Re: overwriting method in baseclass

[Steven Bethard]

Harald Massa wrote:
Hello!
I am using a library (= code of so else) within Python. Somewhere in this 
library there is:

class foo:
        def baa(self, parameters):
         print "something"
         self.baazanan(some other parameters)
class mirbo(foo):
      def baazanan(self, lalala):
          print "heylo tada"
class fujiko(foo):
      def baazanan(self, ltara):
          print "sing a song with me"
....
now I want to change the common baa-method. so that
def baa(self, parameters):
      print "soemthing special"
      self.baazanan(some other parameters)
Of course, I use a Python- and GPL-Licence compatible library, I can 
change the source of foo, and use my changed library.

But someday, it happened before, there will be an update by the publisher 
to that library.... and I have to do all again.

So, what is the most elegant solution to administer these changes? 
Given these classes:
py> class foo:
...     def baa(self):
...         print "something"
...         self.baazanan()
...
py> class mirbo(foo):
...     def baazanan(self):
...         print "heylo tada"
...
py> class fujiko(foo):
...     def baazanan(self):
...         print "sing a song with me"
...
You should be able to redefine the method and assign it to the foo class:
py> def new_baa(self):
...     print "soemthing special"
...     self.baazanan()
...
py> foo.baa = new_baa
Then any instances created after this assignment should use the new baa 
method you defined:

py> mirbo().baa()
soemthing special
heylo tada
py> fujiko().baa()
soemthing special
sing a song with me
You also might bring up this point to the maintainer of the library -- 
if they know your intents, they can make this easier for you...

STeVe
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