Wrapping classes

[Jeremy Sanders]

Is it possible to implement some sort of "lazy" creation of objects only
when the object is used, but behaving in the same way as the object?

For instance:

class Foo:
  def __init__(self, val):
    """This is really slow."""
    self.num = val

# this doesn't call Foo.__init__ yet
a = lazyclass(Foo, 6)

# Foo is only initalised here
print a.num

What I really want to do is make an object which looks like a numarray,
but only computes its contents the first time it is used.

Thanks

Jeremy