% % (c) The AQUA Project, Glasgow University, 1994-1998 % \section[TysPrim]{Wired-in knowledge about primitive types} \begin{code}

    -- | This module defines TyCons that can't be expressed in Haskell.
    --   They are all, therefore, wired-in TyCons.  C.f module TysWiredIn
    module TysPrim(
    	alphaTyVars, betaTyVars, alphaTyVar, betaTyVar, gammaTyVar, deltaTyVar,
    	alphaTy, betaTy, gammaTy, deltaTy,
    	openAlphaTy, openBetaTy, openAlphaTyVar, openBetaTyVar, openAlphaTyVars,
            argAlphaTy, argAlphaTyVar, argBetaTy, argBetaTyVar,

    	primTyCons,

    	charPrimTyCon, 		charPrimTy,
    	intPrimTyCon,		intPrimTy,
    	wordPrimTyCon,		wordPrimTy,
    	addrPrimTyCon,		addrPrimTy,
    	floatPrimTyCon,		floatPrimTy,
    	doublePrimTyCon,	doublePrimTy,

    	statePrimTyCon,		mkStatePrimTy,
    	realWorldTyCon,		realWorldTy, realWorldStatePrimTy,

    	arrayPrimTyCon,			mkArrayPrimTy,
    	byteArrayPrimTyCon,		byteArrayPrimTy,
    	mutableArrayPrimTyCon,		mkMutableArrayPrimTy,
    	mutableByteArrayPrimTyCon,	mkMutableByteArrayPrimTy,
    	mutVarPrimTyCon,		mkMutVarPrimTy,

    	mVarPrimTyCon,			mkMVarPrimTy,
            tVarPrimTyCon,                  mkTVarPrimTy,
    	stablePtrPrimTyCon,		mkStablePtrPrimTy,
    	stableNamePrimTyCon,		mkStableNamePrimTy,
    	bcoPrimTyCon,			bcoPrimTy,
    	weakPrimTyCon,  		mkWeakPrimTy,
    	threadIdPrimTyCon,		threadIdPrimTy,

    	int32PrimTyCon,		int32PrimTy,
    	word32PrimTyCon,	word32PrimTy,

    	int64PrimTyCon,		int64PrimTy,
    	word64PrimTyCon,	word64PrimTy,

    	-- * Any
    	anyTyCon, anyTyConOfKind, anyTypeOfKind
      ) where

    #include "HsVersions.h"

    import Var		( TyVar, mkTyVar )
    import Name		( Name, BuiltInSyntax(..), mkInternalName, mkWiredInName )
    import OccName		( mkTcOcc )
    import OccName		( mkTyVarOccFS, mkTcOccFS )
    import TyCon		( TyCon, mkPrimTyCon, mkLiftedPrimTyCon, mkAnyTyCon )
    import Type
    import Coercion
    import SrcLoc
    import Unique		( mkAlphaTyVarUnique )
    import PrelNames
    import FastString
    import Outputable

    import Data.Char

\end{code} %************************************************************************ %* * \subsection{Primitive type constructors} %* * %************************************************************************ \begin{code}

    primTyCons :: [TyCon]
    primTyCons
      = [ addrPrimTyCon
        , arrayPrimTyCon
        , byteArrayPrimTyCon
        , charPrimTyCon
        , doublePrimTyCon
        , floatPrimTyCon
        , intPrimTyCon
        , int32PrimTyCon
        , int64PrimTyCon
        , bcoPrimTyCon
        , weakPrimTyCon
        , mutableArrayPrimTyCon
        , mutableByteArrayPrimTyCon
        , mVarPrimTyCon
        , tVarPrimTyCon
        , mutVarPrimTyCon
        , realWorldTyCon
        , stablePtrPrimTyCon
        , stableNamePrimTyCon
        , statePrimTyCon
        , threadIdPrimTyCon
        , wordPrimTyCon
        , word32PrimTyCon
        , word64PrimTyCon
        , anyTyCon
        ]

