At 07:21 PM 01/20/2006 +1000, Nick Coghlan wrote: >Yeah, it came up in response to PJE's suggestion of task-local variables for >generators. The basic concept we came up with is that if you're writing a >generator that uses a specific context, remember to save the original and >restore it around any calls to yield (at least, I came up with the idea and >no-one objected to the approach [1]).
That's only because Guido shut down the thread. :) For the use cases I had in mind, your approach simply doesn't scale, because it requires every yield-point to have global knowledge of all "changes to global state" that may have occurred somewhere above it in the coroutine call stack. The only reason I didn't point this out is that Guido had asked for a postponement of the discussion. Since then, I've begun implementing a library that accomodates such use cases, as well as a wide variety of other context-management use cases. Source code is at http://svn.eby-sarna.com/Contextual/ and the docs are at http://svn.eby-sarna.com/Contextual/context.txt?view=markup The library uses the current draft of PEP 343 as the basis for implementation, and includes a few helper functions that can be used to emulate the "with:" statement in Python 2.4 so that it can be used and tested. So far, my impression is that the current 343 spec is at least adequate, and maybe even elegant. _______________________________________________ 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
