Better documentation on Sets and Maps, and more.

sdk/lib/core/string.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 dart.core;
 
 /**
  * The String class represents sequences of characters. Strings are
  * immutable. A string is represented by a sequence of Unicode UTF-16
  * code units accessible through the [codeUnitAt] or the
@@ skipping 161 matching lines @@
    *     2029          ; White_Space # Zp   PARAGRAPH SEPARATOR
    *     202F          ; White_Space # Zs   NARROW NO-BREAK SPACE
    *     205F          ; White_Space # Zs   MEDIUM MATHEMATICAL SPACE
    *     3000          ; White_Space # Zs   IDEOGRAPHIC SPACE
    *
    *     FEFF          ; BOM                ZERO WIDTH NO_BREAK SPACE
    */
   String trim();
 
   /**
-   * Returns whether this string contains [other] starting
-   * at [startIndex] (inclusive).
+   * Returns whether this string contains a match of [other].
+   *
+   * If [startIndex] is provided, only matches at or after that index
+   * are considered.
+   *
+   * It is an error if [startIndex] is negative or greater than [length].
    */
-  bool contains(Pattern other, [int startIndex]);
+  bool contains(Pattern other, [int startIndex = 0]);
 
   /**
    * Returns a new string where the first occurence of [from] in this string
    * is replaced with [to].
    */
   String replaceFirst(Pattern from, String to);
 
   /**
    * Returns a new string where all occurences of [from] in this string
    * are replaced with [replace].
@@ skipping 266 matching lines @@
         _position = position - 1;
         _currentCodePoint = _combineSurrogatePair(prevCodeUnit, codeUnit);
         return true;
       }
     }
     _position = position;
     _currentCodePoint = codeUnit;
     return true;
   }
 }