    mkPrimTc :: FastString -> Unique -> TyCon -> Name
    mkPrimTc fs unique tycon
      = mkWiredInName gHC_PRIM (mkTcOccFS fs)
    		  unique
    		  (ATyCon tycon)	-- Relevant TyCon
    		  UserSyntax		-- None are built-in syntax

    charPrimTyConName, intPrimTyConName, int32PrimTyConName, int64PrimTyConName, wordPrimTyConName, word32PrimTyConName, word64PrimTyConName, addrPrimTyConName, floatPrimTyConName, doublePrimTyConName, statePrimTyConName, realWorldTyConName, arrayPrimTyConName, byteArrayPrimTyConName, mutableArrayPrimTyConName, mutableByteArrayPrimTyConName, mutVarPrimTyConName, mVarPrimTyConName, tVarPrimTyConName, stablePtrPrimTyConName, stableNamePrimTyConName, bcoPrimTyConName, weakPrimTyConName, threadIdPrimTyConName :: Name
    charPrimTyConName    	      = mkPrimTc (fsLit "Char#") charPrimTyConKey charPrimTyCon
    intPrimTyConName     	      = mkPrimTc (fsLit "Int#") intPrimTyConKey  intPrimTyCon
    int32PrimTyConName	      = mkPrimTc (fsLit "Int32#") int32PrimTyConKey int32PrimTyCon
    int64PrimTyConName   	      = mkPrimTc (fsLit "Int64#") int64PrimTyConKey int64PrimTyCon
    wordPrimTyConName    	      = mkPrimTc (fsLit "Word#") wordPrimTyConKey wordPrimTyCon
    word32PrimTyConName  	      = mkPrimTc (fsLit "Word32#") word32PrimTyConKey word32PrimTyCon
    word64PrimTyConName  	      = mkPrimTc (fsLit "Word64#") word64PrimTyConKey word64PrimTyCon
    addrPrimTyConName    	      = mkPrimTc (fsLit "Addr#") addrPrimTyConKey addrPrimTyCon
    floatPrimTyConName   	      = mkPrimTc (fsLit "Float#") floatPrimTyConKey floatPrimTyCon
    doublePrimTyConName  	      = mkPrimTc (fsLit "Double#") doublePrimTyConKey doublePrimTyCon
    statePrimTyConName   	      = mkPrimTc (fsLit "State#") statePrimTyConKey statePrimTyCon
    realWorldTyConName   	      = mkPrimTc (fsLit "RealWorld") realWorldTyConKey realWorldTyCon
    arrayPrimTyConName   	      = mkPrimTc (fsLit "Array#") arrayPrimTyConKey arrayPrimTyCon
    byteArrayPrimTyConName	      = mkPrimTc (fsLit "ByteArray#") byteArrayPrimTyConKey byteArrayPrimTyCon
    mutableArrayPrimTyConName     = mkPrimTc (fsLit "MutableArray#") mutableArrayPrimTyConKey mutableArrayPrimTyCon
    mutableByteArrayPrimTyConName = mkPrimTc (fsLit "MutableByteArray#") mutableByteArrayPrimTyConKey mutableByteArrayPrimTyCon
    mutVarPrimTyConName	      = mkPrimTc (fsLit "MutVar#") mutVarPrimTyConKey mutVarPrimTyCon
    mVarPrimTyConName	      = mkPrimTc (fsLit "MVar#") mVarPrimTyConKey mVarPrimTyCon
    tVarPrimTyConName	      = mkPrimTc (fsLit "TVar#") tVarPrimTyConKey tVarPrimTyCon
    stablePtrPrimTyConName        = mkPrimTc (fsLit "StablePtr#") stablePtrPrimTyConKey stablePtrPrimTyCon
    stableNamePrimTyConName       = mkPrimTc (fsLit "StableName#") stableNamePrimTyConKey stableNamePrimTyCon
    bcoPrimTyConName 	      = mkPrimTc (fsLit "BCO#") bcoPrimTyConKey bcoPrimTyCon
    weakPrimTyConName  	      = mkPrimTc (fsLit "Weak#") weakPrimTyConKey weakPrimTyCon
    threadIdPrimTyConName  	      = mkPrimTc (fsLit "ThreadId#") threadIdPrimTyConKey threadIdPrimTyCon

