Instrospection question

[Peter Otten]

Matias Surdi wrote:

> I have the following code:
> 
> --------------------------
> import new
> 
> class A:
>      def a(self):
>          print "Original"
> 
> def other(cad):
>      return cad + " modified"
> 
> def replace_method(method):
>      def b(self,*args,**kwargs):
>          result = method(*args,**kwargs)
>          return other(result)
>      return b
> 
> 
> a = A()
> 
> setattr(a,"a",new.instancemethod(replace_method(a.a) ,a,A))
> 
> a.a()
> 
> #Result should be:
> # Original modified
> 
> ------------------------------
> 
> As you can see, what I'm trying to do is "replace" a method with another 
> one wich is the same method but with a function applied to it (in this 
> case, a string concatenation ( +" modified"))
> 
> Can anybody help me with this?

Change A.a() to return a value:

class A:
    def a(self):
        return "Original"

# ...

print a.a()

and it should work. You can then start to simplify:

class A:
     def a(self):
         return "Original"

def other(cad):
     return cad + " modified"

def replace_method(method):
     def b(*args,**kwargs):
         result = method(*args,**kwargs)
         return other(result)
     return b

a = A()

a.a = replace_method(a.a)

print a.a()

Peter