X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FVarSet.lhs;h=6f03aad1bf05c1ce4c051fee1688969a98d166e5;hp=1bef89a371741c7b02b218b5fd826286f0bb8f2c;hb=16b9e80dc14db24509f051f294b5b51943285090;hpb=3efa0623150111e8157141441ee5571452f8e139

diff --git a/compiler/basicTypes/VarSet.lhs b/compiler/basicTypes/VarSet.lhs
index 1bef89a..6f03aad 100644
--- a/compiler/basicTypes/VarSet.lhs
+++ b/compiler/basicTypes/VarSet.lhs
@@ -4,32 +4,27 @@
 %
 
 \begin{code}
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
 module VarSet (
+        -- * Var, Id and TyVar set types
 	VarSet, IdSet, TyVarSet,
+	
+	-- ** Manipulating these sets
 	emptyVarSet, unitVarSet, mkVarSet,
 	extendVarSet, extendVarSetList, extendVarSet_C,
 	elemVarSet, varSetElems, subVarSet,
 	unionVarSet, unionVarSets,
 	intersectVarSet, intersectsVarSet, disjointVarSet,
 	isEmptyVarSet, delVarSet, delVarSetList, delVarSetByKey,
-	minusVarSet, foldVarSet, filterVarSet,
+	minusVarSet, foldVarSet, filterVarSet, fixVarSet,
 	lookupVarSet, mapVarSet, sizeVarSet, seqVarSet,
 	elemVarSetByKey
     ) where
 
 #include "HsVersions.h"
 
-import Var
+import Var      ( Var, TyVar, Id )
 import Unique
 import UniqSet
-import UniqFM
 \end{code}
 
 %************************************************************************
@@ -68,6 +63,7 @@ extendVarSet_C  :: (Var->Var->Var) -> VarSet -> Var -> VarSet
 
 delVarSetByKey	:: VarSet -> Unique -> VarSet
 elemVarSetByKey :: Unique -> VarSet -> Bool
+fixVarSet       :: (VarSet -> VarSet) -> VarSet -> VarSet
 
 emptyVarSet	= emptyUniqSet
 unitVarSet	= unitUniqSet
@@ -105,6 +101,12 @@ elemVarSetByKey	= elemUniqSet_Directly
 intersectsVarSet s1 s2 = not (s1 `disjointVarSet` s2)
 disjointVarSet   s1 s2 = isEmptyVarSet (s1 `intersectVarSet` s2)
 subVarSet        s1 s2 = isEmptyVarSet (s1 `minusVarSet` s2)
+
+-- Iterate f to a fixpoint
+fixVarSet f s | new_s `subVarSet` s = s
+	      | otherwise	    = fixVarSet f new_s 
+	      where
+		new_s = f s
 \end{code}
 
 \begin{code}