How to inspect slot wrappers arguments in Python?

[Gabriel Genellina]

En Sat, 01 Oct 2011 12:13:45 -0300, julian bilcke  
<julian.bilcke at gmail.com> escribió:

> I would like to get the list of parameters I need to initialize an AST  
> node.
>
> I'm trying to use the `inspect` module, however it seems I can't use it  
> on a
> built-in (native?) class, or else I misunderstood. [...]
>
>     >>> import inspect
>     >>> import ast
>     >>> inspect.getargspec(ast.If.__init__)
>     Traceback (most recent call last):
>       File "<stdin>", line 1, in <module>
>       File
> "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/inspect.py",
> line 813, in getargspec
>         raise TypeError('{!r} is not a Python function'.format(func))
>     TypeError: <slot wrapper '__init__' of '_ast.AST' objects> is not a
> Python function
>
> I am wondering if there is another way to get these parameters
> automatically? (ie. without compiling myself a dict)

I'm afraid there is no way; this kind of introspection does not work for  
functions written in C. The function itself usually has a generic  
signature resembling (*args, **kw), and its parameters are usually  
unpacked calling a suitable variant of PyArg_ParseXXX. The information  
about the number and type of expected arguments is encoded in its 'format'  
parameter, and is not stored anywhere.

-- 
Gabriel Genellina