[Python-Dev] Policy for making changes to the AST (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Tue Apr 5 11:49:49 CEST 2011


Add py.test as an application that uses the AST to support Jython, PyPy and CPython in a portable way. I always assumed AST was created because bytecode was too CPython specific (but then I've never implemented a language).

Historically, that's incorrect. The AST structure was introduced to simplify the implementation of (C)Python. Exposing it to Python modules was done primarily because it's neat and was easy to do - not because any specific use was expected, and certainly not as the primary motivation for having an AST. It was clear (to me, at least) back then that the AST will change over time (hence the module was originally called _ast).

Regards, Martin



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