Oh, I completely agree that `yield *` is not just desugared into the above
for...of loop form. I'm just saying that that's how most developers will
likely look at it. Adding a while loop that calls the inner iterator's next
with the same value wouldn't change what developers would expect here.

I'm not arguing for one solution or another - just making the point that if
it'll be anything like python's yield from - when developers _think_ of
yield* they'll think of pumping an iterator from another iterator and
expect the behaviour of throw to be similar.

On Sat, Jan 31, 2015 at 9:14 PM, Allen Wirfs-Brock <allen at wirfs-brock.com>
wrote:

>
> On Jan 31, 2015, at 10:13 AM, Benjamin (Inglor) Gruenbaum wrote:
>
> > I think that people would generally will _expect_ `yield *` to be have
> like yield inside a loop. So most people would expect:
> >
> > ```
> > yield* iterator
> > ```
> >
> > To behave like:
> >
> > ```
> > for(let val of iterator){
> >     yield val;
> > }
> >
> > ```
> >
> > While I'm not (yet) suggesting that the behaviour should be similar in
> both cases this is definitely something to consider before deciding on
> throwing or suppressing.
>
> They are similar, but the transparency requirement of yield* has priority
> It's not a pure desugaring.  For example, yield* passes throw the
> IteratorResu;lt objects produced by the inner iterator.  The above
> desugaring can't do that.
>
> Allen
>
>
>
>
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Oh, I completely agree that `yield *` is not just desugared into the above
for...of loop form. I'm just saying that that's how most developers will
likely look at it. Adding a while loop that calls the inner iterator's next
with the same value wouldn't change what developers would expect here.

I'm not arguing for one solution or another - just making the point that if
it'll be anything like python's yield from - when developers _think_ of
yield* they'll think of pumping an iterator from another iterator and
expect the behaviour of throw to be similar.