diff options
Diffstat (limited to 'ghc/compiler/deSugar/DsListComp.lhs')
| -rw-r--r-- | ghc/compiler/deSugar/DsListComp.lhs | 96 |
1 files changed, 50 insertions, 46 deletions
diff --git a/ghc/compiler/deSugar/DsListComp.lhs b/ghc/compiler/deSugar/DsListComp.lhs index 6192d5a4c2..643ba2ea01 100644 --- a/ghc/compiler/deSugar/DsListComp.lhs +++ b/ghc/compiler/deSugar/DsListComp.lhs @@ -44,9 +44,10 @@ There will be at least one ``qualifier'' in the input. \begin{code} dsListComp :: [LStmt Id] + -> LHsExpr Id -> Type -- Type of list elements -> DsM CoreExpr -dsListComp lquals elt_ty +dsListComp lquals body elt_ty = getDOptsDs `thenDs` \dflags -> let quals = map unLoc lquals @@ -58,7 +59,7 @@ dsListComp lquals elt_ty || isParallelComp quals -- Foldr-style desugaring can't handle -- parallel list comprehensions - then deListComp quals (mkNilExpr elt_ty) + then deListComp quals body (mkNilExpr elt_ty) else -- Foldr/build should be enabled, so desugar -- into foldrs and builds @@ -68,7 +69,7 @@ dsListComp lquals elt_ty c_ty = mkFunTys [elt_ty, n_ty] n_ty in newSysLocalsDs [c_ty,n_ty] `thenDs` \ [c, n] -> - dfListComp c n quals `thenDs` \ result -> + dfListComp c n quals body `thenDs` \ result -> dsLookupGlobalId buildName `thenDs` \ build_id -> returnDs (Var build_id `App` Type elt_ty `App` mkLams [n_tyvar, c, n] result) @@ -142,15 +143,15 @@ The introduced tuples are Boxed, but only because I couldn't get it to work with the Unboxed variety. \begin{code} -deListComp :: [Stmt Id] -> CoreExpr -> DsM CoreExpr +deListComp :: [Stmt Id] -> LHsExpr Id -> CoreExpr -> DsM CoreExpr -deListComp (ParStmt stmtss_w_bndrs : quals) list +deListComp (ParStmt stmtss_w_bndrs : quals) body list = mappM do_list_comp stmtss_w_bndrs `thenDs` \ exps -> mkZipBind qual_tys `thenDs` \ (zip_fn, zip_rhs) -> -- Deal with [e | pat <- zip l1 .. ln] in example above deBindComp pat (Let (Rec [(zip_fn, zip_rhs)]) (mkApps (Var zip_fn) exps)) - quals list + quals body list where bndrs_s = map snd stmtss_w_bndrs @@ -163,35 +164,35 @@ deListComp (ParStmt stmtss_w_bndrs : quals) list qual_tys = map mk_bndrs_tys bndrs_s do_list_comp (stmts, bndrs) - = dsListComp (stmts ++ [noLoc $ ResultStmt (mk_hs_tuple_expr bndrs)]) + = dsListComp stmts (mk_hs_tuple_expr bndrs) (mk_bndrs_tys bndrs) mk_bndrs_tys bndrs = mkCoreTupTy (map idType bndrs) -- Last: the one to return -deListComp [ResultStmt expr] list -- Figure 7.4, SLPJ, p 135, rule C above - = dsLExpr expr `thenDs` \ core_expr -> - returnDs (mkConsExpr (exprType core_expr) core_expr list) +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) -- Non-last: must be a guard -deListComp (ExprStmt guard ty : quals) list -- rule B above +deListComp (ExprStmt guard _ _ : quals) body list -- rule B above = dsLExpr guard `thenDs` \ core_guard -> - deListComp quals list `thenDs` \ core_rest -> + deListComp quals body list `thenDs` \ core_rest -> returnDs (mkIfThenElse core_guard core_rest list) -- [e | let B, qs] = let B in [e | qs] -deListComp (LetStmt binds : quals) list - = deListComp quals list `thenDs` \ core_rest -> +deListComp (LetStmt binds : quals) body list + = deListComp quals body list `thenDs` \ core_rest -> dsLet binds core_rest -deListComp (BindStmt pat list1 : quals) core_list2 -- rule A' above +deListComp (BindStmt