unfork DDC's copy of most SDK libraries

pkg/dev_compiler/tool/input_sdk/lib/core/function.dart

-// Copyright (c) 2011, 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 base class for all function types.
- *
- * A function value, or an instance of a class with a "call" method, is a
- * subtype of a function type, and as such, a subtype of [Function].
- */
-abstract class Function {
-  /**
-   * Dynamically call [function] with the specified arguments.
-   *
-   * Acts the same as calling function with positional arguments
-   * corresponding to the elements of [positionalArguments] and
-   * named arguments corresponding to the elements of [namedArguments].
-   *
-   * This includes giving the same errors if [function] isn't callable or
-   * if it expects different parameters.
-   *
-   * Example:
-   *       Map<Symbol, dynamic> namedArguments = new Map<Symbol, dynamic>();
-   *       namedArguments[const Symbol("f")] = 4;
-   *       namedArguments[const Symbol("g")] = 5;
-   *       Function.apply(foo, [1,2,3], namedArguments);
-   *
-   * gives exactly the same result as
-   *       foo(1, 2, 3, f: 4, g: 5).
-   *
-   * If [positionalArguments] is null, it's considered an empty list.
-   * If [namedArguments] is omitted or null, it is considered an empty map.
-   */
-  external static apply(Function function,
-                        List positionalArguments,
-                        [Map<Symbol, dynamic> namedArguments]);
-
-  /**
-   * Returns a hash code value that is compatible with `operator==`.
-   */
-  int get hashCode;
-
-  /**
-   * Test whether another object is equal to this function.
-   *
-   * System-created function objects are only equal to other functions.
-   *
-   * Two function objects are known to represent the same function if
-   *
-   * - It is the same object. Static and top-level functions are compile time
-   *   constants when used as values, so referring to the same function twice
-   *   always give the same object,
-   * - or if they refer to the same member method extracted from the same object.
-   *   Extracting a member method as a function value twice gives equal, but
-   *   not necessarily identical, function values.
-   *
-   * Function expressions never give rise to equal function objects. Each time
-   * a function expression is evaluated, it creates a new closure value that
-   * is not known to be equal to other closures created by the same expression.
-   *
-   * Classes implementing `Function` by having a `call` method should have their
-   * own `operator==` and `hashCode` depending on the object.
-   */
-  bool operator==(Object other);
-}