X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsExpr.lhs;h=5d7ff191dfa44dd71fc58af6af0bf7a46e76b395;hb=10fcd78ccde892feccda3f5eacd221c1de75feea;hp=4f2760ec479e9650aac5fe47de9e97d0d781a2a2;hpb=f7ecf7234c224489be8a5e63fced903b655d92ee;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/DsExpr.lhs b/ghc/compiler/deSugar/DsExpr.lhs index 4f2760e..5d7ff19 100644 --- a/ghc/compiler/deSugar/DsExpr.lhs +++ b/ghc/compiler/deSugar/DsExpr.lhs @@ -1,197 +1,163 @@ % -% (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} -#include "HsVersions.h" +module DsExpr ( dsExpr, dsLet ) where -module DsExpr ( dsExpr ) where +#include "HsVersions.h" -IMP_Ubiq() -IMPORT_DELOOPER(DsLoop) -- partly to get dsBinds, partly to chk dsExpr import HsSyn ( failureFreePat, HsExpr(..), OutPat(..), HsLit(..), ArithSeqInfo(..), - Stmt(..), Match(..), Qualifier, HsBinds, PolyType, - GRHSsAndBinds - ) -import TcHsSyn ( SYN_IE(TypecheckedHsExpr), SYN_IE(TypecheckedHsBinds), - SYN_IE(TypecheckedRecordBinds), SYN_IE(TypecheckedPat), - SYN_IE(TypecheckedStmt) + Stmt(..), HsMatchContext(..), HsDoContext(..), + Match(..), HsBinds(..), MonoBinds(..), + mkSimpleMatch ) +import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, TypecheckedStmt, outPatType ) + +-- NB: The desugarer, which straddles the source and Core worlds, sometimes +-- needs to see source types (newtypes etc), and sometimes not +-- So WATCH OUT; check each use of split*Ty functions. +-- Sigh. This is a pain. + +import TcType ( tcSplitAppTy, tcSplitFunTys, tcSplitTyConApp_maybe, tcTyConAppArgs, + isIntegerTy, tcSplitTyConApp, isUnLiftedType, Type ) +import Type ( splitFunTys ) import CoreSyn +import CoreUtils ( exprType, mkIfThenElse, bindNonRec ) import DsMonad -import DsCCall ( dsCCall ) -import DsHsSyn ( outPatType ) -import DsListComp ( dsListComp ) -import DsUtils ( mkAppDs, mkConDs, mkPrimDs, dsExprToAtom, - mkErrorAppDs, showForErr, EquationInfo, - MatchResult, SYN_IE(DsCoreArg) +import DsBinds ( dsMonoBinds, AutoScc(..) ) +import DsGRHSs ( dsGuarded ) +import DsCCall ( dsCCall, resultWrapper ) +import DsListComp ( dsListComp, dsPArrComp ) +import DsUtils ( mkErrorAppDs, mkStringLit, mkStringLitFS, + mkConsExpr, mkNilExpr, mkIntegerLit ) -import Match ( matchWrapper ) +import Match ( matchWrapper, matchSimply ) -import CoreUnfold ( Unfolding ) -import CoreUtils ( coreExprType, substCoreExpr, argToExpr, - mkCoreIfThenElse, unTagBinders ) +import FieldLabel ( FieldLabel, fieldLabelTyCon ) import CostCentre ( mkUserCC ) -import FieldLabel ( fieldLabelType, FieldLabel ) -import Id ( mkTupleCon, idType, nullIdEnv, addOneToIdEnv, - getIdUnfolding, dataConArgTys, dataConFieldLabels, - recordSelectorFieldLabel - ) -import Literal ( mkMachInt, Literal(..) ) -import MagicUFs ( MagicUnfoldingFun ) -import Name ( Name{--O only-} ) -import PprStyle ( PprStyle(..) ) -import PprType ( GenType ) -import PrelVals ( rEC_CON_ERROR_ID, rEC_UPD_ERROR_ID, voidId ) -import Pretty ( ppShow, ppBesides, ppPStr, ppStr ) -import TyCon ( isDataTyCon, isNewTyCon ) -import Type ( splitSigmaTy, splitFunTy, typePrimRep, - getAppDataTyConExpandingDicts, getAppTyCon, applyTy, - maybeBoxedPrimType - ) -import TysPrim ( voidTy ) -import TysWiredIn ( mkTupleTy, nilDataCon, consDataCon, - charDataCon, charTy - ) -import TyVar ( nullTyVarEnv, addOneToTyVarEnv, GenTyVar{-instance Eq-} ) -import Usage ( SYN_IE(UVar) ) -import Util ( zipEqual, pprError, panic, assertPanic ) - -mk_nil_con ty = mkCon nilDataCon [] [ty] [] -- micro utility... +import Id ( Id, idType, recordSelectorFieldLabel ) +import PrelInfo ( rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID ) +import DataCon ( DataCon, dataConWrapId, dataConFieldLabels, dataConInstOrigArgTys ) +import DataCon ( isExistentialDataCon ) +import Literal ( Literal(..) ) +import TyCon ( tyConDataCons ) +import TysWiredIn ( tupleCon, listTyCon, charDataCon, intDataCon ) +import BasicTypes ( RecFlag(..), Boxity(..), ipNameName ) +import Maybes ( maybeToBool ) +import PrelNames ( hasKey, ratioTyConKey, toPName ) +import Util ( zipEqual, zipWithEqual ) +import Outputable + +import Ratio ( numerator, denominator ) \end{code} -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. %************************************************************************ %* * -\subsection[DsExpr-vars-and-cons]{Variables and constructors} +\subsection{dsLet} %* * %************************************************************************ -\begin{code} -dsExpr :: TypecheckedHsExpr -> DsM CoreExpr +@dsLet@ is a match-result transformer, taking the @MatchResult@ for the body +and transforming it into one for the let-bindings enclosing the body. -dsExpr e@(HsVar var) = dsApp e [] -\end{code} +This may seem a bit odd, but (source) let bindings can contain unboxed +binds like +\begin{verbatim} + C x# = e +\end{verbatim} +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 +-- We need to do a case right away, rather than building +-- a tuple and doing selections. +-- Silently ignore INLINE pragmas... +dsLet bind@(MonoBind (AbsBinds [] [] exports inlines binds) sigs is_rec) body + | or [isUnLiftedType (idType g) | (_, g, l) <- exports] + = ASSERT (case is_rec of {NonRecursive -> True; other -> False}) + -- Unlifted bindings are always non-recursive + -- and are always a Fun or Pat monobind + -- + -- ToDo: in some bizarre case it's conceivable that there + -- could be dict binds in the 'binds'. (See the notes + -- below. Then pattern-match would fail. Urk.) + case binds of + FunMonoBind fun _ matches loc + -> putSrcLocDs loc $ + matchWrapper (FunRhs fun) matches `thenDs` \ (args, rhs) -> + ASSERT( null args ) -- Functions aren't lifted + returnDs (bindNonRec fun rhs body_w_exports) + + PatMonoBind pat grhss loc + -> putSrcLocDs loc $ + dsGuarded grhss `thenDs` \ rhs -> + mk_error_app pat `thenDs` \ error_expr -> + matchSimply rhs PatBindRhs pat body_w_exports error_expr + + other -> pprPanic "dsLet: unlifted" (ppr bind $$ ppr body) + where + body_w_exports = foldr bind_export body exports + bind_export (tvs, g, l) body = ASSERT( null tvs ) + bindNonRec g (Var l) body + + mk_error_app pat = mkErrorAppDs iRREFUT_PAT_ERROR_ID + (exprType body) + (showSDoc (ppr pat)) + +-- Ordinary case for bindings +dsLet (MonoBind binds sigs is_rec) body + = dsMonoBinds NoSccs binds [] `thenDs` \ prs -> + returnDs (Let (Rec prs) body) + -- Use a Rec regardless of is_rec. + -- Why? Because it allows the MonoBinds to be all + -- mixed up, which is what happens in one rare case + -- Namely, for an AbsBind with no tyvars and no dicts, + -- but which does have dictionary bindings. + -- See notes with TcSimplify.inferLoop [NO TYVARS] + -- It turned out that wrapping a Rec here was the easiest solution + -- + -- NB The previous case dealt with unlifted bindings, so we + -- only have to deal with lifted ones now; so Rec is ok +\end{code} %************************************************************************ %* * -\subsection[DsExpr-literals]{Literals} +\subsection[DsExpr-vars-and-cons]{Variables, constructors, literals} %* * %************************************************************************ -We give int/float literals type Integer and Rational, respectively. -The typechecker will (presumably) have put \tr{from{Integer,Rational}s} -around them. - -ToDo: put in range checks for when converting "i" -(or should that be in the typechecker?) - -For numeric