Dynamically adding and removing methods

[Steven Bethard]

Terry Reedy wrote:
> "Ron Adam" <rrr at ronadam.com> wrote in message 
> news:sXA_e.112986$xl6.67455 at tornado.tampabay.rr.com...
> 
>>Actually I think I'm getting more confused.  At some point the function
>>is wrapped.  Is it when it's assigned, referenced, or called?
> 
> 
> When it is referenced via the class.
>  If you lookup in class.__dict__, the function is still a function.
> 
> 
>>>>class C(object):
> ...   def meth(self): pass
> ...
> 
>>>>C.__dict__['meth']
> <function meth at 0x0090B018>
> 
>>>>C.meth
> <unbound method C.meth>
> 
>>>>C().meth
> <bound method C.meth of <__main__.C object at 0x008E4688>>
> 
> I am not sure, without looking, how much of this is language definition and 
> how much CPython implementation, but I think mostly the latter

Well, being that the descriptor machinery is defined in the language 
reference[1][2], I'd have to say it's entirely the former.  The 
descriptor machinery says basically that, for classes,
     C.meth
should always be doing the equivalent of:
     C.__dict__['meth'].__get__(None, C)
and for instances,
     c.meth
should always be doing the equivalent of:
     type(c).__dict__['meth'].__get__(c, type(c))

[1] http://docs.python.org/ref/descriptors.html
[2] http://docs.python.org/ref/descriptor-invocation.html

STeVe