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 _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com