X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsExpr.lhs;h=b2aed066491a74a319ce0c8a45e7ce1f7c014dd1;hb=438596897ebbe25a07e1c82085cfbc5bdb00f09e;hp=9030f94c3499e8d429e418dbae5ef4d59ead484d;hpb=68afb16743cafd5b7495771d359891c6dfc5a186;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/DsExpr.lhs b/ghc/compiler/deSugar/DsExpr.lhs index 9030f94..b2aed06 100644 --- a/ghc/compiler/deSugar/DsExpr.lhs +++ b/ghc/compiler/deSugar/DsExpr.lhs @@ -1,69 +1,111 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 +% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[DsExpr]{Matching expressions (Exprs)} \begin{code} +module DsExpr ( dsExpr, dsLet ) where + #include "HsVersions.h" -module DsExpr ( dsExpr ) where -import Ubiq -import DsLoop -- partly to get dsBinds, partly to chk dsExpr +import HsSyn ( failureFreePat, + HsExpr(..), OutPat(..), HsLit(..), ArithSeqInfo(..), + Stmt(..), StmtCtxt(..), Match(..), HsBinds(..), MonoBinds(..), + ) +import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, + TypecheckedStmt, + maybeBoxedPrimType -import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..), - Match, Qual, HsBinds, Stmt, PolyType ) -import TcHsSyn ( TypecheckedHsExpr(..), TypecheckedHsBinds(..), - TypecheckedRecordBinds(..), TypecheckedPat(..) ) import CoreSyn import DsMonad +import DsBinds ( dsMonoBinds ) +import DsGRHSs ( dsGuarded ) import DsCCall ( dsCCall ) import DsListComp ( dsListComp ) -import DsUtils ( mkAppDs, mkConDs, mkPrimDs, dsExprToAtom, - mkErrorAppDs, showForErr, EquationInfo, - MatchResult - ) -import Match ( matchWrapper ) +import DsUtils ( mkErrorAppDs ) +import Match ( matchWrapper, matchSimply ) -import CoreUnfold ( UnfoldingDetails(..), UnfoldingGuidance(..), - FormSummary ) -import CoreUtils ( coreExprType, substCoreExpr, argToExpr, - mkCoreIfThenElse, unTagBinders ) +import CoreUtils ( coreExprType ) import CostCentre ( mkUserCC ) -import FieldLabel ( fieldLabelType, FieldLabel ) -import Id ( mkTupleCon, idType, nullIdEnv, addOneToIdEnv, - getIdUnfolding, dataConArgTys, dataConFieldLabels, - recordSelectorFieldLabel +import FieldLabel ( FieldLabel ) +import Id ( Id, idType, recordSelectorFieldLabel ) +import Const ( Con(..) ) +import DataCon ( DataCon, dataConId, dataConTyCon, dataConArgTys, dataConFieldLabels ) +import Const ( mkMachInt, Literal(..) ) +import PrelVals ( rEC_CON_ERROR_ID, rEC_UPD_ERROR_ID, iRREFUT_PAT_ERROR_ID ) +import TyCon ( isNewTyCon ) +import DataCon ( isExistentialDataCon ) +import Type ( splitFunTys, mkTyConApp, + splitAlgTyConApp, splitTyConApp_maybe, + splitAppTy, isUnLiftedType, Type ) -import Literal ( mkMachInt, Literal(..) ) -import MagicUFs ( MagicUnfoldingFun ) -import Name ( Name{--O only-} ) -import PprStyle ( PprStyle(..) ) -import PprType ( GenType ) -import PrelInfo ( mkTupleTy, unitTy, nilDataCon, consDataCon, - charDataCon, charTy, rEC_CON_ERROR_ID, - rEC_UPD_ERROR_ID +import TysWiredIn ( tupleCon, unboxedTupleCon, + consDataCon, listTyCon, mkListTy, + charDataCon, charTy, stringTy ) -import Pretty ( ppShow, ppBesides, ppPStr, ppStr ) -import TyCon ( isDataTyCon, isNewTyCon ) -import Type ( splitSigmaTy, splitFunTy, typePrimRep, - getAppDataTyCon, getAppTyCon, applyTy - ) -import TyVar ( nullTyVarEnv, addOneToTyVarEnv, GenTyVar{-instance Eq-} ) -import Usage ( UVar(..) ) -import Util ( zipEqual, pprError, panic, assertPanic ) +import BasicTypes ( RecFlag(..) ) +import Maybes ( maybeToBool ) +import Util ( zipEqual, zipWithEqual ) +import Outputable +\end{code} -maybeBoxedPrimType = panic "DsExpr.maybeBoxedPrimType" -splitTyArgs = panic "DsExpr.splitTyArgs" -mk_nil_con ty = mkCon nilDataCon [] [ty] [] -- micro