| // 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: |
| /// |
| /// Lists |
| /// 1. Create a fresh instance [collection] of a class that implements [List<E>]. |
| /// |
| /// An implementation is, of course, free to optimize by pre-allocating a list |
| /// of the correct capacity when its size is statically known. Note that when |
| /// [if] and [for] come into play, it's no longer always possible to |
| /// statically tell the final size of the resulting flattened list. |
| /// |
| /// 2. For each [element] in the list 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. |
| /// . . . |
| /// @description Checks that if [element] of list 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 |
| |
| import "../../Utils/expect.dart"; |
| |
| main() { |
| var list1exp = <num>[]; |
| var i = 2; |
| for (; i < 10; i += 3) { |
| if (i.isOdd) { |
| list1exp.add(i + 0.5); |
| } else { |
| list1exp.add(i); |
| } |
| } |
| list1exp.add(i); |
| Expect.isTrue(list1exp is List<num>); |
| Expect.runtimeIsType<List<num>>(list1exp); |
| |
| i = 2; |
| var list1 = <num>[for (; i < 10; i += 3) if (i.isOdd) i + 0.5 else i]; |
| list1.add(i); |
| // list1exp [2, 5.5, 8, 11] |
| Expect.isTrue(list1 is List<num>); |
| Expect.runtimeIsType<List<num>>(list1); |
| Expect.listEquals(list1exp, list1); |
| } |