From dcc8f0a89f1ff43684b6e0f34b9ded3ec6b96e1c Mon Sep 17 00:00:00 2001 From: Twan van Laarhoven Date: Thu, 17 Jan 2008 17:32:05 +0000 Subject: [PATCH] Monadify deSugar/DsListComp: use do, return, applicative, standard monad functions --- compiler/deSugar/DsListComp.lhs | 213 ++++++++++++++++++--------------------- 1 file changed, 98 insertions(+), 115 deletions(-) diff --git a/compiler/deSugar/DsListComp.lhs b/compiler/deSugar/DsListComp.lhs index f4ab7b3..35ff21f 100644 --- a/compiler/deSugar/DsListComp.lhs +++ b/compiler/deSugar/DsListComp.lhs @@ -75,7 +75,7 @@ dsListComp lquals body elt_ty = do result <- dfListComp c n quals body build_id <- dsLookupGlobalId buildName - returnDs (Var build_id `App` Type elt_ty `App` mkLams [n_tyvar, c, n] result) + return (Var build_id `App` Type elt_ty `App` mkLams [n_tyvar, c, n] result) where -- We must test for ParStmt anywhere, not just at the head, because an extension @@ -247,7 +247,7 @@ deListComp :: [Stmt Id] -> LHsExpr Id -> CoreExpr -> DsM CoreExpr deListComp (ParStmt stmtss_w_bndrs : quals) body list = do - exps_and_qual_tys <- mappM dsInnerListComp stmtss_w_bndrs + exps_and_qual_tys <- mapM dsInnerListComp stmtss_w_bndrs let (exps, qual_tys) = unzip exps_and_qual_tys (zip_fn, zip_rhs) <- mkZipBind qual_tys @@ -260,23 +260,23 @@ deListComp (ParStmt stmtss_w_bndrs : quals) body list bndrs_s = map snd stmtss_w_bndrs -- pat is the pattern ((x1,..,xn), (y1,..,ym)) in the example above - pat = mkBigLHsPatTup pats + pat = mkBigLHsPatTup pats pats = map mkBigLHsVarPatTup bndrs_s -- Last: the one to return -deListComp [] body list -- Figure 7.4, SLPJ, p 135, rule C above - = dsLExpr body `thenDs` \ core_body -> - returnDs (mkConsExpr (exprType core_body) core_body list) +deListComp [] body list = do -- Figure 7.4, SLPJ, p 135, rule C above + core_body <- dsLExpr body + return (mkConsExpr (exprType core_body) core_body list) -- Non-last: must be a guard -deListComp (ExprStmt guard _ _ : quals) body list -- rule B above - = dsLExpr guard `thenDs` \ core_guard -> - deListComp quals body list `thenDs` \ core_rest -> - returnDs (mkIfThenElse core_guard core_rest list) +deListComp (ExprStmt guard _ _ : quals) body list = do -- rule B above + core_guard <- dsLExpr guard + core_rest <- deListComp quals body list + return (mkIfThenElse core_guard core_rest list) -- [e | let B, qs] = let B in [e | qs] -deListComp (LetStmt binds : quals) body list - = deListComp quals body list `thenDs` \ core_rest -> +deListComp (LetStmt binds : quals) body list = do + core_rest <- deListComp quals body list dsLocalBinds binds core_rest deListComp (stmt@(TransformStmt _ _ _) : quals) body list = do @@ -287,8 +287,8 @@ deListComp (stmt@(GroupStmt _ _) : quals) body list = do (inner_list_expr, pat) <- dsGroupStmt stmt deBindComp pat inner_list_expr quals body list -deListComp (BindStmt pat list1 _ _ : quals) body core_list2 -- rule A' above - = dsLExpr list1 `thenDs` \ core_list1 -> +deListComp (BindStmt pat list1 _ _ : quals) body core_list2 = do -- rule A' above + core_list1 <- dsLExpr list1 deBindComp pat core_list1 quals body core_list2 \end{code} @@ -350,19 +350,19 @@ dfListComp :: Id -> Id -- 'c' and 'n' -> DsM