ECMA TC 39 / W3C HTML and WebApps WG coordination
brendan at mozilla.com
Fri Sep 25 17:08:45 PDT 2009
On Sep 25, 2009, at 4:57 PM, Maciej Stachowiak wrote:
> On Sep 25, 2009, at 1:18 PM, Brendan Eich wrote:
>> So if you are doing more ArrayLike interfaces, let's keep talking.
>> Don't let at least my catchalls-considered-harmful statements stop
>> progress on ArrayLikes.
> Perhaps when catchalls are considered for ECMAScript, there could b
> a way to encapsulate the specific pattern of index access, so you
> can have magical getters and setters for all index properties
> (integer numbers in range to be an array index) without having to
> install a full catchall for all properties.
Good point -- implementing array-likes via catchalls has been on our
minds since the ES4 "meta" days , although we never split hooks
based on property name being non-negative (possibly also <= 2^32 - 1
-- or is it <= 2^32 - 2?!).
With WebIDL folks' help we will probably take down ArrayLike first,
without going whole-hog for catchalls. The "catchalls climb the meta
ladder" problem is more profound than the index/length magic (even the
awful uint32 domain) of array-likes. I agree with Waldemar, we should
make progress on array-likes without getting hung up on catchalls.
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