Explicitly implementing some DOM iterable APIs for performance

sdk/lib/svg/dart2js/svg_dart2js.dart

 library dart.dom.svg;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:_collection-dev';
 import 'dart:html';
 import 'dart:html_common';
 import 'dart:_js_helper' show Creates, Returns, JavaScriptIndexingBehavior, JSName;
 import 'dart:_foreign_helper' show JS;
 // DO NOT EDIT - unless you are editing documentation as per:
@@ skipping 2994 matching lines @@
 
 
 @DocsEditable
 @DomName('SVGLengthList')
 class LengthList extends Object with ListMixin<Length>, ImmutableListMixin<Length> implements JavaScriptIndexingBehavior, List<Length> native "SVGLengthList" {
 
   @DomName('SVGLengthList.numberOfItems')
   @DocsEditable
   final int numberOfItems;
 
-  Length operator[](int index) => this.getItem(index);
-
+  Length operator[](int index) {
+    if (JS("bool", "# >>> 0 !== # || # >= #", index,
+        index, index, length))
+      throw new RangeError.range(index, 0, length);
+    return this.getItem(index);
+  }
   void operator[]=(int index, Length value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
   }
   // -- start List<Length> mixins.
   // Length is the element type.
 
   // SVG Collections expose numberOfItems rather than length.
   int get length => numberOfItems;
 
   void set length(int value) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Length get first {
+    if (this.length > 0) {
+      return JS('Length', '#[0]', this);
+    }
+    throw new StateError("No elements");
+  }
+
+  Length get last {
+    int len = this.length;
+    if (len > 0) {
+      return JS('Length', '#[#]', this, len - 1);
+    }
+    throw new StateError("No elements");
+  }
+
+  Length get single {
+    int len = this.length;
+    if (len == 1) {
+      return JS('Length', '#[0]', this);
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Length elementAt(int index) => this[index];
   // -- end List<Length> mixins.
 
   @DomName('SVGLengthList.appendItem')
   @DocsEditable
   Length appendItem(Length item) native;
 
   @DomName('SVGLengthList.clear')
   @DocsEditable
   void clear() native;
 
@@ skipping 426 matching lines @@
 
 
 @DocsEditable
 @DomName('SVGNumberList')
 class NumberList extends Object with ListMixin<Number>, ImmutableListMixin<Number> implements JavaScriptIndexingBehavior, List<Number> native "SVGNumberList" {
 
   @DomName('SVGNumberList.numberOfItems')
   @DocsEditable
   final int numberOfItems;
 
-  Number operator[](int index) => this.getItem(index);
-
+  Number operator[](int index) {
+    if (JS("bool", "# >>> 0 !== # || # >= #", index,
+        index, index, length))
+      throw new RangeError.range(index, 0, length);
+    return this.getItem(index);
+  }
   void operator[]=(int index, Number value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
   }
   // -- start List<Number> mixins.
   // Number is the element type.
 
   // SVG Collections expose numberOfItems rather than length.
   int get length => numberOfItems;
 
   void set length(int value) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Number get first {
+    if (this.length > 0) {
+      return JS('Number', '#[0]', this);
+    }
+    throw new StateError("No elements");
+  }
+
+  Number get last {
+    int len = this.length;
+    if (len > 0) {
+      return JS('Number', '#[#]', this, len - 1);
+    }
+    throw new StateError("No elements");
+  }
+
+  Number get single {
+    int len = this.length;
+    if (len == 1) {
+      return JS('Number', '#[0]', this);
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Number elementAt(int index) => this[index];
   // -- end List<Number> mixins.
 
   @DomName('SVGNumberList.appendItem')
   @DocsEditable
   Number appendItem(Number item) native;
 
   @DomName('SVGNumberList.clear')
   @DocsEditable
   void clear() native;
 
@@ skipping 657 matching lines @@
 
 
 @DocsEditable
 @DomName('SVGPathSegList')
 class PathSegList extends Object with ListMixin<PathSeg>, ImmutableListMixin<PathSeg> implements JavaScriptIndexingBehavior, List<PathSeg> native "SVGPathSegList" {
 
   @DomName('SVGPathSegList.numberOfItems')
   @DocsEditable
   final int numberOfItems;
 
-  PathSeg operator[](int index) => this.getItem(index);
-
+  PathSeg operator[](int index) {
+    if (JS("bool", "# >>> 0 !== # || # >= #", index,
+        index, index, length))
+      throw new RangeError.range(index, 0, length);
+    return this.getItem(index);
+  }
   void operator[]=(int index, PathSeg value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
   }
   // -- start List<PathSeg> mixins.
   // PathSeg is the element type.
 
   // SVG Collections expose numberOfItems rather than length.
   int get length => numberOfItems;
 
   void set length(int value) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  PathSeg get first {
+    if (this.length > 0) {
+      return JS('PathSeg', '#[0]', this);
+    }
+    throw new StateError("No elements");
+  }
+
+  PathSeg get last {
+    int len = this.length;
+    if (len > 0) {
+      return JS('PathSeg', '#[#]', this, len - 1);
+    }
+    throw new StateError("No elements");
+  }
+
+  PathSeg get single {
+    int len = this.length;
+    if (len == 1) {
+      return JS('PathSeg', '#[0]', this);
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  PathSeg elementAt(int index) => this[index];
   // -- end List<PathSeg> mixins.
 
