LanguageFeatures/Control-flow-collections/dynamic_semantics_set_A04_t02.dart

/*
 * Copyright (c) 2019, 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.
 */
/**
 * @assertion Dynamic Semantics
 * The new dynamic semantics are a superset of the original behavior. To avoid
 * redundancy and handle nested uses, the semantics are expressed in terms of a
 * separate procedure below:
 * . . .
 * Sets
 * 1. Create a fresh instance [collection] of a class that implements [Set<E>].
 *
 * 2. For each [element] in the set literal:
 *     i. Evaluate [element] using the procedure below.
 *
 * 3. The result of the literal expression is [collection].
 * . . .
 * To evaluate a collection [element]:
 * This procedure handles elements in both list and map literals because the
 * only difference is how a base expression element or entry element is handled.
 * The control flow parts are the same so are unified here.
 * . . .
 * 4. Else, if [element] is a C-style [for] element:
 *
 *      i. Evaluate the initializer clause of the element, if there is one.
 *     ii. Loop:
 *           a. Evaluate the condition expression to a value [condition].
 *              If there is no condition expression, use [true].
 *           b. If the boolean conversion of [condition] is not [true], exit
 *              the loop.
 *           c. Evaluate the body element using this procedure in the scope of
 *              the variable declared by the initializer clause if there is one.
 *           d. If there is an increment clause, execute it. in the stream are
 *         processed, complete [streamDone] with [null].
 * . . .
 * @description Checks that if [element] of set literal is a C-style [for]
 * element, this element is evaluated using the specified procedure. Checks that
 * the initializer clause of the element does not exist.
 * @author ngl@unipro.ru
 */
// SharedOptions=--enable-experiment=constant-update-2018
import "../../Utils/expect.dart";

main() {
  var set1exp = new Set<num>();
  var i = 0;
  for (; i < 10; i += 3) {
    if (i.isOdd) {
      set1exp.add(i + 0.5);
    } else {
      set1exp.add(i);
    }
  }
  Expect.isTrue(set1exp is Set<num>);

  i = 0;
  var set1 = <num>{for (; i < 10; i += 3) if (i.isOdd) i + 0.5 else i};
  // set1exp {0, 3.5, 6, 9.5, 12}
  Expect.isTrue(set1 is Set<num>);
  Expect.setEquals(set1exp, set1);
}