On Aug 21, 2014, at 12:04 AM, Andy Wingo wrote: > On Wed 20 Aug 2014 19:55, Brendan Eich <[email protected]> writes: > >> Kevin Smith wrote: >>> function *echo() input { >>> while (true) yield input.value; >>> } >> >> So input is bound to the next() actual parameter value on each >> resumption. That's not bad shed-coloring! >> >> Andy, Dave: WDYT? > > I think changing things right now is the wrong thing to do. Since this > is a compatible extension, we don't have to think about this for ES6. > Just putting that out there ;) > > That said, first thoughts: > > * I assume "input" could then be captured by nested scopes. This > would be a bit strange but could work. > > * Really you'd want to be able to destructure too, as you can in every > other part of the grammar that introduces names. That's probably > not a great thing to do here, though. > > * I assume Kevin meant: > > function *echo input { while (true) yield input } > > To me it smells, but perhaps that is just my grumpiness ;) > > Explicitly being able to place the initial yield would be nicer, but > then it's more difficult to ensure that the initial yield comes before > other yields. > > I say punt ;) >
I've been thinking about ways to explicitly place the initial yield. One ideal is a reserved keyword sequence starting with 'yield`, such as `yield continue` to mark the initial yield point. If a generator function does not contain an explicit `yield continue`, then it is implicit at the start of the function body. I don't think it is necessary to statically ensure that `yield continue` comes before any other `yield`. It would simply be a runtime detected error if it does not. Allen _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
