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. 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? Actually, I even wonder if it is a good idea to look up the name directly in the class scope - we may want to inject a local comprehension scope here, as for Py3 comprehensions and genexprs, and just switch the fall-through of the declarations on or off based on the code semantics. Stefan _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
