Dynamic dispatch and inheritance in python
- by Bill Zimmerman
Hi,
I'm trying to modify Guido's multimethod (dynamic dispatch code):
http://www.artima.com/weblogs/viewpost.jsp?thread=101605
to handle inheritance and possibly out of order arguments.
e.g. (inheritance problem)
class A(object):
pass
class B(A):
pass
@multimethod(A,A)
def foo(arg1,arg2):
print 'works'
foo(A(),A()) #works
foo(A(),B()) #fails
Is there a better way than iteratively checking for the super() of each item until one is found?
e.g. (argument ordering problem)
I was thinking of this from a collision detection standpoint.
e.g.
foo(Car(),Truck()) and
foo(Truck(), Car()) and
should both trigger
foo(Car,Truck) # Note: @multimethod(Truck,Car) will throw an exception if @multimethod(Car,Truck) was registered first?
I'm looking specifically for an 'elegant' solution. I know that I could just brute force my way through all the possibilities, but I'm trying to avoid that. I just wanted to get some input/ideas before sitting down and pounding out a solution.
Thanks