utility... -\end{code} +%************************************************************************ +%* * +\subsection{dsLet} +%* * +%************************************************************************ + +@dsLet@ is a match-result transformer, taking the MatchResult for the body +and transforming it into one for the let-bindings enclosing the body. + +This may seem a bit odd, but (source) let bindings can contain unboxed +binds like -The funny business to do with variables is that we look them up in the -Id-to-Id and Id-to-Id maps that the monadery is carrying -around; if we get hits, we use the value accordingly. + C x# = e + +This must be transformed to a case expression and, if the type has +more than one constructor, may fail. + +\begin{code} +dsLet :: TypecheckedHsBinds -> CoreExpr -> DsM CoreExpr + +dsLet EmptyBinds body + = returnDs body + +dsLet (ThenBinds b1 b2) body + = dsLet b2 body `thenDs` \ body' -> + dsLet b1 body' + +-- Special case for bindings which bind unlifted variables +dsLet (MonoBind (AbsBinds [] [] binder_triples bind) sigs is_rec) body + | or [isUnLiftedType (idType g) | (_, g, l) <- binder_triples] + = ASSERT (case is_rec of {NonRecursive -> True; other -> False}) + putSrcLocDs loc $ + dsGuarded grhss `thenDs` \ rhs -> + let + body' = foldr bind body binder_triples + bind (tyvars, g, l) body = ASSERT( null tyvars ) + bindNonRec g (Var l) body + in + mkErrorAppDs iRREFUT_PAT_ERROR_ID result_ty (showSDoc (ppr pat)) `thenDs` \ error_expr -> + matchSimply rhs PatBindMatch pat body' error_expr + where + PatMonoBind pat grhss loc = bind + result_ty = coreExprType body + +-- Ordinary case for bindings +dsLet (MonoBind binds sigs is_rec) body + = dsMonoBinds False binds [] `thenDs` \ prs -> + case is_rec of + Recursive -> returnDs (Let (Rec prs) body) + NonRecursive -> returnDs (foldr mk_let body prs) + where + mk_let (bndr,rhs) body = Let (NonRec bndr rhs) body +\end{code} %************************************************************************ %* * @@ -74,7 +116,7 @@ around; if we get hits, we use the value accordingly. \begin{code} dsExpr :: TypecheckedHsExpr -> DsM CoreExpr -dsExpr (HsVar var) = dsApp (HsVar var) [] +dsExpr e@(HsVar var) = returnDs (Var var) \end{code} %************************************************************************ @@ -101,14 +143,16 @@ See also below where we look for @DictApps@ for \tr{plusInt}, etc. \begin{code} dsExpr (HsLitOut (HsString s) _) | _NULL_ s - = returnDs (mk_nil_con charTy) + = returnDs (mkNilExpr charTy) | _LENGTH_ s == 1 = let - the_char = mkCon charDataCon [] [] [LitArg (MachChar (_HEAD_ s))] - the_nil = mk_nil_con charTy + the_char = mkConApp charDataCon [mkLit (MachChar (_HEAD_ s))] + the_nil = mkNilExpr charTy + the_cons = mkConApp consDataCon [Type charTy, the_char, the_nil] in - mkConDs consDataCon [charTy] [the_char, the_nil] + returnDs the_cons + -- "_" => build (\ c n -> c 'c' n) -- LATER @@ -137,58 +181,60 @@ dsExpr (HsLitOut (HsString str) _) -- the Core-to-STG pass will wrap it in an application of "unpackCStringId". dsExpr (HsLitOut (HsString str) _) - = returnDs (Lit (NoRepStr str)) + = returnDs (mkLit (NoRepStr str stringTy)) -dsExpr (HsLitOut (HsLitLit s) ty) - = returnDs ( mkCon data_con [] [] [LitArg (MachLitLit s kind)] ) +dsExpr (HsLitOut (HsLitLit str) ty) + = returnDs ( mkConApp data_con [mkLit (MachLitLit str prim_ty)] ) where - (data_con, kind) + (data_con, prim_ty) = case (maybeBoxedPrimType ty) of - Just (boxing_data_con, prim_ty) - -> (boxing_data_con, typePrimRep prim_ty) + Just (boxing_data_con, prim_ty) -> (boxing_data_con, prim_ty) Nothing - -> pprError "ERROR: ``literal-literal'' not a single-constructor