On Fri, 26 Apr 2013 07:39:32 +0200, Peter Otten wrote: > A class body is basically a function body that is executed once. To > allow an assignment > >>>> x = 42 >>>> class A: > ... x = x > ... > > which is not possible inside a function
As far as I can tell, the documentation says that this assignment should also be impossible inside a class. Unless I'm missing something, I think this is a bug. http://docs.python.org/3/reference/executionmodel.html [...] > However, while the above gives some technical background it doesn't > explain why this scheme was chosen. My guess is that when Python got > closures nobody was willing to do the extra work to make class bodies > namespace-aware. The alternative, disallowing x = x in classes, would > have seriously broken backwards-compatibility. Not so. x = x was not allowed in classes before there were closures: [steve@ando ~]$ python1.5 Python 1.5.2 (#1, Aug 27 2012, 09:09:18) [GCC 4.1.2 20080704 (Red Hat 4.1.2-52)] on linux2 Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam >>> >>> >>> def f(): ... x = 1 ... class Test: ... x = x ... return Test ... >>> T = f() Traceback (innermost last): File "<stdin>", line 1, in ? File "<stdin>", line 3, in f File "<stdin>", line 4, in Test NameError: x -- Steven -- http://mail.python.org/mailman/listinfo/python-list
