classification
Title: Nested class __name__
Type: Stage:
Components: Interpreter Core Versions: Python 2.7, Python 2.6
process
Status: closed Resolution:
Dependencies: Superseder:
Assigned To: gvanrossum Nosy List: georg.brandl, gvanrossum, mstefanro, xiaq
Priority: low Keywords:

Created on 2002-11-05 17:56 by gvanrossum, last changed 2012-07-29 19:01 by mstefanro. This issue is now closed.

Messages (7)
msg13078 - (view) Author: Guido van Rossum (gvanrossum) * (Python committer) Date: 2002-11-05 17:56
The __name__ attribute of a nested class should be set
to 'outer.inner', both for classic and for new-style
classes. E.g.

>>> class C:
...     class C1: pass
... 
>>> C.C1.__name__
'C.C1'
>>> 
msg13079 - (view) Author: Guido van Rossum (gvanrossum) * (Python committer) Date: 2002-11-14 23:13
Logged In: YES 
user_id=6380

Hm, but should this also be done for functions inside
classes?  E.g.

class C:
 def foo(self): pass

assert C.foo.__name__ == "C.foo"
assert C.__dict__["foo"].__name__ == "C.foo"

And what about classes inside functions?

def f():
  class C: pass
  return C

assert f().__name__ == "f.C"

???
msg13080 - (view) Author: Guido van Rossum (gvanrossum) * (Python committer) Date: 2003-02-11 23:01
Logged In: YES 
user_id=6380

I'm less sure I even want this now, and not at all sure how
to do it any more, so lowering priority.
msg13081 - (view) Author: Georg Brandl (georg.brandl) * (Python committer) Date: 2007-03-10 07:22
Any interest for Python 3000 on this? Otherwise we can close it.
msg13082 - (view) Author: Guido van Rossum (gvanrossum) * (Python committer) Date: 2007-03-10 18:21
I don't think so.  Closing.
msg166775 - (view) Author: Cheer Xiao (xiaq) Date: 2012-07-29 15:22
There is a bigger problem:

>>> class C:
...     class D:
...         pass
...
>>> repr(C)
"<class '__main__.C'>"
>>> repr(C.D)
"<class '__main__.D'>"

Default repr on nested classes produce specious results.

The problem become pratical when you have two nested classes C1.D and C2.D in module m, which end up being both "m.D" in exception traceback. 

Classes nested in function are likely to contain some information from the function arguments and are thus different on each function call, making it impossible to have a general way to name them. Thus I propose embedding the resulting class's `id` in __name__, like what i'm doing manually in a hulking way:

>>> def factory(foo):
...     class C(object):
...         bar = foo
...     func_name = 'factory'
...     C.__name__ = '%s generated classobj at 0x%x' % (func_name, id(C))
...     return C
...
>>> factory(0)
<class '__main__.factory generated classobj at 0x32273c0'>
>>> factory(0)
<class '__main__.factory generated classobj at 0x32245b0'>

Please consider reopening this issue.
msg166802 - (view) Author: Stefan Mihaila (mstefanro) * Date: 2012-07-29 19:01
Only an issue in Python2.

    >>> A.B.__qualname__
    'A.B'
    >>> repr(A.B)
    "<class '__main__.A.B'>"
History
Date User Action Args
2012-07-29 19:01:53mstefanrosetnosy: + mstefanro

messages: + msg166802
versions: + Python 2.6, Python 2.7
2012-07-29 15:22:26xiaqsetnosy: + xiaq
messages: + msg166775
2002-11-05 17:56:34gvanrossumcreate