\begin{code}
module TyCon(
- TyCon, ArgVrcs, FieldLabel,
+ TyCon, FieldLabel,
PrimRep(..),
tyConPrimRep,
isFunTyCon, isUnLiftedTyCon, isProductTyCon,
isAlgTyCon, isDataTyCon, isSynTyCon, isNewTyCon, isPrimTyCon,
- isEnumerationTyCon,
+ isEnumerationTyCon, isGadtSyntaxTyCon,
isTupleTyCon, isUnboxedTupleTyCon, isBoxedTupleTyCon, tupleTyConBoxity,
- isRecursiveTyCon, newTyConRep, newTyConRhs,
- isHiBootTyCon,
+ isRecursiveTyCon, newTyConRep, newTyConRhs, newTyConCo,
+ isHiBootTyCon, isSuperKindTyCon,
+ isCoercionTyCon_maybe, isCoercionTyCon,
- tcExpandTyCon_maybe, coreExpandTyCon_maybe,
+ tcExpandTyCon_maybe, coreExpandTyCon_maybe, stgExpandTyCon_maybe,
makeTyConAbstract, isAbstractTyCon,
mkClassTyCon,
mkFunTyCon,
mkPrimTyCon,
+ mkVoidPrimTyCon,
mkLiftedPrimTyCon,
mkTupleTyCon,
mkSynTyCon,
+ mkSuperKindTyCon,
+ mkCoercionTyCon,
tyConName,
tyConKind,
tyConUnique,
tyConTyVars,
- tyConArgVrcs,
algTyConRhs, tyConDataCons, tyConDataCons_maybe, tyConFamilySize,
tyConSelIds,
tyConStupidTheta,
#include "HsVersions.h"
-import {-# SOURCE #-} TypeRep ( Type, PredType )
- -- Should just be Type(Type), but this fails due to bug present up to
- -- and including 4.02 involving slurping of hi-boot files. Bug is now fixed.
-
+import {-# SOURCE #-} TypeRep ( Kind, Type, Coercion, PredType )
import {-# SOURCE #-} DataCon ( DataCon, isVanillaDataCon )
-
import Var ( TyVar, Id )
import Class ( Class )
-import Kind ( Kind )
import BasicTypes ( Arity, RecFlag(..), Boxity(..), isBoxed )
import Name ( Name, nameUnique, NamedThing(getName) )
import PrelNames ( Unique, Uniquable(..) )
tyConTyVars :: [TyVar], -- Scopes over (a) the [PredType] in AlgTyConRhs.DataTyCon
-- (b) the cached types in AlgTyConRhs.NewTyCon
-- But not over the data constructors
- argVrcs :: ArgVrcs,
-
algTcSelIds :: [Id], -- Its record selectors (empty if none):
+ algTcGadtSyntax :: Bool, -- True <=> the data type was declared using GADT syntax
+ -- That doesn't mean it's a true GADT; only that the "where"
+ -- form was used. This field is used only to guide
+ -- pretty-printinng
algTcStupidTheta :: [PredType], -- The "stupid theta" for the data type
-- (always empty for GADTs)
-- Just cl if this tycon came from a class declaration
}
+ | TupleTyCon {
+ tyConUnique :: Unique,
+ tyConName :: Name,
+ tyConKind :: Kind,
+ tyConArity :: Arity,
+ tyConBoxed :: Boxity,
+ tyConTyVars :: [TyVar],
+ dataCon :: DataCon,
+ hasGenerics :: Bool
+ }
+
+ | SynTyCon {
+ tyConUnique :: Unique,
+ tyConName :: Name,
+ tyConKind :: Kind,
+ tyConArity :: Arity,
+
+ tyConTyVars :: [TyVar], -- Bound tyvars
+ synTcRhs :: Type -- Right-hand side, mentioning these type vars.
+ -- Acts as a template for the expansion when
+ -- the tycon is applied to some types.
