How to replace a method in an instance.

[Steven W. Orr]

On Friday, Aug 24th 2007 at 12:26 -0400, quoth Steven W. Orr:

=>On Friday, Aug 24th 2007 at 09:12 -0700, quoth kyosohma at gmail.com:
=>
=>=>On Aug 24, 11:02 am, "Steven W. Orr" <ste... at syslang.net> wrote:
=>=>> In the program below, I want this instance to end up calling repmeth
=>=>> whenever inst.m1 is called. As it is now, I get this error:
=>=>>
=>=>> Hello from init
=>=>> inst =  <__main__.CC instance at 0x402105ec>
=>=>> Traceback (most recent call last):
=>=>>    File "./foo9.py", line 17, in ?
=>=>>      inst.m1()
=>=>> TypeError: repmeth() takes exactly 1 argument (0 given)
=>=>>
=>=>> #! /usr/bin/python
=>=>> def repmeth( self ):
=>=>>      print "repmeth"
=>=>>
=>=>> class CC:
=>=>>      def __init__( self ):
=>=>>          self.m1 = repmeth
=>=>>          print 'Hello from init'
=>=>>
=>=>>      def m1 ( self ):
=>=>>          print "m1"
=>=>>
=>=>> inst = CC()
=>=>> inst.m1()
=>
=>=>Remove "self" from repmeth as it's not required in a function, only in
=>=>functions that are defined within a class. Of course, a function in a
=>=>class is also know as a method.
=>
=>Sorry. I need repmeth to have self passed to it automatically if it's 
=>called. I didn't mean to obfuscate the problem by not making a reference 
=>to self in repmeth. 
=>
=>Am I being clear?

On Friday, Aug 24th 2007 at 18:44 +0200, quoth Wildemar Wildenburger:

=>Steven W. Orr wrote:
=>> Sorry. I need repmeth to have self passed to it automatically if it's
=>> called. I didn't mean to obfuscate the problem by not making a 
reference
=>> to self in repmeth.
=>>
=>> Am I being clear?
=>>
=>>
=>Sort of. Maybe you fare better if you state what you want to achieve,
=>instead of how you think you should do it. Chances are you don't need to
=>replace a method in __init__, but there's another, less tricky way.
  
Ok. I have a collection of classes that are produced by a factory. They   
all inherit from a baseclass. One (maybe more) of the classes inherits a  
method that he shouldn't. All I want is to be able to change that
particular class so that he will have the special method that he needs    
instead of the default one that he inherits. I was thinking that instead 
of making a special class for CC to inherit from which would give him his 
special replacement method(s), I could simply assign them in a manner 
which would more easily lend itself to later being table driven.

If I had a choice, I'd rather not do it in init. Instead, I'd rather be 
able to say something like 
CC.m1 = repmeth
but since in the real world, CC inherits from his baseclass, the above 
assignment causes the baseclass to be altered. :-(

Please tell me if I need to provide more.

-- 
Time flies like the wind. Fruit flies like a banana. Stranger things have  .0.
happened but none stranger than this. Does your driver's license say Organ ..0
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individuals! What if this weren't a hypothetical question?
steveo at syslang.net