On Fri, Dec 5, 2014 at 11:34 PM, Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> wrote: >> I don't think this is implementation-dependent. > > The docs say that it is: > > https://docs.python.org/3/reference/simple_stmts.html#the-global-statement > > Names listed in a global statement MUST NOT [emphasis added] be > defined as formal parameters or in a for loop control target, > class definition, function definition, or import statement. > > CPython implementation detail: The current implementation does not > enforce the two restrictions, but programs should not abuse this > freedom, as future implementations may enforce them or silently > change the meaning of the program.
Interesting, I didn't know that either. But the first restriction _is_ enforced: rosuav@sikorsky:~$ python3 Python 3.5.0a0 (default:23ab1197df0b, Nov 20 2014, 12:57:44) [GCC 4.7.2] on linux Type "help", "copyright", "credits" or "license" for more information. >>> def x(y): ... global y ... File "<stdin>", line 2 SyntaxError: name 'y' is parameter and global Likewise in CPython 2.7: rosuav@sikorsky:~$ python Python 2.7.3 (default, Mar 13 2014, 11:03:55) [GCC 4.7.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> def x(y): ... global y ... File "<stdin>", line 1 SyntaxError: name 'y' is local and global ChrisA -- https://mail.python.org/mailman/listinfo/python-list
