X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Data%2FList.hs;h=2a37187899045ffd11198db16aa80c76f5d99d1a;hb=9fa9bc17072a58c0bae2cce4764d38677e96ac29;hp=9082db586a6c279b8e4ed0297548bc9a2770bd42;hpb=260e7f2ed9a43c6ecf5a556d77817f39ed2893ab;p=ghc-base.git

diff --git a/Data/List.hs b/Data/List.hs
index 9082db5..2a37187 100644
--- a/Data/List.hs
+++ b/Data/List.hs
@@ -1,6 +1,6 @@
 {-# OPTIONS -fno-implicit-prelude #-}
 -----------------------------------------------------------------------------
--- 
+-- |
 -- Module      :  Data.List
 -- Copyright   :  (c) The University of Glasgow 2001
 -- License     :  BSD-style (see the file libraries/core/LICENSE)
@@ -9,7 +9,7 @@
 -- Stability   :  provisional
 -- Portability :  portable
 --
--- $Id: List.hs,v 1.2 2001/12/21 15:07:21 simonmar Exp $
+-- $Id: List.hs,v 1.4 2002/04/24 16:31:39 simonmar Exp $
 --
 -- Operations on lists.
 --
@@ -90,6 +90,7 @@ module Data.List
    , length	       -- :: [a] -> Int
    , (!!)	       -- :: [a] -> Int -> a
    , foldl	       -- :: (a -> b -> a) -> a -> [b] -> a
+   , foldl'	       -- :: (a -> b -> a) -> a -> [b] -> a
    , foldl1	       -- :: (a -> a -> a) -> [a] -> a
    , scanl             -- :: (a -> b -> a) -> a -> [b] -> [a]
    , scanl1            -- :: (a -> a -> a) -> [a] -> [a]
@@ -521,6 +522,14 @@ unfoldr f b  =
    Just (a,new_b) -> a : unfoldr f new_b
    Nothing        -> []
 
+
+-- -----------------------------------------------------------------------------
+-- strict version of foldl
+
+foldl'           :: (a -> b -> a) -> a -> [b] -> a
+foldl' f a []     = a
+foldl' f a (x:xs) = let a' = f a x in a' `seq` foldl' f a' xs
+
 -- -----------------------------------------------------------------------------
 -- List sum and product