Set length property

[Brendan Eich]

Tab Atkins Jr. wrote:
>> IME they're ducktyped by the presence of forEach (this is far from perfect).
>> >  Length has nothing to do with iterability. What about generators?
>
> I don't want to go looking anything up right now, but I have lots of
> memories of things looking for the presence of "length" to denote an
> array-like.

Array-like != iterable.

Eager length is a problem for lazy lists (iterators).

/be