type: " - (ppBesides [ppPStr s, ppStr "; type: ", ppr PprDebug ty]) + -> pprPanic "ERROR: ``literal-literal'' not a single-constructor type: " + (hcat [ptext str, text "; type: ", ppr ty]) -dsExpr (HsLitOut (HsInt i) _) - = returnDs (Lit (NoRepInteger i)) +dsExpr (HsLitOut (HsInt i) ty) + = returnDs (mkLit (NoRepInteger i ty)) -dsExpr (HsLitOut (HsFrac r) _) - = returnDs (Lit (NoRepRational r)) +dsExpr (HsLitOut (HsFrac r) ty) + = returnDs (mkLit (NoRepRational r ty)) -- others where we know what to do: dsExpr (HsLitOut (HsIntPrim i) _) - = if (i >= toInteger minInt && i <= toInteger maxInt) then - returnDs (Lit (mkMachInt i)) - else - error ("ERROR: Int constant " ++ show i ++ out_of_range_msg) + | (i >= toInteger minInt && i <= toInteger maxInt) + = returnDs (mkLit (mkMachInt i)) + | otherwise + = error ("ERROR: Int constant " ++ show i ++ out_of_range_msg) dsExpr (HsLitOut (HsFloatPrim f) _) - = returnDs (Lit (MachFloat f)) + = returnDs (mkLit (MachFloat f)) -- ToDo: range checking needed! dsExpr (HsLitOut (HsDoublePrim d) _) - = returnDs (Lit (MachDouble d)) + = returnDs (mkLit (MachDouble d)) -- ToDo: range checking needed! dsExpr (HsLitOut (HsChar c) _) - = returnDs ( mkCon charDataCon [] [] [LitArg (MachChar c)] ) + = returnDs ( mkConApp charDataCon [mkLit (MachChar c)] ) dsExpr (HsLitOut (HsCharPrim c) _) - = returnDs (Lit (MachChar c)) + = returnDs (mkLit (MachChar c)) dsExpr (HsLitOut (HsStringPrim s) _) - = returnDs (Lit (MachStr s)) + = returnDs (mkLit (MachStr s)) -- end of literals magic. -- dsExpr expr@(HsLam a_Match) = matchWrapper LambdaMatch [a_Match] "lambda" `thenDs` \ (binders, matching_code) -> - returnDs ( mkValLam binders matching_code ) + returnDs (mkLams binders matching_code) + +dsExpr expr@(HsApp fun arg) + = dsExpr fun `thenDs` \ core_fun -> + dsExpr arg `thenDs` \ core_arg -> + returnDs (core_fun `App` core_arg) -dsExpr expr@(HsApp e1 e2) = dsApp expr [] -dsExpr expr@(OpApp e1 op e2) = dsApp expr [] \end{code} Operator sections. At first it looks as if we can convert @@ -213,38 +259,42 @@ If \tr{expr} is actually just a variable, say, then the simplifier will sort it out. \begin{code} +dsExpr (OpApp e1 op _ e2) + = dsExpr op `thenDs` \ core_op -> + -- for the type of y, we need the type of op's 2nd argument + let + (x_ty:y_ty:_, _) = splitFunTys (coreExprType core_op) + in + dsExpr e1 `thenDs` \ x_core -> + dsExpr e2 `thenDs` \ y_core -> + returnDs (mkApps core_op [x_core, y_core]) + dsExpr (SectionL expr op) - = dsExpr op `thenDs` \ core_op -> - dsExpr expr `thenDs` \ core_expr -> - dsExprToAtom core_expr $ \ y_atom -> - - -- for the type of x, we need the type of op's 2nd argument + = dsExpr op `thenDs` \ core_op -> + -- for the type of y, we need the type of op's 2nd argument let - x_ty = case (splitSigmaTy (coreExprType core_op)) of { (_, _, tau_ty) -> - case (splitTyArgs tau_ty) of { - ((_:arg2_ty:_), _) -> arg2_ty; - _ -> panic "dsExpr:SectionL:arg 2 ty" - }} + (x_ty:y_ty:_, _) = splitFunTys (coreExprType core_op) in - newSysLocalDs x_ty `thenDs` \ x_id -> - returnDs (mkValLam [x_id] (core_op `App` y_atom `App` VarArg x_id)) + dsExpr expr `thenDs` \ x_core -> + newSysLocalDs x_ty `thenDs` \ x_id -> + newSysLocalDs y_ty `thenDs` \ y_id -> + + returnDs (bindNonRec x_id x_core $ + Lam y_id (mkApps core_op [Var x_id, Var y_id])) -- dsExpr (SectionR op expr) -- \ x -> op x expr dsExpr (SectionR op expr) = dsExpr op `thenDs` \ core_op -> - dsExpr expr `thenDs` \ core_expr -> - dsExprToAtom core_expr $ \ y_atom -> - - -- for the type of x, we need the type of op's 1st argument + -- for the type of x, we need the type of op's 2nd argument let - x_ty = case (splitSigmaTy (coreExprType core_op)) of { (_, _, tau_ty) -> - case (splitTyArgs tau_ty) of { - ((arg1_ty:_), _) -> arg1_ty; - _ -> panic "dsExpr:SectionR:arg 1 ty" - }} + (x_ty:y_ty:_, _) = splitFunTys (coreExprType core_op) in - newSysLocalDs x_ty `thenDs` \ x_id -> - returnDs (mkValLam [x_id] (core_op `App` VarArg x_id `App` y_atom)) + dsExpr expr `thenDs` \ y_core -> + newSysLocalDs x_ty `thenDs` \ x_id -> + newSysLocalDs y_ty `thenDs` \ y_id -> + + returnDs (bindNonRec y_id y_core $ + Lam x_id (mkApps core_op [Var x_id, Var y_id])) dsExpr (CCall label args may_gc is_asm result_ty) = mapDs dsExpr args `thenDs` \ core_args -> @@ -254,34 +304,59 @@ dsExpr (CCall label args may_gc is_asm result_ty) dsExpr (HsSCC cc expr) = dsExpr expr `thenDs` \ core_expr -> getModuleAndGroupDs `thenDs` \ (mod_name, group_name) -> - returnDs ( SCC (mkUserCC cc mod_name group_name) core_expr) + returnDs (Note (SCC (mkUserCC cc mod_name group_name)) core_expr) -dsExpr expr@(HsCase discrim matches src_loc) - = putSrcLocDs src_loc $ +-- special case to handle unboxed tuple patterns + +dsExpr (HsCase discrim matches@[PatMatch (TuplePat ps boxed) (GRHSMatch rhs)] + src_loc) + | all var_pat ps + = putSrcLocDs src_loc $ dsExpr discrim `thenDs` \ core_discrim -> matchWrapper CaseMatch matches "case" `thenDs` \ ([discrim_var], matching_code) -> - returnDs ( mkCoLetAny (NonRec discrim_var core_discrim) matching_code ) - -dsExpr (ListComp expr quals) - = dsExpr expr `thenDs` \ core_expr -> - dsListComp core_expr quals - -dsExpr (HsLet binds expr) - = dsBinds binds `thenDs` \ core_binds -> - dsExpr expr `thenDs` \ core_expr -> - returnDs ( mkCoLetsAny core_binds core_expr ) + case matching_code of + Case (Var x) bndr alts | x == discrim_var -> + returnDs (Case core_discrim bndr alts) + _ -> panic ("dsExpr: tuple pattern:\n" ++ showSDoc (ppr matching_code)) -dsExpr (HsDoOut stmts m_id mz_id src_loc) +dsExpr (HsCase discrim matches src_loc) + = putSrcLocDs src_loc $ + dsExpr discrim `thenDs` \ core_discrim -> + matchWrapper CaseMatch matches "case" `thenDs` \ ([discrim_var], matching_code) -> + returnDs (bindNonRec discrim_var core_discrim matching_code) + +dsExpr (HsLet binds body) + = dsExpr body `thenDs` \ body' -> + dsLet binds body' + +dsExpr (HsDoOut do_or_lc stmts return_id then_id zero_id result_ty src_loc) + | maybeToBool maybe_list_comp + = -- Special case for list comprehensions + putSrcLocDs src_loc $ + dsListComp stmts elt_ty + + | otherwise = putSrcLocDs src_loc $ - panic "dsExpr:HsDoOut" + dsDo do_or_lc stmts return_id then_id zero_id result_ty + where + maybe_list_comp + = case (do_or_lc, splitTyConApp_maybe result_ty) of + (ListComp, Just (tycon, [elt_ty])) + | tycon == listTyCon + -> Just elt_ty + other -> Nothing + -- We need the ListComp form to use deListComp (rather than the "do" form) + -- because the "return" in a do block is a call to "PrelBase.return", and + -- not a ReturnStmt. Only the ListComp form has ReturnStmts + + Just elt_ty = maybe_list_comp dsExpr (HsIf guard_expr then_expr else_expr src_loc) = putSrcLocDs src_loc $ dsExpr guard_expr `thenDs` \ core_guard -> dsExpr then_expr `thenDs` \ core_then -> dsExpr else_expr `thenDs` \ core_else -> - returnDs (mkCoreIfThenElse core_guard core_then core_else) - + returnDs (mkIfThenElse core_guard core_then core_else) \end{code} @@ -290,9 +365,11 @@ Type lambda and application \begin{code} dsExpr (TyLam tyvars expr) = dsExpr expr `thenDs` \ core_expr -> - returnDs (mkTyLam tyvars core_expr) + returnDs (mkLams tyvars core_expr) -dsExpr expr@(TyApp e tys) = dsApp expr [] +dsExpr (TyApp expr tys) + = dsExpr expr `thenDs` \ core_expr -> + returnDs (mkTyApps core_expr tys) \end{code} @@ -300,59 +377,57 @@ Various data construction things ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \begin{code} dsExpr (ExplicitListOut ty xs) - = case xs of - [] -> returnDs (mk_nil_con ty) - (y:ys) -> - dsExpr y `thenDs` \ core_hd -> - dsExpr (ExplicitListOut ty ys) `thenDs` \ core_tl -> - mkConDs consDataCon [ty] [core_hd, core_tl] - -dsExpr (ExplicitTuple expr_list) - = mapDs dsExpr expr_list `thenDs` \ core_exprs -> - mkConDs (mkTupleCon (length expr_list)) - (map coreExprType core_exprs) - core_exprs - --- Two cases, one for ordinary constructors and one for newtype constructors -dsExpr (HsCon con tys args) - | isDataTyCon tycon -- The usual datatype case - = mapDs dsExpr args `thenDs` \ args_exprs -> - mkConDs con tys args_exprs - - | otherwise -- The newtype case - = ASSERT( isNewTyCon tycon ) - ASSERT( null rest_args ) - dsExpr first_arg `thenDs` \ arg_expr -> - returnDs (Coerce (CoerceIn con) result_ty arg_expr) + = go xs + where + list_ty = mkListTy ty + + go [] = returnDs (mkNilExpr ty) + go (x:xs) = dsExpr x `thenDs` \ core_x -> + go xs `thenDs` \ core_xs -> + returnDs (mkConApp consDataCon [Type ty, core_x, core_xs]) +dsExpr (ExplicitTuple expr_list boxed) + = mapDs dsExpr expr_list `thenDs` \ core_exprs -> + returnDs (mkConApp ((if boxed + then tupleCon + else unboxedTupleCon) (length expr_list)) + (map (Type . coreExprType) core_exprs ++ core_exprs)) + +dsExpr (HsCon con_id [ty] [arg]) + | isNewTyCon tycon + = dsExpr arg `thenDs` \ arg' -> + returnDs (Note (Coerce result_ty (coreExprType arg')) arg') where - (first_arg:rest_args) = args - (args_tys, result_ty) = splitFunTy (foldl applyTy (idType con) tys) - (tycon,_) = getAppTyCon result_ty + result_ty = mkTyConApp tycon [ty] + tycon = dataConTyCon con_id + +dsExpr (HsCon con_id tys args) + = mapDs dsExpr args `thenDs` \ args2 -> + returnDs (mkConApp con_id (map Type tys ++ args2)) dsExpr (ArithSeqOut expr (From from)) = dsExpr expr `thenDs` \ expr2 -> dsExpr from `thenDs` \ from2 -> - mkAppDs expr2 [] [from2] + returnDs (App expr2 from2) dsExpr (ArithSeqOut expr (FromTo from two)) = dsExpr expr `thenDs` \ expr2 -> dsExpr from `thenDs` \ from2 -> dsExpr two `thenDs` \ two2 -> - mkAppDs expr2 [] [from2, two2] + returnDs (mkApps expr2 [from2, two2]) dsExpr (ArithSeqOut expr (FromThen from thn)) = dsExpr expr `thenDs` \ expr2 -> dsExpr from `thenDs` \ from2 -> dsExpr thn `thenDs` \ thn2 -> - mkAppDs expr2 [] [from2, thn2] + returnDs (mkApps expr2 [from2, thn2]) dsExpr (ArithSeqOut expr (FromThenTo from thn two)) = dsExpr expr `thenDs` \ expr2 -> dsExpr from `thenDs` \ from2 -> dsExpr thn `thenDs` \ thn2 -> dsExpr two `thenDs` \ two2 -> - mkAppDs expr2 [] [from2, thn2, two2] + returnDs (mkApps expr2 [from2, thn2, two2]) \end{code} Record construction and update @@ -373,26 +448,20 @@ before printing it as \begin{code} -dsExpr (RecordCon con_expr rbinds) +dsExpr (RecordConOut data_con con_expr rbinds) = dsExpr con_expr `thenDs` \ con_expr' -> let - con_id = get_con con_expr' - (arg_tys, _) = splitFunTy (coreExprType con_expr') + (arg_tys, _) = splitFunTys (coreExprType con_expr') mk_arg (arg_ty, lbl) = case [rhs | (sel_id,rhs,_) <- rbinds, lbl == recordSelectorFieldLabel sel_id] of (rhs:rhss) -> ASSERT( null rhss ) dsExpr rhs - [] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showForErr lbl) + [] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showSDoc (ppr lbl)) in - mapDs mk_arg (arg_tys `zipEqual` dataConFieldLabels con_id) `thenDs` \ con_args -> - mkAppDs con_expr' [] con_args - where - -- "con_expr'" is simply an application of the constructor Id - -- to types and (perhaps) dictionaries. This gets the constructor... - get_con (Var con) = con - get_con (App fun _) = get_con fun + mapDs mk_arg (zipEqual "dsExpr:RecordCon" arg_tys (dataConFieldLabels data_con)) `thenDs` \ con_args -> + returnDs (mkApps con_expr' con_args) \end{code} Record update is a little harder. Suppose we have the decl: @@ -417,49 +486,58 @@ might do some argument-evaluation first; and may have to throw away some dictionaries. \begin{code} -dsExpr (RecordUpdOut record_expr dicts rbinds) - = dsExpr record_expr `thenDs` \ record_expr' -> +dsExpr (RecordUpdOut record_expr record_out_ty dicts rbinds) + = dsExpr record_expr `thenDs` \ record_expr' -> -- Desugar the rbinds, and generate let-bindings if -- necessary so that we don't lose sharing - dsRbinds rbinds $ \ rbinds' -> + + let + ds_rbind (sel_id, rhs, pun_flag) + = dsExpr rhs `thenDs` \ rhs' -> + returnDs (recordSelectorFieldLabel sel_id, rhs') + in + mapDs ds_rbind rbinds `thenDs` \ rbinds' -> let - record_ty = coreExprType record_expr' - (tycon, inst_tys, cons) = _trace "getAppDataTyCon.DsExpr" $ getAppDataTyCon record_ty - cons_to_upd = filter has_all_fields cons + record_in_ty = coreExprType record_expr' + (tycon, in_inst_tys, cons) = splitAlgTyConApp record_in_ty + (_, out_inst_tys, _) = splitAlgTyConApp record_out_ty + cons_to_upd = filter has_all_fields cons -- initial_args are passed to every constructor - initial_args = map TyArg inst_tys ++ map VarArg dicts + initial_args = map Type out_inst_tys ++ map Var dicts - mk_val_arg (field, arg_id) - = case [arg | (f, arg) <- rbinds', - field == recordSelectorFieldLabel f] of - (arg:args) -> ASSERT(null args) - arg - [] -> VarArg arg_id + mk_val_arg field old_arg_id + = case [rhs | (f, rhs) <- rbinds', field == f] of + (rhs:rest) -> ASSERT(null rest) rhs + [] -> Var old_arg_id mk_alt con - = newSysLocalsDs (dataConArgTys con inst_tys) `thenDs` \ arg_ids -> + = newSysLocalsDs (dataConArgTys con in_inst_tys) `thenDs` \ arg_ids -> let - val_args = map mk_val_arg (dataConFieldLabels con `zipEqual` arg_ids) + val_args = zipWithEqual "dsExpr:RecordUpd" mk_val_arg + (dataConFieldLabels con) arg_ids + rhs = mkApps (mkApps (Var (dataConId con)) initial_args) val_args in - returnDs (con, arg_ids, mkGenApp (mkGenApp (Var con) initial_args) val_args) + returnDs (DataCon con, arg_ids, rhs) mk_default | length cons_to_upd == length cons - = returnDs NoDefault + = returnDs [] | otherwise - = newSysLocalDs record_ty `thenDs` \ deflt_id -> - mkErrorAppDs rEC_UPD_ERROR_ID record_ty "" `thenDs` \ err -> - returnDs (BindDefault deflt_id err) + = mkErrorAppDs rEC_UPD_ERROR_ID record_out_ty "" `thenDs` \ err -> + returnDs [(DEFAULT, [], err)] in + -- Record stuff doesn't work for existentials + ASSERT( all (not . isExistentialDataCon) cons ) + + newSysLocalDs record_in_ty `thenDs` \ case_bndr -> mapDs mk_alt cons_to_upd `thenDs` \ alts -> mk_default `thenDs` \ deflt -> - returnDs (Case record_expr' (AlgAlts alts deflt)) - + returnDs (Case record_expr' case_bndr (alts ++ deflt)) where - has_all_fields :: Id -> Bool + has_all_fields :: DataCon -> Bool has_all_fields con_id = all ok rbinds where @@ -475,183 +553,104 @@ complicated; reminiscent of fully-applied constructors. \begin{code} dsExpr (DictLam dictvars expr) = dsExpr expr `thenDs` \ core_expr -> - returnDs( mkValLam dictvars core_expr ) + returnDs (mkLams dictvars core_expr) ------------------ -dsExpr expr@(DictApp e dicts) -- becomes a curried application - = dsApp expr [] +dsExpr (DictApp expr dicts) -- becomes a curried application + = dsExpr expr `thenDs` \ core_expr -> + returnDs (foldl (\f d -> f `App` (Var d)) core_expr dicts) \end{code} -@SingleDicts@ become @Locals@; @Dicts@ turn into tuples, unless -of length 0 or 1. -@ClassDictLam dictvars methods expr@ is ``the opposite'': -\begin{verbatim} -\ x -> case x of ( dictvars-and-methods-tuple ) -> expr -\end{verbatim} \begin{code} -dsExpr (SingleDict dict) -- just a local - = lookupEnvWithDefaultDs dict (Var dict) - -dsExpr (Dictionary dicts methods) - = -- hey, these things may have been substituted away... - zipWithDs lookupEnvWithDefaultDs - dicts_and_methods dicts_and_methods_exprs - `thenDs` \ core_d_and_ms -> - (case num_of_d_and_ms of - 0 -> returnDs cocon_unit -- unit - - 1 -> returnDs (head core_d_and_ms) -- just a single Id - - _ -> -- tuple 'em up - mkConDs (mkTupleCon num_of_d_and_ms) - (map coreExprType core_d_and_ms) - core_d_and_ms - ) - where - dicts_and_methods = dicts ++ methods - dicts_and_methods_exprs = map Var dicts_and_methods - num_of_d_and_ms = length dicts_and_methods - -dsExpr (ClassDictLam dicts methods expr) - = dsExpr expr `thenDs` \ core_expr -> - case num_of_d_and_ms of - 0 -> newSysLocalDs unitTy `thenDs` \ new_x -> - returnDs (mkValLam [new_x] core_expr) - - 1 -> -- no untupling - returnDs (mkValLam dicts_and_methods core_expr) - - _ -> -- untuple it - newSysLocalDs tuple_ty `thenDs` \ new_x -> - returnDs ( - Lam (ValBinder new_x) - (Case (Var new_x) - (AlgAlts - [(tuple_con, dicts_and_methods, core_expr)] - NoDefault))) - where - num_of_d_and_ms = length dicts + length methods - dicts_and_methods = dicts ++ methods - tuple_ty = mkTupleTy num_of_d_and_ms (map idType dicts_and_methods) - tuple_con = mkTupleCon num_of_d_and_ms #ifdef DEBUG -- HsSyn constructs that just shouldn't be here: -dsExpr (HsDo _ _) = panic "dsExpr:HsDo" +dsExpr (HsDo _ _ _) = panic "dsExpr:HsDo" dsExpr (ExplicitList _) = panic "dsExpr:ExplicitList" dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig" dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn" #endif -cocon_unit = mkCon (mkTupleCon 0) [] [] [] -- out here to avoid CAF (sigh) out_of_range_msg -- ditto = " out of range: [" ++ show minInt ++ ", " ++ show maxInt ++ "]\n" \end{code} %-------------------------------------------------------------------- -@(dsApp e [t_1,..,t_n, e_1,..,e_n])@ returns something with the same -value as: -\begin{verbatim} -e t_1 ... t_n e_1 .. e_n -\end{verbatim} - -We're doing all this so we can saturate constructors (as painlessly as -possible). +Basically does the translation given in the Haskell~1.3 report: \begin{code} -type DsCoreArg = GenCoreArg CoreExpr{-NB!-} TyVar UVar - -dsApp :: TypecheckedHsExpr -- expr to desugar - -> [DsCoreArg] -- accumulated ty/val args: NB: - -> DsM CoreExpr -- final result - -dsApp (HsApp e1 e2) args - = dsExpr e2 `thenDs` \ core_e2 -> - dsApp e1 (VarArg core_e2 : args) - -dsApp (OpApp e1 op e2) args - = dsExpr e1 `thenDs` \ core_e1 -> - dsExpr e2 `thenDs` \ core_e2 -> - dsApp op (VarArg core_e1 : VarArg core_e2 : args) - -dsApp (DictApp expr dicts) args - = -- now, those dicts may have been substituted away... - zipWithDs lookupEnvWithDefaultDs dicts (map Var dicts) - `thenDs` \ core_dicts -> - dsApp expr (map VarArg core_dicts ++ args) - -dsApp (TyApp expr tys) args - = dsApp expr (map TyArg tys ++ args) - --- we might should look out for SectionLs, etc., here, but we don't - -dsApp (HsVar v) args - = lookupEnvDs v `thenDs` \ maybe_expr -> - case maybe_expr of - Just expr -> apply_to_args expr args - - Nothing -> -- we're only saturating constructors and PrimOps - case getIdUnfolding v of - GenForm _ _ the_unfolding EssentialUnfolding - -> do_unfold nullTyVarEnv nullIdEnv (unTagBinders the_unfolding) args - - _ -> apply_to_args (Var v) args - - -dsApp