Use patching for regexp implementation.

runtime/lib/regexp.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.
-
-class JSRegExpMatch implements Match {
-  JSRegExpMatch(this.regexp, this.str, this._match);
-
-  int start() {
-    return _start(0);
-  }
-
-  int end() {
-    return _end(0);
-  }
-
-  int _start(int groupIdx) {
-    return _match[(groupIdx * MATCH_PAIR)];
-  }
-
-  int _end(int groupIdx) {
-    return _match[(groupIdx * MATCH_PAIR) + 1];
-  }
-
-  String group(int groupIdx) {
-    if (groupIdx < 0 || groupIdx > regexp._groupCount) {
-      throw new IndexOutOfRangeException(groupIdx);
-    }
-    int startIndex = _start(groupIdx);
-    int endIndex = _end(groupIdx);
-    if (startIndex == -1) {
-      assert(endIndex == -1);
-      return null;
-    }
-    return str.substringUnchecked_(startIndex, endIndex);
-  }
-
-  String operator [](int groupIdx) {
-    return this.group(groupIdx);
-  }
-
-  List<String> groups(List<int> groupsSpec) {
-    var groupsList = new List<String>(groupsSpec.length);
-    for (int i = 0; i < groupsSpec.length; i++) {
-      groupsList[i] = group(groupsSpec[i]);
-    }
-    return groupsList;
-  }
-
-  int groupCount() {
-    return regexp._groupCount;
-  }
-
-  String get pattern() => regexp.pattern;
-
-  final RegExp regexp;
-  final String str;
-  final List<int> _match;
-  static final int MATCH_PAIR = 2;
-}
-
-
-class JSSyntaxRegExp implements RegExp {
-  const factory JSSyntaxRegExp(
-      String pattern,
-      [bool multiLine = false,
-       bool ignoreCase = false]) native "JSSyntaxRegExp_factory";
-
-  Match firstMatch(String str) {
-    List match = _ExecuteMatch(str, 0);
-    if (match === null) {
-      return null;
-    }
-    return new JSRegExpMatch(this, str, match);
-  }
-
-  Iterable<Match> allMatches(String str) {
-    List<Match> result = new List<Match>();
-    int length = str.length;
-    int startIndex = 0;
-    while (true) {
-      List match = _ExecuteMatch(str, startIndex);
-      if (match == null) {
-        break;
-      }
-      result.add(new JSRegExpMatch(this, str, match));
-      int endIndex = match[1];
-      if (endIndex == length) {
-        break;
-      } else if (match[0] == endIndex) {
-        ++startIndex;  // empty match, advance and restart
-      } else {
-        startIndex = endIndex;
-      }
-    }
-    return result;
-  }
-
-  bool hasMatch(String str) {
-    List match = _ExecuteMatch(str, 0);
-    return (match === null) ? false : true;
-  }
-
-  String stringMatch(String str) {
-    List match = _ExecuteMatch(str, 0);
-    if (match === null) {
-      return null;
-    }
-    return str.substringUnchecked_(match[0], match[1]);
-  }
-
-  String get pattern() native "JSSyntaxRegExp_getPattern";
-
-  bool get multiLine() native "JSSyntaxRegExp_multiLine";
-
-  bool get ignoreCase() native "JSSyntaxRegExp_ignoreCase";
-
-  int get _groupCount() native "JSSyntaxRegExp_getGroupCount";
-
-  List _ExecuteMatch(String str, int start_index)
-      native "JSSyntaxRegExp_ExecuteMatch";
-}