On Apr 24, 2014, at 10:24 AM, Brendan Eich wrote: > Allen Wirfs-Brock wrote: >> If (and it's still an open question) it make sense semantically to call >> "return" on for-of initiated generators on unwind, then that is what we >> should do. > > That's not the proposal, though, is it? > > Isn't the maybe-call of return for any iterator, whether a generator iterator > or other object, and isn't it unconditional on whether the for-of implicitly > created a fresh iterator via @@iterator?
Right, any iterator with a @@return (or whatever). But at the meeting (Thursday) we also discussed that for-of would act on the assumption that the normal case was getting a fresh iterator that was intended to be finalized (ether via exhaustion or implicit @@return calls on early loop exits). In the rarer case where somebody needs multiple loops over a single iterator they would avoid for-or and use while or for(;;) loops. But I don't think the difference between my shorter description and the actual proposal is germane to the arguments that catching loop early unwind exits is/isn't too expensive. Allen _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
