[project @ 2001-07-20 15:22:21 by simonpj]

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

diff --git a/ghc/compiler/basicTypes/IdInfo.lhs b/ghc/compiler/basicTypes/IdInfo.lhs
index 7e030fd..27919e5 100644 (file)
--- a/ghc/compiler/basicTypes/IdInfo.lhs
+++ b/ghc/compiler/basicTypes/IdInfo.lhs
@@ -20,7 +20,7 @@ module IdInfo (
 
        -- Arity
        ArityInfo(..),
-       exactArity, atLeastArity, unknownArity, hasArity,
+       exactArity, unknownArity, hasArity,
        arityInfo, setArityInfo, ppArityInfo, arityLowerBound,
 
        -- New demand and strictness info
@@ -289,7 +289,7 @@ setUnfoldingInfo  info uf
   = info { unfoldingInfo = uf }
 
 setDemandInfo    info dd = info { demandInfo = dd }
-setArityInfo     info ar = info { arityInfo = ar  }
+setArityInfo     info ar = info { arityInfo = Just ar  }
 setCgInfo         info cg = info { cgInfo = cg }
 setCprInfo        info cp = info { cprInfo = cp }
 setLBVarInfo      info lb = info { lbvarInfo = lb }
@@ -304,7 +304,7 @@ vanillaIdInfo :: IdInfo
 vanillaIdInfo 
   = IdInfo {
            cgInfo              = noCgInfo,
-           arityInfo           = UnknownArity,
+           arityInfo           = unknownArity,
            demandInfo          = wwLazy,
            specInfo            = emptyCoreRules,
             tyGenInfo          = noTyGenInfo,
@@ -338,42 +338,31 @@ of their arities; so it should not be asking...    (but other things
 besides the code-generator need arity info!)
 
 \begin{code}
-data ArityInfo
-  = UnknownArity       -- No idea
+type ArityInfo = Maybe Arity
+       -- A partial application of this Id to up to n-1 value arguments
+       -- does essentially no work.  That is not necessarily the
+       -- same as saying that it has n leading lambdas, because coerces
+       -- may get in the way.
 
-  | ArityExactly Arity -- Arity is exactly this.  We use this when importing a
-                       -- function; it's already been compiled and we know its
-                       -- arity for sure.
-
-  | ArityAtLeast Arity -- A partial application of this Id to up to n-1 value arguments
-                       -- does essentially no work.  That is not necessarily the
-                       -- same as saying that it has n leading lambdas, because coerces
-                       -- may get in the way.
-
-                       -- functions in the module being compiled.  Their arity
-                       -- might increase later in the compilation process, if
-                       -- an extra lambda floats up to the binding site.
-  deriving( Eq )
+       -- The arity might increase later in the compilation process, if
+       -- an extra lambda floats up to the binding site.
 
 seqArity :: ArityInfo -> ()
 seqArity a = arityLowerBound a `seq` ()
 
-exactArity   = ArityExactly
-atLeastArity = ArityAtLeast
-unknownArity = UnknownArity
+exactArity   = Just
+unknownArity = Nothing
 
 arityLowerBound :: ArityInfo -> Arity
-arityLowerBound UnknownArity     = 0
-arityLowerBound (ArityAtLeast n) = n
-arityLowerBound (ArityExactly n) = n
+arityLowerBound Nothing  = 0
+arityLowerBound (Just n) = n
 
 hasArity :: ArityInfo -> Bool
-hasArity UnknownArity = False
-hasArity other       = True
+hasArity Nothing = False
+hasArity other   = True
 
-ppArityInfo UnknownArity        = empty
-ppArityInfo (ArityExactly arity) = hsep [ptext SLIT("ArityExactly"), int arity]
-ppArityInfo (ArityAtLeast arity) = hsep [ptext SLIT("ArityAtLeast"), int arity]
+ppArityInfo Nothing     = empty
+ppArityInfo (Just arity) = hsep [ptext SLIT("Arity"), int arity]
 \end{code}
 
 %************************************************************************