[Python-Dev] Rough idea for adding introspection information for builtins (original) (raw)

Serhiy Storchaka storchaka at gmail.com
Tue Mar 19 08:37:35 CET 2013

On 19.03.13 06:45, Larry Hastings wrote:

4. Store a string that looks like the Python declaration of the signature, and parse it (Nick's suggestion). For foo above, this would be "(arg,b=3,*,kwonly='a')". Length: 23 bytes.

Strip parenthesis and it will be only 21 bytes long.

We'd want one more mild hack: the DSL will support positional parameters, and inspect.Signature supports positional parameters, so it'd be nice to render that information. But we can't represent that in Python syntax (or at least not yet!), so we can't let ast.parse see it. My suggestion: run it through ast.parse, and if it throws a SyntaxError see if the problem was a slash. If it was, remove the slash, reprocess through ast.parse, and remember that all parameters are positional-only (and barf if there are kwonly, args, or kwargs).

It will be simpler to use some one-character separator which shouldn't be used unquoted in the signature. I.e. LF.

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