[Tutor] Mixing in and Mixing out classes in python

[Alan Gauld]

"Tomaz Bevec" <tomazbevec at yahoo.com> wrote

> I'm working on a simulation of cellular growth patterns ...and cells
> can potentially gain and lose these "behaviors" over the course
> of the simulation.

OK, That might be a valid scenario.
But personally I'd probably implement that as an
attribute of the cell - a list of behaviours and build
a Behaviour class with subclasses. The methods
of which take a Cell class as their argument.

It is then trivial to add remove behaviours.
And simply call them in a loop

for b in self.behavious:
    b.doit(self)

Or maybe have a dictionary of behaviours
if you even want to call specific ones.

eg

def myMeth(self):
      # do sometjing
      try: self.behaviours['behaviourMyMeth'](self)
      except KeyError: pass
      # do the rest

> I have however thought of a number of ways to work around this,
> and per your suggestion I think I'll just try something else,

I'd come back to the old OOP adage, inheritance is for Is-A 
relationships.
Is you Cell a behaviour or does it Have-A behaviour?

With mixins that adage tends to get bent since mixins are often
functional in nature but if the function is not intrinsic to the class
I tend to use delegation.

> any idea on how to dynamically mix out I'd be glad to here it.

I don't know but I'm sure its possible if you understand the class
internals well enough.

Regards,

Alan G.