Re: [Tutor] class instance with identity crisis

[Kent Johnson]

A couple of ideas:
You could have dry() return the new weapon:
  def dry(self):
    return Prune()
then the client code would be
weapon = weapon.dry()
You could have the weapon encapsulate another object and delegate to it.
Finally, you actually can change the class of an object just by assigning to 
self.__class__:
 >>> class A:
 ...   def show(self):
 ...     print "I'm an A"
 ...
 >>> class B:
 ...   def show(self):
 ...     print "I'm a B"
 ...
 >>> a=A()
 >>> a.__class__
<class __main__.A at 0x008CE750>
 >>> a.show()
I'm an A
 >>> a.__class__ = B
 >>> type(a)
<type 'instance'>
 >>> a.show()
I'm a B
So if you change
  self = Prune()
to
  self.__class__ = Prune
I think you will get the behaviour you are looking for.
I would look for another way to solve your problem, though - I agree with Pierre that this is likely 
to be confusing.

Kent
Barnaby Scott wrote:
This is probably a very easy question, and one that I was shocked to find I
was stuck on, having thought I understood classes!
I was wondering how you can get an instance of a class to change itself into
something else (given certain circumstances), but doing so from within a
method. So:
class Damson:
    def __str__(self):
        return 'damson'
    def dry(self):
        self = Prune()
class Prune:
    def __str__(self):
        return 'prune'
weapon = Damson()
weapon.dry()
print weapon
All the old hands will of course know this will produce the output
damson
but something in me suggests it should produce
prune
After all, 'self' refers to the instance 'weapon'.
Obviously one could reassign weapon to a Prune outside the class definition,
but I was hoping to write something in which, given certain circustances
arising, the instance would change itself into something else.
Time to go back to school!
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http://mail.python.org/mailman/listinfo/tutor