[Python] Classes are not members of their respective modules??

Robert Dickinson
Hmmm.... this works for me:

C:\>python
ActivePython 2.1, build 210 ActiveState)
based on Python 2.1 (#15, Apr 19 2001, 10:28:27) [MSC 32 bit (Intel)] on
win32
Type "help", "copyright", "credits" or "license" for more information.
...
('FancyURLopener', <class urllib.FancyURLopener at 0080C0D4>)
('URLopener', <class urllib.URLopener at 00815894>)
('addbase', <class urllib.addbase at 00816DF4>)
('addclosehook', <class urllib.addclosehook at 00816E64>)
('addinfo', <class urllib.addinfo at 00818874>)
('addinfourl', <class urllib.addinfourl at 008188E4>)
('ftpwrapper', <class urllib.ftpwrapper at 007E500C>)
>>>

That's strange, they certainly should be there (every name
accessible through module.name should be there, in fact).

Have you somehow got hold of an incompletely-constructed
module? That can happen if importation of a module fails
part way through.

Thanks for confirming my astonishment. I was sure they should be there too.
Maybe I'm making some egregious error in my code. This executes in my
sys.settrace() function, on a "call"-type call to that function. The module
must be fully initialized because I'm calling a user method in a class in
that module.

functions =
inspect.getmembers(module,inspect.isfunction)
print "functions: %s"%functions
classes = inspect.getmembers(module,inspect.isclass)
if classes==[]:
moduleDict = module.__dict__
for mkey in moduleDict.keys():
if inspect.isclass(moduleDict[mkey]):
classes.append((mkey,moduleDict[mkey]))
print "classes: %s"%classes

always prints:
functions: [....] #lists functions properly
classes: [] #always empty

I thought that perhaps the inspect.isclass function didn't do what I thought
it should, so I tried just printing the moduleDict (in place of the "for
mkey.." loop above) and, sure enough, the class names are not in there. :-O

I'm willing to accept that I've made a stupid mistake, but I sure can't find
it. Any suggestions?


Greg Ewing wrote:

There are tricks modules can play, depending on what module you're
using, it may not actually be what you think it is. Some modules use
lazy importing to load heavy class defn's only when needed, others may
define classes using functions which only create the class object when a
method or function is called, yet others may use objects which are very
class-like, but which are not in fact classes (though that doesn't seem
to be the problem here). Alternately, are you maybe passing the wrong
module (for instance, an old version with just the functions)?

assert module.className == classObject, "You can't get to it normally,
possibly using the wrong module object"

assert type(module) == types.ModuleType, "It's not a regular module
object, it's a stand-in doing weird things"

BTW, would help in debugging if we knew what the module is (e.g. is it
one of the mx.* or wx.* modules, or a standard library module, a
third-party module for which you have source, or a module you created
yourself?

Good luck,
Mike


Robert Dickinson wrote: