"Bill Chiles" <[EMAIL PROTECTED]> wrote: > > For Common Lispers and probably Schemers, Python has some surprising > semantics around scope and lifetime extent of variables. Three that > leap out at me are:
One thing to remember is that Python is not Scheme/Lisp. It borrows some ideas from Scheme/Lisp, but that borrowing does not necessitate a it also use a completely equivalent scoping mechanism. From what I have been hearing about Python 2.6, and 3.0, the three "surprises" you describe are not going to be "fixed" (with respect to expected Scheme/Lisp semantics). Feel free to argue as to why they should be "fixed" in Py3k (unless Guido says, "you're dreaming"), but please do so in the py3k list. - Josiah > * function parameters with default values are NOT new bindings for each > invocation, so a > default value of [] changes if you destructively modify this list > object in the function > * loop variables are NOT distinct lexical variables. The binding gloms > on to a variable in the > function's scope, both changing that lexical binding and not creating > a new one for the > loop (that goes away when the loop's scope ends) > * loop variables are NOT distinct bindings per iteration, leading to > the surprising results > below _______________________________________________ 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