\end{code} %************************************************************************ %* * \subsection{Support code} %* * %************************************************************************ alphaTyVars is a list of type variables for use in templates: ["a", "b", ..., "z", "t1", "t2", ... ] \begin{code}

    tyVarList :: Kind -> [TyVar]
    tyVarList kind = [ mkTyVar (mkInternalName (mkAlphaTyVarUnique u)
    				(mkTyVarOccFS (mkFastString name))
    			 	noSrcSpan) kind
    	         | u <- [2..],
    		   let name | c <= 'z'  = [c]
    		            | otherwise = 't':show u
    			    where c = chr (u-2 + ord 'a')
    	         ]

    alphaTyVars :: [TyVar]
    alphaTyVars = tyVarList liftedTypeKind

    betaTyVars :: [TyVar]
    betaTyVars = tail alphaTyVars

    alphaTyVar, betaTyVar, gammaTyVar, deltaTyVar :: TyVar
    (alphaTyVar:betaTyVar:gammaTyVar:deltaTyVar:_) = alphaTyVars

    alphaTys :: [Type]
    alphaTys = mkTyVarTys alphaTyVars
    alphaTy, betaTy, gammaTy, deltaTy :: Type
    (alphaTy:betaTy:gammaTy:deltaTy:_) = alphaTys

    	-- openAlphaTyVar is prepared to be instantiated
    	-- to a lifted or unlifted type variable.  It's used for the
    	-- result type for "error", so that we can have (error Int# "Help")
    openAlphaTyVars :: [TyVar]
    openAlphaTyVar, openBetaTyVar :: TyVar
    openAlphaTyVars@(openAlphaTyVar:openBetaTyVar:_) = tyVarList openTypeKind

    openAlphaTy, openBetaTy :: Type
    openAlphaTy = mkTyVarTy openAlphaTyVar
    openBetaTy  = mkTyVarTy openBetaTyVar

    argAlphaTyVar, argBetaTyVar :: TyVar
    (argAlphaTyVar : argBetaTyVar : _) = tyVarList argTypeKind
    argAlphaTy, argBetaTy :: Type
    argAlphaTy = mkTyVarTy argAlphaTyVar
    argBetaTy  = mkTyVarTy argBetaTyVar

\end{code} %************************************************************************ %* * Any %* * %************************************************************************ Note [Any types] ~~~~~~~~~~~~~~~~ The type constructor Any::* has these properties * It is defined in module GHC.Prim, and exported so that it is available to users. For this reason it's treated like any other primitive type: - has a fixed unique, anyTyConKey, - lives in the global name cache - built with TyCon.PrimTyCon * It is lifted, and hence represented by a pointer * It is inhabited by at least one value, namely bottom * You can unsafely coerce any lifted type to Ayny, and back. * It does not claim to be a *data* type, and that's important for the code generator, because the code gen may *enter* a data value but never enters a function value. * It is used to instantiate otherwise un-constrained type variables of kind * For example length Any [] See Note [Strangely-kinded void TyCons] In addition, we have a potentially-infinite family of types, one for each kind /other than/ *, needed to instantiate otherwise un-constrained type variables of kinds other than *. This is a bit like tuples; there is a potentially-infinite family. They have slightly different characteristics to Any::*: * They are built with TyCon.AnyTyCon * They have non-user-writable names like "Any(*->*)" * They are not exported by GHC.Prim * They are uninhabited (of course; not kind *) * They have a unique derived from their OccName (see Note [Uniques of Any]) * Their Names do not live in the global name cache Note [Uniques of Any] ~~~~~~~~~~~~~~~~~~~~~ Although Any(*->*), say, doesn't have a binding site, it still needs to have a Unique. Unlike tuples (which are also an infinite family) there is no convenient way to index them, so we use the Unique from their OccName instead. That should be unique, - both wrt each other, because their strings differ - and wrt any other Name, because Names get uniques with various 'char' tags, but the OccName of Any will get a Unique built with mkTcOccUnique, which has a particular 'char' tag; see Unique.mkTcOccUnique! Note [Strangely-kinded void TyCons] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ See Trac #959 for more examples When the type checker finds a type variable with no binding, which means it can be instantiated with an arbitrary type, it usually instantiates it to Void. Eg. length [] ===> length Any (Nil Any) But in really obscure programs, the type variable might have a kind other than *, so we need to invent a suitably-kinded type. This commit uses Any for kind * Any(*->*) for kind *->* etc \begin{code}