CoreExpr -- Last: the one to return -dfListComp c_id n_id [] body - = dsLExpr body `thenDs` \ core_body -> - returnDs (mkApps (Var c_id) [core_body, Var n_id]) +dfListComp c_id n_id [] body = do + core_body <- dsLExpr body + return (mkApps (Var c_id) [core_body, Var n_id]) -- Non-last: must be a guard -dfListComp c_id n_id (ExprStmt guard _ _ : quals) body - = dsLExpr guard `thenDs` \ core_guard -> - dfListComp c_id n_id quals body `thenDs` \ core_rest -> - returnDs (mkIfThenElse core_guard core_rest (Var n_id)) - -dfListComp c_id n_id (LetStmt binds : quals) body - -- new in 1.3, local bindings - = dfListComp c_id n_id quals body `thenDs` \ core_rest -> +dfListComp c_id n_id (ExprStmt guard _ _ : quals) body = do + core_guard <- dsLExpr guard + core_rest <- dfListComp c_id n_id quals body + return (mkIfThenElse core_guard core_rest (Var n_id)) + +dfListComp c_id n_id (LetStmt binds : quals) body = do + -- new in 1.3, local bindings + core_rest <- dfListComp c_id n_id quals body dsLocalBinds binds core_rest dfListComp c_id n_id (stmt@(TransformStmt _ _ _) : quals) body = do @@ -430,9 +430,9 @@ mkZipBind :: [Type] -> DsM (Id, CoreExpr) -- (a2:as'2) -> (a1, a2) : zip as'1 as'2)] mkZipBind elt_tys = do - ass <- mappM newSysLocalDs elt_list_tys - as' <- mappM newSysLocalDs elt_tys - as's <- mappM newSysLocalDs elt_list_tys + ass <- mapM newSysLocalDs elt_list_tys + as' <- mapM newSysLocalDs elt_tys + as's <- mapM newSysLocalDs elt_list_tys zip_fn <- newSysLocalDs zip_fn_ty @@ -470,8 +470,8 @@ mkUnzipBind elt_tys = do ax <- newSysLocalDs elt_tuple_ty axs <- newSysLocalDs elt_list_tuple_ty ys <- newSysLocalDs elt_tuple_list_ty - xs <- mappM newSysLocalDs elt_tys - xss <- mappM newSysLocalDs elt_list_tys + xs <- mapM newSysLocalDs elt_tys + xss <- mapM newSysLocalDs elt_list_tys unzip_fn <- newSysLocalDs unzip_fn_ty @@ -523,12 +523,10 @@ dsPArrComp :: [Stmt Id] -> DsM CoreExpr dsPArrComp [ParStmt qss] body _ = -- parallel comprehension dePArrParComp qss body -dsPArrComp qs body _ = -- no ParStmt in `qs' - dsLookupGlobalId singletonPName `thenDs` \sglP -> - let unitArray = mkApps (Var sglP) [Type unitTy, - mkCoreTup []] - in - dePArrComp qs body (mkLHsPatTup []) unitArray +dsPArrComp qs body _ = do -- no ParStmt in `qs' + sglP <- dsLookupGlobalId singletonPName + let unitArray = mkApps (Var sglP) [Type unitTy, mkCoreTup []] + dePArrComp qs body (mkLHsPatTup []) unitArray @@ -542,22 +540,19 @@ dePArrComp :: [Stmt Id] -- -- <<[:e' | :]>> pa ea = mapP (\pa -> e') ea -- -dePArrComp [] e' pa cea = - dsLookupGlobalId mapPName `thenDs` \mapP -> - let ty = parrElemType cea - in - deLambda ty pa e' `thenDs` \(clam, - ty'e') -> - returnDs $ mkApps (Var mapP) [Type ty, Type ty'e', clam, cea] +dePArrComp [] e' pa cea = do + mapP <- dsLookupGlobalId mapPName + let ty = parrElemType cea + (clam, ty'e') <- deLambda ty pa e' + return $ mkApps (Var mapP) [Type ty, Type ty'e', clam, cea] -- -- <<[:e' | b, qs:]>> pa ea = <<[:e' | qs:]>> pa (filterP (\pa -> b) ea) -- -dePArrComp (ExprStmt b _ _ : qs) body pa cea = - dsLookupGlobalId filterPName `thenDs` \filterP -> - let ty = parrElemType cea - in - deLambda ty pa b `thenDs` \(clam,_) -> - dePArrComp qs body