[project @ 2003-07-21 15:14:18 by ross]

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

diff --git a/ghc/compiler/utils/Bag.lhs b/ghc/compiler/utils/Bag.lhs
index fcb9a9c..ed9a540 100644 (file)
--- a/ghc/compiler/utils/Bag.lhs
+++ b/ghc/compiler/utils/Bag.lhs
@@ -1,28 +1,28 @@
 %
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
 \section[Bags]{@Bag@: an unordered collection with duplicates}
 
 \begin{code}
-#include "HsVersions.h"
-
 module Bag (
        Bag,    -- abstract type
 
        emptyBag, unitBag, unionBags, unionManyBags,
        mapBag,
        elemBag,
-       filterBag, partitionBag, concatBag, foldBag, foldrBag,
+       filterBag, partitionBag, concatBag, foldBag, foldrBag, foldlBag,
        isEmptyBag, consBag, snocBag,
        listToBag, bagToList
     ) where
 
-IMP_Ubiq(){-uitous-}
-IMPORT_1_3(List(partition))
+#include "HsVersions.h"
+
+import Outputable
+import List            ( partition )
+\end{code}
 
-import Outputable      --( interpp'SP )
-import Pretty
 
+\begin{code}
 data Bag a
   = EmptyBag
   | UnitBag    a
@@ -130,6 +130,16 @@ foldrBag k z (TwoBags b1 b2) = foldrBag k (foldrBag k z b2) b1
 foldrBag k z (ListBag xs)    = foldr k z xs
 foldrBag k z (ListOfBags bs) = foldr (\b r -> foldrBag k r b) z bs
 
+foldlBag :: (r -> a -> r) -> r
+        -> Bag a
+        -> r
+
+foldlBag k z EmptyBag        = z
+foldlBag k z (UnitBag x)     = k z x
+foldlBag k z (TwoBags b1 b2) = foldlBag k (foldlBag k z b1) b2
+foldlBag k z (ListBag xs)    = foldl k z xs
+foldlBag k z (ListOfBags bs) = foldl (\r b -> foldlBag k r b) z bs
+
 
 mapBag :: (a -> b) -> Bag a -> Bag b
 mapBag f EmptyBag       = EmptyBag
@@ -149,10 +159,10 @@ bagToList b = foldrBag (:) [] b
 
 \begin{code}
 instance (Outputable a) => Outputable (Bag a) where
-    ppr sty EmptyBag       = ptext SLIT("emptyBag")
-    ppr sty (UnitBag a)     = ppr sty a
-    ppr sty (TwoBags b1 b2) = hsep [ppr sty b1 <> comma, ppr sty b2]
-    ppr sty (ListBag as)    = interpp'SP sty as
-    ppr sty (ListOfBags bs) = brackets (interpp'SP sty bs)
+    ppr EmptyBag       = ptext SLIT("emptyBag")
+    ppr (UnitBag a)     = ppr a
+    ppr (TwoBags b1 b2) = hsep [ppr b1 <> comma, ppr b2]
+    ppr (ListBag as)    = interpp'SP as
+    ppr (ListOfBags bs) = brackets (interpp'SP bs)
 
 \end{code}