[project @ 2002-12-05 23:49:43 by mthomas]

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

diff --git a/ghc/compiler/utils/Bag.lhs b/ghc/compiler/utils/Bag.lhs
index 6085e37..ed9a540 100644 (file)
--- a/ghc/compiler/utils/Bag.lhs
+++ b/ghc/compiler/utils/Bag.lhs
@@ -1,29 +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,
-       elemBag, mapBag,
-       filterBag, partitionBag, concatBag, foldBag,
+       mapBag,
+       elemBag,
+       filterBag, partitionBag, concatBag, foldBag, foldrBag, foldlBag,
        isEmptyBag, consBag, snocBag,
-       listToBag, bagToList, bagToList_append
+       listToBag, bagToList
     ) where
 
-#ifdef COMPILING_GHC
-IMP_Ubiq(){-uitous-}
-IMPORT_1_3(List(partition))
+#include "HsVersions.h"
 
-import Outputable      ( interpp'SP )
-import Pretty
-#endif
+import Outputable
+import List            ( partition )
+\end{code}
 
+
+\begin{code}
 data Bag a
   = EmptyBag
   | UnitBag    a
@@ -53,8 +52,9 @@ unionBags b EmptyBag = b
 unionBags b1 b2      = TwoBags b1 b2
 
 consBag :: a -> Bag a -> Bag a
-consBag elt bag = (unitBag elt) `unionBags` bag
 snocBag :: Bag a -> a -> Bag a
+
+consBag elt bag = (unitBag elt) `unionBags` bag
 snocBag bag elt = bag `unionBags` (unitBag elt)
 
 isEmptyBag EmptyBag        = True
@@ -120,6 +120,26 @@ foldBag t u e (TwoBags b1 b2) = foldBag t u (foldBag t u e b2) b1
 foldBag t u e (ListBag xs)    = foldr (t.u) e xs
 foldBag t u e (ListOfBags bs) = foldr (\b r -> foldBag t u r b) e bs
 
+foldrBag :: (a -> r -> r) -> r
+        -> Bag a
+        -> r
+
+foldrBag k z EmptyBag        = z
+foldrBag k z (UnitBag x)     = k x z
+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
@@ -134,27 +154,15 @@ listToBag [] = EmptyBag
 listToBag vs = ListBag vs
 
 bagToList :: Bag a -> [a]
-bagToList EmptyBag     = []
-bagToList (ListBag vs) = vs
-bagToList b = bagToList_append b []
-
-    -- (bagToList_append b xs) flattens b and puts xs on the end.
-bagToList_append EmptyBag       xs = xs
-bagToList_append (UnitBag x)    xs = x:xs
-bagToList_append (TwoBags b1 b2) xs = bagToList_append b1 (bagToList_append b2 xs)
-bagToList_append (ListBag xx)    xs = xx++xs
-bagToList_append (ListOfBags bs) xs = foldr bagToList_append xs bs
+bagToList b = foldrBag (:) [] b
 \end{code}
 
 \begin{code}
-#ifdef COMPILING_GHC
-
 instance (Outputable a) => Outputable (Bag a) where
-    ppr sty EmptyBag       = ppStr "emptyBag"
-    ppr sty (UnitBag a)     = ppr sty a
-    ppr sty (TwoBags b1 b2) = ppCat [ppr sty b1, pp'SP, ppr sty b2]
-    ppr sty (ListBag as)    = interpp'SP sty as
-    ppr sty (ListOfBags bs) = ppCat [ppLbrack, interpp'SP sty bs, ppRbrack]
+    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)
 
-#endif {- COMPILING_GHC -}
 \end{code}