pa (mkApps (Var filterP) [Type ty, clam, cea]) +dePArrComp (ExprStmt b _ _ : qs) body pa cea = do + filterP <- dsLookupGlobalId filterPName + let ty = parrElemType cea + (clam,_) <- deLambda ty pa b + dePArrComp qs body pa (mkApps (Var filterP) [Type ty, clam, cea]) -- -- <<[:e' | p <- e, qs:]>> pa ea = @@ -572,27 +567,24 @@ dePArrComp (ExprStmt b _ _ : qs) body pa cea = -- in -- <<[:e' | qs:]>> (pa, p) (crossMapP ea ef) -- -dePArrComp (BindStmt p e _ _ : qs) body pa cea = - dsLookupGlobalId filterPName `thenDs` \filterP -> - dsLookupGlobalId crossMapPName `thenDs` \crossMapP -> - dsLExpr e `thenDs` \ce -> - let ety'cea = parrElemType cea - ety'ce = parrElemType ce - false = Var falseDataConId - true = Var trueDataConId - in - newSysLocalDs ety'ce `thenDs` \v -> - matchSimply (Var v) (StmtCtxt PArrComp) p true false `thenDs` \pred -> - let cef | isIrrefutableHsPat p = ce - | otherwise = mkApps (Var filterP) [Type ety'ce, mkLams [v] pred, ce] - in - mkLambda ety'cea pa cef `thenDs` \(clam, - _ ) -> - let ety'cef = ety'ce -- filter doesn't change the element type - pa' = mkLHsPatTup [pa, p] - in - dePArrComp qs body pa' (mkApps (Var crossMapP) - [Type ety'cea, Type ety'cef, cea, clam]) +dePArrComp (BindStmt p e _ _ : qs) body pa cea = do + filterP <- dsLookupGlobalId filterPName + crossMapP <- dsLookupGlobalId crossMapPName + ce <- dsLExpr e + let ety'cea = parrElemType cea + ety'ce = parrElemType ce + false = Var falseDataConId + true = Var trueDataConId + v <- newSysLocalDs ety'ce + pred <- matchSimply (Var v) (StmtCtxt PArrComp) p true false + let cef | isIrrefutableHsPat p = ce + | otherwise = mkApps (Var filterP) [Type ety'ce, mkLams [v] pred, ce] + (clam, _) <- mkLambda ety'cea pa cef + let ety'cef = ety'ce -- filter doesn't change the element type + pa' = mkLHsPatTup [pa, p] + + dePArrComp qs body pa' (mkApps (Var crossMapP) + [Type ety'cea, Type ety'cef, cea, clam]) -- -- <<[:e' | let ds, qs:]>> pa ea = -- <<[:e' | qs:]>> (pa, (x_1, ..., x_n)) @@ -600,26 +592,23 @@ dePArrComp (BindStmt p e _ _ : qs) body pa cea = -- where -- {x_1, ..., x_n} = DV (ds) -- Defined Variables -- -dePArrComp (LetStmt ds : qs) body pa cea = - dsLookupGlobalId mapPName `thenDs` \mapP -> - let xs = map unLoc (collectLocalBinders ds) - ty'cea = parrElemType cea - in - newSysLocalDs ty'cea `thenDs` \v -> - dsLocalBinds ds (mkCoreTup (map Var xs)) `thenDs` \clet -> - newSysLocalDs (exprType clet) `thenDs` \let'v -> - let projBody = mkDsLet (NonRec let'v clet) $ - mkCoreTup [Var v, Var let'v] - errTy = exprType projBody - errMsg = "DsListComp.dePArrComp: internal error!" - in - mkErrorAppDs pAT_ERROR_ID errTy errMsg `thenDs` \cerr -> - matchSimply (Var v) (StmtCtxt PArrComp) pa projBody cerr`thenDs` \ccase -> - let pa' = mkLHsPatTup [pa, mkLHsPatTup (map nlVarPat xs)] - proj = mkLams [v] ccase - in - dePArrComp qs body pa' (mkApps (Var mapP) - [Type ty'cea, Type errTy, proj, cea]) +dePArrComp (LetStmt ds : qs) body pa cea = do + mapP <- dsLookupGlobalId mapPName + let xs = map unLoc (collectLocalBinders ds) + ty'cea = parrElemType cea + v <- newSysLocalDs ty'cea + clet <- dsLocalBinds ds (mkCoreTup (map Var xs)) + let'v <- newSysLocalDs (exprType clet) + let