Big merge from experimental to bleeding edge.

runtime/lib/integers_patch.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.
 // Dart core library.
 
 // VM implementation of int.
 
 patch class int {
-  /* patch */ static int parse(String str) native "Integer_parse";
+  static int _parse(String str) native "Integer_parse";
+
+  static void _throwFormatException(String source) {
+    throw new FormatException(source);
+  }
+
+  /* patch */ static int parse(String source,
+                               { int radix,
+                                 int onError(String str) }) {
+    if (source is! String) throw new ArgumentError(source);
+    if (radix == null) {
+      if (onError == null) return _parse(source);
+      try {
+        return _parse(source);
+      } on FormatException {
+        return onError(source);
+      }
+    }
+    if (radix is! int) throw new ArgumentError("Radix is not an integer");
+    if (radix < 2 || radix > 36) {
+      throw new RangeError("Radix $radix not in range 2..36");
+    }
+    if (onError == null) {
+      onError = _throwFormatException;
+    }
+    // Remove leading and trailing white space.
+    source = source.trim();
+    if (source.isEmpty) return onError(source);
+
+    bool negative = false;
+    int result = 0;
+
+    // The value 99 is used to represent a non-digit. It is too large to be
+    // a digit value in any of the used bases.
+    const NA = 99;
+    const List<int> digits = const <int>[
+      00, 01, 02, 03, 04, 05, 06, 07, 08, 09, NA, NA, NA, NA, NA, NA,  // 0x30
+      NA, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,  // 0x40
+      25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, NA, NA, NA, NA, NA,  // 0x50
+      NA, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,  // 0x60
+      25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, NA, NA, NA, NA, NA,  // 0x70
+    ];
+
+    int i = 0;
+    int code = source.charCodeAt(i);
+    if (code == 0x2d || code == 0x2b) { // Starts with a plus or minus-sign.
+      negative = (code == 0x2d);
+      if (source.length == 1) return onError(source);
+      i = 1;
+      code = source.charCodeAt(i);
+    }
+    do {
+      if (code < 0x30 || code > 0x7f) return onError(source);
+      int digit = digits[code - 0x30];
+      if (digit >= radix) return onError(source);
+      result = result * radix + digit;
+      i++;
+      if (i == source.length) break;
+      code = source.charCodeAt(i);
+    } while (true);
+    return negative ? -result : result;
+  }
 }