How to replace a method in an instance.

[Bruno Desthuilliers]

Steven W. Orr a écrit :
> 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()
> 
> TIA

# using old-style classes:
import new

def repmeth( self ):
     print "repmeth"

class CC:
     def __init__( self ):
         self.m1 = new.instancemethod(repmeth, self, type(self))
         print 'Hello from init'

     def m1 ( self ):
         print "m1"

inst = CC()
inst.m1()

# using newstyle classes:
def repmeth( self ):
     print "repmeth"

class CC(object):
     def __init__( self ):
         self.m1 = repmeth.__get__(self, type(self))
         print 'Hello from init'

     def m1 ( self ):
         print "m1"

inst = CC()
inst.m1()

HTH