Codemirror dart port StringStream datatype babysteps.

tools/codemirror/dart/lib/codemirror.dart

+// Copyright (c) 2011, 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.

[mattsh, 2011/12/30 13:48:16]

maybe include a reference back to the original codemirror source, and a TODO
here to figure out what to put here

+
+#library('codemirror');
+
+#import('dart:html');
+#import('dart:core');
+
+/* The character stream used by a [Mode]'s parser. */
+class StringStream {
+  int _pos, start;
+  String _string;
+
+  StringStream(this._string) { _pos = 0; start = 0; }
+
+  bool eol() => _pos >= _string.length;
+
+  bool sol() => _pos == 0;
+
+  String peek() => _string[_pos];
+
+  String next() {
+    if (_pos < _string.length) return _string[_pos++];
+    return null;
+  }
+
+  String eat(match) {
+    var ch = peek();
+    //TODO(pquitslund): patterns?
+    if (ch == match){
+      ++_pos;
+      return ch;
+    }
+    return null;
+  }
+
+  bool eatWhile(match) {
+    var start = _pos;
+    while (eat(match) != null){}
+    return _pos > start;
+  }
+
+  bool eatSpace() {
+    return eatWhile(' ');
+  }
+
+  void skipToEnd() {
+    _pos = _string.length;
+  }
+
+  bool skipTo(ch) {
+    int found = _string.indexOf(ch, _pos);
+    if (found == -1) return false;
+    _pos = found;
+    return true;
+  }
+
+  void backUp(n) {
+    _pos -= n;
+  }
+
+  int column() => countColumn(_string, start);
+
+  int indentation() => countColumn(_string);
+
+  bool match(String pattern, [bool consume =false,

[mattsh, 2011/12/30 13:48:16]

space before false

+                              bool caseInsensitive = false]) {
+
+    if (caseInsensitive) {
+      String cased(str) => caseInsensitive ? str.toLowerCase() : str;
+      if (cased(_string).indexOf(cased(pattern), _pos) != _pos) return false;

[mattsh, 2011/12/30 13:48:16]

my personal preference is braces around all 'if' branches, just for clarity, so
I'd have the { return false; } in braces, but your choice.

[Bob Nystrom, 2012/01/04 00:22:40]

I believe we generally don't do braces for single-line ifs.

+    }
+    else if (!_string.substring(_pos).contains(pattern)) return false;
+
+    if (consume) _pos += pattern.length;
+    return true;
+  }
+
+  String current() => _string.substring(start, _pos);
+}
+
+//TODO(pquitslund): the codemirror default, surely gets overwritten...
+var tabSize = 8;

[mattsh, 2011/12/30 13:48:16]

int instead of var

+
+// Counts the column offset in a string, taking tabs into account.
+// Used mostly to find indentation.
+int countColumn(String string, [int end = null]) {
+  if (end == null) {
+    end = string.indexOf(' ');
+    if (end == -1) end = string.length;
+  }
+  int n = 0;
+  for (int i = 0; i < end; ++i) {
+    if (string[i] == "\t") {
+      n += tabSize - (n % tabSize);
+    } else{
+      ++n;
+    }
+  }
+  return n;
+}
+
+//TODO(pquitslund): remove once frog doesn't require a main in libs
+void main(){
+
+}