Claude Pache wrote:
Le 12 juin 2013 à 18:14, Andreas Rossberg<[email protected]> a écrit :
On 12 June 2013 14:12, Claude Pache<[email protected]> wrote:
<snip>
On the other hand, I see a small advantage of the "weird" requirement for iterators to be
iterables themselves: It allows to discriminate between true iterators and merely
"nextable" objects.
And in the spirit of "duck typing", why would you want to do that?
Just so that an error is surely thrown in case I feed a for/of loop with a non-iter{ator|able}. In
the spirit of duck-typing, I consider that "having an `@@iterator` method" is a more
robust check than "having an `@@iterator` or a `next` method". Not a big deal, however.
I think it is a medium-sized deal :-).
First, it's conceptually cleaner to have one symbol-named property test
than two, symbol and then string name fallback.
Second, it is indeed more robust in this instance: 'next' is a common
name, with many contextual meanings and likely uses.
And
how do you want to treat an iterable with a 'next' method, but whose
@@iterator method does not return 'this'? Is that a "true" iterator?
(The fact that such a beast can even exist shows how fuzzy those
notions are.)
You're right, but I don't expect to encounter such a beast often. Concretely,
they are buggy objects that would not receive any special treatment (they are
iterable whenever an `@@iterator` method is expected, and they are iterated
whenever a `next` method is required).
This just isn't a problem in practice. Let's solve real problems, look
at cowpaths and nearby cliffs, not try to push boilerplate onto all
programmers out of an off-target desire to make get-@iterator a "type
coercion".
/be
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