literals, we try to detect there use at a standard type -(Int, Float, etc.) are directly put in the right constructor. -[NB: down with the @App@ conversion.] -Otherwise, we punt, putting in a "NoRep" Core literal (where the -representation decisions are delayed)... - -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) - - | _LENGTH_ s == 1 - = let - the_char = mkCon charDataCon [] [] [LitArg (MachChar (_HEAD_ s))] - the_nil = mk_nil_con charTy - in - mkConDs consDataCon [TyArg charTy, VarArg the_char, VarArg the_nil] - --- "_" => build (\ c n -> c 'c' n) -- LATER - --- "str" ==> build (\ c n -> foldr charTy T c n "str") - -{- LATER: -dsExpr (HsLitOut (HsString str) _) - = newTyVarsDs [alphaTyVar] `thenDs` \ [new_tyvar] -> - let - new_ty = mkTyVarTy new_tyvar - in - newSysLocalsDs [ - charTy `mkFunTy` (new_ty `mkFunTy` new_ty), - new_ty, - mkForallTy [alphaTyVar] - ((charTy `mkFunTy` (alphaTy `mkFunTy` alphaTy)) - `mkFunTy` (alphaTy `mkFunTy` alphaTy)) - ] `thenDs` \ [c,n,g] -> - returnDs (mkBuild charTy new_tyvar c n g ( - foldl App - (CoTyApp (CoTyApp (Var foldrId) charTy) new_ty) *** ensure non-prim type *** - [VarArg c,VarArg n,LitArg (NoRepStr str)])) --} - --- otherwise, leave it as a NoRepStr; --- the Core-to-STG pass will wrap it in an application of "unpackCStringId". - -dsExpr (HsLitOut (HsString str) _) - = returnDs (Lit (NoRepStr str)) - -dsExpr (HsLitOut (HsLitLit s) ty) - = returnDs ( mkCon data_con [] [] [LitArg (MachLitLit s kind)] ) - where - (data_con, kind) - = case (maybeBoxedPrimType ty) of - Just (boxing_data_con, prim_ty) - -> (boxing_data_con, typePrimRep prim_ty) - Nothing - -> pprError "ERROR: ``literal-literal'' not a single-constructor type: " - (ppBesides [ppPStr s, ppStr "; type: ", ppr PprDebug ty]) - -dsExpr (HsLitOut (HsInt i) ty) - = returnDs (Lit (NoRepInteger i ty)) - -dsExpr (HsLitOut (HsFrac r) ty) - = returnDs (Lit (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) - -dsExpr (HsLitOut (HsFloatPrim f) _) - = returnDs (Lit (MachFloat f)) - -- ToDo: range checking needed! - -dsExpr (HsLitOut (HsDoublePrim d) _) - = returnDs (Lit (MachDouble d)) - -- ToDo: range checking needed! - -dsExpr (HsLitOut (HsChar c) _) - = returnDs ( mkCon charDataCon [] [] [LitArg (MachChar c)] ) - -dsExpr (HsLitOut (HsCharPrim c) _) - = returnDs (Lit (MachChar c)) - -dsExpr (HsLitOut (HsStringPrim s) _) - = returnDs (Lit (MachStr s)) +dsExpr :: TypecheckedHsExpr -> DsM CoreExpr --- end of literals magic. -- +dsExpr (HsVar var) = returnDs (Var var) +dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip)) +dsExpr (HsLit lit) = dsLit lit +-- HsOverLit has been gotten rid of by the type checker dsExpr expr@(HsLam a_Match) - = matchWrapper LambdaMatch [a_Match] "lambda" `thenDs` \ (binders, matching_code) -> - returnDs ( mkValLam binders matching_code ) + = matchWrapper LambdaExpr [a_Match] `thenDs` \ (binders, matching_code) -> + returnDs (mkLams binders matching_code) -dsExpr expr@(HsApp e1 e2) = dsApp expr [] -dsExpr expr@(OpApp e1 op e2) = dsApp expr [] +dsExpr expr@(HsApp fun arg) + = dsExpr fun `thenDs` \ core_fun -> + dsExpr arg `thenDs` \ core_arg -> + returnDs (core_fun `App` core_arg) \end{code} Operator sections. At first it looks as if we can convert @@ -216,192 +182,261 @@ 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 + 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 (VarArg 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 (splitFunTy tau_ty) of { - ((_:arg2_ty:_), _) -> arg2_ty; - _ -> panic "dsExpr:SectionL:arg 2 ty" }} + (x_ty:y_ty:_, _) = splitFunTys (exprType core_op) + -- Must look through an implicit-parameter type; + -- newtype impossible; hence Type.splitFunTys 