\begin{code}
module TyCon(
-- * Main TyCon data types
- TyCon, FieldLabel,
+ TyCon, FieldLabel,
AlgTyConRhs(..), visibleDataCons,
TyConParent(..),
SynTyConRhs(..),
+ CoTyConDesc(..),
AssocFamilyPermutation,
-- ** Constructing TyCons
mkClassTyCon,
mkFunTyCon,
mkPrimTyCon,
- mkVoidPrimTyCon,
+ mkKindTyCon,
mkLiftedPrimTyCon,
mkTupleTyCon,
mkSynTyCon,
mkSuperKindTyCon,
mkCoercionTyCon,
mkForeignTyCon,
+ mkAnyTyCon,
-- ** Predicates on TyCons
isAlgTyCon,
isPrimTyCon,
isTupleTyCon, isUnboxedTupleTyCon, isBoxedTupleTyCon,
isSynTyCon, isClosedSynTyCon, isOpenSynTyCon,
- isSuperKindTyCon,
+ isSuperKindTyCon, isDecomposableTyCon,
isCoercionTyCon, isCoercionTyCon_maybe,
- isForeignTyCon,
+ isForeignTyCon, isAnyTyCon, tyConHasKind,
isInjectiveTyCon,
isDataTyCon, isProductTyCon, isEnumerationTyCon,
%************************************************************************
\begin{code}
--- | Represents type constructors. Type constructors are introduced by things such as:
+-- | TyCons represent type constructors. Type constructors are introduced by things such as:
--
-- 1) Data declarations: @data Foo = ...@ creates the @Foo@ type constructor of kind @*@
--
FunTyCon {
tyConUnique :: Unique,
tyConName :: Name,
- tyConKind :: Kind,
+ tc_kind :: Kind,
tyConArity :: Arity
}
| AlgTyCon {
tyConUnique :: Unique,
tyConName :: Name,
- tyConKind :: Kind,
+ tc_kind :: Kind,
tyConArity :: Arity,
tyConTyVars :: [TyVar], -- ^ The type variables used in the type constructor.
-- that doesn't mean it's a true GADT; only that the "where"
-- form was used. This field is used only to guide
-- pretty-printing
+
algTcStupidTheta :: [PredType], -- ^ The \"stupid theta\" for the data type (always empty for GADTs).
-- A \"stupid theta\" is the context to the left of an algebraic type
-- declaration, e.g. @Eq a@ in the declaration @data Eq a => T a ...@.
| TupleTyCon {
tyConUnique :: Unique,
tyConName :: Name,
- tyConKind :: Kind,
+ tc_kind :: Kind,
tyConArity :: Arity,
tyConBoxed :: Boxity,
tyConTyVars :: [TyVar],
| SynTyCon {
tyConUnique :: Unique,
tyConName :: Name,
- tyConKind :: Kind,
+ tc_kind :: Kind,
tyConArity :: Arity,
tyConTyVars :: [TyVar], -- Bound tyvars
| PrimTyCon {
tyConUnique :: Unique,
tyConName :: Name,
- tyConKind :: Kind,
- tyConArity :: Arity, -- SLPJ Oct06: I'm not sure what the significance
- -- of the arity of a primtycon is!
-
- primTyConRep :: PrimRep,
- -- ^ Many primitive tycons are unboxed, but some are
- -- boxed (represented by pointers). This 'PrimRep' holds
- -- that information
-
- isUnLifted :: Bool, -- ^ Most primitive tycons are unlifted (may not contain bottom)
- -- but foreign-imported ones may be lifted
- tyConExtName :: Maybe FastString -- ^ @Just e@ for foreign-imported types, holds the name of the imported thing
+ tc_kind :: Kind,
+ tyConArity :: Arity, -- SLPJ Oct06: I'm not sure what the significance
+ -- of the arity of a primtycon is!
+
+ primTyConRep :: PrimRep, -- ^ Many primitive tycons are unboxed, but some are
+ -- boxed (represented by pointers). This 'PrimRep' holds
+ -- that information.
+ -- Only relevant if tc_kind = *
+
+ isUnLifted :: Bool, -- ^ Most primitive tycons are unlifted (may not contain bottom)
+ -- but foreign-imported ones may be lifted
+
+ tyConExtName :: Maybe FastString -- ^ @Just e@ for foreign-imported types,
+ -- holds the name of the imported thing
}
-- | Type coercions, such as @(~)@, @sym@, @trans@, @left@ and @right@.
- -- INVARIANT: coercions are always fully applied
- | CoercionTyCon {
+ -- INVARIANT: Coercion TyCons are always fully applied
+ -- But note that a CoTyCon can be *over*-saturated in a type.