+ }
+
| PrimTyCon { -- Primitive types; cannot be defined in Haskell
-- Now includes foreign-imported types
+ -- Also includes Kinds
tyConUnique :: Unique,
tyConName :: Name,
tyConKind :: Kind,
tyConArity :: Arity,
- argVrcs :: ArgVrcs,
primTyConRep :: PrimRep,
-- Many primitive tycons are unboxed, but some are
tyConExtName :: Maybe FastString -- Just xx for foreign-imported types
}
- | TupleTyCon {
+ | CoercionTyCon { -- E.g. (:=:), sym, trans, left, right
+ -- INVARIANT: coercions are always fully applied
tyConUnique :: Unique,
- tyConName :: Name,
- tyConKind :: Kind,
+ tyConName :: Name,
tyConArity :: Arity,
- tyConBoxed :: Boxity,
- tyConTyVars :: [TyVar],
- dataCon :: DataCon,
- hasGenerics :: Bool
+ coKindFun :: [Type] -> Kind
+ }
+
+ | SuperKindTyCon { -- Super Kinds, TY (box) and CO (diamond).
+ -- They have no kind; and arity zero
+ tyConUnique :: Unique,
+ tyConName :: Name
}
- | SynTyCon {
- tyConUnique :: Unique,
- tyConName :: Name,
- tyConKind :: Kind,
- tyConArity :: Arity,
+type KindCon = TyCon
- tyConTyVars :: [TyVar], -- Bound tyvars
- synTcRhs :: Type, -- Right-hand side, mentioning these type vars.
- -- Acts as a template for the expansion when
- -- the tycon is applied to some types.
- argVrcs :: ArgVrcs
- }
+type SuperKindCon = TyCon
type FieldLabel = Name
-type ArgVrcs = [(Bool,Bool)] -- Tyvar variance info: [(occPos,occNeg)]
- -- [] means "no information, assume the worst"
-
data AlgTyConRhs
= AbstractTyCon -- We know nothing about this data type, except
-- that it's represented by a pointer
nt_rhs :: Type, -- Cached: the argument type of the constructor
-- = the representation type of the tycon
+ -- The free tyvars of this type are the tyConTyVars
+
+ nt_co :: TyCon, -- The coercion used to create the newtype
+ -- from the representation
+ -- See Note [Newtype coercions]
nt_etad_rhs :: ([TyVar], Type) ,
-- The same again, but this time eta-reduced
visibleDataCons (NewTyCon{ data_con = c }) = [c]
\end{code}
+Note [Newtype coercions]
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+The NewTyCon field nt_co is a a TyCon (a coercion constructor in fact)
+which is used for coercing from the representation type of the
+newtype, to the newtype itself. For example,
+
+ newtype T a = MkT [a]
+
+the NewTyCon for T will contain nt_co = CoT where CoT t : [t] :=: T t.
+This TyCon is a CoercionTyCon, so it does not have a kind on its own;
+it basically has its own typing rule for the fully-applied version.
+If the newtype T has k type variables then CoT has arity k.