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 (VarArg 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 (splitFunTy tau_ty) of { - ((arg1_ty:_), _) -> arg1_ty; - _ -> panic "dsExpr:SectionR:arg 1 ty" }} + (x_ty:y_ty:_, _) = splitFunTys (exprType core_op) + -- See comment with SectionL 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 -> -dsExpr (CCall label args may_gc is_asm result_ty) + returnDs (bindNonRec y_id y_core $ + Lam x_id (mkApps core_op [Var x_id, Var y_id])) + +dsExpr (HsCCall lbl args may_gc is_asm result_ty) = mapDs dsExpr args `thenDs` \ core_args -> - dsCCall label core_args may_gc is_asm result_ty + dsCCall lbl core_args may_gc is_asm result_ty -- dsCCall does all the unboxification, etc. 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) + getModuleDs `thenDs` \ mod_name -> + returnDs (Note (SCC (mkUserCC cc mod_name)) core_expr) + +-- special case to handle unboxed tuple patterns. + +dsExpr (HsCase discrim matches src_loc) + | all ubx_tuple_match matches + = putSrcLocDs src_loc $ + dsExpr discrim `thenDs` \ core_discrim -> + matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], matching_code) -> + 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)) + where + ubx_tuple_match (Match [TuplePat ps Unboxed] _ _) = True + ubx_tuple_match _ = False -dsExpr expr@(HsCase discrim matches 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 ( 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 False binds `thenDs` \ core_binds -> - dsExpr expr `thenDs` \ core_expr -> - returnDs ( mkCoLetsAny core_binds core_expr ) + dsExpr discrim `thenDs` \ core_discrim -> + matchWrapper CaseAlt matches `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 (HsWith expr binds) + = dsExpr expr `thenDs` \ expr' -> + foldlDs dsIPBind expr' binds + where + dsIPBind body (n, e) + = dsExpr e `thenDs` \ e' -> + returnDs (Let (NonRec (ipNameName n) e') body) + +-- We need the `ListComp' form to use `deListComp' (rather than the "do" form) +-- because the interpretation of `stmts' depends on what sort of thing it is. +-- +dsExpr (HsDoOut ListComp stmts return_id then_id fail_id result_ty src_loc) + = -- Special case for list comprehensions + putSrcLocDs src_loc $ + dsListComp stmts elt_ty + where + (_, [elt_ty]) = tcSplitTyConApp result_ty -dsExpr (HsDoOut stmts then_id zero_id src_loc) +dsExpr (HsDoOut DoExpr stmts return_id then_id fail_id result_ty src_loc) = putSrcLocDs src_loc $ - dsDo then_id zero_id stmts + dsDo DoExpr stmts return_id then_id fail_id result_ty + +dsExpr (HsDoOut PArrComp stmts return_id then_id fail_id result_ty src_loc) + = -- Special case for array comprehensions + putSrcLocDs src_loc $ + dsPArrComp stmts elt_ty + where + (_, [elt_ty]) = tcSplitTyConApp result_ty 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} -Type lambda and application -~~~~~~~~~~~~~~~~~~~~~~~~~~~ +\noindent +\underline{\bf 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} -Various data construction things -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +\noindent +\underline{\bf 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 [TyArg ty, VarArg core_hd, VarArg core_tl] - -dsExpr (ExplicitTuple expr_list) - = mapDs dsExpr expr_list `thenDs` \ core_exprs -> - mkConDs (mkTupleCon (length expr_list)) - (map (TyArg . coreExprType) core_exprs ++ map VarArg 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 (map TyArg tys ++ map VarArg args_exprs) +dsExpr (ExplicitList ty xs) + = go xs + where + go [] = returnDs (mkNilExpr ty) + go (x:xs) = dsExpr x `thenDs` \ core_x -> + go xs `thenDs` \ core_xs -> + returnDs (mkConsExpr ty core_x core_xs) - | 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) +-- we