%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1998
%
\section[DataCon]{@DataCon@: Data Constructors}
ConTag, fIRST_TAG,
mkDataCon,
dataConRepType, dataConSig, dataConFullSig,
- dataConName, dataConTag, dataConTyCon, dataConUserType,
- dataConUnivTyVars, dataConExTyVars, dataConAllTyVars, dataConResTys,
+ dataConName, dataConIdentity, dataConTag, dataConTyCon, dataConUserType,
+ dataConUnivTyVars, dataConExTyVars, dataConAllTyVars,
dataConEqSpec, eqSpecPreds, dataConTheta, dataConStupidTheta,
- dataConInstArgTys, dataConOrigArgTys,
+ dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy,
dataConInstOrigArgTys, dataConRepArgTys,
dataConFieldLabels, dataConFieldType,
dataConStrictMarks, dataConExStricts,
#include "HsVersions.h"
-import Type ( Type, ThetaType,
- substTyWith, substTyVar, mkTopTvSubst,
- mkForAllTys, mkFunTys, mkTyConApp, mkTyVarTy, mkTyVarTys,
- splitTyConApp_maybe, newTyConInstRhs,
- mkPredTys, isStrictPred, pprType, mkPredTy
- )
-import Coercion ( isEqPred, mkEqPred )
-import TyCon ( TyCon, FieldLabel, tyConDataCons,
- isProductTyCon, isTupleTyCon, isUnboxedTupleTyCon,
- isNewTyCon, isRecursiveTyCon )
-import Class ( Class, classTyCon )
-import Name ( Name, NamedThing(..), nameUnique, mkSysTvName, mkSystemName )
-+ import Var ( TyVar, CoVar, Id, mkTyVar, tyVarKind, setVarUnique,
-+ mkCoVar )
-import BasicTypes ( Arity, StrictnessMark(..) )
+import Type
+import Coercion
+import TyCon
+import Class
+import Name
+import Var
+import BasicTypes
import Outputable
-import Unique ( Unique, Uniquable(..) )
-import ListSetOps ( assoc, minusList )
-import Util ( zipEqual, zipWithEqual )
-import List ( partition )
-import Maybes ( expectJust )
+import Unique
+import ListSetOps
+import Util
+import Maybes
import FastString
\end{code}
-- dcEqSpec = [a:=:(x,y)]
-- dcTheta = [Ord x]
-- dcOrigArgTys = [a,List b]
- -- dcTyCon = T
+ -- dcRepTyCon = T
dcVanilla :: Bool, -- True <=> This is a vanilla Haskell 98 data constructor
-- Its type is of form
-- The declaration format is held in the TyCon (algTcGadtSyntax)
dcUnivTyVars :: [TyVar], -- Universally-quantified type vars
+ -- INVARIANT: length matches arity of the dcRepTyCon
+
dcExTyVars :: [TyVar], -- Existentially-quantified type vars
-- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE TYVARS
-- FOR THE PARENT TyCon. With GADTs the data con might not even have
-- [This is a change (Oct05): previously, vanilla datacons guaranteed to
-- have the same type variables as their parent TyCon, but that seems ugly.]
+ -- INVARIANT: the UnivTyVars and ExTyVars all have distinct OccNames
+ -- Reason: less confusing, and easier to generate IfaceSyn
+
dcEqSpec :: [(TyVar,Type)], -- Equalities derived from the result type,
-- *as written by the programmer*
-- This field allows us to move conveniently between the two ways
dcOrigArgTys :: [Type], -- Original argument types
-- (before unboxing and flattening of strict fields)
-
- -- Result type of constructor is T t1..tn
- dcTyCon :: TyCon, -- Result tycon, T
+ dcOrigResTy :: Type, -- Original result type
+ -- NB: for a data instance, the original user result type may
+ -- differ from the DataCon's representation TyCon. Example
+ -- data instance T [a] where MkT :: a -> T [a]
+ -- The OrigResTy is T [a], but the dcRepTyCon might be :T123
-- Now the strictness annotations and field labels of the constructor
dcStrictMarks :: [StrictnessMark],
dcFields :: [FieldLabel],
-- Field labels for this constructor, in the
- -- same order as the argument types;
+ -- same order as the dcOrigArgTys;
-- length = 0 (if not a record) or dataConSourceArity.
-- Constructor representation
-- and *including* existential dictionaries
dcRepStrictness :: [StrictnessMark], -- One for each *representation* argument
+ -- See also Note [Data-con worker strictness] in MkId.lhs
+
+ -- Result type of constructor is T t1..tn
+ dcRepTyCon :: TyCon, -- Result tycon, T
dcRepType :: Type, -- Type of the constructor
-- forall a x y. (a:=:(x,y), Ord x) => x -> y -> MkT a
-- The 'Nothing' case of DCIds is important
-- Not only is this efficient,
-- but it also ensures that the wrapper is replaced
- -- by the worker (becuase it *is* the wroker)
+ -- by the worker (becuase it *is* the worker)
-- even when there are no args. E.g. in
-- f (:) x
-- the (:) *is* the worker.
eq_spec theta
orig_arg_tys tycon
stupid_theta ids
+-- Warning: mkDataCon is not a good place to check invariants.
