[project @ 1998-02-02 17:27:26 by simonm]

[ghc-hetmet.git] / ghc / lib / ghc / PrelMaybe.lhs

diff --git a/ghc/lib/ghc/PrelMaybe.lhs b/ghc/lib/ghc/PrelMaybe.lhs
deleted file mode 100644 (file)
index 974e5de..0000000
--- a/ghc/lib/ghc/PrelMaybe.lhs
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-%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
-%
-\section[PrelMaybe]{Module @PrelMaybe@}
-
-The @Maybe@ type.
-
-\begin{code}
-{-# OPTIONS -fno-implicit-prelude #-}
-
-module PrelMaybe where
-
-import PrelBase
-
-data  Maybe a  =  Nothing | Just a     deriving (Eq, Ord, Show {- Read -})
-
-maybe :: b -> (a -> b) -> Maybe a -> b
-maybe n f Nothing  = n
-maybe n f (Just x) = f x
-
-instance  Functor Maybe  where
-    map f Nothing       = Nothing
-    map f (Just a)      = Just (f a)
-
-instance  Monad Maybe  where
-    (Just x) >>= k      = k x
-    Nothing  >>= k      = Nothing
-
-    (Just x) >>  k      = k
-    Nothing  >>  k      = Nothing
-
-    return              = Just
-
-instance  MonadZero Maybe  where
-    zero                = Nothing
-
-instance  MonadPlus Maybe  where
-    Nothing ++ ys       = ys
-    xs      ++ ys       = xs
-\end{code}
-
-
-
-