+ -- E.g. (sym g1) Int will be represented as (TyConApp sym [g1,Int])
+ | CoTyCon {
tyConUnique :: Unique,
tyConName :: Name,
tyConArity :: Arity,
- coKindFun :: [Type] -> (Type,Type)
- -- ^ Function that when given a list of the type arguments to the 'TyCon'
- -- constructs the types that the resulting coercion relates.
- --
- -- INVARIANT: 'coKindFun' is always applied to exactly 'tyConArity' args
- -- E.g. for @trans (c1 :: ta=tb) (c2 :: tb=tc)@, the 'coKindFun' returns
- -- the kind as a pair of types: @(ta, tc)@
+ coTcDesc :: CoTyConDesc
+ }
+
+ -- | Any types. Like tuples, this is a potentially-infinite family of TyCons
+ -- one for each distinct Kind. They have no values at all.
+ -- Because there are infinitely many of them (like tuples) they are
+ -- defined in GHC.Prim and have names like "Any(*->*)".
+ -- Their Unique is derived from the OccName.
+ -- See Note [Any types] in TysPrim
+ | AnyTyCon {
+ tyConUnique :: Unique,
+ tyConName :: Name,
+ tc_kind :: Kind -- Never = *; that is done via PrimTyCon
+ -- See Note [Any types] in TysPrim
}
-- | Super-kinds. These are "kinds-of-kinds" and are never seen in Haskell source programs.
-- See Note [Newtype eta]
- nt_co :: Maybe TyCon -- ^ A 'TyCon' (which is always a 'CoercionTyCon') that can have a 'Coercion'
+ nt_co :: Maybe TyCon -- ^ A 'TyCon' (which is always a 'CoTyCon') that can have a 'Coercion'
-- extracted from it to create the @newtype@ from the representation 'Type'.
--
-- This field is optional for non-recursive @newtype@s only.
-- of the current 'TyCon' (not the family one). INVARIANT:
-- the number of types matches the arity of the family 'TyCon'
--
- -- 3) A 'CoercionTyCon' identifying the representation
+ -- 3) A 'CoTyCon' identifying the representation
-- type with the type instance family
| FamilyTyCon
TyCon
| SynonymTyCon Type -- ^ The synonym mentions head type variables. It acts as a
-- template for the expansion when the 'TyCon' is applied to some
-- types.
+
+--------------------
+data CoTyConDesc
+ = CoSym | CoTrans
+ | CoLeft | CoRight
+ | CoCsel1 | CoCsel2 | CoCselR
+ | CoInst
+
+ | CoAxiom -- C tvs : F lhs-tys ~ rhs-ty
+ { co_ax_tvs :: [TyVar]
+ , co_ax_lhs :: Type
+ , co_ax_rhs :: Type }
+
+ | CoUnsafe
\end{code}
Note [Newtype coercions]
newtype T a = MkT (a -> a)
the NewTyCon for T will contain nt_co = CoT where CoT t : T t ~ t ->
-t. This TyCon is a CoercionTyCon, so it does not have a kind on its
+t. This TyCon is a CoTyCon, 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 at
most k. In the case that the right hand side is a type application
CoT @ s
which encodes as (TyConApp instCoercionTyCon [TyConApp CoT [], s])
-But in GHC we instead make CoT into a new piece of type syntax, CoercionTyCon,
+But in GHC we instead make CoT into a new piece of type syntax, CoTyCon,
(like instCoercionTyCon, symCoercionTyCon etc), which must always
be saturated, but which encodes as
TyConApp CoT [s]
%************************************************************************
A PrimRep is somewhat similar to a CgRep (see codeGen/SMRep) and a
-MachRep (see cmm/MachOp), although each of these types has a distinct
+MachRep (see cmm/CmmExpr), although each of these types has a distinct
and clearly defined purpose:
- A PrimRep is a CgRep + information about signedness + information
= FunTyCon {
tyConUnique = nameUnique name,
tyConName = name,
- tyConKind = kind,
+ tc_kind = kind,
tyConArity = 2
}
= AlgTyCon {
tyConName = name,
tyConUnique = nameUnique name,
- tyConKind = kind,
+ tc_kind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
