ECMA TC 39 / W3C HTML and WebApps WG coordination

Waldemar Horwat waldemar at
Fri Sep 25 16:00:33 PDT 2009

Brendan Eich wrote:
> I will stop the over-citing madness here and now :-P.
> The struggle to formalize ArrayLike, which seems like a common goal for 
> ES the core language and for WebIDL's ES bindings, makes me want to give 
> an exception to the "catchalls considered harmful for new interfaces" 
> injunction. I agree that indexing into array-likes, with no liveness 
> magic, seems containable and desirable. ES folks haven't nailed down 
> ArrayLike yet (our fault) and we would benefit from collaboration with 
> WebIDL folks here.
> 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.
> I expect some ES folks may demur now :-).

I am on the record for strongly opposing catch-alls.  It's unproductive to repeat the reasons because that would sidetrack the discussion and the reasons mentioned by Brendan are sufficient to make the idea deeply flawed.  We've gone around that rathole many times in the past.

However, I have no particular objections to making additional kinds of array-like objects.  This does not suffer from the same problems that catchalls in general do.


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