First cut of mini dart:html.

tool/input_sdk/lib/html/html_common/css_class_set.dart

+// 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.
+
+part of html_common;
+
+abstract class CssClassSetImpl implements CssClassSet {
+
+  static final RegExp _validTokenRE = new RegExp(r'^\S+$');
+
+  String _validateToken(String value) {
+    if (_validTokenRE.hasMatch(value)) return value;
+    throw new ArgumentError.value(value, 'value', 'Not a valid class token');
+  }
+
+  String toString() {
+    return readClasses().join(' ');
+  }
+
+  /**
+   * Adds the class [value] to the element if it is not on it, removes it if it
+   * is.
+   *
+   * If [shouldAdd] is true, then we always add that [value] to the element. If
+   * [shouldAdd] is false then we always remove [value] from the element.
+   */
+  bool toggle(String value, [bool shouldAdd]) {
+    _validateToken(value);
+    Set<String> s = readClasses();
+    bool result = false;
+    if (shouldAdd == null) shouldAdd = !s.contains(value);
+    if (shouldAdd) {
+      s.add(value);
+      result = true;
+    } else {
+      s.remove(value);
+    }
+    writeClasses(s);
+    return result;
+  }
+
+  /**
+   * Returns [:true:] if classes cannot be added or removed from this
+   * [:CssClassSet:].
+   */
+  bool get frozen => false;
+
+  // interface Iterable - BEGIN
+  Iterator<String> get iterator => readClasses().iterator;
+  // interface Iterable - END
+
+  // interface Collection - BEGIN
+  void forEach(void f(String element)) {
+    readClasses().forEach(f);
+  }
+
+  String join([String separator = ""]) => readClasses().join(separator);
+
+  Iterable map(f(String element)) => readClasses().map(f);
+
+  Iterable<String> where(bool f(String element)) => readClasses().where(f);
+
+  Iterable expand(Iterable f(String element)) => readClasses().expand(f);
+
+  bool every(bool f(String element)) => readClasses().every(f);
+
+  bool any(bool f(String element)) => readClasses().any(f);
+
+  bool get isEmpty => readClasses().isEmpty;
+
+  bool get isNotEmpty => readClasses().isNotEmpty;
+
+  int get length => readClasses().length;
+
+  String reduce(String combine(String value, String element)) {
+    return readClasses().reduce(combine);
+  }
+
+  dynamic fold(dynamic initialValue,
+      dynamic combine(dynamic previousValue, String element)) {
+    return readClasses().fold(initialValue, combine);
+  }
+  // interface Collection - END
+
+  // interface Set - BEGIN
+  /**
+   * Determine if this element contains the class [value].
+   *
+   * This is the Dart equivalent of jQuery's
+   * [hasClass](http://api.jquery.com/hasClass/).
+   */
+  bool contains(Object value) {
+    if (value is! String) return false;
+    _validateToken(value);
+    return readClasses().contains(value);
+  }
+
+  /** Lookup from the Set interface. Not interesting for a String set. */
+  String lookup(Object value) => contains(value) ? value : null;
+
+  /**
+   * Add the class [value] to element.
+   *
+   * This is the Dart equivalent of jQuery's
+   * [addClass](http://api.jquery.com/addClass/).
+   */
+  bool add(String value) {
+    _validateToken(value);
+    // TODO - figure out if we need to do any validation here
+    // or if the browser natively does enough.
+    return modify((s) => s.add(value));
+  }
+
+  /**
+   * Remove the class [value] from element, and return true on successful
+   * removal.
+   *
+   * This is the Dart equivalent of jQuery's
+   * [removeClass](http://api.jquery.com/removeClass/).
+   */
+  bool remove(Object value) {
+    _validateToken(value);
+    if (value is! String) return false;
+    Set<String> s = readClasses();
+    bool result = s.remove(value);
+    writeClasses(s);
+    return result;
+  }
+
+  /**
+   * Add all classes specified in [iterable] to element.
