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Diffstat (limited to 'compiler/iface/BuildTyCl.lhs')
| -rw-r--r-- | compiler/iface/BuildTyCl.lhs | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/compiler/iface/BuildTyCl.lhs b/compiler/iface/BuildTyCl.lhs new file mode 100644 index 0000000000..f81f2e7d07 --- /dev/null +++ b/compiler/iface/BuildTyCl.lhs @@ -0,0 +1,256 @@ +% +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 +% + +\begin{code} +module BuildTyCl ( + buildSynTyCon, buildAlgTyCon, buildDataCon, + buildClass, + mkAbstractTyConRhs, mkNewTyConRhs, mkDataTyConRhs + ) where + +#include "HsVersions.h" + +import IfaceEnv ( newImplicitBinder ) +import TcRnMonad + +import DataCon ( DataCon, isNullarySrcDataCon, dataConTyVars, + mkDataCon, dataConFieldLabels, dataConOrigArgTys ) +import Var ( tyVarKind, TyVar, Id ) +import VarSet ( isEmptyVarSet, intersectVarSet, elemVarSet ) +import TysWiredIn ( unitTy ) +import BasicTypes ( RecFlag, StrictnessMark(..) ) +import Name ( Name ) +import OccName ( mkDataConWrapperOcc, mkDataConWorkerOcc, mkClassTyConOcc, + mkClassDataConOcc, mkSuperDictSelOcc ) +import MkId ( mkDataConIds, mkRecordSelId, mkDictSelId ) +import Class ( mkClass, Class( classTyCon), FunDep, DefMeth(..) ) +import TyCon ( mkSynTyCon, mkAlgTyCon, visibleDataCons, tyConStupidTheta, + tyConDataCons, isNewTyCon, mkClassTyCon, TyCon( tyConTyVars ), + isRecursiveTyCon, + ArgVrcs, AlgTyConRhs(..), newTyConRhs ) +import Type ( mkArrowKinds, liftedTypeKind, typeKind, + tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, + splitTyConApp_maybe, splitAppTy_maybe, getTyVar_maybe, + mkPredTys, mkTyVarTys, ThetaType, Type, + substTyWith, zipTopTvSubst, substTheta ) +import Outputable +import List ( nub ) + +\end{code} + + +\begin{code} +------------------------------------------------------ +buildSynTyCon name tvs rhs_ty arg_vrcs + = mkSynTyCon name kind tvs rhs_ty arg_vrcs + where + kind = mkArrowKinds (map tyVarKind tvs) (typeKind rhs_ty) + + +------------------------------------------------------ +buildAlgTyCon :: Name -> [TyVar] + -> ThetaType -- Stupid theta + -> AlgTyConRhs + -> ArgVrcs -> RecFlag + -> Bool -- True <=> want generics functions + -> TcRnIf m n TyCon + +buildAlgTyCon tc_name tvs stupid_theta rhs arg_vrcs is_rec want_generics + = do { let { tycon = mkAlgTyCon tc_name kind tvs arg_vrcs stupid_theta + rhs fields is_rec want_generics + ; kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind + ; fields = mkTyConSelIds tycon rhs + } + ; return tycon } + +------------------------------------------------------ +mkAbstractTyConRhs :: AlgTyConRhs +mkAbstractTyConRhs = AbstractTyCon + +mkDataTyConRhs :: [DataCon] -> AlgTyConRhs +mkDataTyConRhs cons + = DataTyCon { data_cons = cons, is_enum = all isNullarySrcDataCon cons } + +mkNewTyConRhs :: TyCon -> DataCon -> AlgTyConRhs +mkNewTyConRhs tycon con + = NewTyCon { data_con = con, + nt_rhs = rhs_ty, + nt_etad_rhs = eta_reduce tvs rhs_ty, + nt_rep = mkNewTyConRep tycon rhs_ty } + where + tvs = dataConTyVars con + rhs_ty = head (dataConOrigArgTys con) + -- Newtypes are guaranteed vanilla, so OrigArgTys will do + + eta_reduce [] ty = ([], ty) + eta_reduce (a:as) ty | null as', + Just (fun, arg) <- splitAppTy_maybe ty', + Just tv <- getTyVar_maybe arg, + tv == a, + not (a `elemVarSet` tyVarsOfType fun) + = ([], fun) -- Successful eta reduction + | otherwise + = (a:as', ty') + where + (as', ty') = eta_reduce as ty + +mkNewTyConRep :: TyCon -- The original type constructor + -> Type -- The arg type of its constructor + -> Type -- Chosen representation type +-- The "representation type" is guaranteed not to be another newtype +-- at the outermost level; but it might have newtypes in type arguments + +-- Find the representation type for this newtype TyCon +-- Remember that the representation type is the *ultimate* representation +-- type, looking through other newtypes. +-- +-- The non-recursive newtypes are easy, because they look transparent +-- to splitTyConApp_maybe, but recursive ones really are represented as +-- TyConApps (see TypeRep). +-- +-- The trick is to to deal correctly with recursive newtypes +-- such as newtype T = MkT T + +mkNewTyConRep tc rhs_ty + | null (tyConDataCons tc) = unitTy + -- External Core programs can have newtypes with no data constructors + | otherwise = go [tc] rhs_ty + where + -- Invariant: tcs have been seen before + go tcs rep_ty + = case splitTyConApp_maybe rep_ty of + Just (tc, tys) + | tc `elem` tcs -> unitTy -- Recursive loop + | isNewTyCon tc -> ASSERT( isRecursiveTyCon tc ) + -- Non-recursive ones have been + -- dealt with by splitTyConApp_maybe + go (tc:tcs) (substTyWith tvs tys