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83 lines
2.5 KiB
JavaScript
83 lines
2.5 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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description: Referencing the arguments object from a default parameter (generator function expression)
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esid: sec-generator-function-definitions-runtime-semantics-evaluation
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es6id: 14.4.14
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features: [default-parameters]
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info: |
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GeneratorExpression : function * ( FormalParameters ) { GeneratorBody }
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[...]
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3. Let closure be GeneratorFunctionCreate(Normal, FormalParameters,
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GeneratorBody, scope, strict).
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[...]
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9.2.1 [[Call]] ( thisArgument, argumentsList)
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[...]
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7. Let result be OrdinaryCallEvaluateBody(F, argumentsList).
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[...]
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9.2.1.3 OrdinaryCallEvaluateBody ( F, argumentsList )
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1. Let status be FunctionDeclarationInstantiation(F, argumentsList).
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[...]
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9.2.12 FunctionDeclarationInstantiation(func, argumentsList)
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[...]
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23. Let iteratorRecord be Record {[[iterator]]:
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CreateListIterator(argumentsList), [[done]]: false}.
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24. If hasDuplicates is true, then
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[...]
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25. Else,
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b. Let formalStatus be IteratorBindingInitialization for formals with
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iteratorRecord and env as arguments.
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[...]
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14.1.19 Runtime Semantics: IteratorBindingInitialization
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FormalsList : FormalsList , FormalParameter
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1. Let status be the result of performing IteratorBindingInitialization for
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FormalsList using iteratorRecord and environment as the arguments.
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2. ReturnIfAbrupt(status).
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3. Return the result of performing IteratorBindingInitialization for
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FormalParameter using iteratorRecord and environment as the arguments.
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---*/
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var callCount = 0;
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var f;
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f = function*(x, _ = 0) {
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assert.sameValue(x, undefined, 'parameter binding value (initial)');
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assert.sameValue(
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arguments[0], undefined, 'arguments property value (initial)'
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);
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arguments[0] = 1;
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assert.sameValue(
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x, undefined, 'parameter binding value (after arguments modification)'
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);
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assert.sameValue(
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arguments[0], 1, 'arguments property value (after arguments modification)'
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);
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x = 2;
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assert.sameValue(
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x, 2, 'parameter binding value (after parameter binding modification)'
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);
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assert.sameValue(
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arguments[0],
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1,
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'arguments property value (after parameter binding modification)'
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);
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callCount = callCount + 1;
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};
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f().next();
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assert.sameValue(callCount, 1, 'generator function invoked exactly once');
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