+
+In the paper we'd write
+ axiom CoT : (forall t. [t]) :=: (forall t. T t)
+and then when we used CoT at a particular type, s, we'd say
+ CoT @ s
+which encodes as (TyConApp instCoercionTyCon [TyConApp CoT [], s])
+
+But in GHC we instead make CoT into a new piece of type syntax
+(like instCoercionTyCon, symCoercionTyCon etc), which must always
+be saturated, but which encodes as
+ TyConAp CoT [s]
+In the vocabulary of the paper it's as if we had axiom declarations
+like
+ axiom CoT t : ([t] :=: T t)
+
Note [Newtype eta]
~~~~~~~~~~~~~~~~~~
Consider
-- This is the making of a TyCon. Just the same as the old mkAlgTyCon,
-- but now you also have to pass in the generic information about the type
-- constructor - you can get hold of it easily (see Generics module)
-mkAlgTyCon name kind tyvars argvrcs stupid rhs sel_ids is_rec gen_info
+mkAlgTyCon name kind tyvars stupid rhs sel_ids is_rec gen_info gadt_syn
= AlgTyCon {
tyConName = name,
tyConUnique = nameUnique name,
tyConKind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
- argVrcs = argvrcs,
algTcStupidTheta = stupid,
algTcRhs = rhs,
algTcSelIds = sel_ids,
algTcClass = Nothing,
algTcRec = is_rec,
+ algTcGadtSyntax = gadt_syn,
hasGenerics = gen_info
}
-mkClassTyCon name kind tyvars argvrcs rhs clas is_rec
+mkClassTyCon name kind tyvars rhs clas is_rec
= AlgTyCon {
tyConName = name,
tyConUnique = nameUnique name,
tyConKind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
- argVrcs = argvrcs,
algTcStupidTheta = [],
algTcRhs = rhs,
algTcSelIds = [],
algTcClass = Just clas,
algTcRec = is_rec,
+ algTcGadtSyntax = False, -- Doesn't really matter
hasGenerics = False
}
-- as primitive, but *lifted*, TyCons for now. They are lifted
-- because the Haskell type T representing the (foreign) .NET
-- type T is actually implemented (in ILX) as a thunk<T>
-mkForeignTyCon name ext_name kind arity arg_vrcs
+mkForeignTyCon name ext_name kind arity
= PrimTyCon {
tyConName = name,
tyConUnique = nameUnique name,
tyConKind = kind,
tyConArity = arity,
- argVrcs = arg_vrcs,
primTyConRep = PtrRep, -- they all do
isUnLifted = False,
tyConExtName = ext_name
-- most Prim tycons are lifted
-mkPrimTyCon name kind arity arg_vrcs rep
- = mkPrimTyCon' name kind arity arg_vrcs rep True
+mkPrimTyCon name kind arity rep
+ = mkPrimTyCon' name kind arity rep True
+
+mkVoidPrimTyCon name kind arity
+ = mkPrimTyCon' name kind arity VoidRep True
-- but RealWorld is lifted
-mkLiftedPrimTyCon name kind arity arg_vrcs rep
- = mkPrimTyCon' name kind arity arg_vrcs rep False
+mkLiftedPrimTyCon name kind arity rep
+ = mkPrimTyCon' name kind arity rep False
-mkPrimTyCon' name kind arity arg_vrcs rep is_unlifted
+mkPrimTyCon' name kind arity rep is_unlifted
= PrimTyCon {
tyConName = name,
tyConUnique = nameUnique name,
tyConKind = kind,
tyConArity = arity,
- argVrcs = arg_vrcs,
primTyConRep = rep,
isUnLifted = is_unlifted,
tyConExtName = Nothing
}
-mkSynTyCon name kind tyvars rhs argvrcs
+mkSynTyCon name kind tyvars rhs
= SynTyCon {
tyConName = name,
tyConUnique = nameUnique name,
tyConKind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
- synTcRhs = rhs,
- argVrcs = argvrcs
+ synTcRhs = rhs
+ }
+
+mkCoercionTyCon name arity kindRule
+ = CoercionTyCon {
+ tyConName = name,
+ tyConUnique = nameUnique name,
+ tyConArity = arity,
+ coKindFun = kindRule
}
+
