Bait taken: Arguments about arguments

David-Sarah Hopwood david.hopwood at
Thu Jan 15 19:27:29 PST 2009

Brendan Eich wrote:
> On Jan 15, 2009, at 4:54 PM, David-Sarah Hopwood wrote:
>> Brendan Eich wrote:
>>> On Jan 15, 2009, at 9:50 AM, Erik Arvidsson wrote:
>>>> Is there a reason why we need to restrict the argArray to apply this
>>>> much? I think it would be very useful to allow anything array like
>>>> here.
>>> Please define "array like" and give examples (possibly including DOM
>>> nodelists, which thanks to "live update" are are neither lists nor
>>> arrays, rather more like cursors).
>> "array-like" means having 'length' and array index properties.
> And the constraint that index < length for all index properties?


> And other constraints from ES1-3 [section 15.4] as follows?


If I'd meant to include those constraints, I would have said so.
The constraints are not needed here. You just read 'length' using
[[Get]], and then read each array index property from 0 to
ToUint32(length)-1 inclusive using [[Get]]. This is how all of the
generic methods that operate on array-like objects work.

I think you're making mountains out of molehills in this subthread;
a Function.prototype.apply that treats its arguments array generically
is quite easy to specify (and implement).

David-Sarah Hopwood

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