On Sep 10, 2014, at 9:00 AM, Andreas Rossberg wrote: > On 10 September 2014 17:56, Allen Wirfs-Brock <[email protected]> wrote: >> We agree at our June meeting to add the "return" method to generators and to >> conditionally call "return" (if it is present) when a for-of loop terminates >> before it exhausts its generator. See >> https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-06/jun-5.md#conclusionresolution-2 >> . IteratorClose is part of the implementation of this features and was >> added in Rev 27 of the spec. >> >> I believe that #1 is implicit in that decision as it has always been an ES6 >> goal that most library methods should be self-hostable in ES. That means >> that for-of like iteration in those methods should be specified in a manner >> that matches the observable semantics of for-of. > > It wasn't all that clear to me, but that's good to hear. Does a > similar argument apply to constructs like rest and spread?
Yes, except that I don't think the "body" of those loops can actually abnormally exit (or in the case of processing parameter lists, the iterator is an internal list iterator that doesn't have a 'return'). But that code should be reviewed to make sure I don't miss something. Allen _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
