Module header tidyup, phase 1

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

diff --git a/compiler/basicTypes/VarSet.lhs b/compiler/basicTypes/VarSet.lhs
index 55e82a8..7e08d9d 100644 (file)
--- a/compiler/basicTypes/VarSet.lhs
+++ b/compiler/basicTypes/VarSet.lhs
@@ -1,7 +1,7 @@
 %
+% (c) The University of Glasgow 2006
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-\section{@VarSet@: Variable sets}
 
 \begin{code}
 module VarSet (
@@ -10,7 +10,7 @@ module VarSet (
        extendVarSet, extendVarSetList, extendVarSet_C,
        elemVarSet, varSetElems, subVarSet,
        unionVarSet, unionVarSets,
-       intersectVarSet, intersectsVarSet,
+       intersectVarSet, intersectsVarSet, disjointVarSet,
        isEmptyVarSet, delVarSet, delVarSetList, delVarSetByKey,
        minusVarSet, foldVarSet, filterVarSet,
        lookupVarSet, mapVarSet, sizeVarSet, seqVarSet,
@@ -19,10 +19,10 @@ module VarSet (
 
 #include "HsVersions.h"
 
-import Var             ( Var, Id, TyVar )
-import Unique          ( Unique )
+import Var
+import Unique
 import UniqSet
-import UniqFM          ( delFromUFM_Directly, addToUFM_C )
+import UniqFM
 \end{code}
 
 %************************************************************************
@@ -69,9 +69,10 @@ extendVarSetList= addListToUniqSet
 intersectVarSet        = intersectUniqSets
 
 intersectsVarSet:: VarSet -> VarSet -> Bool    -- True if non-empty intersection
-       -- (s1 `intersectsVarSet` s2) doesn't compute s2 if s1 is empty
+disjointVarSet  :: VarSet -> VarSet -> Bool    -- True if empty intersection
 subVarSet      :: VarSet -> VarSet -> Bool     -- True if first arg is subset of second
-       -- (s1 `subVarSet` s2) doesn't compute s2 if s1 is empty
+       -- (s1 `intersectsVarSet` s2) doesn't compute s2 if s1 is empty; 
+       -- ditto disjointVarSet, subVarSet
 
 unionVarSet    = unionUniqSets
 unionVarSets   = unionManyUniqSets
@@ -94,8 +95,9 @@ elemVarSetByKey       = elemUniqSet_Directly
 
 \begin{code}
 -- See comments with type signatures
-intersectsVarSet s1 s2 = not (isEmptyVarSet (s1 `intersectVarSet` s2))
-a `subVarSet` b = isEmptyVarSet (a `minusVarSet` b)
+intersectsVarSet s1 s2 = not (s1 `disjointVarSet` s2)
+disjointVarSet   s1 s2 = isEmptyVarSet (s1 `intersectVarSet` s2)
+subVarSet        s1 s2 = isEmptyVarSet (s1 `minusVarSet` s2)
 \end{code}
 
 \begin{code}