On 01/25/2011 10:23 AM, Stefan Behnel wrote: > Robert Bradshaw, 25.01.2011 10:00: > >> On Mon, Jan 24, 2011 at 11:33 PM, Stefan Behnel wrote: >> >>> Vitja Makarov, 25.01.2011 08:15: >>> >>>> I want to write simple code to find unbound variables. >>>> >> I'm assuming you mean unassigned (as opposed to unbound in, e.g., a closure)? >> [...] >> It probably wouldn't be too hard to walk the tree to discover this >> kind of information, recording on each NameNode as one goes along what >> its possible states are. >> > A general "NameNode dependency walk" of the tree could give us *loads* of > information, also for better type inference. Knowing that a Python variable > is definitely not None from a given point on, or that it has a specific > type at one point and a different type at another would be really cool. > > Basically, we could build a dependency tree for each NameNode (at its > specific point in the tree, not just through its symtab Entry) that > references its assignment RHSs, but including a representation of relevant > branches in the code. > > But I also agree that loops are evil. :-/ >
A related problems is use of uninitialized local variables. I recently had problems with that, and gcc warnings are less than perfect in this area. I think we ideally should raise a compiler error if it can be proven that a variable is uninitialized. I'm even in favour of following Java and raise an error (or at least a warning) if it can't be proven that it is initialized; such code is usually poorly written anyway and it really doesn't hurt to initialize the variable to 0. Dag Sverre _______________________________________________ Cython-dev mailing list Cython-dev@codespeak.net http://codespeak.net/mailman/listinfo/cython-dev