projBody = mkDsLet (NonRec let'v clet) $ + mkCoreTup [Var v, Var let'v] + errTy = exprType projBody + errMsg = "DsListComp.dePArrComp: internal error!" + cerr <- mkErrorAppDs pAT_ERROR_ID errTy errMsg + ccase <- matchSimply (Var v) (StmtCtxt PArrComp) pa projBody cerr + let pa' = mkLHsPatTup [pa, mkLHsPatTup (map nlVarPat xs)] + proj = mkLams [v] ccase + dePArrComp qs body pa' (mkApps (Var mapP) + [Type ty'cea, Type errTy, proj, cea]) -- -- The parser guarantees that parallel comprehensions can only appear as -- singeltons qualifier lists, which we already special case in the caller. @@ -634,31 +623,27 @@ dePArrComp (ParStmt _ : _) _ _ _ = -- where -- {x_1, ..., x_n} = DV (qs) -- -dePArrParComp qss body = - deParStmt qss `thenDs` \(pQss, - ceQss) -> - dePArrComp [] body pQss ceQss +dePArrParComp qss body = do + (pQss, ceQss) <- deParStmt qss + dePArrComp [] body pQss ceQss where deParStmt [] = -- empty parallel statement lists have no source representation panic "DsListComp.dePArrComp: Empty parallel list comprehension" - deParStmt ((qs, xs):qss) = -- first statement + deParStmt ((qs, xs):qss) = do -- first statement let res_expr = mkLHsVarTup xs - in - dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs -> + cqs <- dsPArrComp (map unLoc qs) res_expr undefined parStmts qss (mkLHsVarPatTup xs) cqs --- parStmts [] pa cea = return (pa, cea) - parStmts ((qs, xs):qss) pa cea = -- subsequent statements (zip'ed) - dsLookupGlobalId zipPName `thenDs` \zipP -> + parStmts ((qs, xs):qss) pa cea = do -- subsequent statements (zip'ed) + zipP <- dsLookupGlobalId zipPName let pa' = mkLHsPatTup [pa, mkLHsVarPatTup xs] - ty'cea = parrElemType cea - res_expr = mkLHsVarTup xs - in - dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs -> + ty'cea = parrElemType cea + res_expr = mkLHsVarTup xs + cqs <- dsPArrComp (map unLoc qs) res_expr undefined let ty'cqs = parrElemType cqs - cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs] - in + cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs] parStmts qss pa' cea' -- generate Core corresponding to `\p -> e' @@ -668,8 +653,7 @@ deLambda :: Type -- type of the argument -> LHsExpr Id -- body -> DsM (CoreExpr, Type) deLambda ty p e = - dsLExpr e `thenDs` \ce -> - mkLambda ty p ce + mkLambda ty p =<< dsLExpr e -- generate Core for a lambda pattern match, where the body is already in Core -- @@ -677,14 +661,13 @@ mkLambda :: Type -- type of the argument -> LPat Id -- argument pattern -> CoreExpr -- desugared body -> DsM (CoreExpr, Type) -mkLambda ty p ce = - newSysLocalDs ty `thenDs` \v -> - let errMsg = "DsListComp.deLambda: internal error!" - ce'ty = exprType ce - in - mkErrorAppDs pAT_ERROR_ID ce'ty errMsg `thenDs` \cerr -> - matchSimply (Var v) (StmtCtxt PArrComp) p ce cerr `thenDs` \res -> - returnDs (mkLams [v] res, ce'ty) +mkLambda ty p ce = do + v <- newSysLocalDs ty + let errMsg = do "DsListComp.deLambda: internal error!" + ce'ty = exprType ce + cerr <- mkErrorAppDs pAT_ERROR_ID ce'ty errMsg + res <- matchSimply (Var v) (StmtCtxt PArrComp) p ce cerr + return (mkLams [v] res, ce'ty) -- obtain the element type of the parallel array produced by the given Core -- expression -- 1.7.10.4