+-- If the programmer writes the wrong result type in the decl, thus:
+-- data T a where { MkT :: S }
+-- then it's possible that the univ_tvs may hit an assertion failure
+-- if you pull on univ_tvs. This case is checked by checkValidDataCon,
+-- so the error is detected properly... it's just that asaertions here
+-- are a little dodgy.
+
= ASSERT( not (any isEqPred theta) )
-- We don't currently allow any equality predicates on
-- a data constructor (apart from the GADT ones in eq_spec)
con
where
is_vanilla = null ex_tvs && null eq_spec && null theta
- con = ASSERT( is_vanilla || not (isNewTyCon tycon) )
- -- Invariant: newtypes have a vanilla data-con
- MkData {dcName = name, dcUnique = nameUnique name,
+ con = MkData {dcName = name, dcUnique = nameUnique name,
dcVanilla = is_vanilla, dcInfix = declared_infix,
dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs,
dcEqSpec = eq_spec,
dcStupidTheta = stupid_theta, dcTheta = theta,
- dcOrigArgTys = orig_arg_tys, dcTyCon = tycon,
+ dcOrigArgTys = orig_arg_tys, dcOrigResTy = orig_res_ty,
+ dcRepTyCon = tycon,
dcRepArgTys = rep_arg_tys,
- dcStrictMarks = arg_stricts, dcRepStrictness = rep_arg_stricts,
+ dcStrictMarks = arg_stricts,
+ dcRepStrictness = rep_arg_stricts,
dcFields = fields, dcTag = tag, dcRepType = ty,
dcIds = ids }
real_arg_tys = dict_tys ++ orig_arg_tys
real_stricts = map mk_dict_strict_mark theta ++ arg_stricts
+ -- Example
+ -- data instance T (b,c) where
+ -- TI :: forall e. e -> T (e,e)
+ --
+ -- The representation tycon looks like this:
+ -- data :R7T b c where
+ -- TI :: forall b1 c1. (b1 ~ c1) => b1 -> :R7T b1 c1
+ orig_res_ty = mkFamilyTyConApp tycon (substTyVars (mkTopTvSubst eq_spec) univ_tvs)
+
-- Representation arguments and demands
-- To do: eliminate duplication with MkId
(rep_arg_stricts, rep_arg_tys) = computeRep real_stricts real_arg_tys
dataConName :: DataCon -> Name
dataConName = dcName
+-- generate a name in the format: package:Module.OccName
+-- and the unique identity of the name
+dataConIdentity :: DataCon -> String
+dataConIdentity dataCon
+ = prettyName
+ where
+ prettyName = pretty packageModule ++ "." ++ pretty occ
+ nm = getName dataCon
+ packageModule = nameModule nm
+ occ = getOccName dataCon
+ pretty :: Outputable a => a -> String
+ pretty = showSDoc . ppr
+
dataConTag :: DataCon -> ConTag
dataConTag = dcTag
dataConTyCon :: DataCon -> TyCon
-dataConTyCon = dcTyCon
+dataConTyCon = dcRepTyCon
dataConRepType :: DataCon -> Type
dataConRepType = dcRepType
-- Core constructor application (Con dc args)
dataConRepStrictness dc = dcRepStrictness dc
-dataConSig :: DataCon -> ([TyVar], ThetaType, [Type])
+dataConSig :: DataCon -> ([TyVar], ThetaType, [Type], Type)
dataConSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec,
- dcTheta = theta, dcOrigArgTys = arg_tys, dcTyCon = tycon})
- = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ theta, arg_tys)
+ dcTheta = theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty})
+ = (univ_tvs ++ ex_tvs, eqSpecPreds eq_spec ++ theta, arg_tys, res_ty)
dataConFullSig :: DataCon
- -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, [Type])
+ -> ([TyVar], [TyVar], [(TyVar,Type)], ThetaType, [Type], Type)
dataConFullSig (MkData {dcUnivTyVars = univ_tvs, dcExTyVars = ex_tvs, dcEqSpec = eq_spec,
- dcTheta = theta, dcOrigArgTys = arg_tys, dcTyCon = tycon})
- = (univ_tvs, ex_tvs, eq_spec, theta, arg_tys)
+ dcTheta = theta, dcOrigArgTys = arg_tys, dcOrigResTy = res_ty})
+ = (univ_tvs, ex_tvs, eq_spec, theta, arg_tys, res_ty)
+
+dataConOrigResTy :: DataCon -> Type
+dataConOrigResTy dc = dcOrigResTy dc
dataConStupidTheta :: DataCon -> ThetaType
dataConStupidTheta dc = dcStupidTheta dc
-dataConResTys :: DataCon -> [Type]
-dataConResTys dc = [substTyVar env tv | tv <- dcUnivTyVars dc]
- where
- env = mkTopTvSubst (dcEqSpec dc)
-
dataConUserType :: DataCon -> Type
-- The user-declared type of the data constructor
-- in the nice-to-read form
--- T :: forall a. a -> T [a]
+-- T :: forall a b. a -> b -> T [a]
-- rather than
--- T :: forall b. forall a. (a=[b]) => a -> T b
+-- T :: forall a c. forall b. (c=[a]) => a -> b -> T c
+-- NB: If the constructor is part of a data instance, the result type
+-- mentions the family tycon, not the internal one.
