1// Copyright 2013 the V8 project authors. All rights reserved. 2// Redistribution and use in source and binary forms, with or without 3// modification, are permitted provided that the following conditions are 4// met: 5// 6// * Redistributions of source code must retain the above copyright 7// notice, this list of conditions and the following disclaimer. 8// * Redistributions in binary form must reproduce the above 9// copyright notice, this list of conditions and the following 10// disclaimer in the documentation and/or other materials provided 11// with the distribution. 12// * Neither the name of Google Inc. nor the names of its 13// contributors may be used to endorse or promote products derived 14// from this software without specific prior written permission. 15// 16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28// Flags: --harmony-generators 29 30// Test basic generator syntax. 31 32// Yield statements. 33function* g() { yield 3; yield 4; } 34 35// Yield expressions. 36function* g() { (yield 3) + (yield 4); } 37 38// You can have a generator in strict mode. 39function* g() { "use strict"; yield 3; yield 4; } 40 41// Generators can have return statements also, which internally parse to a kind 42// of yield expression. 43function* g() { yield 1; return; } 44function* g() { yield 1; return 2; } 45function* g() { yield 1; return 2; yield "dead"; } 46 47// Generator expression. 48(function* () { yield 3; }); 49 50// Named generator expression. 51(function* g() { yield 3; }); 52 53// A generator without a yield is specified as causing an early error. This 54// behavior is currently unimplemented. See 55// https://bugs.ecmascript.org/show_bug.cgi?id=1283. 56function* g() { } 57 58// A YieldExpression in the RHS of a YieldExpression is currently specified as 59// causing an early error. This behavior is currently unimplemented. See 60// https://bugs.ecmascript.org/show_bug.cgi?id=1283. 61function* g() { yield yield 1; } 62function* g() { yield 3 + (yield 4); } 63 64// Generator definitions with a name of "yield" are not specifically ruled out 65// by the spec, as the `yield' name is outside the generator itself. However, 66// in strict-mode, "yield" is an invalid identifier. 67function* yield() { (yield 3) + (yield 4); } 68assertThrows("function* yield() { \"use strict\"; (yield 3) + (yield 4); }", 69 SyntaxError); 70 71// In sloppy mode, yield is a normal identifier, outside of generators. 72function yield(yield) { yield: yield (yield + yield (0)); } 73 74// Yield is always valid as a key in an object literal. 75({ yield: 1 }); 76function* g() { yield ({ yield: 1 }) } 77function* g() { yield ({ get yield() { return 1; }}) } 78 79// Checks that yield is a valid label in sloppy mode, but not valid in a strict 80// mode or in generators. 81function f() { yield: 1 } 82assertThrows("function f() { \"use strict\"; yield: 1 }", SyntaxError) 83assertThrows("function* g() { yield: 1 }", SyntaxError) 84 85// Yield is only a keyword in the body of the generator, not in nested 86// functions. 87function* g() { function f() { yield (yield + yield (0)); } } 88 89// Yield needs a RHS. 90assertThrows("function* g() { yield; }", SyntaxError); 91 92// Yield in a generator is not an identifier. 93assertThrows("function* g() { yield = 10; }", SyntaxError); 94 95// Yield binds very loosely, so this parses as "yield (3 + yield 4)", which is 96// invalid. 97assertThrows("function* g() { yield 3 + yield 4; }", SyntaxError); 98 99// Yield is still a future-reserved-word in strict mode 100assertThrows("function f() { \"use strict\"; var yield = 13; }", SyntaxError); 101 102// The name of the NFE is let-bound in G, so is invalid. 103assertThrows("function* g() { yield (function yield() {}); }", SyntaxError); 104 105// In generators, yield is invalid as a formal argument name. 106assertThrows("function* g(yield) { yield (10); }", SyntaxError); 107