Re: [Haskell-cafe] Overloading functions based on arguments?

On Fri, 2009-02-13 at 13:25 +0300, Eugene Kirpichov wrote:

class Foobar a b where foobar :: a -> b -> Int

instance Foobar String Int where ... instance Foobar Int String where ...

But we typically do not to this. It's ugly. Classes work nicely when there is some kind of parametrisation going on, where a function can work with any instance of some interface. Ad-hoc overloading in the style of Java/C++ just isn't done, even though it can be encoded by the above trick. In the simple case just us a different name. If you would have lots of variations then consider other approaches like passing a data type containing some of the arguments (since that can encode alternatives). Duncan

2009/2/13 Daniel Kraft :

...

Hi,

I just came across a problem like this: Suppose I've got two related functions that do similar things, and I want to call them the same... Like in:

foobar :: String -> Int -> Int foobar :: Int -> String -> Int

(Bad example, but I hope you got the point.)

Is this kind of overloading (instead of the polymorphism based overloading) possible in Haskell? Namely to have two functions with the same name but different signatures so they could be distinguished by a call's parameters? I fear not... So I guess I have to name the functions differently, right?

Thanks, Daniel