    anyTyConName :: Name
    anyTyConName = mkPrimTc (fsLit "Any") anyTyConKey anyTyCon

    anyTyCon :: TyCon
    anyTyCon = mkLiftedPrimTyCon anyTyConName liftedTypeKind 0 PtrRep

    anyTypeOfKind :: Kind -> Type
    anyTypeOfKind kind = mkTyConApp (anyTyConOfKind kind) []

    anyTyConOfKind :: Kind -> TyCon
    -- Map all superkinds of liftedTypeKind to liftedTypeKind
    anyTyConOfKind kind
      | liftedTypeKind `isSubKind` kind = anyTyCon
      | otherwise                       = tycon
      where
    	  -- Derive the name from the kind, thus:
    	  --     Any(*->*), Any(*->*->*)
    	  -- These are names that can't be written by the user,
    	  -- and are not allocated in the global name cache
        str = "Any" ++ showSDoc (pprParendKind kind)

        occ   = mkTcOcc str
        uniq  = getUnique occ  -- See Note [Uniques of Any]
        name  = mkWiredInName gHC_PRIM occ uniq (ATyCon tycon) UserSyntax
        tycon = mkAnyTyCon name kind

\end{code} %************************************************************************ %* * \subsection[TysPrim-basic]{Basic primitive types (@Char#@, @Int#@, etc.)} %* * %************************************************************************ \begin{code}

    -- only used herein
    pcPrimTyCon :: Name -> Int -> PrimRep -> TyCon
    pcPrimTyCon name arity rep
      = mkPrimTyCon name kind arity rep
      where
        kind        = mkArrowKinds (replicate arity liftedTypeKind) result_kind
        result_kind = unliftedTypeKind

    pcPrimTyCon0 :: Name -> PrimRep -> TyCon
    pcPrimTyCon0 name rep
      = mkPrimTyCon name result_kind 0 rep
      where
        result_kind = unliftedTypeKind

    charPrimTy :: Type
    charPrimTy	= mkTyConTy charPrimTyCon
    charPrimTyCon :: TyCon
    charPrimTyCon	= pcPrimTyCon0 charPrimTyConName WordRep

    intPrimTy :: Type
    intPrimTy	= mkTyConTy intPrimTyCon
    intPrimTyCon :: TyCon
    intPrimTyCon	= pcPrimTyCon0 intPrimTyConName IntRep

    int32PrimTy :: Type
    int32PrimTy	= mkTyConTy int32PrimTyCon
    int32PrimTyCon :: TyCon
    int32PrimTyCon	= pcPrimTyCon0 int32PrimTyConName IntRep

    int64PrimTy :: Type
    int64PrimTy	= mkTyConTy int64PrimTyCon
    int64PrimTyCon :: TyCon
    int64PrimTyCon	= pcPrimTyCon0 int64PrimTyConName Int64Rep

    wordPrimTy :: Type
    wordPrimTy	= mkTyConTy wordPrimTyCon
    wordPrimTyCon :: TyCon
    wordPrimTyCon	= pcPrimTyCon0 wordPrimTyConName WordRep

