[project @ 2002-09-27 08:20:43 by simonpj]

[ghc-hetmet.git] / ghc / compiler / basicTypes / NameSet.lhs

diff --git a/ghc/compiler/basicTypes/NameSet.lhs b/ghc/compiler/basicTypes/NameSet.lhs
index ad313f7..8aaaf4e 100644 (file)
--- a/ghc/compiler/basicTypes/NameSet.lhs
+++ b/ghc/compiler/basicTypes/NameSet.lhs
@@ -10,6 +10,7 @@ module NameSet (
        emptyNameSet, unitNameSet, mkNameSet, unionNameSets, unionManyNameSets,
        minusNameSet, elemNameSet, nameSetToList, addOneToNameSet, addListToNameSet, 
        delFromNameSet, delListFromNameSet, isEmptyNameSet, foldNameSet, filterNameSet,
+       intersectsNameSet, intersectNameSet,
        
        -- Free variables
        FreeVars, isEmptyFVs, emptyFVs, plusFVs, plusFV, 
@@ -46,6 +47,9 @@ delFromNameSet           :: NameSet -> Name -> NameSet
 delListFromNameSet :: NameSet -> [Name] -> NameSet
 foldNameSet       :: (Name -> b -> b) -> b -> NameSet -> b
 filterNameSet     :: (Name -> Bool) -> NameSet -> NameSet
+intersectNameSet   :: NameSet -> NameSet -> NameSet
+intersectsNameSet  :: NameSet -> NameSet -> Bool       -- True if non-empty intersection
+       -- (s1 `intersectsVarSet` s2) doesn't compute s2 if s1 is empty
 
 isEmptyNameSet    = isEmptyUniqSet
 emptyNameSet     = emptyUniqSet
@@ -61,8 +65,11 @@ nameSetToList     = uniqSetToList
 delFromNameSet    = delOneFromUniqSet
 foldNameSet      = foldUniqSet
 filterNameSet    = filterUniqSet
+intersectNameSet  = intersectUniqSets
 
 delListFromNameSet set ns = foldl delFromNameSet set ns
+
+intersectsNameSet s1 s2 = not (isEmptyNameSet (s1 `intersectNameSet` s2))
 \end{code}