   @DomName('SVGPathSegList.appendItem')
   @DocsEditable
   PathSeg appendItem(PathSeg newItem) native;
 
   @DomName('SVGPathSegList.clear')
   @DocsEditable
   void clear() native;
 
@@ skipping 687 matching lines @@
 
 
 @DocsEditable
 @DomName('SVGStringList')
 class StringList extends Object with ListMixin<String>, ImmutableListMixin<String> implements JavaScriptIndexingBehavior, List<String> native "SVGStringList" {
 
   @DomName('SVGStringList.numberOfItems')
   @DocsEditable
   final int numberOfItems;
 
-  String operator[](int index) => this.getItem(index);
-
+  String operator[](int index) {
+    if (JS("bool", "# >>> 0 !== # || # >= #", index,
+        index, index, length))
+      throw new RangeError.range(index, 0, length);
+    return this.getItem(index);
+  }
   void operator[]=(int index, String value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
   }
   // -- start List<String> mixins.
   // String is the element type.
 
   // SVG Collections expose numberOfItems rather than length.
   int get length => numberOfItems;
 
   void set length(int value) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  String get first {
+    if (this.length > 0) {
+      return JS('String', '#[0]', this);
+    }
+    throw new StateError("No elements");
+  }
+
+  String get last {
+    int len = this.length;
+    if (len > 0) {
+      return JS('String', '#[#]', this, len - 1);
+    }
+    throw new StateError("No elements");
+  }
+
+  String get single {
+    int len = this.length;
+    if (len == 1) {
+      return JS('String', '#[0]', this);
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  String elementAt(int index) => this[index];
   // -- end List<String> mixins.
 
   @DomName('SVGStringList.appendItem')
   @DocsEditable
   String appendItem(String item) native;
 
   @DomName('SVGStringList.clear')
   @DocsEditable
   void clear() native;
 
@@ skipping 960 matching lines @@
 
 
 @DocsEditable
 @DomName('SVGTransformList')
 class TransformList extends Object with ListMixin<Transform>, ImmutableListMixin<Transform> implements List<Transform>, JavaScriptIndexingBehavior native "SVGTransformList" {
 
   @DomName('SVGTransformList.numberOfItems')
   @DocsEditable
   final int numberOfItems;
 
-  Transform operator[](int index) => this.getItem(index);
-
+  Transform operator[](int index) {
+    if (JS("bool", "# >>> 0 !== # || # >= #", index,
+        index, index, length))
+      throw new RangeError.range(index, 0, length);
+    return this.getItem(index);
+  }
   void operator[]=(int index, Transform value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
   }
   // -- start List<Transform> mixins.
   // Transform is the element type.
 
   // SVG Collections expose numberOfItems rather than length.
   int get length => numberOfItems;
 
   void set length(int value) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  Transform get first {
+    if (this.length > 0) {
+      return JS('Transform', '#[0]', this);
+    }
+    throw new StateError("No elements");
+  }
+
+  Transform get last {
+    int len = this.length;
+    if (len > 0) {
+      return JS('Transform', '#[#]', this, len - 1);
+    }
+    throw new StateError("No elements");
+  }
+
+  Transform get single {
+    int len = this.length;
+    if (len == 1) {
+      return JS('Transform', '#[0]', this);
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  Transform elementAt(int index) => this[index];
   // -- end List<Transform> mixins.
 
   @DomName('SVGTransformList.appendItem')
   @DocsEditable
   Transform appendItem(Transform item) native;
 
   @DomName('SVGTransformList.clear')
   @DocsEditable
   void clear() native;
 
@@ skipping 321 matching lines @@
 
 
 @DocsEditable
 @DomName('SVGElementInstanceList')
 class _ElementInstanceList extends Object with ListMixin<ElementInstance>, ImmutableListMixin<ElementInstance> implements JavaScriptIndexingBehavior, List<ElementInstance> native "SVGElementInstanceList" {
 
   @DomName('SVGElementInstanceList.length')
   @DocsEditable
   int get length => JS("int", "#.length", this);
 
-  ElementInstance operator[](int index) => this.item(index);
-
+  ElementInstance operator[](int index) {
+    if (JS("bool", "# >>> 0 !== # || # >= #", index,
+        index, index, length))
+      throw new RangeError.range(index, 0, length);
+    return this.item(index);
+  }
   void operator[]=(int index, ElementInstance value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
   }
   // -- start List<ElementInstance> mixins.
   // ElementInstance is the element type.
 
 
   void set length(int value) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
+  ElementInstance get first {
+    if (this.length > 0) {
+      return JS('ElementInstance', '#[0]', this);
+    }
+    throw new StateError("No elements");
+  }
+
+  ElementInstance get last {
+    int len = this.length;
+    if (len > 0) {
+      return JS('ElementInstance', '#[#]', this, len - 1);
+    }
+    throw new StateError("No elements");
+  }
+
+  ElementInstance get single {
+    int len = this.length;
+    if (len == 1) {
+      return JS('ElementInstance', '#[0]', this);
+    }
+    if (len == 0) throw new StateError("No elements");
+    throw new StateError("More than one element");
+  }
+
+  ElementInstance elementAt(int index) => this[index];
   // -- end List<ElementInstance> mixins.
 
   @DomName('SVGElementInstanceList.item')
   @DocsEditable
   ElementInstance item(int index) native;
 }
 // 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.
 
@@ skipping 262 matching lines @@
 
 
 @DocsEditable
 @DomName('SVGVKernElement')
 abstract class _SVGVKernElement extends SvgElement native "SVGVKernElement" {
 
   @DomName('SVGVKernElement.SVGVKernElement')
   @DocsEditable
   factory _SVGVKernElement() => _SvgElementFactoryProvider.createSvgElement_tag("vkern");
 }