First version of Codecs and Converters.

sdk/lib/convert/converter.dart

Index: sdk/lib/convert/converter.dart
diff --git a/sdk/lib/convert/converter.dart b/sdk/lib/convert/converter.dart
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+// Copyright (c) 2013, 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.convert;
+
+/**
+ * A [Converter] converts data from one representation into another.
+ *
+ * *Converters are still experimental and are subject to change without notice.*
+ *
+ */
+abstract class Converter<S, T> {
+  /**
+   * Converts [input] and returns the result of the conversion.
+   */
+  T convert(S input);
+
+  /**
+   * Fuses `this` with [other].
+   *
+   * Encoding with the resulting converter is equivalent to converting with
+   * `this` before converting with `other`.
+   */
+  Converter<S, dynamic> fuse(Converter<T, dynamic> other) {
+    return new _FusedConverter<S, T, dynamic>(this, other);
+  }
+}
+
+/**
+ * Fuses two converters.
+ *
+ * For a non-chunked conversion converts the input in sequence.
+ */
+class _FusedConverter<S, M, T> extends Converter<S, T> {
+  final Converter _first;
+  final Converter _second;
+
+  _FusedConverter(this._first, this._second);
+
+  T convert(S input) => _second.convert(_first.convert(input));
+}