On Tue, Apr 15, 2008 at 2:21 AM, Stefan Behnel <[EMAIL PROTECTED]> wrote: > Neal Norwitz wrote: > > Iteration with the dict methods (e.g., keys -> iterkeys()), > > map/zip/filter returning iterator rather than list. > > That's only an optimisation, it's not functionally required. A list behaves > like an iterator in most use cases, so it's rather unlikely that Py3 code > will > break in the backport because of this (and it's very unlikely that static > analysis can catch the cases where it breaks). There should be a rule to > optimise "list(map(...))" into "map(...)" and "list(x.keys())" into plain > "x.keys()" etc., but I don't think there is much more to do here.
It's not just an optimization if a copy won't fit in memory. I'd like the solution to be closer to 100% than 95%. > > int -> (int, long) > > Is there any case where this might be required? I don't see any reason why > back-converted Py3 code should break here. What would "long()" be needed for > in working Py3 code that "int()" doesn't provide in Py2? > > Although you might have been referring to "isinstance(x, int)" in Py3? Yes, sorry, I wasn't explicit. isinstance is specifically what I was referring to (or other type checks such as type(x) in (int, long)). > > str -> basestring or (str, unicode) > > This is an issue, although I think that Py3 is explicit enough here to make > this easy to handle by static renaming (and maybe optimising "isinstance(s, > (str, bytes))" into "..., basestring))"). > > > > > __bool__ -> __nonzero__ > > exec/execfile > > input -> rawinput > > Also valid issues that can be handled through renaming and static syntactic > adjustments. > > > > > Most things that have a fixer in 2to3 would also require one in 3to2. > > I think the more explicit syntax in Py3 will actually make it easier to > back-convert the code statically from 3to2 than to migrate it from 2to3. Sure, that's the idea. I haven't seen any action on 3to2 (although I'm very behind on email). Stefan, could you try to implement some of these and report back how it works? n _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
