asyncgenerator
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Syntax
In the async generator examples, a syntax like
await yield f()
is used. However, this does not seem to be parseable by the ES6 grammar and https://github.com/lukehoban/ecmascript-asyncawait. await
expects an UnaryExpression, while yield
produces an AssignmentExpression.
Good point. It would have to be
await (yield f())
In the implementation in Traceur, I have added a parser rule for await yield without parens. I think this grammar change should be added to this or @lukehoban's proposal because await yield
will be a common idiom with async generators in place.
@mnieper What is the grammar rule you are proposing?
I don't speak Ecma, but I wouldn't it suffice to say
UnaryExpression :
...
await [Lexical goal InputElementRegExp] UnaryExpression
await ... YieldExpression
?
@mnieper Trying to clean up our parser a bit and the YieldExpression
probably needs a [In]
there to allow:
await yield 42 in obj
Yes, this makes perfect sense.
@mnieper want to file a bug here if you want this syntax in the async functions proposal?