create a list from the array elements and convert them into a list using +-- `PrelPArr.toP' +-- +-- * the main disadvantage to this scheme is that `toP' traverses the list +-- twice: once to determine the length and a second time to put to elements +-- into the array; this inefficiency could be avoided by exposing some of +-- the innards of `PrelPArr' to the compiler (ie, have a `PrelPArrBase') so +-- that we can exploit the fact that we already know the length of the array +-- here at compile time +-- +dsExpr (ExplicitPArr ty xs) + = dsLookupGlobalValue toPName `thenDs` \toP -> + dsExpr (ExplicitList ty xs) `thenDs` \coreList -> + returnDs (mkApps (Var toP) [Type ty, coreList]) - where - (first_arg:rest_args) = args - (args_tys, result_ty) = splitFunTy (foldl applyTy (idType con) tys) - (tycon,_) = getAppTyCon result_ty +dsExpr (ExplicitTuple expr_list boxity) + = mapDs dsExpr expr_list `thenDs` \ core_exprs -> + returnDs (mkConApp (tupleCon boxity (length expr_list)) + (map (Type . exprType) core_exprs ++ core_exprs)) dsExpr (ArithSeqOut expr (From from)) = dsExpr expr `thenDs` \ expr2 -> dsExpr from `thenDs` \ from2 -> - mkAppDs expr2 [VarArg 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 [VarArg from2, VarArg 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 [VarArg from2, VarArg 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 [VarArg from2, VarArg thn2, VarArg two2] + returnDs (mkApps expr2 [from2, thn2, two2]) + +dsExpr (PArrSeqOut expr (FromTo from two)) + = dsExpr expr `thenDs` \ expr2 -> + dsExpr from `thenDs` \ from2 -> + dsExpr two `thenDs` \ two2 -> + returnDs (mkApps expr2 [from2, two2]) + +dsExpr (PArrSeqOut expr (FromThenTo from thn two)) + = dsExpr expr `thenDs` \ expr2 -> + dsExpr from `thenDs` \ from2 -> + dsExpr thn `thenDs` \ thn2 -> + dsExpr two `thenDs` \ two2 -> + returnDs (mkApps expr2 [from2, thn2, two2]) + +dsExpr (PArrSeqOut expr _) + = panic "DsExpr.dsExpr: Infinite parallel array!" + -- the parser shouldn't have generated it and the renamer and typechecker + -- shouldn't have let it through \end{code} -Record construction and update -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +\noindent +\underline{\bf Record construction and update} +% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For record construction we do this (assuming T has three arguments) - +\begin{verbatim} T { op2 = e } ==> let err = /\a -> recConErr a T (recConErr t1 "M.lhs/230/op1") e (recConErr t1 "M.lhs/230/op3") - -recConErr then converts its arugment string into a proper message +\end{verbatim} +@recConErr@ then converts its arugment string into a proper message before printing it as - +\begin{verbatim} M.lhs, line 230: missing field op1 was evaluated +\end{verbatim} +We also handle @C{}@ as valid construction syntax for an unlabelled +constructor @C@, setting all of @C@'s fields to bottom. \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, _) = tcSplitFunTys (exprType con_expr') + -- A newtype in the corner should be opaque; + -- hence TcType.tcSplitFunTys 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)) + unlabelled_bottom arg_ty = mkErrorAppDs rEC_CON_ERROR_ID arg_ty "" + + labels = dataConFieldLabels data_con in - mapDs mk_arg (zipEqual "dsExpr:RecordCon" arg_tys (dataConFieldLabels con_id)) `thenDs` \ con_args -> - mkAppDs con_expr' (map VarArg 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 + + (if null labels + then mapDs unlabelled_bottom arg_tys + else mapDs mk_arg (zipEqual "dsExpr:RecordCon" arg_tys labels)) + `thenDs` \ con_args -> + + returnDs (mkApps con_expr' con_args) \end{code} Record update is a little harder. Suppose we have the decl: - +\begin{verbatim} data