bool get isText => !isBinding;
-}
-
-class _TemplateIterator {
-  final Element _templateElement;
-  final List<Node> terminators = [];
-  final CompoundBinding inputs;
-  List iteratedValue;
-
-  StreamSubscription _sub;
-  StreamSubscription _valueBinding;
-
-  _TemplateIterator(this._templateElement)
-    : inputs = new CompoundBinding(resolveInputs) {
-
-    _valueBinding = new PathObserver(inputs, 'value').bindSync(valueChanged);
-  }
-
-  static Object resolveInputs(Map values) {
-    if (values.containsKey('if') && !_Bindings._toBoolean(values['if'])) {
-      return null;
-    }
-
-    if (values.containsKey('repeat')) {
-      return values['repeat'];
-    }
-
-    if (values.containsKey('bind')) {
-      return [values['bind']];
-    }
-
-    return null;
-  }
-
-  void valueChanged(value) {
-    clear();
-    if (value is! List) return;
-
-    iteratedValue = value;
-
-    if (value is Observable) {
-      _sub = value.changes.listen(_handleChanges);
-    }
-
-    int len = iteratedValue.length;
-    if (len > 0) {
-      _handleChanges([new ListChangeRecord(0, addedCount: len)]);
-    }
-  }
-
-  Node getTerminatorAt(int index) {
-    if (index == -1) return _templateElement;
-    var terminator = terminators[index];
-    if (terminator is! Element) return terminator;
-
-    var subIterator = terminator._templateIterator;
-    if (subIterator == null) return terminator;
-
-    return subIterator.getTerminatorAt(subIterator.terminators.length - 1);
-  }
-
-  void insertInstanceAt(int index, Node fragment) {
-    var previousTerminator = getTerminatorAt(index - 1);
-    var terminator = fragment.$dom_lastChild;
-    if (terminator == null) terminator = previousTerminator;
-
-    terminators.insert(index, terminator);
-    var parent = _templateElement.parentNode;
-    parent.insertBefore(fragment, previousTerminator.nextNode);
-  }
-
-  void removeInstanceAt(int index) {
-    var previousTerminator = getTerminatorAt(index - 1);
-    var terminator = getTerminatorAt(index);
-    terminators.removeAt(index);
-
-    var parent = _templateElement.parentNode;
-    while (terminator != previousTerminator) {
-      var node = terminator;
-      terminator = node.previousNode;
-      _Bindings._removeChild(parent, node);
-    }
-  }
-
-  void removeAllInstances() {
-    if (terminators.length == 0) return;
-
-    var previousTerminator = _templateElement;
-    var terminator = getTerminatorAt(terminators.length - 1);
-    terminators.length = 0;
-
-    var parent = _templateElement.parentNode;
-    while (terminator != previousTerminator) {
-      var node = terminator;
-      terminator = node.previousNode;
-      _Bindings._removeChild(parent, node);
-    }
-  }
-
-  void clear() {
-    unobserve();
-    removeAllInstances();
-    iteratedValue = null;
-  }
-
-  getInstanceModel(model, syntax) {
-    if (syntax != null) {
-      return syntax.getInstanceModel(_templateElement, model);
-    }
-    return model;
-  }
-
-  getInstanceFragment(syntax) {
-    if (syntax != null) {
-      return syntax.getInstanceFragment(_templateElement);
-    }
-    return _templateElement.createInstance();
-  }
-
-  void _handleChanges(List<ListChangeRecord> splices) {
-    var syntax = TemplateElement.syntax[_templateElement.attributes['syntax']];
-
-    for (var splice in splices) {
-      if (splice is! ListChangeRecord) continue;
-
-      for (int i = 0; i < splice.removedCount; i++) {
-        removeInstanceAt(splice.index);
-      }
-
-      for (var addIndex = splice.index;
-          addIndex < splice.index + splice.addedCount;
-          addIndex++) {
-
-        var model = getInstanceModel(iteratedValue[addIndex], syntax);
-
-        var fragment = getInstanceFragment(syntax);
-
-        _Bindings._addBindings(fragment, model, syntax);
-        _Bindings._addTemplateInstanceRecord(fragment, model);
-
-        insertInstanceAt(addIndex, fragment);
-      }
-    }
-  }
-
-  void unobserve() {
-    if (_sub == null) return;
-    _sub.cancel();
-    _sub = null;
-  }
-
-  void abandon() {
-    unobserve();
-    _valueBinding.cancel();
-    inputs.dispose();
-  }
-}
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.