array like objects

David-Sarah Hopwood david-sarah at
Tue Dec 15 12:32:39 PST 2009

Brendan Eich wrote:
> On Dec 15, 2009, at 11:18 AM, David-Sarah Hopwood wrote:
>> Brendan Eich wrote:
>>> In ES specs and real implementations, internal methods and various
>>> corresponding implementation hooks are called based on [[Class]] of the
>>> directly referenced object, in contrast.
> Sorry, I wrote "called" where I meant "defined".
>> As for implementation, [[Class]] could be derived from some other type
>> tag that gives sufficient information to do such lookup, but [[Class]] by
>> itself is not sufficient.
> I'm not sure what you mean. Sure, [[Class]] in the spec is
> string-valued, so it can't be a vtable pointer. But in implementations
> that use C++, there is not only a class name-string associated with
> every instance, but a suite of internal methods or hooks.

Exactly: [[Class]] is associated with each instance and so are the other
internal methods/properties, but that doesn't imply that other properties
are "defined based on" [[Class]].

David-Sarah Hopwood  ⚥

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