X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsExpr.lhs;h=6ae0d0c8ab4cb47d36e6a9e1a98281df433d99b0;hb=5e34dfe261bf18325fc035ed92f716f3a6249142;hp=5d7ff191dfa44dd71fc58af6af0bf7a46e76b395;hpb=10fcd78ccde892feccda3f5eacd221c1de75feea;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/DsExpr.lhs b/ghc/compiler/deSugar/DsExpr.lhs index 5d7ff19..6ae0d0c 100644 --- a/ghc/compiler/deSugar/DsExpr.lhs +++ b/ghc/compiler/deSugar/DsExpr.lhs @@ -4,56 +4,60 @@ \section[DsExpr]{Matching expressions (Exprs)} \begin{code} -module DsExpr ( dsExpr, dsLet ) where +module DsExpr ( dsExpr, dsLet, dsLit ) where #include "HsVersions.h" -import HsSyn ( failureFreePat, - HsExpr(..), OutPat(..), HsLit(..), ArithSeqInfo(..), - Stmt(..), HsMatchContext(..), HsDoContext(..), - Match(..), HsBinds(..), MonoBinds(..), - mkSimpleMatch +import Match ( matchWrapper, matchSimply ) +import MatchLit ( dsLit ) +import DsBinds ( dsMonoBinds, AutoScc(..) ) +import DsGRHSs ( dsGuarded ) +import DsCCall ( dsCCall ) +import DsListComp ( dsListComp, dsPArrComp ) +import DsUtils ( mkErrorAppDs, mkStringLit, mkConsExpr, mkNilExpr, selectMatchVar ) +import DsMonad + +#ifdef GHCI + -- Template Haskell stuff iff bootstrapped +import DsMeta ( dsBracket, dsReify ) +#endif + +import HsSyn ( HsExpr(..), Pat(..), HsLit(..), ArithSeqInfo(..), + Stmt(..), HsMatchContext(..), HsStmtContext(..), + Match(..), HsBinds(..), MonoBinds(..), HsConDetails(..), + mkSimpleMatch, isDoExpr ) -import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, TypecheckedStmt, outPatType ) +import TcHsSyn ( TypecheckedHsExpr, TypecheckedHsBinds, TypecheckedStmt, hsPatType ) -- 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 TcType ( tcSplitAppTy, tcSplitFunTys, tcTyConAppArgs, + tcSplitTyConApp, isUnLiftedType, Type, + mkAppTy ) import Type ( splitFunTys ) import CoreSyn +import Literal ( Literal(..) ) import CoreUtils ( exprType, mkIfThenElse, bindNonRec ) -import DsMonad -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, matchSimply ) - import FieldLabel ( FieldLabel, fieldLabelTyCon ) import CostCentre ( mkUserCC ) -import Id ( Id, idType, recordSelectorFieldLabel ) +import Id ( Id, idType, idName, recordSelectorFieldLabel ) import PrelInfo ( rEC_CON_ERROR_ID, iRREFUT_PAT_ERROR_ID ) import DataCon ( DataCon, dataConWrapId, dataConFieldLabels, dataConInstOrigArgTys ) import DataCon ( isExistentialDataCon ) -import Literal ( Literal(..) ) +import Name ( Name ) import TyCon ( tyConDataCons ) -import TysWiredIn ( tupleCon, listTyCon, charDataCon, intDataCon ) +import TysWiredIn ( tupleCon, mkTupleTy ) import BasicTypes ( RecFlag(..), Boxity(..), ipNameName ) -import Maybes ( maybeToBool ) -import PrelNames ( hasKey, ratioTyConKey, toPName ) +import PrelNames ( toPName ) +import SrcLoc ( noSrcLoc ) import Util ( zipEqual, zipWithEqual ) import Outputable - -import Ratio ( numerator, denominator ) +import FastString \end{code} @@ -84,6 +88,13 @@ dsLet (ThenBinds b1 b2) body = dsLet b2 body `thenDs` \ body' -> dsLet b1 body' +dsLet (IPBinds binds is_with) body + = foldlDs dsIPBind body binds + where + dsIPBind body (n, e) + = dsExpr e `thenDs` \ e' -> + returnDs (Let (NonRec (ipNameName n) e') 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. @@ -99,8 +110,8 @@ dsLet bind@(MonoBind (AbsBinds [] [] exports inlines binds) sigs is_rec) body -- below. Then pattern-match would fail. Urk.) case binds of FunMonoBind fun _ matches loc - -> putSrcLocDs loc $ - matchWrapper (FunRhs fun) matches `thenDs` \ (args, rhs) -> + -> putSrcLocDs loc $ + matchWrapper (FunRhs (idName fun)) matches `thenDs` \ (args, rhs) -> ASSERT( null args ) -- Functions aren't lifted returnDs (bindNonRec fun rhs body_w_exports) @@ -145,6 +156,7 @@ dsLet (MonoBind binds sigs is_rec) body \begin{code} dsExpr :: TypecheckedHsExpr -> DsM CoreExpr +dsExpr (HsPar x) = dsExpr x dsExpr (HsVar var) = returnDs (Var var) dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip)) dsExpr (HsLit lit) = dsLit lit @@ -254,29 +266,22 @@ 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) +dsExpr (HsDo ListComp stmts _ result_ty