Support async generators #2101
Support async generators #2101
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lahma
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Hi @ariya ! Here's a PR to allow parsing about 6000 more scripts that were unparseable before, basically allowing async generators and couple more error checks. |
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Great work @lahma, thanks! I will take a look. |
| @@ -49,7 +51,6 @@ export const Messages = { | |||
| StrictLHSPrefix: 'Prefix increment/decrement may not have eval or arguments operand in strict mode', | |||
| StrictModeWith: 'Strict mode code may not include a with statement', | |||
| StrictOctalLiteral: 'Octal literals are not allowed in strict mode.', | |||
| StrictParamDupe: 'Strict mode function may not have duplicate parameter names', | |||
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Removed this in favor of DuplicateParameter which aligns with V8
| @@ -20,13 +20,14 @@ interface Context { | |||
| allowIn: boolean; | |||
| allowStrictDirective: boolean; | |||
| allowYield: boolean; | |||
| await: boolean; | |||
| isAsync: boolean; | |||
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Renamed this as await is keyword and isAsync describes the context
| @@ -256,6 +258,12 @@ export class Parser { | |||
| this.errorHandler.tolerate(this.unexpectedTokenError(token, message)); | |||
| } | |||
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| tolerateInvalidLoopStatement() { | |||
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Had to create separate function as for statement parsing started to fail due to cyclomatic complexity
| @@ -613,7 +621,7 @@ export class Parser { | |||
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| switch (this.lookahead.type) { | |||
| case Token.Identifier: | |||
| if ((this.context.isModule || this.context.await) && this.lookahead.value === 'await') { | |||
| if ((this.context.isModule || this.context.isAsync) && this.lookahead.value === 'await') { | |||
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I think this now reads better, isModule, isAsync
| @@ -785,19 +792,20 @@ export class Parser { | |||
| return this.finalize(node, new Node.FunctionExpression(null, params.params, method, isGenerator)); | |||
| } | |||
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| parsePropertyMethodAsyncFunction(): Node.FunctionExpression { | |||
| parsePropertyMethodAsyncFunction(isGenerator: boolean): Node.FunctionExpression { | |||
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Might make sense at some point to put isGenerator into context
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This is Boolean trap, though we already have some cases like that in the same file.
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So should I put this into context as part of this PR or what changes required?
| @@ -2125,7 +2146,7 @@ export class Parser { | |||
| return this.finalize(node, new Node.Property('init', key, computed, value, method, shorthand)); | |||
| } | |||
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| parseRestProperty(params, kind): Node.RestElement { | |||
| parseRestProperty(params): Node.RestElement { | |||
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Removed the unused parameter as style checks gave warning and couldn't see a reason to keep
| @@ -3018,6 +3043,12 @@ export class Parser { | |||
| } | |||
| this.expect(')'); | |||
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| if (options.hasDuplicateParameterNames) { | |||
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Moved checks to single place where can validate against context
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@ariya anything you want me to tweak here? |
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Thank you @lahma 👍 |
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You're most welcome, thanks for merging! |
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@lahma i've merged your changes also in my fork |
| @@ -1342,6 +1356,10 @@ export class Parser { | |||
| expr = this.inheritCoverGrammar(this.matchKeyword('new') ? this.parseNewExpression : this.parsePrimaryExpression); | |||
| } | |||
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| if (isSuper && this.match('(') && !this.context.inClassConstructor) { | |||
Async generators are valid constructs and went through issues parsing them. Couple issues surfaced on class handling side but unrelated to async generators per se.
Before
✔ 54265 valid programs parsed without error
✔ 6748 invalid programs produced a parsing error
✔ 1101 invalid programs did not produce a parsing error (and allowed by the whitelist file)
✔ 16288 valid programs produced a parsing error (and allowed by the whitelist file)
After
✔ 60262 valid programs parsed without error
✔ 6747 invalid programs produced a parsing error
✔ 1102 invalid programs did not produce a parsing error (and allowed by the whitelist file)
✔ 10291 valid programs produced a parsing error (and allowed by the whitelist file)
fixes #1990