+   *
+   * This is the Dart equivalent of jQuery's
+   * [addClass](http://api.jquery.com/addClass/).
+   */
+  void addAll(Iterable<String> iterable) {
+    // TODO - see comment above about validation.
+    modify((s) => s.addAll(iterable.map(_validateToken)));
+  }
+
+  /**
+   * Remove all classes specified in [iterable] from element.
+   *
+   * This is the Dart equivalent of jQuery's
+   * [removeClass](http://api.jquery.com/removeClass/).
+   */
+  void removeAll(Iterable<Object> iterable) {
+    modify((s) => s.removeAll(iterable.map(_validateToken)));
+  }
+
+  /**
+   * Toggles all classes specified in [iterable] on element.
+   *
+   * Iterate through [iterable]'s items, and add it if it is not on it, or
+   * remove it if it is. This is the Dart equivalent of jQuery's
+   * [toggleClass](http://api.jquery.com/toggleClass/).
+   * If [shouldAdd] is true, then we always add all the classes in [iterable]
+   * element. If [shouldAdd] is false then we always remove all the classes in
+   * [iterable] from the element.
+   */
+  void toggleAll(Iterable<String> iterable, [bool shouldAdd]) {
+    iterable.forEach((e) => toggle(e, shouldAdd));
+  }
+
+  void retainAll(Iterable<Object> iterable) {
+    modify((s) => s.retainAll(iterable));
+  }
+
+  void removeWhere(bool test(String name)) {
+    modify((s) => s.removeWhere(test));
+  }
+
+  void retainWhere(bool test(String name)) {
+    modify((s) => s.retainWhere(test));
+  }
+
+  bool containsAll(Iterable<Object> collection) =>
+    readClasses().containsAll(collection);
+
+  Set<String> intersection(Set<Object> other) =>
+    readClasses().intersection(other);
+
+  Set<String> union(Set<String> other) =>
+    readClasses().union(other);
+
+  Set<String> difference(Set<String> other) =>
+    readClasses().difference(other);
+
+  String get first => readClasses().first;
+  String get last => readClasses().last;
+  String get single => readClasses().single;
+  List<String> toList({ bool growable: true }) =>
+      readClasses().toList(growable: growable);
+  Set<String> toSet() => readClasses().toSet();
+  Iterable<String> take(int n) => readClasses().take(n);
+  Iterable<String> takeWhile(bool test(String value)) =>
+      readClasses().takeWhile(test);
+  Iterable<String> skip(int n) => readClasses().skip(n);
+  Iterable<String> skipWhile(bool test(String value)) =>
+      readClasses().skipWhile(test);
+  String firstWhere(bool test(String value), { String orElse() }) =>
+      readClasses().firstWhere(test, orElse: orElse);
+  String lastWhere(bool test(String value), { String orElse()}) =>
+      readClasses().lastWhere(test, orElse: orElse);
+  String singleWhere(bool test(String value)) =>
+      readClasses().singleWhere(test);
+  String elementAt(int index) => readClasses().elementAt(index);
+
+  void clear() {
+    // TODO(sra): Do this without reading the classes.
+    modify((s) => s.clear());
+  }
+  // interface Set - END
+
+  /**
+   * Helper method used to modify the set of css classes on this element.
+   *
+   *   f - callback with:
+   *   s - a Set of all the css class name currently on this element.
+   *
+   *   After f returns, the modified set is written to the
+   *       className property of this element.
+   */
+  modify( f(Set<String> s)) {
+    Set<String> s = readClasses();
+    var ret = f(s);
+    writeClasses(s);
+    return ret;
+  }
+
+  /**
+   * Read the class names from the Element class property,
+   * and put them into a set (duplicates are discarded).
+   * This is intended to be overridden by specific implementations.
+   */
+  Set<String> readClasses();
+
+  /**
+   * Join all the elements of a set into one string and write
+   * back to the element.
+   * This is intended to be overridden by specific implementations.
+   */
+  void writeClasses(Set<String> s);
+}