src_loc) = -- Special case for list comprehensions putSrcLocDs src_loc $ dsListComp stmts elt_ty where (_, [elt_ty]) = tcSplitTyConApp result_ty -dsExpr (HsDoOut DoExpr stmts return_id then_id fail_id result_ty src_loc) +dsExpr (HsDo do_or_lc stmts ids result_ty src_loc) + | isDoExpr do_or_lc = putSrcLocDs src_loc $ - dsDo DoExpr stmts return_id then_id fail_id result_ty + dsDo do_or_lc stmts ids result_ty -dsExpr (HsDoOut PArrComp stmts return_id then_id fail_id result_ty src_loc) +dsExpr (HsDo PArrComp stmts _ result_ty src_loc) = -- Special case for array comprehensions putSrcLocDs src_loc $ dsPArrComp stmts elt_ty @@ -329,7 +334,7 @@ dsExpr (ExplicitList ty xs) -- here at compile time -- dsExpr (ExplicitPArr ty xs) - = dsLookupGlobalValue toPName `thenDs` \toP -> + = dsLookupGlobalId toPName `thenDs` \toP -> dsExpr (ExplicitList ty xs) `thenDs` \coreList -> returnDs (mkApps (Var toP) [Type ty, coreList]) @@ -411,7 +416,7 @@ dsExpr (RecordConOut data_con con_expr rbinds) -- hence TcType.tcSplitFunTys mk_arg (arg_ty, lbl) - = case [rhs | (sel_id,rhs,_) <- rbinds, + = case [rhs | (sel_id,rhs) <- rbinds, lbl == recordSelectorFieldLabel sel_id] of (rhs:rhss) -> ASSERT( null rhss ) dsExpr rhs @@ -451,10 +456,10 @@ might do some argument-evaluation first; and may have to throw away some dictionaries. \begin{code} -dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts []) +dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty []) = dsExpr record_expr -dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts rbinds) +dsExpr expr@(RecordUpdOut record_expr record_in_ty record_out_ty rbinds) = getSrcLocDs `thenDs` \ src_loc -> dsExpr record_expr `thenDs` \ record_expr' -> @@ -466,7 +471,7 @@ dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts rbinds) out_inst_tys = tcTyConAppArgs record_out_ty -- Newtype opaque mk_val_arg field old_arg_id - = case [rhs | (sel_id, rhs, _) <- rbinds, + = case [rhs | (sel_id, rhs) <- rbinds, field == recordSelectorFieldLabel sel_id] of (rhs:rest) -> ASSERT(null rest) rhs [] -> HsVar old_arg_id @@ -477,18 +482,18 @@ dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts rbinds) let val_args = zipWithEqual "dsExpr:RecordUpd" mk_val_arg (dataConFieldLabels con) arg_ids - rhs = foldl HsApp (DictApp (TyApp (HsVar (dataConWrapId con)) - out_inst_tys) - dicts) + rhs = foldl HsApp (TyApp (HsVar (dataConWrapId con)) out_inst_tys) val_args in - returnDs (mkSimpleMatch [ConPat con record_in_ty [] [] (map VarPat arg_ids)] + returnDs (mkSimpleMatch [ConPatOut con (PrefixCon (map VarPat arg_ids)) record_in_ty [] []] rhs record_out_ty src_loc) in -- Record stuff doesn't work for existentials - ASSERT( all (not . isExistentialDataCon) data_cons ) + -- The type checker checks for this, but we need + -- worry only about the constructors that are to be updated + ASSERT2( all (not . isExistentialDataCon) cons_to_upd, ppr expr ) -- It's important to generate the match with matchWrapper, -- and the right hand sides with applications of the wrapper Id @@ -501,7 +506,7 @@ dsExpr (RecordUpdOut record_expr record_in_ty record_out_ty dicts rbinds) where updated_fields :: [FieldLabel] - updated_fields = [recordSelectorFieldLabel sel_id | (sel_id,_,_) <- rbinds] + 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 @@ -537,11 +542,24 @@ dsExpr (DictApp expr dicts) -- becomes a curried application returnDs (foldl (\f d -> f `App` (Var d)) core_expr dicts) \end{code} +Here is where we desugar the Template Haskell brackets and escapes + +\begin{code} +-- Template Haskell stuff + +#ifdef GHCI /* Only if bootstrapping */ +dsExpr (HsBracketOut x ps) = dsBracket x ps +dsExpr (HsReify r) = dsReify r +dsExpr (HsSplice n e _) = pprPanic "dsExpr:splice" (ppr e) +#endif + +\end{code} + + \begin{code} #ifdef DEBUG -- HsSyn constructs that just shouldn't be here: -dsExpr (HsDo _ _ _) = panic "dsExpr:HsDo" dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig" dsExpr (ArithSeqIn _) = panic "dsExpr:ArithSeqIn" dsExpr (PArrSeqIn _) = panic "dsExpr:PArrSeqIn" @@ -554,25 +572,22 @@ dsExpr (PArrSeqIn _) = panic "dsExpr:PArrSeqIn" Basically