anything_else args - = dsExpr anything_else `thenDs` \ core_expr -> - apply_to_args core_expr args - --- a DsM version of mkGenApp: -apply_to_args :: CoreExpr -> [DsCoreArg] -> DsM CoreExpr - -apply_to_args fun args +dsDo :: StmtCtxt + -> [TypecheckedStmt] + -> Id -- id for: return m + -> Id -- id for: (>>=) m + -> Id -- id for: zero m + -> Type -- Element type; the whole expression has type (m t) + -> DsM CoreExpr + +dsDo do_or_lc stmts return_id then_id zero_id result_ty = let - (ty_args, val_args) = foldr sep ([],[]) args + (_, b_ty) = splitAppTy result_ty -- result_ty must be of the form (m b) + + go [ReturnStmt expr] + = dsExpr expr `thenDs` \ expr2 -> + returnDs (mkApps (Var return_id) [Type b_ty, expr2]) + + go (GuardStmt expr locn : stmts) + = do_expr expr locn `thenDs` \ expr2 -> + go stmts `thenDs` \ rest -> + returnDs (mkIfThenElse expr2 rest (App (Var zero_id) (Type b_ty))) + + go (ExprStmt expr locn : stmts) + = do_expr expr locn `thenDs` \ expr2 -> + let + (_, a_ty) = splitAppTy (coreExprType expr2) -- Must be of form (m a) + in + if null stmts then + returnDs expr2 + else + go stmts `thenDs` \ rest -> + newSysLocalDs a_ty `thenDs` \ ignored_result_id -> + returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, + Lam ignored_result_id rest]) + + go (LetStmt binds : stmts ) + = go stmts `thenDs` \ rest -> + dsLet binds rest + + go (BindStmt pat expr locn : stmts) + = putSrcLocDs locn $ + dsExpr expr `thenDs` \ expr2 -> + let + (_, a_ty) = splitAppTy (coreExprType expr2) -- Must be of form (m a) + zero_expr = TyApp (HsVar zero_id) [b_ty] + main_match = PatMatch pat (SimpleMatch ( + HsDoOut do_or_lc stmts return_id then_id zero_id result_ty locn)) + the_matches + = if failureFreePat pat + then [main_match] + else [main_match, PatMatch (WildPat a_ty) (SimpleMatch zero_expr)] + in + matchWrapper DoBindMatch the_matches match_msg + `thenDs` \ (binders, matching_code) -> + returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, + mkLams binders matching_code]) in - mkAppDs fun ty_args val_args - where - sep a@(LitArg l) (tys,vals) = (tys, (Lit l):vals) - sep a@(VarArg e) (tys,vals) = (tys, e:vals) - sep a@(TyArg ty) (tys,vals) = (ty:tys, vals) - sep a@(UsageArg _) _ = panic "DsExpr:apply_to_args:UsageArg" -\end{code} + go stmts + where + do_expr expr locn = putSrcLocDs locn (dsExpr expr) -\begin{code} -dsRbinds :: TypecheckedRecordBinds -- The field bindings supplied - -> ([(Id, CoreArg)] -> DsM CoreExpr) -- A continuation taking the field - -- bindings with atomic rhss - -> DsM CoreExpr -- The result of the continuation, - -- wrapped in suitable Lets - -dsRbinds [] continue_with - = continue_with [] - -dsRbinds ((sel_id, rhs, pun_flag) : rbinds) continue_with - = dsExpr rhs `thenDs` \ rhs' -> - dsExprToAtom rhs' $ \ rhs_atom -> - dsRbinds rbinds $ \ rbinds' -> - continue_with ((sel_id, rhs_atom) : rbinds') -\end{code} + match_msg = case do_or_lc of + DoStmt -> "`do' statement" + ListComp -> "comprehension" +\end{code} \begin{code} -do_unfold ty_env val_env (Lam (TyBinder tyvar) body) (TyArg ty : args) - = do_unfold (addOneToTyVarEnv ty_env tyvar ty) val_env body args - -do_unfold ty_env val_env (Lam (ValBinder binder) body) (VarArg expr : args) - = dsExprToAtom expr $ \ arg_atom -> - do_unfold ty_env - (addOneToIdEnv val_env binder (argToExpr arg_atom)) - body args - -do_unfold ty_env val_env body args - = -- Clone the remaining part of the template - uniqSMtoDsM (substCoreExpr val_env ty_env body) `thenDs` \ body' -> - - -- Apply result to remaining arguments - apply_to_args body' args +var_pat (WildPat _) = True +var_pat (VarPat _) = True +var_pat _ = False \end{code} +