    word32PrimTy :: Type
    word32PrimTy	= mkTyConTy word32PrimTyCon
    word32PrimTyCon :: TyCon
    word32PrimTyCon	= pcPrimTyCon0 word32PrimTyConName WordRep

    word64PrimTy :: Type
    word64PrimTy	= mkTyConTy word64PrimTyCon
    word64PrimTyCon :: TyCon
    word64PrimTyCon	= pcPrimTyCon0 word64PrimTyConName Word64Rep

    addrPrimTy :: Type
    addrPrimTy	= mkTyConTy addrPrimTyCon
    addrPrimTyCon :: TyCon
    addrPrimTyCon	= pcPrimTyCon0 addrPrimTyConName AddrRep

    floatPrimTy	:: Type
    floatPrimTy	= mkTyConTy floatPrimTyCon
    floatPrimTyCon :: TyCon
    floatPrimTyCon	= pcPrimTyCon0 floatPrimTyConName FloatRep

    doublePrimTy :: Type
    doublePrimTy	= mkTyConTy doublePrimTyCon
    doublePrimTyCon	:: TyCon
    doublePrimTyCon	= pcPrimTyCon0 doublePrimTyConName DoubleRep

\end{code} %************************************************************************ %* * \subsection[TysPrim-state]{The @State#@ type (and @_RealWorld@ types)} %* * %************************************************************************ State# is the primitive, unlifted type of states. It has one type parameter, thus State# RealWorld or State# s where s is a type variable. The only purpose of the type parameter is to keep different state threads separate. It is represented by nothing at all. \begin{code}

    mkStatePrimTy :: Type -> Type
    mkStatePrimTy ty = mkTyConApp statePrimTyCon [ty]
    statePrimTyCon :: TyCon
    statePrimTyCon	 = pcPrimTyCon statePrimTyConName 1 VoidRep

\end{code} RealWorld is deeply magical. It is *primitive*, but it is not *unlifted* (hence ptrArg). We never manipulate values of type RealWorld; it's only used in the type system, to parameterise State#. \begin{code}

    realWorldTyCon :: TyCon
    realWorldTyCon = mkLiftedPrimTyCon realWorldTyConName liftedTypeKind 0 PtrRep
    realWorldTy :: Type
    realWorldTy	     = mkTyConTy realWorldTyCon
    realWorldStatePrimTy :: Type
    realWorldStatePrimTy = mkStatePrimTy realWorldTy	-- State# RealWorld

\end{code} Note: the ``state-pairing'' types are not truly primitive, so they are defined in \tr{TysWiredIn.lhs}, not here. %************************************************************************ %* * \subsection[TysPrim-arrays]{The primitive array types} %* * %************************************************************************ \begin{code}

    arrayPrimTyCon, mutableArrayPrimTyCon, mutableByteArrayPrimTyCon,
        byteArrayPrimTyCon :: TyCon
    arrayPrimTyCon		  = pcPrimTyCon  arrayPrimTyConName	       1 PtrRep
    mutableArrayPrimTyCon	  = pcPrimTyCon  mutableArrayPrimTyConName     2 PtrRep
    mutableByteArrayPrimTyCon = pcPrimTyCon  mutableByteArrayPrimTyConName 1 PtrRep
    byteArrayPrimTyCon	  = pcPrimTyCon0 byteArrayPrimTyConName	         PtrRep

    mkArrayPrimTy :: Type -> Type
    mkArrayPrimTy elt    	    = mkTyConApp arrayPrimTyCon [elt]
    byteArrayPrimTy :: Type
    byteArrayPrimTy	    	    = mkTyConTy byteArrayPrimTyCon
    mkMutableArrayPrimTy :: Type -> Type -> Type
    mkMutableArrayPrimTy s elt  = mkTyConApp mutableArrayPrimTyCon [s, elt]
    mkMutableByteArrayPrimTy :: Type -> Type
    mkMutableByteArrayPrimTy s  = mkTyConApp mutableByteArrayPrimTyCon [s]

