List types

Scott Turner [email protected]
Mon, 13 Nov 2000 04:13:07 -0500


You could make a type like this:

    data C a b = Raw b | Cooked ( a -> C a b )

    ap :: C a b -> a -> C a b
    ap (Cooked f) v = f v

    cook :: C a (a -> t) -> C a t
    cook (Cooked f) = Cooked g
      where
        g a = cook (f a)
    cook (Raw f) = Cooked g
      where
        g a = Raw (f a)

    foo x y z = x <= y && y <= z
    f3 = cook $ cook $ cook $ Raw foo
    test = f3 `ap` 1 `ap` 2 `ap` 3

Though you could do something similar with a list-based approach.
								-- Scott

At 20:12 2000-11-12 -0800, you wrote:
>I would like to be able to make a list that contains functions which take
>arguments of a certain type 'a'. However I don't know how many 'a'
>arguments there are. For example I'd like to be able to make a list of
>f,g, and h.
>
>f::a->b
>g::a->a->b
>h::a->a->a->b
>[f,g,h]
>
>I want to be able to curry the a's one at a time.

--
Scott Turner
[email protected]       http://www.ma.ultranet.com/~pkturner