[Python-Dev] Two laments about CPython's AST Nodes (original) (raw)

Frank Wierzbicki fwierzbicki at gmail.com
Fri Aug 21 15:46:35 CEST 2009

On Thu, Aug 20, 2009 at 6:11 PM, "Martin v. Löwis"<martin at v.loewis.de> wrote:

Couldn't you just generate a check function for your tree that would be invoked before you try to process a tree that a script got access to? That would be one way, though now that I understand CPython's AST design better, I am tempted to follow the lead. If I had a private AST and and a public mirror for ast.py, the design could become much simpler, and probably faster for normal parsing.

If you are asking that a type check is made on assigning a value to these fields - I'm not quite sure whether you could implement that check reliably. Wouldn't it be possible to bypass it by filling a value directly into dict?

If you can come up with a patch that checks in a reliable manner, I would be in favor of adding that (in 2.7 and 3.2), taking out the corresponding checks when converting to the internal AST. Great, I may give it a try, but changing the AST impl for Jython 2.6 will probably be my short term answer.

-Frank

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