+-- Super kinds always have arity zero
+mkSuperKindTyCon name
+ = SuperKindTyCon {
+ tyConName = name,
+ tyConUnique = nameUnique name
+ }
\end{code}
\begin{code}
isSynTyCon (SynTyCon {}) = True
isSynTyCon _ = False
+isGadtSyntaxTyCon :: TyCon -> Bool
+isGadtSyntaxTyCon (AlgTyCon { algTcGadtSyntax = res }) = res
+isGadtSyntaxTyCon other = False
+
isEnumerationTyCon :: TyCon -> Bool
isEnumerationTyCon (AlgTyCon {algTcRhs = DataTyCon { is_enum = res }}) = res
isEnumerationTyCon other = False
-- isForeignTyCon identifies foreign-imported type constructors
isForeignTyCon (PrimTyCon {tyConExtName = Just _}) = True
isForeignTyCon other = False
+
+isSuperKindTyCon :: TyCon -> Bool
+isSuperKindTyCon (SuperKindTyCon {}) = True
+isSuperKindTyCon other = False
+
+isCoercionTyCon_maybe :: TyCon -> Maybe (Arity, [Type] -> Kind)
+isCoercionTyCon_maybe (CoercionTyCon {tyConArity = ar, coKindFun = rule})
+ = Just (ar, rule)
+isCoercionTyCon_maybe other = Nothing
+
+isCoercionTyCon (CoercionTyCon {}) = True
+isCoercionTyCon other = False
\end{code}
tcExpandTyCon_maybe other_tycon tys = Nothing
---------------
--- For the *Core* view, we expand synonyms *and* non-recursive newtypes
+-- For the *Core* view, we expand synonyms only as well
+{-
coreExpandTyCon_maybe (AlgTyCon {algTcRec = NonRecursive, -- Not recursive
algTcRhs = NewTyCon { nt_etad_rhs = etad_rhs }}) tys
= case etad_rhs of -- Don't do this in the pattern match, lest we accidentally
-- match the etad_rhs of a *recursive* newtype
(tvs,rhs) -> expand tvs rhs tys
-
+-}
coreExpandTyCon_maybe tycon tys = tcExpandTyCon_maybe tycon tys
+---------------
+-- For the *STG* view, we expand synonyms *and* non-recursive newtypes
+stgExpandTyCon_maybe (AlgTyCon {algTcRec = NonRecursive, -- Not recursive
+ algTcRhs = NewTyCon { nt_etad_rhs = etad_rhs }}) tys
+ = case etad_rhs of -- Don't do this in the pattern match, lest we accidentally
+ -- match the etad_rhs of a *recursive* newtype
+ (tvs,rhs) -> expand tvs rhs tys
+
+stgExpandTyCon_maybe tycon tys = coreExpandTyCon_maybe tycon tys
+
----------------
expand :: [TyVar] -> Type -- Template
-> [Type] -- Args
newTyConRep (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_rep = rep }}) = (tvs, rep)
newTyConRep tycon = pprPanic "newTyConRep" (ppr tycon)
+newTyConCo :: TyCon -> TyCon
+newTyConCo (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_co = co }}) = co
+newTyConCo tycon = pprPanic "newTyConCo" (ppr tycon)
+
tyConPrimRep :: TyCon -> PrimRep
tyConPrimRep (PrimTyCon {primTyConRep = rep}) = rep
tyConPrimRep tc = ASSERT(not (isUnboxedTupleTyCon tc)) PtrRep
tyConStupidTheta tycon = pprPanic "tyConStupidTheta" (ppr tycon)
\end{code}
-@tyConArgVrcs_maybe@ gives a list of (occPos,occNeg) flags, one for
-each tyvar, if available. See @calcAlgTyConArgVrcs@ for how this is
-actually computed (in another file).
-
-\begin{code}
-tyConArgVrcs :: TyCon -> ArgVrcs
-tyConArgVrcs (FunTyCon {}) = [(False,True),(True,False)]
-tyConArgVrcs (AlgTyCon {argVrcs = oi}) = oi
-tyConArgVrcs (PrimTyCon {argVrcs = oi}) = oi
-tyConArgVrcs (TupleTyCon {tyConArity = arity}) = (replicate arity (True,False))
-tyConArgVrcs (SynTyCon {argVrcs = oi}) = oi
-\end{code}
-
\begin{code}
synTyConDefn :: TyCon -> ([TyVar], Type)
synTyConDefn (SynTyCon {tyConTyVars = tyvars, synTcRhs = ty}) = (tyvars,ty)
projects / ghc-hetmet.git / blobdiff