[Tutor] Attaching methods to class instances

[Zak Arntson]

Hello again, more weird object stuff. I've created a class Object which
not only allows dynamic attaching of attributes and methods. One of the
things I want to provide is the ability to attach both variables AND
methods (that return a variable) to an instance on the fly. For example:

###
pipe = Object()
pipe.give(name="Green Pipe",
          desc="A filthy green pipe.",
          a_weight=10)

print pipe.name()
print pipe.desc()
print pipe.weight
###

This would output the following:

###
Green Pipe
A filthy green pipe.
10
###

Now, I solved the problem, but it required the addition of a _dummy()
method. Here's the source:

###
class Object:
    ## ... other methods ...
    def attach(self, func, name=None):
        setattr(self,
                name or func.__name__,
                new.instancemethod(func, self, Object))

    def give(self, **args):
        for key in args:
            if key.startswith('a_'):
                if key[2:]:
                    setattr(self, key[2:], args[key])
            else:
                self.attach(self._dummy(args[key]), key)

    def _dummy(self, value):
        def f(self):
            return value
        return f
###

As you can see, I had to create a _dummy method. If I replaced
###
            else:
                self.attach(self._dummy(args[key]), key)
###

with

###
            else:
                def f(self):
                    return args[key]
                self.attach(f, key)
###

The new method would ALWAYS return whatever the last value of args[key] was.
Blech. Hence the addition of _dummy. But is there a cleaner way to do this?

---
Zak Arntson
www.harlekin-maus.com - Games - Lots of 'em