X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Futils%2FBag.lhs;h=ebc44ac1479975276eb13f755ed0b1b4f974bb3e;hb=c13f5e5b5f1ea004330e196f568a8ef8dc8e6cbc;hp=481dedfd8e48497a2a82d08bcb64d0a34151b958;hpb=241fdb3509084d0f00bc62f91cf65ade9df5f0e7;p=ghc-hetmet.git

diff --git a/compiler/utils/Bag.lhs b/compiler/utils/Bag.lhs
index 481dedf..ebc44ac 100644
--- a/compiler/utils/Bag.lhs
+++ b/compiler/utils/Bag.lhs
@@ -11,7 +11,7 @@ module Bag (
 
         emptyBag, unitBag, unionBags, unionManyBags,
         mapBag,
-        elemBag,
+        elemBag, lengthBag,
         filterBag, partitionBag, concatBag, foldBag, foldrBag, foldlBag,
         isEmptyBag, isSingletonBag, consBag, snocBag, anyBag,
         listToBag, bagToList,
@@ -41,6 +41,12 @@ emptyBag = EmptyBag
 unitBag :: a -> Bag a
 unitBag  = UnitBag
 
+lengthBag :: Bag a -> Int
+lengthBag EmptyBag        = 0
+lengthBag (UnitBag {})    = 1
+lengthBag (TwoBags b1 b2) = lengthBag b1 + lengthBag b2
+lengthBag (ListBag xs)    = length xs
+
 elemBag :: Eq a => a -> Bag a -> Bool
 elemBag _ EmptyBag        = False
 elemBag x (UnitBag y)     = x == y