does the translation given in the Haskell~1.3 report: \begin{code} -dsDo :: HsDoContext +dsDo :: HsStmtContext Name -> [TypecheckedStmt] - -> Id -- id for: return m - -> Id -- id for: (>>=) m - -> Id -- id for: fail m + -> [Id] -- id for: [return,fail,>>=,>>] and possibly mfixName -> Type -- Element type; the whole expression has type (m t) -> DsM CoreExpr -dsDo do_or_lc stmts return_id then_id fail_id result_ty +dsDo do_or_lc stmts ids 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 + (return_id : fail_id : bind_id : then_id : _) = ids + (m_ty, b_ty) = tcSplitAppTy result_ty -- result_ty must be of the form (m b) + is_do = isDoExpr do_or_lc -- True for both MDo and Do -- For ExprStmt, see the comments near HsExpr.Stmt about -- exactly what ExprStmts mean! -- - -- In dsDo we can only see DoStmt and ListComp (no gaurds) + -- In dsDo we can only see DoStmt and ListComp (no guards) go [ResultStmt expr locn] | is_do = do_expr expr locn @@ -583,9 +598,7 @@ dsDo do_or_lc stmts return_id then_id fail_id result_ty | 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]) + returnDs (mkApps (Var then_id) [Type a_ty, Type b_ty, expr2, rest]) | otherwise -- List comprehension = do_expr expr locn `thenDs` \ expr2 -> @@ -602,79 +615,69 @@ dsDo do_or_lc stmts return_id then_id fail_id result_ty dsLet binds rest go (BindStmt pat expr locn : stmts) - = putSrcLocDs locn $ - dsExpr expr `thenDs` \ expr2 -> + = go stmts `thenDs` \ body -> + putSrcLocDs locn $ -- Rest is associated with this location + dsExpr expr `thenDs` \ rhs -> + mkStringLit (mk_msg locn) `thenDs` \ core_msg -> 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 a do expression, pattern-match failure just calls + -- the monadic 'fail' rather than throwing an exception + fail_expr = mkApps (Var fail_id) [Type b_ty, core_msg] + a_ty = hsPatType pat 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]) + selectMatchVar pat `thenDs` \ var -> + matchSimply (Var var) (StmtCtxt do_or_lc) pat + body fail_expr `thenDs` \ match_code -> + returnDs (mkApps (Var bind_id) [Type a_ty, Type b_ty, rhs, Lam var match_code]) + + go (RecStmt rec_vars rec_stmts rec_rets : stmts) + = go (bind_stmt : stmts) + where + bind_stmt = dsRecStmt m_ty ids rec_vars rec_stmts rec_rets + in go stmts where do_expr expr locn = putSrcLocDs locn (dsExpr expr) + mk_msg locn = "Pattern match failure in do expression at " ++ showSDoc (ppr locn) \end{code} - -%************************************************************************ -%* * -\subsection[DsExpr-literals]{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.] - -See also below where we look for @DictApps@ for \tr{plusInt}, etc. +Translation for RecStmt's: +----------------------------- +We turn (RecStmt [v1,..vn] stmts) into: + + (v1,..,vn) <- mfix (\~(v1,..vn). do stmts + return (v1,..vn)) \begin{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 - (maybe_ty, wrap_fn) = resultWrapper ty - Just rep_ty = maybe_ty - -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) +dsRecStmt :: Type -- Monad type constructor :: * -> * + -> [Id] -- Ids for: [return,fail,>>=,>>,mfix] + -> [Id] -> [TypecheckedStmt] -> [TypecheckedHsExpr] -- Guts of the RecStmt + -> TypecheckedStmt +dsRecStmt m_ty ids@[return_id, _, _, _, mfix_id] vars stmts rets + = ASSERT( length vars == length rets ) + BindStmt tup_pat mfix_app noSrcLoc + where + (var1:rest) = vars -- Always at least one + (ret1:_) = rets + one_var = null rest + + mfix_app = HsApp (TyApp (HsVar mfix_id) [tup_ty]) mfix_arg + mfix_arg = HsLam (mkSimpleMatch [tup_pat] body tup_ty noSrcLoc) + + tup_expr | one_var = ret1 + | otherwise = ExplicitTuple rets Boxed + tup_ty | one_var = idType var1 + | otherwise = mkTupleTy Boxed (length vars) (map idType vars) + tup_pat | one_var = VarPat var1 + | otherwise = LazyPat (TuplePat (map VarPat vars) Boxed) + + body = HsDo DoExpr (stmts ++ [return_stmt]) + ids -- Don't need the mfix, but it does no harm + (mkAppTy m_ty tup_ty) + noSrcLoc + + return_stmt = ResultStmt return_app noSrcLoc + return_app = HsApp (TyApp (HsVar return_id) [tup_ty]) tup_expr \end{code}