Delaney, Timothy C (Timothy) wrote:
> Guido van Rossum wrote:
>
>
>>I'd like the block statement to be defined exclusively in terms of
>>__exit__() though.
>
>
> This does actually suggest something to me (note - just a thought - no
> real idea if it's got any merit).
>
> Are there any use cases proposed for the block-statement (excluding the
> for-loop) that do *not* involve resource cleanup (i.e. need an
> __exit__)?
>
> This could be the distinguishing feature between for-loops and
> block-statements:
>
> 1. If an iterator declares __exit__, it cannot be used in a for-loop.
> For-loops do not guarantee resource cleanup.
>
> 2. If an iterator does not declare __exit__, it cannot be used in a
> block-statement.
> Block-statements guarantee resource cleanup.
>
> This gives separation of API (and thus purpose) whilst maintaining the
> simplicity of the concept. Unfortunately, generators then become a pain
> :( We would need additional syntax to declare that a generator was a
> block generator.
Ah, someone else did post this idea first :)
To deal with the generator issue, one option would be to follow up on Phillip's
idea of a decorator to convert a generator (or perhaps any standard iterator)
into a block iterator.
I think this would also do wonders for emphasising the difference between for
loops and block statements.
Cheers,
Nick.
--
Nick Coghlan | [EMAIL PROTECTED] | Brisbane, Australia
---------------------------------------------------------------
http://boredomandlaziness.skystorm.net
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