X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fprelude%2FTysPrim.lhs;h=4c70bcb7452d30d018b7fe950cf43d10bbac81c8;hp=a5d93350bb4c1fc2bc16e839c3e2e390145c4954;hb=b2524b3960999fffdb3767900f58825903f6560f;hpb=841e81e28f8cc711f624fdca122219a5bbde2fae;ds=sidebyside diff --git a/compiler/prelude/TysPrim.lhs b/compiler/prelude/TysPrim.lhs index a5d9335..4c70bcb 100644 --- a/compiler/prelude/TysPrim.lhs +++ b/compiler/prelude/TysPrim.lhs @@ -14,7 +14,22 @@ module TysPrim( openAlphaTy, openBetaTy, openAlphaTyVar, openBetaTyVar, openAlphaTyVars, argAlphaTy, argAlphaTyVar, argBetaTy, argBetaTyVar, - primTyCons, + -- Kind constructors... + tySuperKindTyCon, tySuperKind, + liftedTypeKindTyCon, openTypeKindTyCon, unliftedTypeKindTyCon, + argTypeKindTyCon, ubxTupleKindTyCon, + + tySuperKindTyConName, liftedTypeKindTyConName, + openTypeKindTyConName, unliftedTypeKindTyConName, + ubxTupleKindTyConName, argTypeKindTyConName, + + -- Kinds + liftedTypeKind, unliftedTypeKind, openTypeKind, + argTypeKind, ubxTupleKind, + mkArrowKind, mkArrowKinds, isCoercionKind, + + funTyCon, funTyConName, + primTyCons, charPrimTyCon, charPrimTy, intPrimTyCon, intPrimTy, @@ -44,7 +59,9 @@ module TysPrim( word32PrimTyCon, word32PrimTy, int64PrimTyCon, int64PrimTy, - word64PrimTyCon, word64PrimTy, + word64PrimTyCon, word64PrimTy, + + eqPredPrimTyCon, -- ty1 ~ ty2 -- * Any anyTyCon, anyTyConOfKind, anyTypeOfKind @@ -54,11 +71,10 @@ module TysPrim( import Var ( TyVar, mkTyVar ) import Name ( Name, BuiltInSyntax(..), mkInternalName, mkWiredInName ) -import OccName ( mkTcOcc ) -import OccName ( mkTyVarOccFS, mkTcOccFS ) -import TyCon ( TyCon, mkPrimTyCon, mkLiftedPrimTyCon, mkAnyTyCon ) +import OccName ( mkTcOcc,mkTyVarOccFS, mkTcOccFS ) +import TyCon +import TypeRep import Type -import TypeRep ( ecKind ) import Coercion import SrcLoc import Unique ( mkAlphaTyVarUnique ) @@ -103,6 +119,7 @@ primTyCons , word32PrimTyCon , word64PrimTyCon , anyTyCon + , eqPredPrimTyCon ] mkPrimTc :: FastString -> Unique -> TyCon -> Name @@ -112,7 +129,7 @@ mkPrimTc fs unique tycon (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, intPrimTyConName, int32PrimTyConName, int64PrimTyConName, wordPrimTyConName, word32PrimTyConName, word64PrimTyConName, addrPrimTyConName, floatPrimTyConName, doublePrimTyConName, statePrimTyConName, realWorldTyConName, arrayPrimTyConName, byteArrayPrimTyConName, mutableArrayPrimTyConName, mutableByteArrayPrimTyConName, mutVarPrimTyConName, mVarPrimTyConName, tVarPrimTyConName, stablePtrPrimTyConName, stableNamePrimTyConName, bcoPrimTyConName, weakPrimTyConName, threadIdPrimTyConName, eqPredPrimTyConName :: Name charPrimTyConName = mkPrimTc (fsLit "Char#") charPrimTyConKey charPrimTyCon intPrimTyConName = mkPrimTc (fsLit "Int#") intPrimTyConKey intPrimTyCon int32PrimTyConName = mkPrimTc (fsLit "Int32#") int32PrimTyConKey int32PrimTyCon @@ -123,8 +140,9 @@ word64PrimTyConName = mkPrimTc (fsLit "Word64#") word64PrimTyConKey word 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 +statePrimTyConName = mkPrimTc (fsLit "State#") statePrimTyConKey statePrimTyCon +eqPredPrimTyConName = mkPrimTc (fsLit "~") eqPredPrimTyConKey eqPredPrimTyCon +realWorldTyConName = mkPrimTc (fsLit "RealWorld") realWorldTyConKey realWorldTyCon arrayPrimTyConName = mkPrimTc (fsLit "Array#") arrayPrimTyConKey arrayPrimTyCon byteArrayPrimTyConName = mkPrimTc (fsLit "ByteArray#") byteArrayPrimTyConKey byteArrayPrimTyCon mutableArrayPrimTyConName = mkPrimTc (fsLit "MutableArray#") mutableArrayPrimTyConKey mutableArrayPrimTyCon @@ -197,109 +215,95 @@ argBetaTy = mkTyVarTy argBetaTyVar %************************************************************************ %* * - Any + FunTyCon %* * %************************************************************************ -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 +\begin{code} +funTyConName :: Name +funTyConName = mkPrimTyConName (fsLit "(->)") funTyConKey funTyCon + +funTyCon :: TyCon +funTyCon = mkFunTyCon funTyConName (mkArrowKinds [argTypeKind, openTypeKind] liftedTypeKind) + -- You might think that (->) should have type (?? -> ? -> *), and you'd be right + -- But if we do that we get kind errors when saying + -- instance Control.Arrow (->) + -- becuase the expected kind is (*->*->*). The trouble is that the + -- expected/actual stuff in the unifier does not go contra-variant, whereas + -- the kind sub-typing does. Sigh. It really only matters if you use (->) in + -- a prefix way, thus: (->) Int# Int#. And this is unusual. + -- because they are never in scope in the source +\end{code} -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) +%************************************************************************ +%* * + Kinds +%* * +%************************************************************************ -But in really obscure programs, the type variable might have a kind -other than *, so we need to invent a suitably-kinded type. +\begin{code} +-- | See "Type#kind_subtyping" for details of the distinction between the 'Kind' 'TyCon's +tySuperKindTyCon, liftedTypeKindTyCon, + openTypeKindTyCon, unliftedTypeKindTyCon, + ubxTupleKindTyCon, argTypeKindTyCon + :: TyCon +tySuperKindTyConName, liftedTypeKindTyConName, + openTypeKindTyConName, unliftedTypeKindTyConName, + ubxTupleKindTyConName, argTypeKindTyConName + :: Name + +tySuperKindTyCon = mkSuperKindTyCon tySuperKindTyConName +liftedTypeKindTyCon = mkKindTyCon liftedTypeKindTyConName tySuperKind +openTypeKindTyCon = mkKindTyCon openTypeKindTyConName tySuperKind +unliftedTypeKindTyCon = mkKindTyCon unliftedTypeKindTyConName tySuperKind +ubxTupleKindTyCon = mkKindTyCon ubxTupleKindTyConName tySuperKind +argTypeKindTyCon = mkKindTyCon argTypeKindTyConName tySuperKind + +-------------------------- +-- ... and now their names + +tySuperKindTyConName = mkPrimTyConName (fsLit "BOX") tySuperKindTyConKey tySuperKindTyCon +liftedTypeKindTyConName = mkPrimTyConName (fsLit "*") liftedTypeKindTyConKey liftedTypeKindTyCon +openTypeKindTyConName = mkPrimTyConName (fsLit "?") openTypeKindTyConKey openTypeKindTyCon +unliftedTypeKindTyConName = mkPrimTyConName (fsLit "#") unliftedTypeKindTyConKey unliftedTypeKindTyCon +ubxTupleKindTyConName = mkPrimTyConName (fsLit "(#)") ubxTupleKindTyConKey ubxTupleKindTyCon +argTypeKindTyConName = mkPrimTyConName (fsLit "??") argTypeKindTyConKey argTypeKindTyCon + +mkPrimTyConName :: FastString -> Unique -> TyCon -> Name +mkPrimTyConName occ key tycon = mkWiredInName gHC_PRIM (mkTcOccFS occ) + key + (ATyCon tycon) + BuiltInSyntax + -- All of the super kinds