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// 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.
/// The run-time type of a function object is 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:
/// ```dart
/// Function.apply(foo, [1, 2, 3], {#f: 4, #g: 5});
/// ```
/// gives exactly the same result as
/// ```dart
/// 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<dynamic>? positionalArguments,
[Map<Symbol, dynamic>? namedArguments]);
/// A hash code value that is compatible with `operator==`.
int get hashCode;
/// Test whether another object is equal to this function.
/// Function objects are only equal to other function objects
/// (an object satisfying `object is Function`),
/// and never to non-function objects.
/// Some function objects are considered equal by `==`
/// because they are recognized as representing the "same function":
/// - 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, as does referring to a local function
/// declaration twice in the same scope where it was declared.
/// - if they refer to the same member method extracted from the same object.
/// Repeatedly extracting an instance method of an object as a function value
/// gives equal, but not necessarily identical, function values.
/// Different evaluations of function literals
/// never give rise to equal function objects.
/// Each time a function literal is evaluated,
/// it creates a new function value that is not equal to any other function
/// value, not even ones created by the same expression.
bool operator ==(Object other);