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hidden attributes

Bengt Richter bokr at oz.net
Tue Dec 17 19:09:49 EST 2002 
On 17 Dec 2002 11:04:30 -0800, mis6 at pitt.edu (Michele Simionato) wrote:

>I've just discovered that the attribute __name__ is hidden i.e.
>not shown by dir:
>
>>>> class C: pass
>...
>>>> C.__name__
>'C'
>>>> dir(C)
>['__doc__', '__module__'] # __name__ is not shown 
>>>> help(dir)
>Help on built-in function dir:
>
>dir(...)
>    dir([object]) -> list of strings
>
>    Return an alphabetized list of names comprising (some of) the attributes
>                                                     ^^^^^^^
>    of the given object, and of attributes reachable from it:
>
>    No argument:  the names in the current scope.
>    Module object:  the module attributes.
>    Type or class object:  its attributes, and recursively the attributes of
>        its bases.
>    Otherwise:  its attributes, its class's attributes, and recursively the
>        attributes of its class's base classes.
>
>Why __name__ is hidden and how do I discover if there other hidden
>attributes I don't know about ?
>
My guess would be that somehow the attribute access for '__name__'
finds its way internally to the value via something like

 >>> import types
 >>> class C: pass
 ...
 >>> types.ClassType.__getattribute__(C, '__name__')
 'C'

but that's a guess. One could check the code, I suppose. I wonder how hard it
would be to write a little Python tool to grep the C sources for hardcoded
attribute names. It might make an interesting listing. Maybe such a script exists?

Regards,
Bengt Richter
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