Terry Reedy wrote: > "Maric Michaud" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > |I faced a strange behavior with generator expression, which seems like a > bug, for both > | python 2.4 and 2.5 : > > Including the latest release (2.5.2)? > > | >>> class A : > | ... a = 1, 2, 3 > | ... b = 1, 2, 3 > | ... C = list((e,f) for e in a for f in b) > | ... > | Traceback (most recent call last): > | File "<stdin>", line 1, in <module> > | File "<stdin>", line 4, in A > | File "<stdin>", line 4, in <genexpr> > | NameError: global name 'b' is not defined > > If you switch 'a' and 'b' in the expression, it will be 'a' that is not > defined. > There was/is a known issue with generator expressions (but not list comps) > treating 'for' clauses after the first differently from the first in > respect to variable resolution. I believe I have seen this discussed on > PyDev list. But I searched the bugs.python.org for 'generator expression' > and '_ _s' and got no relevant hits. > > | Any comment ? I'm ready to report it as a bug if there is no objection. > > If this is in 2.5.2, (and not one else objects), go ahead. > > tjr > > > This behavior is by design (after much much discussion, as Terry says).
See http://www.python.org/dev/peps/pep-0289/#early-binding-versus-late-binding and the threads it references. Michael -- http://mail.python.org/mailman/listinfo/python-list