T = T1 {op1, op2, op3 :: Int} | T2 {op4, op2 :: Int} | T3 - +\end{verbatim} Then we translate as follows: - +\begin{verbatim} r { op2 = e } ===> let op2 = e in @@ -409,268 +444,237 @@ Then we translate as follows: T1 op1 _ op3 -> T1 op1 op2 op3 T2 op4 _ -> T2 op4 op2 other -> recUpdError "M.lhs/230" - -It's important that we use the constructor Ids for T1, T2 etc on the -RHSs, and do not generate a Core Con directly, because the constructor +\end{verbatim} +It's important that we use the constructor Ids for @T1@, @T2@ etc on the +RHSs, and do not generate a Core constructor application directly, because the constructor 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_in_ty record_out_ty dicts []) + = dsExpr record_expr + +dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts rbinds) + = getSrcLocDs `thenDs` \ src_loc -> + 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 - record_ty = coreExprType record_expr' - (tycon, inst_tys, cons) = trace "DsExpr.getAppDataTyConExpandingDicts" $ - getAppDataTyConExpandingDicts record_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 - - mk_val_arg (field, arg_id) - = case [arg | (f, arg) <- rbinds', - field == recordSelectorFieldLabel f] of - (arg:args) -> ASSERT(null args) - arg - [] -> VarArg arg_id + in_inst_tys = tcTyConAppArgs record_in_ty -- Newtype opaque + out_inst_tys = tcTyConAppArgs record_out_ty -- Newtype opaque + + mk_val_arg field old_arg_id + = case [rhs | (sel_id, rhs, _) <- rbinds, + field == recordSelectorFieldLabel sel_id] of + (rhs:rest) -> ASSERT(null rest) rhs + [] -> HsVar old_arg_id mk_alt con - = newSysLocalsDs (dataConArgTys con inst_tys) `thenDs` \ arg_ids -> + = newSysLocalsDs (dataConInstOrigArgTys con in_inst_tys) `thenDs` \ arg_ids -> + -- This call to dataConArgTys won't work for existentials let - val_args = map mk_val_arg (zipEqual "dsExpr:RecordUpd" (dataConFieldLabels con) arg_ids) + val_args = zipWithEqual "dsExpr:RecordUpd" mk_val_arg + (dataConFieldLabels con) arg_ids + rhs = foldl HsApp (DictApp (TyApp (HsVar (dataConWrapId con)) + out_inst_tys) + dicts) + val_args in - returnDs (con, arg_ids, mkGenApp (mkGenApp (Var con) initial_args) val_args) - - mk_default - | length cons_to_upd == length cons - = returnDs NoDefault - | otherwise - = newSysLocalDs record_ty `thenDs` \ deflt_id -> - mkErrorAppDs rEC_UPD_ERROR_ID record_ty "" `thenDs` \ err -> - returnDs (BindDefault deflt_id err) + returnDs (mkSimpleMatch [ConPat con record_in_ty [] [] (map VarPat arg_ids)] + rhs + record_out_ty + src_loc) in - mapDs mk_alt cons_to_upd `thenDs` \ alts -> - mk_default `thenDs` \ deflt -> + -- Record stuff doesn't work for existentials + ASSERT( all (not . isExistentialDataCon) data_cons ) - returnDs (Case record_expr' (AlgAlts alts deflt)) + -- It's important to generate the match with matchWrapper, + -- and the right hand sides with applications of the wrapper Id + -- so that everything works when we are doing fancy unboxing on the + -- constructor aguments. + mapDs mk_alt cons_to_upd `thenDs` \ alts -> + matchWrapper RecUpd alts `thenDs` \ ([discrim_var], matching_code) -> + + returnDs (bindNonRec discrim_var record_expr' matching_code) where - has_all_fields :: Id -> Bool + updated_fields :: [FieldLabel] + updated_fields = [recordSelectorFieldLabel sel_id | (sel_id,_,_) <- rbinds] + + -- Get the type constructor from the first field label, + -- so that we are sure it'll have all its DataCons + -- (In GHCI, it's possible that some TyCons may not have all + -- their constructors, in a module-loop situation.) + tycon = fieldLabelTyCon (head updated_fields) + data_cons = tyConDataCons tycon + cons_to_upd = filter has_all_fields data_cons + + has_all_fields :: DataCon -> Bool has_all_fields con_id - = all ok rbinds + = all (`elem` con_fields) updated_fields where - con_fields = dataConFieldLabels con_id - ok (sel_id, _, _) = recordSelectorFieldLabel sel_id `elem` con_fields + con_fields = dataConFieldLabels con_id \end{code} -Dictionary lambda and application -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +\noindent +\underline{\bf Dictionary lambda and application} +% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @DictLam@ and @DictApp@ turn into the regular old things. (OLD:) @DictFunApp@ also becomes a curried application, albeit slightly more 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 (Var voidId) - - 1 -> returnDs (head core_d_and_ms) -- just a single Id - - _ -> -- tuple 'em up - mkConDs (mkTupleCon num_of_d_and_ms) - (map (TyArg . coreExprType) core_d_and_ms ++ map VarArg 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 voidTy `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 (ExplicitList _) = panic "dsExpr:ExplicitList" +dsExpr (HsDo _ _ _) = panic "dsExpr:HsDo" dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig" dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn" +dsExpr (PArrSeqIn _) = panic "dsExpr:PArrSeqIn" #endif -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} -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) +dsDo :: HsDoContext + -> [TypecheckedStmt] + -> Id -- id for: return m + -> Id -- id for: (>>=) m + -> Id -- id for: fail m + -> Type -- Element type; the whole expression has type (m t) + -> DsM CoreExpr -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) +dsDo do_or_lc stmts return_id then_id fail_id result_ty + = let + (_, b_ty) = tcSplitAppTy result_ty -- result_ty must be of the form (m b) + is_do = case do_or_lc of + DoExpr -> True + _ -> False + + -- For ExprStmt, see the comments near HsExpr.Stmt about + -- exactly what ExprStmts mean! + -- + -- In dsDo we can only see DoStmt and ListComp (no gaurds) + + go [ResultStmt expr locn] + | is_do = do_expr expr locn + | otherwise = do_expr expr locn `thenDs` \ expr2 -> + returnDs (mkApps (Var return_id) [Type b_ty, expr2]) + + go (ExprStmt expr a_ty locn : stmts) + | is_do -- Do expression + = do_expr expr locn `thenDs` \ expr2 -> + 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]) + + | otherwise -- List comprehension + = do_expr expr locn `thenDs` \ expr2 -> + go stmts `thenDs` \ rest -> + let + msg = "Pattern match failure in do expression, " ++ showSDoc (ppr locn) + in + mkStringLit msg `thenDs` \ core_msg -> + returnDs (mkIfThenElse expr2 rest + (App (App (Var fail_id) (Type b_ty)) core_msg)) + + 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 = outPatType pat + fail_expr = HsApp (TyApp (HsVar fail_id) [b_ty]) + (HsLit (HsString (_PK_ msg))) + msg = "Pattern match failure in do expression, " ++ showSDoc (ppr locn) + main_match = mkSimpleMatch [pat] + (HsDoOut do_or_lc stmts return_id then_id + fail_id result_ty locn) + result_ty locn + the_matches + | failureFreePat pat = [main_match] + | otherwise = + [ main_match + , mkSimpleMatch [WildPat a_ty] fail_expr result_ty locn + ] + in + matchWrapper (DoCtxt do_or_lc) the_matches `thenDs` \ (binders, matching_code) -> + returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, + mkLams binders matching_code]) + in + go stmts -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) + where + do_expr expr locn = putSrcLocDs locn (dsExpr expr) +\end{code} -dsApp (TyApp expr tys) args - = dsApp expr (map TyArg tys ++ args) --- we might should look out for SectionLs, etc., here, but we don't +%************************************************************************ +%* * +\subsection[DsExpr-literals]{Literals} +%* * +%************************************************************************ -dsApp (HsVar v) args - = lookupEnvDs v `thenDs` \ maybe_expr -> - mkAppDs (case maybe_expr of { Nothing -> Var v; Just expr -> expr }) args +We give int/float literals type @Integer@ and @Rational@, respectively. +The typechecker will (presumably) have put \tr{from{Integer,Rational}s} +around them. -dsApp anything_else args - = dsExpr anything_else `thenDs` \ core_expr -> - mkAppDs core_expr args -\end{code} +ToDo: put in range checks for when converting ``@i@'' +(or should that be in the typechecker?) -\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 (VarArg rhs') $ \ rhs_atom -> - dsRbinds rbinds $ \ rbinds' -> - continue_with ((sel_id, rhs_atom) : rbinds') -\end{code} +For numeric literals, we try to detect there use at a standard type +(@Int@, @Float@, etc.) are directly put in the right constructor. +[NB: down with the @App@ conversion.] -\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) (arg@(VarArg expr) : args) --- = dsExprToAtom arg $ \ 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 --- mkAppDs body' args -\end{code} +See also below where we look for @DictApps@ for \tr{plusInt}, etc. -Basically does the translation given in the Haskell~1.3 report: \begin{code} -dsDo :: Id -- id for: (>>=) m - -> Id -- id for: zero m - -> [TypecheckedStmt] - -> DsM CoreExpr - -dsDo then_id zero_id (stmt:stmts) - = case stmt of - ExprStmt expr locn -> ASSERT( null stmts ) do_expr expr locn - - ExprStmtOut expr locn a b -> - do_expr expr locn `thenDs` \ expr2 -> - ds_rest `thenDs` \ rest -> - newSysLocalDs a `thenDs` \ ignored_result_id -> - dsApp (HsVar then_id) [TyArg a, TyArg b, VarArg expr2, - VarArg (mkValLam [ignored_result_id] rest)] - - LetStmt binds -> - dsBinds False binds `thenDs` \ binds2 -> - ds_rest `thenDs` \ rest -> - returnDs (mkCoLetsAny binds2 rest) - - BindStmtOut pat expr locn a b -> - do_expr expr locn `thenDs` \ expr2 -> - let - zero_expr = TyApp (HsVar zero_id) [b] - main_match - = PatMatch pat (SimpleMatch (HsDoOut stmts then_id zero_id locn)) - the_matches - = if failureFreePat pat - then [main_match] - else [main_match, PatMatch (WildPat a) (SimpleMatch zero_expr)] - in - matchWrapper DoBindMatch the_matches "`do' statement" - `thenDs` \ (binders, matching_code) -> - dsApp (HsVar then_id) [TyArg a, TyArg b, - VarArg expr2, VarArg (mkValLam binders matching_code)] +dsLit :: HsLit -> DsM CoreExpr +dsLit (HsChar c) = returnDs (mkConApp charDataCon [mkLit (MachChar c)]) +dsLit (HsCharPrim c) = returnDs (mkLit (MachChar c)) +dsLit (HsString str) = mkStringLitFS str +dsLit (HsStringPrim s) = returnDs (mkLit (MachStr s)) +dsLit (HsInteger i) = mkIntegerLit i +dsLit (HsInt i) = returnDs (mkConApp intDataCon [mkIntLit i]) +dsLit (HsIntPrim i) = returnDs (mkIntLit i) +dsLit (HsFloatPrim f) = returnDs (mkLit (MachFloat f)) +dsLit (HsDoublePrim d) = returnDs (mkLit (MachDouble d)) +dsLit (HsLitLit str ty) + = ASSERT( maybeToBool maybe_ty ) + returnDs (wrap_fn (mkLit (MachLitLit str rep_ty))) where - ds_rest = dsDo then_id zero_id stmts - do_expr expr locn = putSrcLocDs locn (dsExpr expr) + (maybe_ty, wrap_fn) = resultWrapper ty + Just rep_ty = maybe_ty -#ifdef DEBUG -dsDo then_expr zero_expr [] = panic "dsDo:[]" -#endif +dsLit (HsRat r ty) + = mkIntegerLit (numerator r) `thenDs` \ num -> + mkIntegerLit (denominator r) `thenDs` \ denom -> + returnDs (mkConApp ratio_data_con [Type integer_ty, num, denom]) + where + (ratio_data_con, integer_ty) + = case tcSplitTyConApp ty of + (tycon, [i_ty]) -> ASSERT(isIntegerTy i_ty && tycon `hasKey` ratioTyConKey) + (head (tyConDataCons tycon), i_ty) \end{code}