On Sun, Apr 3, 2011 at 2:24 PM, Eugene Toder <elto...@gmail.com> wrote: >> However, I'm not sure we *can* do a general-purpose AST transformation >> that handles both new nodes and changes to existing nodes correctly >> for all applications. > > As long as both versions contain the same information we can write a > transformation that does a near-perfect job. > E.g. for my changes I can write a convertor that produces AST in > almost the same form as the current one, the only change being the new > 'docstring' attribute set to None. (That's for converting AST before > optimizations, after optimizations it can contain nodes that couldn't > be represented before). I believe it's similar for Try change that > Benjamin mentioned above. > > Also, if written in Python, conversion can at least serve as a > template even if it doesn't work out of the box.
If it's do-able, your option 2 is probably the way to go. Out of the box, it may just need to raise an exception if asked to down-convert code that uses new constructs that can't readily be expressed using the old AST (I'm specifically thinking of the challenge of converting PEP 380's yield-from). Cheers, Nick. -- Nick Coghlan | ncogh...@gmail.com | Brisbane, Australia _______________________________________________ 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
