On 15-May-2000, S.D.Mechveliani <[EMAIL PROTECTED]> wrote:
> ... only several days ago I have realized or recalled that it is
> possible to replace some algebraic part of Prelude-98 with the
> user prelude. Someone, - thanks for the help, - had confirmed
> this recently: use import qualified Prelude
> import MyPrelude
>
> Probably, this makes the implementation easy.
> A small problem remains, for example, with the code like
> case xs
> of
> [Prelude.Just] -> [Prelude.True]
> (Prelude.Just) Prelude.: xs -> Prelude.Nothing Prelude.: ys
>
> I expect, it would not be good to repeat the definitions of
> data Maybe, data Bool
> in MyPrelude.
Right. Instead, you can simply re-export them:
module MyPrelude(Prelude.Maybe(..), Prelude.Bool(..)) where
import qualified Prelude
Then you can go ahead and use these in code that uses your
standard Prelude:
module Example where
import qualified Prelude
import MyPrelude
conj :: Bool -> Bool -> Bool
conj True x = x
conj False _ = False
--
Fergus Henderson <[EMAIL PROTECTED]> | "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh> | of excellence is a lethal habit"
PGP: finger [EMAIL PROTECTED] | -- the last words of T. S. Garp.