dataConUserType (MkData { dcUnivTyVars = univ_tvs,
dcExTyVars = ex_tvs, dcEqSpec = eq_spec,
dcTheta = theta, dcOrigArgTys = arg_tys,
- dcTyCon = tycon })
+ dcOrigResTy = res_ty })
= mkForAllTys ((univ_tvs `minusList` map fst eq_spec) ++ ex_tvs) $
mkFunTys (mkPredTys theta) $
mkFunTys arg_tys $
- mkTyConApp tycon (map (substTyVar subst) univ_tvs)
- where
- subst = mkTopTvSubst eq_spec
+ res_ty
dataConInstArgTys :: DataCon
-> [Type] -- Instantiated at these types
-- NB: these INCLUDE the existentially quantified dict args
-- but EXCLUDE the data-decl context which is discarded
-- It's all post-flattening etc; this is a representation type
-dataConInstArgTys (MkData {dcRepArgTys = arg_tys,
- dcUnivTyVars = univ_tvs,
- dcExTyVars = ex_tvs}) inst_tys
- = ASSERT( length tyvars == length inst_tys )
+dataConInstArgTys dc@(MkData {dcRepArgTys = arg_tys,
+ dcUnivTyVars = univ_tvs,
+ dcExTyVars = ex_tvs}) inst_tys
+ = ASSERT2 ( length tyvars == length inst_tys
+ , ptext SLIT("dataConInstArgTys") <+> ppr dc $$ ppr tyvars $$ ppr inst_tys)
+
map (substTyWith tyvars inst_tys) arg_tys
where
tyvars = univ_tvs ++ ex_tvs
-- And the same deal for the original arg tys
dataConInstOrigArgTys :: DataCon -> [Type] -> [Type]
dataConInstOrigArgTys dc@(MkData {dcOrigArgTys = arg_tys,
- dcUnivTyVars = univ_tvs,
- dcExTyVars = ex_tvs}) inst_tys
- = ASSERT2( length tyvars == length inst_tys, ptext SLIT("dataConInstOrigArgTys") <+> ppr dc <+> ppr inst_tys )
+ dcUnivTyVars = univ_tvs,
+ dcExTyVars = ex_tvs}) inst_tys
+ = ASSERT2( length tyvars == length inst_tys
+ , ptext SLIT("dataConInstOrigArgTys") <+> ppr dc $$ ppr tyvars $$ ppr inst_tys )
map (substTyWith tyvars inst_tys) arg_tys
where
tyvars = univ_tvs ++ ex_tvs
\begin{code}
isTupleCon :: DataCon -> Bool
-isTupleCon (MkData {dcTyCon = tc}) = isTupleTyCon tc
+isTupleCon (MkData {dcRepTyCon = tc}) = isTupleTyCon tc
isUnboxedTupleCon :: DataCon -> Bool
-isUnboxedTupleCon (MkData {dcTyCon = tc}) = isUnboxedTupleTyCon tc
+isUnboxedTupleCon (MkData {dcRepTyCon = tc}) = isUnboxedTupleTyCon tc
isVanillaDataCon :: DataCon -> Bool
isVanillaDataCon dc = dcVanilla dc
classDataCon :: Class -> DataCon
classDataCon clas = case tyConDataCons (classTyCon clas) of
(dict_constr:no_more) -> ASSERT( null no_more ) dict_constr
+ [] -> panic "classDataCon"
\end{code}
%************************************************************************
-- and for constructors visible
-> Just (tycon, ty_args, data_con, dataConInstArgTys data_con ty_args)
where
- data_con = head (tyConDataCons tycon)
+ data_con = ASSERT( not (null (tyConDataCons tycon)) )
+ head (tyConDataCons tycon)
other -> Nothing
splitProductType str ty
deepSplitProductType_maybe ty
= do { (res@(tycon, tycon_args, _, _)) <- splitProductType_maybe ty
; let {result
- | isNewTyCon tycon && not (isRecursiveTyCon tycon)
+ | isClosedNewTyCon tycon && not (isRecursiveTyCon tycon)
= deepSplitProductType_maybe (newTyConInstRhs tycon tycon_args)
- | isNewTyCon tycon = Nothing -- cannot unbox through recursive newtypes
+ | isNewTyCon tycon = Nothing -- cannot unbox through recursive
+ -- newtypes nor through families
| otherwise = Just res}
; result
}
unbox MarkedStrict ty = [(MarkedStrict, ty)]
unbox MarkedUnboxed ty = zipEqual "computeRep" (dataConRepStrictness arg_dc) arg_tys
where
- (tycon, tycon_args, arg_dc, arg_tys)
+ (_tycon, _tycon_args, arg_dc, arg_tys)
= deepSplitProductType "unbox_strict_arg_ty" ty
\end{code}
projects / ghc-hetmet.git / blobdiff