Document what happens with superfluous parens

[Yoric]

While superfluous parens have no official semantics, they are actually used by browsers to perform laziness tricks:

var foo = function() { ... }; // Parsed lazily by the browser.
var bar = (function() { ... }); // Parsed eagerly by the browser.

It would be very useful to keep superfluous parens in such a case (or perhaps always). I don't know if that's what ratel does currently, so documenting the choice would be useful, too!

Perhaps it should be a parsing option?

[maciejhirsz]

Superfluous parens are always dropped. I don't particularly see a reason to change it since the goal is to produce an AST, not a parse tree. In either case, we do need a proper book for all of this stuff.

[Yoric]

Well, these superfluous parens turn out to have an observable (by timing) effect, so they are de facto part of the language. For instance, in Binary AST, we make the difference between EagerFunctionDeclaration and LazyFunctionDeclaration.

Would it be possible to somehow store the information somewhere?

[maciejhirsz]

Is that the only difference? We can attach a eager|lazy flag to functions if that's the case.

[Yoric]

That would work very well for my usecase (and I believe a number of other usecases).