(Easy ??) question about class definition

[Ken Seehof]

You forgot your self.

>>> def f():
...  print 'spam'
...
>>>
>>> class entry:
...  def __init__(self, name, action):
...   self.name= name
...   self.action= action
...  def selected(self):
...   apply(self.action, ())
...
>>> def f():
...  print 'spam'
...
>>> e = entry('spammer', f)
>>>
>>> e.selected()
spam
>>>

Also, you can use apply instead of exec, and get the added bonus of being able to
add parameters later.

Gregoire Welraeds wrote:

> Hello again,
>
> I think the problem I have is common in OOP... but I don't have any
> beginning of solution.
>
> I got the following problem. Imagine i want to manage a menu. So I define
> 2 classes. First one is the class menu and is basicly a list of entry. The
> second is the item class representing each menu entry. When an item of my
> menu is selected, I want to execute some action... The action I want to
> perform is different for each item. So I get the following
>
> class entry:
>         def __init__(self, name, action):
>                 self.name= name
>                 self.action= action
>         def selected():
>                 exec(self.action)
>         [some methods]
>
> class menu:
>         def __init__(self, name):
>                 self.name= name
>                 self.list=[]
>         [some methods]
> ...
>
> Now self.action is a reference to something I have to define elsewhere. It
> could be a separate function... but then, the function is not bound to a
> class as method are and everybody can use it. And I don't want to have
> each action to be define in the class.
> thus the problem is that each action i bound with an instance of the class
> item.
> I know there are some solutions in Design Pattern but I don't know howto
> implement this in Python.
>
> thanks for your answer.
>
> --
> Life is not fair
> But the root password helps
> --
>
> Gregoire Welraeds
> greg at perceval.be
> Perceval Development team
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