Message3149

CPython will define a __module__ attribute at the beginning of a class 
definition based on the __name__ global.

Jython 2.3a0 on java1.5.0_13
Type "copyright", "credits" or "license" for more information.
>>> class Foo(object):
...     print __module__
... 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in Foo
NameError: name '__module__' is not defined

Python 2.5.1 (r251:54863, Aug 19 2007, 21:02:30) 
[GCC 4.0.1 (Apple Computer, Inc. build 5367)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> class Foo(object):
...     print __module__
... 
__main__
>>> 

CPython actually does this in the class's code object, so this is a 
compiler bug:
>>> c = compile("""\
... class Foo(object):
...     print __module__
... 
... """, 'foo', 'exec')
>>> c.co_consts[1]
<code object Foo at 0x54d4e8, file "foo", line 1>
>>> dis.dis(c.co_consts[1])
  1           0 LOAD_NAME                0 (__name__)
              3 STORE_NAME               1 (__module__)

  2           6 LOAD_NAME                1 (__module__)
              9 PRINT_ITEM          
             10 PRINT_NEWLINE       
             11 LOAD_LOCALS         
             12 RETURN_VALUE