[Python-Dev] Rough idea for adding introspection information for builtins

[Ronald Oussoren]

On 7 Jul, 2013, at 13:35, Larry Hastings <larry at hastings.org> wrote:
> 
> On 07/07/2013 07:25 AM, Ronald Oussoren wrote:
>> Signature objects use a name in angled brackets to indicate that a parameter is positional only, for example "input(<prompt>)". That might be an alternative to adding a "/" in the argument list in pydoc's output.
>> 
> 
> I wasn't aware that Signature objects currently had any support whatsoever for positional-only parameters.  Yes, in theory they do, but in practice they have never seen one, because positional-only parameters only occur in builtins and Signature objects have no metadata for builtins.  (The very problem Argument Clinic eventually hopes to solve!)
> 
> Can you cite an example of this, so I may examine it?

I have a branch of PyObjC that uses this: <https://bitbucket.org/ronaldoussoren/pyobjc-3.0-unstable/overview>. That branch isn't quite stable yet, but does add a __signature__ slot to objc.selector and objc.function (basicly methods of Cocoa classes and automaticly wrapped global functions), both of which only have positional-only arguments. With the patch for pydoc/inspect I mentioned earlier I can then generate somewhat useful documentation for Cocoa classes using pydoc.

A word of warning though: the PyObjC source code isn't the most approachable, the code that generates the Signature object is actually in python (callable_signature in pyobjc-core/Lib/objc/_callable_docstr.py)

Ronald

> 
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> /arry