algTcStupidTheta = stupid,
= TupleTyCon {
tyConUnique = nameUnique name,
tyConName = name,
- tyConKind = kind,
+ tc_kind = kind,
tyConArity = arity,
tyConBoxed = boxed,
tyConTyVars = tyvars,
= PrimTyCon {
tyConName = name,
tyConUnique = nameUnique name,
- tyConKind = kind,
+ tc_kind = kind,
tyConArity = arity,
primTyConRep = PtrRep, -- they all do
isUnLifted = False,
mkPrimTyCon name kind arity rep
= mkPrimTyCon' name kind arity rep True
--- | Create the special void 'TyCon' which is unlifted and has 'VoidRep'
-mkVoidPrimTyCon :: Name -> Kind -> Arity -> TyCon
-mkVoidPrimTyCon name kind arity
- = mkPrimTyCon' name kind arity VoidRep True
+-- | Kind constructors
+mkKindTyCon :: Name -> Kind -> TyCon
+mkKindTyCon name kind
+ = mkPrimTyCon' name kind 0 VoidRep True
-- | Create a lifted primitive 'TyCon' such as @RealWorld@
mkLiftedPrimTyCon :: Name -> Kind -> Arity -> PrimRep -> TyCon
= PrimTyCon {
tyConName = name,
tyConUnique = nameUnique name,
- tyConKind = kind,
+ tc_kind = kind,
tyConArity = arity,
primTyConRep = rep,
isUnLifted = is_unlifted,
= SynTyCon {
tyConName = name,
tyConUnique = nameUnique name,
- tyConKind = kind,
+ tc_kind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
synTcRhs = rhs,
}
-- | Create a coercion 'TyCon'
-mkCoercionTyCon :: Name -> Arity -> ([Type] -> (Type,Type)) -> TyCon
-mkCoercionTyCon name arity kindRule
- = CoercionTyCon {
- tyConName = name,
+mkCoercionTyCon :: Name -> Arity
+ -> CoTyConDesc
+ -> TyCon
+mkCoercionTyCon name arity desc
+ = CoTyCon {
+ tyConName = name,
tyConUnique = nameUnique name,
- tyConArity = arity,
- coKindFun = kindRule
- }
+ tyConArity = arity,
+ coTcDesc = desc }
+
+mkAnyTyCon :: Name -> Kind -> TyCon
+mkAnyTyCon name kind
+ = AnyTyCon { tyConName = name,
+ tc_kind = kind,
+ tyConUnique = nameUnique name }
-- | Create a super-kind 'TyCon'
mkSuperKindTyCon :: Name -> TyCon -- Super kinds always have arity zero
isOpenSynTyCon :: TyCon -> Bool
isOpenSynTyCon tycon = isSynTyCon tycon && isOpenTyCon tycon
+isDecomposableTyCon :: TyCon -> Bool
+-- True iff we can deocmpose (T a b c) into ((T a b) c)
+-- Specifically NOT true of synonyms (open and otherwise) and coercions
+isDecomposableTyCon (SynTyCon {}) = False
+isDecomposableTyCon (CoTyCon {}) = False
+isDecomposableTyCon _other = True
+
-- | Is this an algebraic 'TyCon' declared with the GADT syntax?
isGadtSyntaxTyCon :: TyCon -> Bool
isGadtSyntaxTyCon (AlgTyCon { algTcGadtSyntax = res }) = res
-- | Is this an algebraic 'TyCon' which is just an enumeration of values?
isEnumerationTyCon :: TyCon -> Bool
isEnumerationTyCon (AlgTyCon {algTcRhs = DataTyCon { is_enum = res }}) = res
+isEnumerationTyCon (TupleTyCon {tyConArity = arity}) = arity == 0
isEnumerationTyCon _ = False
-- | Is this a 'TyCon', synonym or otherwise, that may have further instances appear?
isSuperKindTyCon (SuperKindTyCon {}) = True
isSuperKindTyCon _ = False
+-- | Is this an AnyTyCon?
+isAnyTyCon :: TyCon -> Bool
+isAnyTyCon (AnyTyCon {}) = True
+isAnyTyCon _ = False
+
-- | Attempt to pull a 'TyCon' apart into the arity and 'coKindFun' of
-- a coercion 'TyCon'. Returns @Nothing@ if the 'TyCon' is not of the
-- appropriate kind
-isCoercionTyCon_maybe :: TyCon -> Maybe (Arity, [Type] -> (Type,Type))
-isCoercionTyCon_maybe (CoercionTyCon {tyConArity = ar, coKindFun = rule})
- = Just (ar, rule)
+isCoercionTyCon_maybe :: TyCon -> Maybe (Arity, CoTyConDesc)
+isCoercionTyCon_maybe (CoTyCon {tyConArity = ar, coTcDesc = desc})
+ = Just (ar, desc)
isCoercionTyCon_maybe _ = Nothing
-- | Is this a 'TyCon' that represents a coercion?
