complicated class question

[Fred Clift]

If any of you could spare a moment of your time and perhaps help me figure
out a problem I'm having, I'd be most grateful.  If you dont have time or
dont want to bother with me, then feel free to ignore this email message
:).

My problem has to do with looking for a way to override methods in a
system library that I dont want to modify, that is used in a 3rd party
library that I dont want to modify.


I can summarize the problem with a toy example:

class a:
    def foo(self):
        print "hi"


class b:
    def bar(self):
        ainst = a()
        ainst.foo()


say that a is defined in a system library and that b is in a 3rd party
library.

I'd like to get b to use a modified version a, without having to change
the code of either


my code would do something like:

binst = b()
<insert your solution here>
binst.bar()

and I'd like the version of a.foo that is called be

def myfoo(self):
        print "bye"

Does that make sense?


I could just derive a new class from B and override bar, but in this case,
bar is like 80 lines of code and the the use of the a-classed object is
relatively minimal -- I'd have to basically copy the whole thing -
maintainace problems with new versions of the library etc.

I'm stumped :).

If you've read this far, thanks for your kind interest.

Fred

--
Fred Clift - fred at clift.org -- Remember: If brute
force doesn't work, you're just not using enough.