OO in Python? ^^

[bonono at gmail.com]

Magnus Lycka wrote:
> Assume that you didn't use Python, but rather something with
> static typing. How could you make a module such as my_module.py,
> which is capable of working with any type that supports some
> standard copy functionality and the +-operator?

The following is a very short Haskell function I defined which I hope
can give you some idea.

What it does is just take a generic list of things(I want to use it on
string) and break it up into a tuple using any object in token as
seperator (sort of C's strtok).

breakKeyword token xs =
  case break (flip elem token) xs of
    (_,[]) -> (xs,[])
    (ys,z:zs) -> (ys, zs)

This is the function declaration derived by Haskell(I haven't specify
anything above about types)

*MyList> :type breakKeyword
breakKeyword :: (Eq a) => [a] -> [a] -> ([a], [a])

What it means is that breakKeyword can take any list of object type "a"
so long it belongs to the class Eq. It can be char, number or whatever
so long it is an instance of Eq.

All that is needed for my custom data type(whatever it is) is that it
must implment the compare function that "elem" would use to compare if
a given object is in the list of token.

*MyList> :type elem
elem :: (Eq a) => a -> [a] -> Bool