and kinds are defined in Prim and use BuiltInSyntax, + -- because they are never in scope in the source +\end{code} -This commit uses - Any for kind * - Any(*->*) for kind *->* - etc \begin{code} -anyTyConName :: Name -anyTyConName = mkPrimTc (fsLit "Any") anyTyConKey anyTyCon +kindTyConType :: TyCon -> Type +kindTyConType kind = TyConApp kind [] -anyTyCon :: TyCon -anyTyCon = mkLiftedPrimTyCon anyTyConName liftedTypeKind 0 PtrRep +-- | See "Type#kind_subtyping" for details of the distinction between these 'Kind's +liftedTypeKind, unliftedTypeKind, openTypeKind, argTypeKind, ubxTupleKind :: Kind -anyTypeOfKind :: Kind -> Type -anyTypeOfKind kind = mkTyConApp (anyTyConOfKind kind) [] +liftedTypeKind = kindTyConType liftedTypeKindTyCon +unliftedTypeKind = kindTyConType unliftedTypeKindTyCon +openTypeKind = kindTyConType openTypeKindTyCon +argTypeKind = kindTyConType argTypeKindTyCon +ubxTupleKind = kindTyConType ubxTupleKindTyCon -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) +-- | Given two kinds @k1@ and @k2@, creates the 'Kind' @k1 -> k2@ +mkArrowKind :: Kind -> Kind -> Kind +mkArrowKind k1 k2 = FunTy k1 k2 - 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} +-- | Iterated application of 'mkArrowKind' +mkArrowKinds :: [Kind] -> Kind -> Kind +mkArrowKinds arg_kinds result_kind = foldr mkArrowKind result_kind arg_kinds +tySuperKind :: SuperKind +tySuperKind = kindTyConType tySuperKindTyCon +\end{code} %************************************************************************ %* * @@ -380,6 +384,22 @@ doublePrimTyCon = pcPrimTyCon0 doublePrimTyConName DoubleRep %* * %************************************************************************ +Note [The (~) TyCon) +~~~~~~~~~~~~~~~~~~~~ +There is a perfectly ordinary type constructor (~) that represents the type +of coercions (which, remember, are values). For example + Refl Int :: Int ~ Int + +Atcually it is not quite "perfectly ordinary" because it is kind-polymorphic: + Refl Maybe :: Maybe ~ Maybe + +So the true kind of (~) :: forall k. k -> k -> #. But we don't have +polymorphic kinds (yet). However, (~) really only appears saturated in +which case there is no problem in finding the kind of (ty1 ~ ty2). So +we check that in CoreLint (and, in an assertion, in Kind.typeKind). + +Note [The State# TyCon] +~~~~~~~~~~~~~~~~~~~~~~~ State# is the primitive, unlifted type of states. It has one type parameter, thus State# RealWorld @@ -392,8 +412,13 @@ 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 :: TyCon -- See Note [The State# TyCon] statePrimTyCon = pcPrimTyCon statePrimTyConName 1 VoidRep + +eqPredPrimTyCon :: TyCon -- The representation type for equality predicates + -- See Note [The (~) TyCon] +eqPredPrimTyCon = pcPrimTyCon eqPredPrimTyConName 2 VoidRep \end{code} RealWorld is deeply magical. It is *primitive*, but it is not @@ -412,7 +437,6 @@ realWorldStatePrimTy = mkStatePrimTy realWorldTy -- State# RealWorld 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} @@ -555,3 +579,110 @@ threadIdPrimTy = mkTyConTy threadIdPrimTyCon threadIdPrimTyCon :: TyCon threadIdPrimTyCon = pcPrimTyCon0 threadIdPrimTyConName PtrRep \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 + | isLiftedTypeKind 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}