Add apply method signature to Function class.

tests/corelib/apply_test.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.
+
+// Testing Function.apply calls correctly.
+// This test is not testing error handling, only that correct parameters
+// cause a correct call.
+
+int test0() => 42;
+int test0a({int a}) => 37 + a;
+int test1(int i) => i + 1;
+int test1a(int i, {int a}) => i + a;
+int test2(int i, int j) => i + j;
+int test2a(int i, int j, {int a}) => i + j + a;
+
+bool testPassed1([int x]) => ?x;
+bool testPassedX({int x}) => ?x;
+
+class C {
+  int x = 10;
+  int foo(y) => this.x + y;
+}
+
+class Callable {
+  int call(int x, int y) => x + y;
+}
+
+confuse() {
+  try {
+    throw [Function.apply];
+  } catch (e) {
+    return e[0];
+  }
+  return null;
+}
+
+main() {
+  testMap(res, func, map) {

[ngeoffray, 2012/10/05 12:57:29]

Looks better with named parameters:
test(res, func, {map: null, list: null})

[Lasse Reichstein Nielsen, 2012/10/08 07:52:01]

The content of the functions differ, so having a single function with two
optional parameters would just turn it into one function with three distinct
bodies and some switching logic. That's usually a sign that it should be
separate functions.

+    Expect.equals(res, Function.apply(func, null, map));
+    Expect.equals(res, Function.apply(func, [], map));
+  }
+  testList(res, func, list) {
+    Expect.equals(res, Function.apply(func, list));
+    Expect.equals(res, Function.apply(func, list, null));
+    Expect.equals(res, Function.apply(func, list, {}));
+  }
+  test(res, func, list, map) {
+    Expect.equals(res, Function.apply(func, list, map));
+  }
+  testList(42, test0, null);
+  testList(42, test0, []]);
+  testMap(42, test0a, {"a": 5});
+  testList(42, test1, [41]);
+  test(42, test1a, [20], {"a": 22});
+  testList(42, test2, [20, 22]);
+  test(42, test2a, [10, 15], {"a" : 17});
+
+  testList(false, testPassed1, null);
+  testList(false, testPassed1, []);
+  testList(true, testPassed1, [42]);
+
+  testMap(false, testPassedX, null);
+  testMap(false, testPassedX, {});
+  testMap(true, testPassedX, {"x": 42});
+
+  // Test that "this" is correct when calling closurized functions.
+  var cfoo = new C().foo;
+  testList(42, cfoo, [32]);
+
+  // Test that apply works even with a different name.
+  var app = confuse();
+  Expect.equals(42, app(test2, [22, 20]));
+
+  // Test that apply can itself be applied.
+  Expect.equals(42, Function.apply(Function.apply, [test2, [17, 25]]));
+
+  // Test that apply works on callable objects.
+  testList(42, new Callable(), [13, 29]);
+}