X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fprelude%2FTysPrim.lhs;h=4c70bcb7452d30d018b7fe950cf43d10bbac81c8;hp=c69bea12b1ffda115982597b709a8380b310b991;hb=b2524b3960999fffdb3767900f58825903f6560f;hpb=708533dec3189bb624c8467627055a78de07e52b diff --git a/compiler/prelude/TysPrim.lhs b/compiler/prelude/TysPrim.lhs index c69bea1..4c70bcb 100644 --- a/compiler/prelude/TysPrim.lhs +++ b/compiler/prelude/TysPrim.lhs @@ -1,15 +1,35 @@ % % (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, + alphaTy, betaTy, gammaTy, deltaTy, ecTyVars, openAlphaTy, openBetaTy, openAlphaTyVar, openBetaTyVar, openAlphaTyVars, + argAlphaTy, argAlphaTyVar, argBetaTy, argBetaTyVar, + + -- Kind constructors... + tySuperKindTyCon, tySuperKind, + liftedTypeKindTyCon, openTypeKindTyCon, unliftedTypeKindTyCon, + argTypeKindTyCon, ubxTupleKindTyCon, + + tySuperKindTyConName, liftedTypeKindTyConName, + openTypeKindTyConName, unliftedTypeKindTyConName, + ubxTupleKindTyConName, argTypeKindTyConName, - primTyCons, + -- Kinds + liftedTypeKind, unliftedTypeKind, openTypeKind, + argTypeKind, ubxTupleKind, + mkArrowKind, mkArrowKinds, isCoercionKind, + + funTyCon, funTyConName, + primTyCons, charPrimTyCon, charPrimTy, intPrimTyCon, intPrimTy, @@ -39,22 +59,26 @@ module TysPrim( word32PrimTyCon, word32PrimTy, int64PrimTyCon, int64PrimTy, - word64PrimTyCon, word64PrimTy, + word64PrimTyCon, word64PrimTy, + + eqPredPrimTyCon, -- ty1 ~ ty2 - anyPrimTyCon, anyPrimTy, anyPrimTyCon1, mkAnyPrimTyCon + -- * Any + anyTyCon, anyTyConOfKind, anyTypeOfKind ) where #include "HsVersions.h" import Var ( TyVar, mkTyVar ) import Name ( Name, BuiltInSyntax(..), mkInternalName, mkWiredInName ) -import OccName ( mkTyVarOccFS, mkTcOccFS ) -import TyCon ( TyCon, mkPrimTyCon, mkLiftedPrimTyCon ) +import OccName ( mkTcOcc,mkTyVarOccFS, mkTcOccFS ) +import TyCon +import TypeRep import Type +import Coercion import SrcLoc -import Unique ( mkAlphaTyVarUnique, pprUnique ) +import Unique ( mkAlphaTyVarUnique ) import PrelNames -import StaticFlags import FastString import Outputable @@ -94,7 +118,8 @@ primTyCons , wordPrimTyCon , word32PrimTyCon , word64PrimTyCon - , anyPrimTyCon, anyPrimTyCon1 + , anyTyCon + , eqPredPrimTyCon ] mkPrimTc :: FastString -> Unique -> TyCon -> Name @@ -104,7 +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, anyPrimTyConName, anyPrimTyCon1Name :: 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 @@ -115,8 +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 @@ -129,8 +155,6 @@ stableNamePrimTyConName = mkPrimTc (fsLit "StableName#") stableNamePrimTyC bcoPrimTyConName = mkPrimTc (fsLit "BCO#") bcoPrimTyConKey bcoPrimTyCon weakPrimTyConName = mkPrimTc (fsLit "Weak#") weakPrimTyConKey weakPrimTyCon threadIdPrimTyConName = mkPrimTc (fsLit "ThreadId#") threadIdPrimTyConKey threadIdPrimTyCon -anyPrimTyConName = mkPrimTc (fsLit "Any") anyPrimTyConKey anyPrimTyCon -anyPrimTyCon1Name = mkPrimTc (fsLit "Any1") anyPrimTyCon1Key anyPrimTyCon1 \end{code} %************************************************************************ @@ -153,6 +177,9 @@ tyVarList kind = [ mkTyVar (mkInternalName (mkAlphaTyVarUnique u) where c = chr (u-2 + ord 'a') ] +ecTyVars :: [TyVar] +ecTyVars = tyVarList ecKind + alphaTyVars :: [TyVar] alphaTyVars = tyVarList liftedTypeKind @@ -176,10 +203,108 @@ openAlphaTyVars@(openAlphaTyVar:openBetaTyVar:_) = tyVarList openTypeKind openAlphaTy, openBetaTy :: Type openAlphaTy = mkTyVarTy openAlphaTyVar -openBetaTy = mkTyVarTy openBetaTyVar +openBetaTy = mkTyVarTy openBetaTyVar + +argAlphaTyVar, argBetaTyVar :: TyVar +(argAlphaTyVar : argBetaTyVar : _) = tyVarList argTypeKind +argAlphaTy, argBetaTy :: Type +argAlphaTy = mkTyVarTy argAlphaTyVar +argBetaTy = mkTyVarTy argBetaTyVar +\end{code} + + +%************************************************************************ +%* * + FunTyCon +%* * +%************************************************************************ + +\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} + + +%************************************************************************ +%* * + Kinds +%* * +%************************************************************************ + +\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} +\begin{code} +kindTyConType :: TyCon -> Type +kindTyConType kind = TyConApp kind [] + +-- | See "Type#kind_subtyping" for details of the distinction between these 'Kind's +liftedTypeKind, unliftedTypeKind, openTypeKind, argTypeKind, ubxTupleKind :: Kind + +liftedTypeKind = kindTyConType liftedTypeKindTyCon +unliftedTypeKind = kindTyConType unliftedTypeKindTyCon +openTypeKind = kindTyConType openTypeKindTyCon +argTypeKind = kindTyConType argTypeKindTyCon +ubxTupleKind = kindTyConType ubxTupleKindTyCon + +-- | Given two kinds @k1@ and @k2@, creates the 'Kind' @k1 -> k2@ +mkArrowKind :: Kind -> Kind -> Kind +mkArrowKind k1 k2 = FunTy k1 k2 + +-- | 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} + %************************************************************************ %* * \subsection[TysPrim-basic]{Basic primitive types (@Char#@, @Int#@, etc.)} @@ -259,6 +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 @@ -271,8 +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 @@ -291,55 +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. - -%************************************************************************ -%* * - Any -%* * -%************************************************************************ - -The type constructor Any is type to which you can unsafely coerce any -lifted type, and back. - - * It is lifted, and hence represented by a pointer - - * 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's also used to instantiate un-constrained type variables after type -checking. For example - length Any [] -Annoyingly, we sometimes need Anys of other kinds, such as (*->*) etc. -This is a bit like tuples. We define a couple of useful ones here, -and make others up on the fly. If any of these others end up being exported -into interface files, we'll get a crash; at least until we add interface-file -syntax to support them. - -\begin{code} -anyPrimTy :: Type -anyPrimTy = mkTyConApp anyPrimTyCon [] - -anyPrimTyCon :: TyCon -- Kind * -anyPrimTyCon = mkLiftedPrimTyCon anyPrimTyConName liftedTypeKind 0 PtrRep - -anyPrimTyCon1 :: TyCon -- Kind *->* -anyPrimTyCon1 = mkLiftedPrimTyCon anyPrimTyCon1Name kind 0 PtrRep - where - kind = mkArrowKind liftedTypeKind liftedTypeKind - -mkAnyPrimTyCon :: Unique -> Kind -> TyCon --- Grotesque hack alert: the client gives the unique; so equality won't work -mkAnyPrimTyCon unique kind - = WARN( opt_PprStyle_Debug, ptext (sLit "Urk! Inventing strangely-kinded Any TyCon:") <+> ppr unique <+> ppr kind ) - -- See Note [Strangely-kinded void TyCons] in TcHsSyn - tycon - where - name = mkPrimTc (mkFastString ("Any" ++ showSDoc (pprUnique unique))) unique tycon - tycon = mkLiftedPrimTyCon name kind 0 PtrRep -\end{code} - - %************************************************************************ %* * \subsection[TysPrim-arrays]{The primitive array types} @@ -482,3 +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}