ES6 draft, Rev20 is now available

Allen Wirfs-Brock allen at
Wed Oct 30 12:23:22 PDT 2013

On Oct 30, 2013, at 12:09 PM, Anne van Kesteren wrote:

> On Wed, Oct 30, 2013 at 7:01 PM, Boris Zbarsky <bzbarsky at> wrote:
>> On 10/30/13 2:28 PM, Allen Wirfs-Brock wrote:
>>> Those are the sort of objects, that we decided to explicitly exclude
>>> from spread and for-of.
>> Sure.  The question is whether we can compatibly exclude them from
>> sequence<T> in WebIDL.  I expect we can.
>> Anne, do you want to post to public-script-coord about this, or should I?
> (I mostly asked here first since the other breaking changes to IDL to
> align with JavaScript haven't been very popular. But maybe this is
> indeed small enough to get away with.)

Doesn't really depend upon the usage.  If an API is going to return a sequence<T> to JS code, it really should have an @@iterator.  But that is presumably a non-breaking change, from the JS perspective.  If an API wants to accept a sequence<T> it only needs it to have an @@iterator if it is actually going to use JS iterator semantics to process.  There is no reason that an implementation of such a consuming API couldn't do its own fall back to non-iterator based iteration.  That would be a non-breaking solution.

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