[project @ 2005-04-04 11:55:11 by simonpj]

[ghc-hetmet.git] / ghc / compiler / utils / Util.lhs

diff --git a/ghc/compiler/utils/Util.lhs b/ghc/compiler/utils/Util.lhs
index 2f20226..fe877c8 100644 (file)
--- a/ghc/compiler/utils/Util.lhs
+++ b/ghc/compiler/utils/Util.lhs
@@ -9,6 +9,7 @@ module Util (
        -- general list processing
        zipEqual, zipWithEqual, zipWith3Equal, zipWith4Equal,
         zipLazy, stretchZipWith,
+       mapFst, mapSnd,
        mapAndUnzip, mapAndUnzip3,
        nOfThem, filterOut,
        lengthExceeds, lengthIs, lengthAtLeast, listLengthCmp, atLength,
@@ -223,6 +224,12 @@ stretchZipWith p z f (x:xs) ys
 
 
 \begin{code}
+mapFst :: (a->c) -> [(a,b)] -> [(c,b)]
+mapSnd :: (b->c) -> [(a,b)] -> [(a,c)]
+
+mapFst f xys = [(f x, y) | (x,y) <- xys]
+mapSnd f xys = [(x, f y) | (x,y) <- xys]
+
 mapAndUnzip :: (a -> (b, c)) -> [a] -> ([b], [c])
 
 mapAndUnzip f [] = ([],[])