X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FDsExpr.lhs;h=dce8870e0d496c1fceb3670abd0e74fbc1ada1d0;hb=2fc1aec2e74df8c9db286508ab6bf2014ba19998;hp=dd433ec08c3627af65f60730de10e3028e7ad72c;hpb=ff8e1d01524b48e028b09e2b04b2e5303cb6d95f;p=ghc-hetmet.git diff --git a/compiler/deSugar/DsExpr.lhs b/compiler/deSugar/DsExpr.lhs index dd433ec..dce8870 100644 --- a/compiler/deSugar/DsExpr.lhs +++ b/compiler/deSugar/DsExpr.lhs @@ -6,6 +6,13 @@ Desugaring exporessions. \begin{code} +{-# OPTIONS -fno-warn-incomplete-patterns #-} +-- The above warning supression flag is a temporary kludge. +-- While working on this module you are encouraged to remove it and fix +-- any warnings in the module. See +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings +-- for details + module DsExpr ( dsExpr, dsLExpr, dsLocalBinds, dsValBinds, dsLit ) where #include "HsVersions.h" @@ -19,6 +26,7 @@ import DsListComp import DsUtils import DsArrows import DsMonad +import Name #ifdef GHCI import PrelNames @@ -65,19 +73,20 @@ dsLocalBinds (HsIPBinds binds) body = dsIPBinds binds body ------------------------- dsValBinds :: HsValBinds Id -> CoreExpr -> DsM CoreExpr -dsValBinds (ValBindsOut binds _) body = foldrDs ds_val_bind body binds +dsValBinds (ValBindsOut binds _) body = foldrM ds_val_bind body binds ------------------------- +dsIPBinds :: HsIPBinds Id -> CoreExpr -> DsM CoreExpr dsIPBinds (IPBinds ip_binds dict_binds) body = do { prs <- dsLHsBinds dict_binds ; let inner = Let (Rec prs) body -- The dict bindings may not be in -- dependency order; hence Rec - ; foldrDs ds_ip_bind inner ip_binds } + ; foldrM ds_ip_bind inner ip_binds } where ds_ip_bind (L _ (IPBind n e)) body - = dsLExpr e `thenDs` \ e' -> - returnDs (Let (NonRec (ipNameName n) e') body) + = do e' <- dsLExpr e + return (Let (NonRec (ipNameName n) e') body) ------------------------- ds_val_bind :: (RecFlag, LHsBinds Id) -> CoreExpr -> DsM CoreExpr @@ -103,35 +112,36 @@ ds_val_bind (NonRecursive, hsbinds) body -- below. Then pattern-match would fail. Urk.) putSrcSpanDs loc $ case bind of - FunBind { fun_id = L _ fun, fun_matches = matches, fun_co_fn = co_fn, fun_tick = tick } - -> matchWrapper (FunRhs (idName fun)) matches `thenDs` \ (args, rhs) -> - ASSERT( null args ) -- Functions aren't lifted - ASSERT( isIdHsWrapper co_fn ) - mkOptTickBox tick rhs `thenDs` \ rhs' -> - returnDs (bindNonRec fun rhs' body_w_exports) + FunBind { fun_id = L _ fun, fun_matches = matches, fun_co_fn = co_fn, + fun_tick = tick, fun_infix = inf } + -> do (args, rhs) <- matchWrapper (FunRhs (idName fun ) inf) matches + MASSERT( null args ) -- Functions aren't lifted + MASSERT( isIdHsWrapper co_fn ) + rhs' <- mkOptTickBox tick rhs + return (bindNonRec fun rhs' body_w_exports) PatBind {pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty } -> -- let C x# y# = rhs in body -- ==> case rhs of C x# y# -> body putSrcSpanDs loc $ - do { rhs <- dsGuarded grhss ty - ; let upat = unLoc pat - eqn = EqnInfo { eqn_pats = [upat], - eqn_rhs = cantFailMatchResult body_w_exports } - ; var <- selectMatchVar upat - ; result <- matchEquations PatBindRhs [var] [eqn] (exprType body) - ; return (scrungleMatch var rhs result) } + do { rhs <- dsGuarded grhss ty + ; let upat = unLoc pat + eqn = EqnInfo { eqn_pats = [upat], + eqn_rhs = cantFailMatchResult body_w_exports } + ; var <- selectMatchVar upat + ; result <- matchEquations PatBindRhs [var] [eqn] (exprType body) + ; return (scrungleMatch var