spir wrote:
Hello,
I stepped on an issue recently that let me reconsider what we actually do and mean when subtyping, especially when deriving from built-in types. The issue basically is I need to add some information and behaviour to "base data" that can be of any type. (See PS for details.)
When subtyping int, I mean instances of MyInt to basically "act as" an int. This does not mean, in fact, inheriting int's attributes.
It doesn't? How bizarre.
This means instead the integer specific operations to apply on a very special attribute instead of applying on the global object.
That sounds vaguely like delegation. ...
Moreover --this is the reason why I first had to study that point closer--, the present syntax requires the base type to be unique *and* known at design time.
I don't think so. Just write a class factory.
def factory(base): ... class MyThing(base): ... def method(self): ... return "self is a %s" % base.__name__ ... return MyThing ... x = factory(int)() x.method() 'self is a int' y = factory(str)() y.method() 'self is a str'
-- Steven