Aggregate CSS manipulation functions in html lib.

tools/dom/templates/html/impl/impl_Element.darttemplate

 // 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 $LIBRARYNAME;
 
 class _ChildrenElementList extends ListBase<Element> {
   // Raw Element.
   final Element _element;
   final HtmlCollection _childElements;
@@ skipping 119 matching lines @@
     if (result == null) throw new StateError("No elements");
     return result;
   }
 
   Element get single {
     if (length > 1) throw new StateError("More than one element");
     return first;
   }
 }
 
+/** 
+ * An immutable list containing HTML elements. This list contains some
+ * additional methods for ease of CSS manipulation on a group of elements.
+ */
+abstract class ElementList extends ListBase {

[blois, 2013/05/03 22:16:06]

I'd make it:
ElementList<T extends Element> extends ListBase<T>

This way we can expose ElementList<OptionElement>.

[Emily Fortuna, 2013/05/03 23:00:09]

Done.

+  /**
+   * The union of all CSS classes applied to the elements in this list.
+   *
+   * This set makes it easy to add, remove or toggle (add if not present, remove
+   * if present) the classes applied to a collection of elements.
+   *
+   *     htmlList.classes.add('selected');
+   *     htmlList.classes.toggle('isOnline');
+   *     htmlList.classes.remove('selected');
+   */
+  CssClassSet get classes;
+
+  /** Replace the classes with `value` for every element in this list. */
+  set classes(Iterable<String> value);
+}
+
 // TODO(jacobr): this is an inefficient implementation but it is hard to see
 // a better option given that we cannot quite force NodeList to be an
 // ElementList as there are valid cases where a NodeList JavaScript object
 // contains Node objects that are not Elements.
-class _FrozenElementList<T extends Element> extends ListBase<T> {
+class _FrozenElementList<T extends Element> extends ListBase<T> implements ElementList {
   final List<Node> _nodeList;
 
   _FrozenElementList._wrap(this._nodeList);
 
   int get length => _nodeList.length;
 
   Element operator [](int index) => _nodeList[index];
 
   void operator []=(int index, Element value) {
     throw new UnsupportedError('Cannot modify list');
   }
 
   void set length(int newLength) {
     throw new UnsupportedError('Cannot modify list');
   }
 
   void sort([Comparator<Element> compare]) {
     throw new UnsupportedError('Cannot sort list');
   }
 
   Element get first => _nodeList.first;
 
   Element get last => _nodeList.last;
 
   Element get single => _nodeList.single;
-}
 
-class _ElementCssClassSet extends CssClassSet {
+  CssClassSet get classes => new _MultiElementCssClassSet(
+      _nodeList.where((e) => e is Element));
 
-  final Element _element;
-
-  _ElementCssClassSet(this._element);
-
-  Set<String> readClasses() {
-    var s = new LinkedHashSet<String>();
-    var classname = _element.$dom_className;
-
-    for (String name in classname.split(' ')) {
-      String trimmed = name.trim();
-      if (!trimmed.isEmpty) {
-        s.add(trimmed);
-      }
-    }
-    return s;
-  }
-
-  void writeClasses(Set<String> s) {
-    List list = new List.from(s);
-    _element.$dom_className = s.join(' ');
+  void set classes(Iterable<String> value) {
+    _nodeList.where((e) => e is Element).forEach((e) { 
+        e.classes.clear();

[blois, 2013/05/03 22:16:06]

already a setter for classes, just:
e.classes = value?

[Emily Fortuna, 2013/05/03 23:00:09]

Done.

+        e.classes.addAll(value); 
+      });
   }
 }
 
 /**
  * An abstract class, which all HTML elements extend.
  */
 $(ANNOTATIONS)abstract class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   /**
    * Creates an HTML element from a valid fragment of HTML.
@@ skipping 78 matching lines @@
   }
 
   /**
    * Finds all descendent elements of this element that match the specified
    * group of selectors.
    *
    * [selectors] should be a string using CSS selector syntax.
    *
    *     var items = element.query('.itemClassName');
    */
-  List<Element> queryAll(String selectors) =>
+  ElementList queryAll(String selectors) =>
     new _FrozenElementList._wrap($dom_querySelectorAll(selectors));
 
   /**
    * The set of CSS classes applied to this element.
    *
    * This set makes it easy to add, remove or toggle the classes applied to
    * this element.
    *
    *     element.classes.add('selected');
    *     element.classes.toggle('isOnline');
@@ skipping 471 matching lines @@
   const ScrollAlignment._internal(this._value);
   toString() => 'ScrollAlignment.$_value';
 
   /// Attempt to align the element to the top of the scrollable area.
   static const TOP = const ScrollAlignment._internal('TOP');
   /// Attempt to center the element in the scrollable area.
   static const CENTER = const ScrollAlignment._internal('CENTER');
   /// Attempt to align the element to the bottom of the scrollable area.
   static const BOTTOM = const ScrollAlignment._internal('BOTTOM');
 }