Vitja Makarov, 23.08.2012 07:03: > 2012/8/23 Stefan Behnel <stefan...@behnel.de>: >> Vitja Makarov, 22.08.2012 22:34: >>> 2012/8/23 Stefan Behnel: >>>> Vitja Makarov, 22.08.2012 22:11: >>>>> I've found regression: >>>>> >>>>> https://sage.math.washington.edu:8091/hudson/job/cython-devel-tests-pyregr/ >>>> >>>> Interesting. It's a Py2 list comprehension in a class body that's failing >>>> here: >>>> >>>> """ >>>> class TestHelpSubparsersOrdering(HelpTestCase): >>>> subparsers_signatures = [Sig(name=name) >>>> for name in ('a', 'b', 'c', 'd', 'e')] >>>> """ >>>> >>>> I wonder why "name" isn't declared as a variable yet at the point where it >>>> is being looked up in the function call. >>> >>> def lookup_relative(self, name, pos): >>> if name == "name": >>> print name >>> from ipdb import set_trace; set_trace() >>> entry = self.lookup_here(name) >>> if entry is not None and entry.pos[1:] <= pos[1:]: # Lookup fails >>> here >>> return entry >>> if self.outer_scope: >>> return self.outer_scope.lookup_relative(name, pos) >>> return None >>> >>> >>> What is that comparison for? >> >> Ah, yes, it is wrong in this context. It was meant to prevent names defined >> further down in the class body from being considered assignments to the >> name being looked up. Class bodies are not function bodies, assignments in >> them do not make a name "local". As long as it's not assigned, it's not >> defined and must be looked up in the outer scope. > > Do you remember this ticket #671 > > If there is assignment in the class body we first lookup in the class > dict and then in globals. > > B = 0 > def foo(): > B = 1 > class Foo(): > A = B > B = B > class Bar(): > A = B > print Foo.A, Foo.B, Bar.A > foo() > > prints "0 0 1"
In the case at hand, it's not an assignment but a method declaration. Maybe that makes a difference. In any case, this needs some more investigation than I did for my change. I think it can be rolled back completely. >> I think comprehensions are actually the only case where a name is used in >> the source before its declaration. It should work in all other cases. >> >> I had considered solving this problem with the flow control analysis >> information, but I can't see how that helps me to figure out if an entry is >> already assigned (i.e. declared) at a given point in the class body. >> >> Any idea? > > What would you do with maybe assigned case? Hmm, yes - I guess we can't solve the general case at compile time. That's unfortunate, though, because it prevents proper compile time optimisation of builtins in class bodies when their names are assigned at some point, e.g. with a ".type()" method or ".set()", as was the case here. Stefan _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
