-s%
+%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section{@Vars@: Variables}
\begin{code}
module Var (
- Var, IdOrTyVar, VarDetails, -- Abstract
+ Var, VarDetails, -- Abstract
varName, varUnique, varInfo, varType,
setVarName, setVarUnique, setVarType, setVarOcc,
-
-- TyVars
TyVar,
tyVarName, tyVarKind,
-- Ids
Id, DictId,
idName, idType, idUnique, idInfo, modifyIdInfo, maybeModifyIdInfo,
- setIdName, setIdUnique, setIdInfo, lazySetIdInfo,
+ setIdName, setIdUnique, setIdInfo, lazySetIdInfo, zapIdInfo,
mkIdVar, isId, externallyVisibleId
) where
#include "HsVersions.h"
import {-# SOURCE #-} TypeRep( Type, Kind )
-import {-# SOURCE #-} IdInfo( IdInfo, seqIdInfo )
+import {-# SOURCE #-} IdInfo( IdInfo, seqIdInfo, vanillaIdInfo )
import Unique ( Unique, Uniquable(..), mkUniqueGrimily, getKey )
import Name ( Name, OccName, NamedThing(..),
setNameUnique, setNameOcc, nameUnique,
mkSysLocalName, isExternallyVisibleName
)
-import BasicTypes ( Unused )
+import FastTypes
import Outputable
import IOExts ( IORef, newIORef, readIORef, writeIORef )
\end{code}
-
%************************************************************************
%* *
\subsection{The main data type declarations}
in its @VarDetails@.
\begin{code}
-type IdOrTyVar = Var
-
data Var
= Var {
varName :: Name,
- realUnique :: Int#, -- Key for fast comparison
+ realUnique :: FastInt, -- Key for fast comparison
-- Identical to the Unique in the name,
-- cached here for speed
varType :: Type,
, realUnique = getKey (nameUnique name)
, varType = kind
, varDetails = TyVar
-#ifdef DEBUG
- , varInfo = pprPanic "looking at IdInfo of a tyvar" (ppr name)
-#endif
+ , varInfo = pprPanic "mkTyVar" (ppr name)
}
mkSysTyVar :: Unique -> Kind -> TyVar
, realUnique = getKey uniq
, varType = kind
, varDetails = TyVar
-#ifdef DEBUG
- , varInfo = pprPanic "mkSysTyVar" (ppr name)
-#endif
+ , varInfo = pprPanic "mkSysTyVar" (ppr name)
}
where
name = mkSysLocalName uniq SLIT("t")
newMutTyVar :: Name -> Kind -> IO TyVar
-newMutTyVar name kind =
- do loc <- newIORef Nothing
- return (Var { varName = name,
- realUnique = getKey (nameUnique name),
- varType = kind,
- varDetails = MutTyVar loc False})
+newMutTyVar name kind = newTyVar name kind False
newSigTyVar :: Name -> Kind -> IO TyVar
-newSigTyVar name kind =
- do loc <- newIORef Nothing
- return (Var { varName = name,
- realUnique = getKey (nameUnique name),
- varType = kind,
- varDetails = MutTyVar loc True})
+-- Type variables from type signatures are still mutable, because
+-- they may get unified with type variables from other signatures
+-- But they do contain a flag to distinguish them, so we can tell if
+-- we unify them with a non-type-variable.
+newSigTyVar name kind = newTyVar name kind True
+
+newTyVar name kind is_sig
+ = do loc <- newIORef Nothing
+ return (Var { varName = name
+ , realUnique = getKey (nameUnique name)
+ , varType = kind
+ , varDetails = MutTyVar loc is_sig
+ , varInfo = pprPanic "newMutTyVar" (ppr name)
+ })
readMutTyVar :: TyVar -> IO (Maybe Type)
readMutTyVar (Var {varDetails = MutTyVar loc _}) = readIORef loc
\begin{code}
mkUVar :: Unique -> UVar
-mkUVar unique = Var { varName = mkSysLocalName unique SLIT("u"),
- realUnique = getKey unique,
- varDetails = UVar }
+mkUVar unique = Var { varName = name
+ , realUnique = getKey unique
+ , varDetails = UVar
+ , varType = pprPanic "mkUVar (varType)" (ppr name)
+ , varInfo = pprPanic "mkUVar (varInfo)" (ppr name)
+ }
+ where name = mkSysLocalName unique SLIT("u")
mkNamedUVar :: Name -> UVar
mkNamedUVar name = Var { varName = name
, realUnique = getKey (nameUnique name)
, varDetails = UVar
-#ifdef DEBUG
- , varType = pprPanic "looking at Type of a uvar" (ppr name)
- , varInfo = pprPanic "looking at IdInfo of a uvar" (ppr name)
-#endif
+ , varType = pprPanic "mkNamedUVar (varType)" (ppr name)
+ , varInfo = pprPanic "mkNamedUVar (varInfo)" (ppr name)
}
\end{code}
setIdInfo var info = seqIdInfo info `seq` var {varInfo = info}
-- Try to avoid spack leaks by seq'ing
+zapIdInfo :: Id -> Id
+zapIdInfo var = var {varInfo = vanillaIdInfo}
+
modifyIdInfo :: (IdInfo -> IdInfo) -> Id -> Id
modifyIdInfo fn var@(Var {varInfo = info})
= seqIdInfo new_info `seq` var {varInfo = new_info}