Python: Class factory using user input as class names
- by Sano98
Hi everyone,
I want to add class atttributes to a superclass dynamically. Furthermore, I want to create classes that inherit from this superclass dynamically, and the name of those subclasses should depend on user input.
There is a superclass "Unit", to which I can add attributes at runtime. This already works.
def add_attr (cls, name, value):
setattr(cls, name, value)
class Unit(object):
pass
class Archer(Unit):
pass
myArcher = Archer()
add_attr(Unit, 'strength', 5)
print "Strenght ofmyarcher: " + str(myArcher.strength)
Archer.strength = 2
print "Strenght ofmyarcher: " + str(myArcher.strength)
This leads to the desired output:
Strenght ofmyarcher: 5
Strenght ofmyarcher: 2
But now I don't want to predefine the subclass Archer, but I'd rather let the user decide how to call this subclass. I've tried something like this:
class Meta(type, subclassname):
def __new__(cls, subclassname, bases, dct):
return type.__new__(cls, subclassname, Unit, dct)
factory = Meta()
factory.__new__("Soldier")
but no luck. I guess I haven't really understood what new does here.
What I want as a result here is
class Soldier(Unit):
pass
being created by the factory. And if I call the factory with the argument "Knight", I'd like a class Knight, subclass of Unit, to be created.
Any ideas? Many thanks in advance!
Bye
-Sano