\end{code} %************************************************************************ %* * \subsection[TysPrim-mut-var]{The mutable variable type} %* * %************************************************************************ \begin{code}

    mutVarPrimTyCon :: TyCon
    mutVarPrimTyCon = pcPrimTyCon mutVarPrimTyConName 2 PtrRep

    mkMutVarPrimTy :: Type -> Type -> Type
    mkMutVarPrimTy s elt 	    = mkTyConApp mutVarPrimTyCon [s, elt]

\end{code} %************************************************************************ %* * \subsection[TysPrim-synch-var]{The synchronizing variable type} %* * %************************************************************************ \begin{code}

    mVarPrimTyCon :: TyCon
    mVarPrimTyCon = pcPrimTyCon mVarPrimTyConName 2 PtrRep

    mkMVarPrimTy :: Type -> Type -> Type
    mkMVarPrimTy s elt 	    = mkTyConApp mVarPrimTyCon [s, elt]

\end{code} %************************************************************************ %* * \subsection[TysPrim-stm-var]{The transactional variable type} %* * %************************************************************************ \begin{code}

    tVarPrimTyCon :: TyCon
    tVarPrimTyCon = pcPrimTyCon tVarPrimTyConName 2 PtrRep

    mkTVarPrimTy :: Type -> Type -> Type
    mkTVarPrimTy s elt = mkTyConApp tVarPrimTyCon [s, elt]

\end{code} %************************************************************************ %* * \subsection[TysPrim-stable-ptrs]{The stable-pointer type} %* * %************************************************************************ \begin{code}

    stablePtrPrimTyCon :: TyCon
    stablePtrPrimTyCon = pcPrimTyCon stablePtrPrimTyConName 1 AddrRep

    mkStablePtrPrimTy :: Type -> Type
    mkStablePtrPrimTy ty = mkTyConApp stablePtrPrimTyCon [ty]

\end{code} %************************************************************************ %* * \subsection[TysPrim-stable-names]{The stable-name type} %* * %************************************************************************ \begin{code}

    stableNamePrimTyCon :: TyCon
    stableNamePrimTyCon = pcPrimTyCon stableNamePrimTyConName 1 PtrRep

    mkStableNamePrimTy :: Type -> Type
    mkStableNamePrimTy ty = mkTyConApp stableNamePrimTyCon [ty]

\end{code} %************************************************************************ %* * \subsection[TysPrim-BCOs]{The ``bytecode object'' type} %* * %************************************************************************ \begin{code}

    bcoPrimTy    :: Type
    bcoPrimTy    = mkTyConTy bcoPrimTyCon
    bcoPrimTyCon :: TyCon
    bcoPrimTyCon = pcPrimTyCon0 bcoPrimTyConName PtrRep

\end{code} %************************************************************************ %* * \subsection[TysPrim-Weak]{The ``weak pointer'' type} %* * %************************************************************************ \begin{code}

    weakPrimTyCon :: TyCon
    weakPrimTyCon = pcPrimTyCon weakPrimTyConName 1 PtrRep

    mkWeakPrimTy :: Type -> Type
    mkWeakPrimTy v = mkTyConApp weakPrimTyCon [v]

\end{code} %************************************************************************ %* * \subsection[TysPrim-thread-ids]{The ``thread id'' type} %* * %************************************************************************ A thread id is represented by a pointer to the TSO itself, to ensure that they are always unique and we can always find the TSO for a given thread id. However, this has the unfortunate consequence that a ThreadId# for a given thread is treated as a root by the garbage collector and can keep TSOs around for too long. Hence the programmer API for thread manipulation uses a weak pointer to the thread id internally. \begin{code}

    threadIdPrimTy :: Type
    threadIdPrimTy    = mkTyConTy threadIdPrimTyCon
    threadIdPrimTyCon :: TyCon
    threadIdPrimTyCon = pcPrimTyCon0 threadIdPrimTyConName PtrRep

\end{code}