rhs_ty) + where + (tvs, rhs_ty) = newTyConRhs tc + + other -> rep_ty + +------------------------------------------------------ +buildDataCon :: Name -> Bool -> Bool + -> [StrictnessMark] + -> [Name] -- Field labels + -> [TyVar] + -> ThetaType -- Does not include the "stupid theta" + -> [Type] -> TyCon -> [Type] + -> TcRnIf m n DataCon +-- A wrapper for DataCon.mkDataCon that +-- a) makes the worker Id +-- b) makes the wrapper Id if necessary, including +-- allocating its unique (hence monadic) +buildDataCon src_name declared_infix vanilla arg_stricts field_lbls + tyvars ctxt arg_tys tycon res_tys + = do { wrap_name <- newImplicitBinder src_name mkDataConWrapperOcc + ; work_name <- newImplicitBinder src_name mkDataConWorkerOcc + -- This last one takes the name of the data constructor in the source + -- code, which (for Haskell source anyway) will be in the DataName name + -- space, and puts it into the VarName name space + + ; let + stupid_ctxt = mkDataConStupidTheta tycon arg_tys res_tys + data_con = mkDataCon src_name declared_infix vanilla + arg_stricts field_lbls + tyvars stupid_ctxt ctxt + arg_tys tycon res_tys dc_ids + dc_ids = mkDataConIds wrap_name work_name data_con + + ; returnM data_con } + + +-- The stupid context for a data constructor should be limited to +-- the type variables mentioned in the arg_tys +mkDataConStupidTheta tycon arg_tys res_tys + | null stupid_theta = [] -- The common case + | otherwise = filter in_arg_tys stupid_theta + where + tc_subst = zipTopTvSubst (tyConTyVars tycon) res_tys + stupid_theta = substTheta tc_subst (tyConStupidTheta tycon) + -- Start by instantiating the master copy of the + -- stupid theta, taken from the TyCon + + arg_tyvars = tyVarsOfTypes arg_tys + in_arg_tys pred = not $ isEmptyVarSet $ + tyVarsOfPred pred `intersectVarSet` arg_tyvars + +------------------------------------------------------ +mkTyConSelIds :: TyCon -> AlgTyConRhs -> [Id] +mkTyConSelIds tycon rhs + = [ mkRecordSelId tycon fld + | fld <- nub (concatMap dataConFieldLabels (visibleDataCons rhs)) ] + -- We'll check later that fields with the same name + -- from different constructors have the same type. +\end{code} + + +------------------------------------------------------ +\begin{code} +buildClass :: Name -> [TyVar] -> ThetaType + -> [FunDep TyVar] -- Functional dependencies + -> [(Name, DefMeth, Type)] -- Method info + -> RecFlag -> ArgVrcs -- Info for type constructor + -> TcRnIf m n Class + +buildClass class_name tvs sc_theta fds sig_stuff tc_isrec tc_vrcs + = do { tycon_name <- newImplicitBinder class_name mkClassTyConOcc + ; datacon_name <- newImplicitBinder class_name mkClassDataConOcc + -- The class name is the 'parent' for this datacon, not its tycon, + -- because one should import the class to get the binding for + -- the datacon + ; sc_sel_names <- mapM (newImplicitBinder class_name . mkSuperDictSelOcc) + [1..length sc_theta] + -- We number off the superclass selectors, 1, 2, 3 etc so that we + -- can construct names for the selectors. Thus + -- class (C a, C b) => D a b where ... + -- gives superclass selectors + -- D_sc1, D_sc2 + -- (We used to call them D_C, but now we can have two different + -- superclasses both called C!) + + ; fixM (\ clas -> do { -- Only name generation inside loop + + let { op_tys = [ty | (_,_,ty) <- sig_stuff] + ; sc_tys = mkPredTys sc_theta + ; dict_component_tys = sc_tys ++ op_tys + ; sc_sel_ids = [mkDictSelId sc_name clas | sc_name <- sc_sel_names] + ; op_items = [ (mkDictSelId op_name clas, dm_info) + | (op_name, dm_info, _) <- sig_stuff ] } + -- Build the selector id and default method id + + ; dict_con <- buildDataCon datacon_name + False -- Not declared infix + True -- Is vanilla; tyvars same as tycon + (map (const NotMarkedStrict) dict_component_tys) + [{- No labelled fields -}] + tvs [{-No context-}] dict_component_tys + (classTyCon clas) (mkTyVarTys tvs) + + ; let { clas = mkClass class_name tvs fds + sc_theta sc_sel_ids op_items + tycon + + ; tycon = mkClassTyCon tycon_name clas_kind tvs + tc_vrcs rhs clas tc_isrec + -- A class can be recursive, and in the case of newtypes + -- this matters. For example + -- class C a where { op :: C b => a -> b -> Int } + -- Because C has only one operation, it is represented by + -- a newtype, and it should be a *recursive* newtype. + -- [If we don't make it a recursive newtype, we'll expand the + -- newtype like a synonym, but that will lead to an infinite type] + + ; clas_kind = mkArrowKinds (map tyVarKind tvs) liftedTypeKind + + ; rhs = case dict_component_tys of + [rep_ty] -> mkNewTyConRhs tycon dict_con + other -> mkDataTyConRhs [dict_con] + } + ; return clas + })} +\end{code} + + |