X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Futils%2FMaybes.lhs;h=353c3b5a5c32ecccd80a0d265f7b9ad01e86522a;hb=5e34dfe261bf18325fc035ed92f716f3a6249142;hp=6dd9251e66ce17106bbcab40cecfece725572814;hpb=111cee3f1ad93816cb828e38b38521d85c3bcebb;p=ghc-hetmet.git

diff --git a/ghc/compiler/utils/Maybes.lhs b/ghc/compiler/utils/Maybes.lhs
index 6dd9251..353c3b5 100644
--- a/ghc/compiler/utils/Maybes.lhs
+++ b/ghc/compiler/utils/Maybes.lhs
@@ -5,7 +5,6 @@
 
 \begin{code}
 module Maybes (
-	Maybe2(..), Maybe3(..),
 	MaybeErr(..),
 
 	orElse, 
@@ -15,16 +14,10 @@ module Maybes (
 	expectJust,
 	maybeToBool,
 
-	assocMaybe,
-	mkLookupFun, mkLookupFunDef,
+	thenMaybe, seqMaybe, returnMaybe, failMaybe, catMaybes,
+
+	thenMaB, returnMaB, failMaB
 
-	failMaB,
-	failMaybe,
-	seqMaybe,
-	returnMaB,
-	returnMaybe,
-	thenMaB,
-	catMaybes
     ) where
 
 #include "HsVersions.h"
@@ -35,19 +28,6 @@ import Maybe( catMaybes, mapMaybe )
 infixr 4 `orElse`
 \end{code}
 
-
-%************************************************************************
-%*									*
-\subsection[Maybe2,3 types]{The @Maybe2@ and @Maybe3@ types}
-%*									*
-%************************************************************************
-
-\begin{code}
-data Maybe2 a b   = Just2 a b   | Nothing2  deriving (Eq,Show)
-data Maybe3 a b c = Just3 a b c | Nothing3  deriving (Eq,Show)
-\end{code}
-
-
 %************************************************************************
 %*									*
 \subsection[Maybe type]{The @Maybe@ type}
@@ -107,6 +87,11 @@ seqMaybe :: Maybe a -> Maybe a -> Maybe a
 seqMaybe (Just x) _  = Just x
 seqMaybe Nothing  my = my
 
+thenMaybe :: Maybe a -> (a -> Maybe b) -> Maybe b
+thenMaybe ma mb = case ma of
+		    Just x  -> mb x
+		    Nothing -> Nothing
+
 returnMaybe :: a -> Maybe a
 returnMaybe = Just
 
@@ -118,49 +103,6 @@ orElse :: Maybe a -> a -> a
 Nothing  `orElse` y = y
 \end{code}
 
-Lookup functions
-~~~~~~~~~~~~~~~~
-
-@assocMaybe@ looks up in an assocation list, returning
-@Nothing@ if it fails.
-
-\begin{code}
-assocMaybe :: (Eq a) => [(a,b)] -> a -> Maybe b
-
-assocMaybe alist key
-  = lookup alist
-  where
-    lookup []		  = Nothing
-    lookup ((tv,ty):rest) = if key == tv then Just ty else lookup rest
-\end{code}
-
-@mkLookupFun eq alist@ is a function which looks up
-its argument in the association list @alist@, returning a Maybe type.
-@mkLookupFunDef@ is similar except that it is given a value to return
-on failure.
-
-\begin{code}
-mkLookupFun :: (key -> key -> Bool)	-- Equality predicate
-	    -> [(key,val)] 		-- The assoc list
-	    -> key 			-- The key
-	    -> Maybe val		-- The corresponding value
-
-mkLookupFun eq alist s
-  = case [a | (s',a) <- alist, s' `eq` s] of
-      []    -> Nothing
-      (a:_) -> Just a
-
-mkLookupFunDef :: (key -> key -> Bool)	-- Equality predicate
-	       -> [(key,val)] 		-- The assoc list
-	       -> val 			-- Value to return on failure
-	       -> key 			-- The key
-	       -> val			-- The corresponding value
-
-mkLookupFunDef eq alist deflt s
-  = case [a | (s',a) <- alist, s' `eq` s] of
-      []    -> deflt
-      (a:_) -> a
-\end{code}
 
 %************************************************************************
 %*									*