rhs result) } - other -> pprPanic "dsLet: unlifted" (pprLHsBinds hsbinds $$ ppr body) + _ -> pprPanic "dsLet: unlifted" (pprLHsBinds hsbinds $$ ppr body) -- Ordinary case for bindings; none should be unlifted -ds_val_bind (is_rec, binds) body +ds_val_bind (_is_rec, binds) body = do { prs <- dsLHsBinds binds ; ASSERT( not (any (isUnLiftedType . idType . fst) prs) ) case prs of - [] -> return body - other -> return (Let (Rec prs) body) } + [] -> return body + _ -> return (Let (Rec prs) body) } -- Use a Rec regardless of is_rec. -- Why? Because it allows the binds to be all -- mixed up, which is what happens in one rare case @@ -145,7 +155,7 @@ ds_val_bind (is_rec, binds) body isUnboxedTupleBind :: HsBind Id -> Bool isUnboxedTupleBind (PatBind { pat_rhs_ty = ty }) = isUnboxedTupleType ty -isUnboxedTupleBind other = False +isUnboxedTupleBind _ = False scrungleMatch :: Id -> CoreExpr -> CoreExpr -> CoreExpr -- Returns something like (let var = scrut in body) @@ -172,7 +182,7 @@ scrungleMatch var scrut body scrungle (Let binds body) = Let binds (scrungle body) scrungle other = panic ("scrungleMatch: tuple pattern:\n" ++ showSDoc (ppr other)) -\end{code} +\end{code} %************************************************************************ %* * @@ -188,25 +198,20 @@ dsLExpr (L loc e) = putSrcSpanDs loc $ dsExpr e dsExpr :: HsExpr Id -> DsM CoreExpr dsExpr (HsPar e) = dsLExpr e dsExpr (ExprWithTySigOut e _) = dsLExpr e -dsExpr (HsVar var) = returnDs (Var var) -dsExpr (HsIPVar ip) = returnDs (Var (ipNameName ip)) +dsExpr (HsVar var) = return (Var var) +dsExpr (HsIPVar ip) = return (Var (ipNameName ip)) dsExpr (HsLit lit) = dsLit lit dsExpr (HsOverLit lit) = dsOverLit lit dsExpr (HsWrap co_fn e) = dsCoercion co_fn (dsExpr e) dsExpr (NegApp expr neg_expr) - = do { core_expr <- dsLExpr expr - ; core_neg <- dsExpr neg_expr - ; return (core_neg `App` core_expr) } - -dsExpr expr@(HsLam a_Match) - = matchWrapper LambdaExpr a_Match `thenDs` \ (binders, matching_code) -> - returnDs (mkLams binders matching_code) - -dsExpr expr@(HsApp fun arg) - = dsLExpr fun `thenDs` \ core_fun -> - dsLExpr arg `thenDs` \ core_arg -> - returnDs (core_fun `mkDsApp` core_arg) + = App <$> dsExpr neg_expr <*> dsLExpr expr + +dsExpr (HsLam a_Match) + = uncurry mkLams <$> matchWrapper LambdaExpr a_Match + +dsExpr (HsApp fun arg) + = mkDsApp <$> dsLExpr fun <*> dsLExpr arg \end{code} Operator sections. At first it looks as if we can convert @@ -232,53 +237,43 @@ will sort it out. \begin{code} dsExpr (OpApp e1 op _ e2) - = dsLExpr op `thenDs` \ core_op -> - -- for the type of y, we need the type of op's 2nd argument - dsLExpr e1 `thenDs` \ x_core -> - dsLExpr e2 `thenDs` \ y_core -> - returnDs (mkDsApps core_op [x_core, y_core]) + = -- for the type of y, we need the type of op's 2nd argument + mkDsApps <$> dsLExpr op <*> mapM dsLExpr [e1, e2] dsExpr (SectionL expr op) -- Desugar (e !) to ((!) e) - = dsLExpr op `thenDs` \ core_op -> - dsLExpr expr `thenDs` \ x_core -> - returnDs (mkDsApp core_op x_core) + = mkDsApp <$> dsLExpr op <*> dsLExpr expr -- dsLExpr (SectionR op expr) -- \ x -> op x expr -dsExpr (SectionR op expr) - = dsLExpr op `thenDs` \ core_op -> +dsExpr (SectionR op expr) = do + core_op <- dsLExpr op -- for the type of x, we need the type of op's 2nd argument - let - (x_ty:y_ty:_, _) = splitFunTys (exprType core_op) - -- See comment with SectionL - in - dsLExpr 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 (mkDsApps core_op [Var x_id, Var y_id])) + let (x_ty:y_ty:_, _) = splitFunTys (exprType core_op) + -- See comment with SectionL + y_core <- dsLExpr expr + x_id <- newSysLocalDs x_ty + y_id <- newSysLocalDs y_ty + return (bindNonRec y_id y_core $ + Lam x_id (mkDsApps core_op [Var x_id, Var y_id])) -dsExpr (HsSCC cc expr) - = dsLExpr expr `thenDs` \ core_expr -> - getModuleDs `thenDs` \ mod_name -> - returnDs (Note (SCC (mkUserCC cc mod_name)) core_expr) +dsExpr (HsSCC cc expr) = do + mod_name <- getModuleDs + Note (SCC (mkUserCC cc mod_name)) <$> dsLExpr expr -- hdaume: core annotation dsExpr (HsCoreAnn fs expr) - = dsLExpr expr `thenDs` \ core_expr -> - returnDs (Note (CoreNote $ unpackFS fs) core_expr) + = Note (CoreNote $ unpackFS fs) <$> dsLExpr expr -dsExpr (HsCase discrim matches) - = dsLExpr discrim `thenDs` \ core_discrim -> - matchWrapper CaseAlt matches `thenDs` \ ([discrim_var], matching_code) -> - returnDs (scrungleMatch discrim_var core_discrim matching_code) +dsExpr (HsCase discrim matches) = do + core_discrim <- dsLExpr discrim + ([discrim_var], matching_code) <- matchWrapper CaseAlt matches + return (scrungleMatch discrim_var core_discrim matching_code) -- Pepe: The binds are in scope in the body but NOT in the binding group -- This is to avoid silliness in breakpoints -dsExpr (HsLet binds body) - = dsLExpr body `thenDs` \ body' -> +dsExpr (HsLet binds body) = do + body' <- dsLExpr body dsLocalBinds binds body' -- We need the `ListComp' form to use `deListComp' (rather than the "do" form) @@ -303,10 +298,7 @@ dsExpr (HsDo PArrComp stmts body result_ty) [elt_ty] = tcTyConAppArgs result_ty dsExpr (HsIf guard_expr then_expr else_expr) - = dsLExpr guard_expr `thenDs` \ core_guard -> - dsLExpr then_expr `thenDs` \ core_then -> - dsLExpr else_expr `thenDs` \ core_else -> - returnDs (mkIfThenElse core_guard core_then core_else) + = mkIfThenElse <$> dsLExpr guard_expr <*> dsLExpr then_expr <*> dsLExpr else_expr \end{code} @@ -317,10 +309,8 @@ dsExpr (HsIf guard_expr then_expr else_expr) dsExpr (ExplicitList ty xs) = go xs where - go [] = returnDs (mkNilExpr ty) - go (x:xs) = dsLExpr x `thenDs` \ core_x -> - go xs `thenDs` \ core_xs -> - returnDs (mkConsExpr ty core_x core_xs) + go [] = return (mkNilExpr ty) + go (x:xs) = mkConsExpr ty <$> dsLExpr x <*> go xs -- we create a list from the array elements and convert them into a list using -- `PrelPArr.toP' @@ -332,54 +322,35 @@ dsExpr (ExplicitList ty xs) -- that we can exploit the fact that we already know the length of the array -- here at compile time -- -dsExpr (ExplicitPArr ty xs) - = dsLookupGlobalId toPName `thenDs` \toP -> - dsExpr (ExplicitList ty xs) `thenDs` \coreList -> - returnDs (mkApps (Var toP) [Type ty, coreList]) +dsExpr (ExplicitPArr ty xs) = do + toP <- dsLookupGlobalId toPName + coreList <- dsExpr (ExplicitList ty xs) + return (mkApps (Var toP) [Type ty, coreList]) -dsExpr (ExplicitTuple expr_list boxity) - = mappM dsLExpr expr_list `thenDs` \ core_exprs -> - returnDs (mkConApp (tupleCon boxity (length expr_list)) - (map (Type . exprType) core_exprs ++ core_exprs)) +dsExpr (ExplicitTuple expr_list boxity) = do + core_exprs <- mapM dsLExpr expr_list + return (mkConApp (tupleCon boxity (length expr_list)) + (map (Type . exprType) core_exprs ++ core_exprs)) dsExpr (ArithSeq expr (From from)) - = dsExpr expr `thenDs` \ expr2 -> - dsLExpr from `thenDs` \ from2 -> - returnDs (App expr2 from2) + = App <$> dsExpr expr <*> dsLExpr from -dsExpr (ArithSeq expr (FromTo from two)) - = dsExpr expr `thenDs` \ expr2 -> - dsLExpr from `thenDs` \ from2 -> - dsLExpr two `thenDs` \ two2 -> - returnDs (mkApps expr2 [from2, two2]) +dsExpr (ArithSeq expr (FromTo from to)) + = mkApps <$> dsExpr expr <*> mapM dsLExpr [from, to] dsExpr (ArithSeq expr (FromThen from thn)) - = dsExpr expr `thenDs` \ expr2 -> - dsLExpr from `thenDs` \ from2 -> - dsLExpr thn `thenDs` \ thn2 -> - returnDs (mkApps expr2 [from2, thn2]) - -dsExpr (ArithSeq expr (FromThenTo from thn two)) - = dsExpr expr `thenDs` \ expr2 -> - dsLExpr from `thenDs` \ from2 -> - dsLExpr thn `thenDs` \ thn2 -> - dsLExpr two `thenDs` \ two2 -> - returnDs (mkApps expr2 [from2, thn2, two2]) - -dsExpr (PArrSeq expr (FromTo from two)) - = dsExpr expr `thenDs` \ expr2 -> - dsLExpr from `thenDs` \ from2 -> - dsLExpr two `thenDs` \ two2 -> - returnDs (mkApps expr2 [from2, two2]) - -dsExpr (PArrSeq expr (FromThenTo from thn two)) - = dsExpr expr `thenDs` \ expr2 -> - dsLExpr from `thenDs` \ from2 -> - dsLExpr thn `thenDs` \ thn2 -> - dsLExpr two `thenDs` \ two2 -> - returnDs (mkApps expr2 [from2, thn2, two2]) - -dsExpr (PArrSeq expr _) + = mkApps <$> dsExpr expr <*> mapM dsLExpr [from, thn] + +dsExpr (ArithSeq expr (FromThenTo from thn to)) + = mkApps <$> dsExpr expr <*> mapM dsLExpr [from, thn, to] + +dsExpr (PArrSeq expr (FromTo from to)) + = mkApps <$> dsExpr expr <*> mapM dsLExpr [from, to] + +dsExpr (PArrSeq expr (FromThenTo from thn to)) + = mkApps <$> dsExpr expr <*> mapM dsLExpr [from, thn, to] + +dsExpr (PArrSeq _ _) = panic "DsExpr.dsExpr: Infinite parallel array!" -- the parser shouldn't have generated it and the renamer and typechecker -- shouldn't have let it through @@ -407,30 +378,28 @@ 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 (L _ data_con_id) con_expr (HsRecordBinds rbinds)) - = dsExpr con_expr `thenDs` \ con_expr' -> +dsExpr (RecordCon (L _ data_con_id) con_expr rbinds) = do + con_expr' <- dsExpr con_expr let - (arg_tys, _) = tcSplitFunTys (exprType con_expr') - -- A newtype in the corner should be opaque; - -- hence TcType.tcSplitFunTys - - mk_arg (arg_ty, lbl) -- Selector id has the field label as its name - = case [rhs | (L _ sel_id, rhs) <- rbinds, lbl == idName sel_id] of - (rhs:rhss) -> ASSERT( null rhss ) - dsLExpr rhs - [] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showSDoc (ppr lbl)) - unlabelled_bottom arg_ty = mkErrorAppDs rEC_CON_ERROR_ID arg_ty "" - - labels = dataConFieldLabels (idDataCon data_con_id) - -- The data_con_id is guaranteed to be the wrapper id of the constructor - in - - (if null labels - then mappM unlabelled_bottom arg_tys - else mappM mk_arg (zipEqual "dsExpr:RecordCon" arg_tys labels)) - `thenDs` \ con_args -> - - returnDs (mkApps con_expr' con_args) + (arg_tys, _) = tcSplitFunTys (exprType con_expr') + -- A newtype in the corner should be opaque; + -- hence TcType.tcSplitFunTys + + mk_arg (arg_ty, lbl) -- Selector id has the field label as its name + = case findField (rec_flds rbinds) lbl of + (rhs:rhss) -> ASSERT( null rhss ) + dsLExpr rhs + [] -> mkErrorAppDs rEC_CON_ERROR_ID arg_ty (showSDoc (ppr lbl)) + unlabelled_bottom arg_ty = mkErrorAppDs rEC_CON_ERROR_ID arg_ty "" + + labels = dataConFieldLabels (idDataCon data_con_id) + -- The data_con_id is guaranteed to be the wrapper id of the constructor + + con_args <- if null labels + then mapM unlabelled_bottom arg_tys + else mapM mk_arg (zipEqual "dsExpr:RecordCon" arg_tys labels) + + return (mkApps con_expr' con_args) \end{code} Record update is a little harder. Suppose we have the decl: @@ -455,10 +424,11 @@ might do some argument-evaluation first; and may have to throw away some dictionaries. \begin{code} -dsExpr (RecordUpd record_expr (HsRecordBinds []) _ _ _) +dsExpr expr@(RecordUpd record_expr (HsRecFields { rec_flds = fields }) + cons_to_upd in_inst_tys out_inst_tys) + | null fields = dsLExpr record_expr - -dsExpr expr@(RecordUpd record_expr (HsRecordBinds rbinds) cons_to_upd in_inst_tys out_inst_tys) + | otherwise = -- Record stuff doesn't work for existentials -- The type checker checks for this, but we need -- worry only about the constructors that are to be updated @@ -473,7 +443,7 @@ dsExpr expr@(RecordUpd record_expr (HsRecordBinds rbinds) cons_to_upd in_inst_ty (mkFamilyTyConApp tycon out_inst_tys) mk_val_arg field old_arg_id - = case [rhs | (L _ sel_id, rhs) <- rbinds, field == idName sel_id] of + = case findField fields field of (rhs:rest) -> ASSERT(null rest) rhs [] -> nlHsVar old_arg_id @@ -543,6 +513,11 @@ dsExpr (HsBinTick ixT ixF e) = do dsExpr (ExprWithTySig _ _) = panic "dsExpr:ExprWithTySig" #endif + +findField :: [HsRecField Id arg] -> Name -> [arg] +findField rbinds lbl + = [rhs | HsRecField { hsRecFieldId = id, hsRecFieldArg = rhs } <- rbinds + , lbl == idName (unLoc id) ] \end{code} %-------------------------------------------------------------------- @@ -566,7 +541,7 @@ dsDo stmts body result_ty = do { rhs2 <- dsLExpr rhs ; then_expr2 <- dsExpr then_expr ; rest <- go stmts - ; returnDs (mkApps then_expr2 [rhs2, rest]) } + ; return (mkApps then_expr2 [rhs2, rest]) } go (LetStmt binds : stmts) = do { rest <- go stmts @@ -574,14 +549,16 @@ dsDo stmts body result_ty go (BindStmt pat rhs bind_op fail_op : stmts) = - do { body <- go stmts + do { body <- go stmts + ; rhs' <- dsLExpr rhs + ; bind_op' <- dsExpr bind_op ; var <- selectSimpleMatchVarL pat + ; let bind_ty = exprType bind_op' -- rhs -> (pat -> res1) -> res2 + res1_ty = funResultTy (funArgTy (funResultTy bind_ty)) ; match <- matchSinglePat (Var var) (StmtCtxt DoExpr) pat - result_ty (cantFailMatchResult body) + res1_ty (cantFailMatchResult body) ; match_code <- handle_failure pat match fail_op - ; rhs' <- dsLExpr rhs - ; bind_op' <- dsExpr bind_op - ; returnDs (mkApps bind_op' [rhs', Lam var match_code]) } + ; return (mkApps bind_op' [rhs', Lam var match_code]) } -- In a do expression, pattern-match failure just calls -- the monadic 'fail' rather than throwing an exception @@ -593,6 +570,7 @@ dsDo stmts body result_ty | otherwise = extractMatchResult match (error "It can't fail") +mk_fail_msg :: Located e -> String mk_fail_msg pat = "Pattern match failure in do expression at " ++ showSDoc (ppr (getLoc pat)) \end{code} @@ -631,7 +609,7 @@ dsMDo tbl stmts body result_ty go (ExprStmt rhs _ rhs_ty : stmts) = do { rhs2 <- dsLExpr rhs ; rest <- go stmts - ; returnDs (mkApps (Var then_id) [Type rhs_ty, Type b_ty, rhs2, rest]) } + ; return (mkApps (Var then_id) [Type rhs_ty, Type b_ty, rhs2, rest]) } go (BindStmt pat rhs _ _ : stmts) = do { body <- go stmts @@ -643,7 +621,7 @@ dsMDo tbl stmts body result_ty ; match_code <- extractMatchResult match fail_expr ; rhs' <- dsLExpr rhs - ; returnDs (mkApps (Var bind_id) [Type (hsLPatType pat), Type b_ty, + ; return (mkApps (Var bind_id) [Type (hsLPatType pat), Type b_ty, rhs', Lam var match_code]) } go (RecStmt rec_stmts later_ids rec_ids rec_rets binds : stmts)