Phillip J. Eby wrote:
> At 01:58 PM 5/6/2005 +1000, Delaney, Timothy C (Timothy) wrote:
>
>>Personally, I'm of the opinion that we should make a significant break
>>(no pun intended ;) and have for-loops attempt to ensure that iterators
>>are exhausted.
>
>
> This is simply not backward compatible with existing, perfectly valid and
> sensible code.
> Therefore, this can't happen till Py3K.
>
> The only way I could see to allow this is if:
>
> 1. Calling __iter__ on the target of the for loop returns the same object
> 2. The for loop owns the only reference to that iterator.
>
> However, #2 is problematic for non-CPython implementations, and in any case
> the whole thing seems terribly fragile.
Is it better to have:
1. A single looping construct that does everything,
2. or several more specialized loops that are distinct?
I think the second may be better for performance reasons. So it bay
would better to just add a third loop construct just for iterators.
a. for-loop -->iterable sequences and lists only
b. while-loop --> bool evaluations only
c. do-loop --> iterators only
Choice c. could mimic a. and b. with an iterator when the situation
requires a for-loop or while-loop with special handling.
Ron_Adam
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