P.J. Eby wrote: > At 06:28 AM 3/16/2009 +1000, Nick Coghlan wrote: >> There are some practical hurdles to that idea (specifically, creating a >> callable which uses its parent's namespace rather than having its own), >> but the basic concept seems sound. > > Actually, that bit's pretty simple -- they're just "nonlocal" > variables. But the cost of creating that function, and the cost of > having cell variables in the surrounding function is potentially high. > (In CPython at least, function calls are optimized in certain ways when > the function only has "fast" locals, and no "cell" locals.)
Some additional complexities occurred to me today - they go by the names "return", "break" and "continue". With the current design those are perfectly well defined inside a with statement, but they pose a pretty serious hurdle for a practical implementation of glyph's idea. So I'm going to stick with the more modest approach of a new control flow exception for PEP 377. I still find the callable block idea somewhat intriguing, but if it ever happens it should be a new construct rather than overloading the meaning of the with statement. Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia --------------------------------------------------------------- _______________________________________________ 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