isCoercionTyCon :: TyCon -> Bool
-isCoercionTyCon (CoercionTyCon {}) = True
-isCoercionTyCon _ = False
+isCoercionTyCon (CoTyCon {}) = True
+isCoercionTyCon _ = False
-- | Identifies implicit tycons that, in particular, do not go into interface
-- files (because they are implicitly reconstructed when the interface is
isTupleTyCon tycon
isImplicitTyCon _other = True
-- catches: FunTyCon, PrimTyCon,
- -- CoercionTyCon, SuperKindTyCon
+ -- CoTyCon, SuperKindTyCon
\end{code}
tyConHasGenerics (TupleTyCon {hasGenerics = hg}) = hg
tyConHasGenerics _ = False -- Synonyms
+tyConKind :: TyCon -> Kind
+tyConKind (FunTyCon { tc_kind = k }) = k
+tyConKind (AlgTyCon { tc_kind = k }) = k
+tyConKind (TupleTyCon { tc_kind = k }) = k
+tyConKind (SynTyCon { tc_kind = k }) = k
+tyConKind (PrimTyCon { tc_kind = k }) = k
+tyConKind (AnyTyCon { tc_kind = k }) = k
+tyConKind tc = pprPanic "tyConKind" (ppr tc) -- SuperKindTyCon and CoTyCon
+
+tyConHasKind :: TyCon -> Bool
+tyConHasKind (SuperKindTyCon {}) = False
+tyConHasKind (CoTyCon {}) = False
+tyConHasKind _ = True
+
-- | As 'tyConDataCons_maybe', but returns the empty list of constructors if no constructors
-- could be found
tyConDataCons :: TyCon -> [DataCon]
-- | Extract an 'AlgTyConRhs' with information about data constructors from an algebraic or tuple
-- 'TyCon'. Panics for any other sort of 'TyCon'
algTyConRhs :: TyCon -> AlgTyConRhs
-algTyConRhs (AlgTyCon {algTcRhs = rhs}) = rhs
-algTyConRhs (TupleTyCon {dataCon = con}) = DataTyCon { data_cons = [con], is_enum = False }
+algTyConRhs (AlgTyCon {algTcRhs = rhs}) = rhs
+algTyConRhs (TupleTyCon {dataCon = con, tyConArity = arity})
+ = DataTyCon { data_cons = [con], is_enum = arity == 0 }
algTyConRhs other = pprPanic "algTyConRhs" (ppr other)
\end{code}
-- has more than one constructor, or represents a primitive or function type constructor then
-- @Nothing@ is returned. In any other case, the function panics
tyConSingleDataCon_maybe :: TyCon -> Maybe DataCon
-tyConSingleDataCon_maybe (AlgTyCon {algTcRhs = DataTyCon {data_cons = [c] }}) = Just c
-tyConSingleDataCon_maybe (AlgTyCon {algTcRhs = NewTyCon { data_con = c }}) = Just c
-tyConSingleDataCon_maybe (AlgTyCon {}) = Nothing
-tyConSingleDataCon_maybe (TupleTyCon {dataCon = con}) = Just con
-tyConSingleDataCon_maybe (PrimTyCon {}) = Nothing
-tyConSingleDataCon_maybe (FunTyCon {}) = Nothing -- case at funty
-tyConSingleDataCon_maybe tc = pprPanic "tyConSingleDataCon_maybe: unexpected tycon " $ ppr tc
+tyConSingleDataCon_maybe (TupleTyCon {dataCon = c}) = Just c
+tyConSingleDataCon_maybe (AlgTyCon {algTcRhs = DataTyCon { data_cons = [c] }}) = Just c
+tyConSingleDataCon_maybe (AlgTyCon {algTcRhs = NewTyCon { data_con = c }}) = Just c
+tyConSingleDataCon_maybe _ = Nothing
\end{code}
\begin{code}
instance Uniquable TyCon where
getUnique tc = tyConUnique tc
+instance Outputable CoTyConDesc where
+ ppr CoSym = ptext (sLit "SYM")
+ ppr CoTrans = ptext (sLit "TRANS")
+ ppr CoLeft = ptext (sLit "LEFT")
+ ppr CoRight = ptext (sLit "RIGHT")
+ ppr CoCsel1 = ptext (sLit "CSEL1")
+ ppr CoCsel2 = ptext (sLit "CSEL2")
+ ppr CoCselR = ptext (sLit "CSELR")
+ ppr CoInst = ptext (sLit "INST")
+ ppr CoUnsafe = ptext (sLit "UNSAFE")
+ ppr (CoAxiom {}) = ptext (sLit "AXIOM")
+
instance Outputable TyCon where
ppr tc = ppr (getName tc)
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