mirror of https://github.com/tc39/test262.git
90 lines
2.8 KiB
JavaScript
90 lines
2.8 KiB
JavaScript
// Copyright (C) 2016 the V8 project authors. All rights reserved.
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// This code is governed by the BSD license found in the LICENSE file.
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/*---
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esid: sec-generator-function-definitions-runtime-semantics-evaluation
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es6id: 14.4.14
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description: >
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Abrupt completion returned after protocol violation (and a `return` method
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is defined)
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info: |
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YieldExpression : yield * AssignmentExpression
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1. Let exprRef be the result of evaluating AssignmentExpression.
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2. Let value be ? GetValue(exprRef).
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3. Let iterator be ? GetIterator(value).
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4. Let received be NormalCompletion(undefined).
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5. Repeat
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a. If received.[[Type]] is normal, then
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[...]
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b. Else if received.[[Type]] is throw, then
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i. Let throw be ? GetMethod(iterator, "throw").
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ii. If throw is not undefined, then
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[...]
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iii. Else,
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1. NOTE: If iterator does not have a throw method, this throw is
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going to terminate the yield* loop. But first we need to give
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iterator a chance to clean up.
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2. Perform ? IteratorClose(iterator, Completion{[[Type]]: normal,
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[[Value]]: empty, [[Target]]: empty}).
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3. NOTE: The next step throws a TypeError to indicate that there
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was a yield* protocol violation: iterator does not have a throw
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method.
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4. Throw a TypeError exception.
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7.4.6 IteratorClose
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1. Assert: Type(iterator) is Object.
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2. Assert: completion is a Completion Record.
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3. Let return be ? GetMethod(iterator, "return").
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4. If return is undefined, return Completion(completion).
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5. Let innerResult be Call(return, iterator, « »).
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6. If completion.[[Type]] is throw, return Completion(completion).
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7. If innerResult.[[Type]] is throw, return Completion(innerResult).
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8. If Type(innerResult.[[Value]]) is not Object, throw a TypeError exception.
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9. Return Completion(completion).
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features: [generators, Symbol.iterator]
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---*/
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var badIter = {};
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var throwCount = 0;
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var thisValue, args;
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var poisonedReturn = {
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next: function() {
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return { done: false };
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},
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return: function() {
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thisValue = this;
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args = arguments;
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return 'this value has no effect on the protocol';
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}
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};
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Object.defineProperty(poisonedReturn, 'throw', {
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get: function() {
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throwCount += 1;
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}
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});
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badIter[Symbol.iterator] = function() {
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return poisonedReturn;
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};
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function* g() {
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try {
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yield * badIter;
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} catch (err) {
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caught = err;
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}
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}
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var iter = g();
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var caught;
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iter.next();
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iter.throw();
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assert.sameValue(throwCount, 1);
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assert.sameValue(thisValue, poisonedReturn, '"this" value');
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assert.sameValue(
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typeof args, 'object', 'method invoked, arguments object provided'
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);
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assert.sameValue(args.length, 0);
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assert.sameValue(typeof caught, 'object', 'object value thrown');
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assert.sameValue(caught.constructor, TypeError);
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