pat list1 _ _ : quals) body core_list2 -- rule A' above = dsLExpr list1 `thenDs` \ core_list1 -> - deBindComp pat core_list1 quals core_list2 + deBindComp pat core_list1 quals body core_list2 \end{code} \begin{code} -deBindComp pat core_list1 quals core_list2 +deBindComp pat core_list1 quals body core_list2 = let u3_ty@u1_ty = exprType core_list1 -- two names, same thing @@ -208,7 +209,7 @@ deBindComp pat core_list1 quals core_list2 core_fail = App (Var h) (Var u3) letrec_body = App (Var h) core_list1 in - deListComp quals core_fail `thenDs` \ rest_expr -> + deListComp quals body core_fail `thenDs` \ rest_expr -> matchSimply (Var u2) (StmtCtxt ListComp) pat rest_expr core_fail `thenDs` \ core_match -> let @@ -289,25 +290,26 @@ TE[ e | p <- l , q ] c n = let \begin{code} dfListComp :: Id -> Id -- 'c' and 'n' -> [Stmt Id] -- the rest of the qual's + -> LHsExpr Id -> DsM CoreExpr -- Last: the one to return -dfListComp c_id n_id [ResultStmt expr] - = dsLExpr expr `thenDs` \ core_expr -> - returnDs (mkApps (Var c_id) [core_expr, Var n_id]) +dfListComp c_id n_id [] body + = dsLExpr body `thenDs` \ core_body -> + returnDs (mkApps (Var c_id) [core_body, Var n_id]) -- Non-last: must be a guard -dfListComp c_id n_id (ExprStmt guard ty : quals) - = dsLExpr guard `thenDs` \ core_guard -> - dfListComp c_id n_id quals `thenDs` \ core_rest -> +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) +dfListComp c_id n_id (LetStmt binds : quals) body -- new in 1.3, local bindings - = dfListComp c_id n_id quals `thenDs` \ core_rest -> + = dfListComp c_id n_id quals body `thenDs` \ core_rest -> dsLet binds core_rest -dfListComp c_id n_id (BindStmt pat list1 : quals) +dfListComp c_id n_id (BindStmt pat list1 _ _ : quals) body -- evaluate the two lists = dsLExpr list1 `thenDs` \ core_list1 -> @@ -320,7 +322,7 @@ dfListComp c_id n_id (BindStmt pat list1 : quals) newSysLocalsDs [b_ty,x_ty] `thenDs` \ [b,x] -> -- build rest of the comprehesion - dfListComp c_id b quals `thenDs` \ core_rest -> + dfListComp c_id b quals body `thenDs` \ core_rest -> -- build the pattern match matchSimply (Var x) (StmtCtxt ListComp) @@ -350,26 +352,28 @@ dfListComp c_id n_id (BindStmt pat list1 : quals) -- [:e | qss:] = <<[:e | qss:]>> () [:():] -- dsPArrComp :: [Stmt Id] + -> LHsExpr Id -> Type -- Don't use; called with `undefined' below -> DsM CoreExpr -dsPArrComp qs _ = +dsPArrComp qs body _ = dsLookupGlobalId replicatePName `thenDs` \repP -> let unitArray = mkApps (Var repP) [Type unitTy, mkIntExpr 1, mkCoreTup []] in - dePArrComp qs (mkTuplePat []) unitArray + dePArrComp qs body (mkTuplePat []) unitArray -- the work horse -- dePArrComp :: [Stmt Id] + -> LHsExpr Id -> LPat Id -- the current generator pattern -> CoreExpr -- the current generator expression -> DsM CoreExpr -- -- <<[:e' | :]>> pa ea = mapP (\pa -> e') ea -- -dePArrComp [ResultStmt e'] pa cea = +dePArrComp [] e' pa cea = dsLookupGlobalId mapPName `thenDs` \mapP -> let ty = parrElemType cea in @@ -379,19 +383,19 @@ dePArrComp [ResultStmt e'] pa cea = -- -- <<[:e' | b, qs:]>> pa ea = <<[:e' | qs:]>> pa (filterP (\pa -> b) ea) -- -dePArrComp (ExprStmt b _ : qs) pa cea = +dePArrComp (ExprStmt b _ _ : qs) body pa cea = dsLookupGlobalId filterPName `thenDs` \filterP -> let ty = parrElemType cea in deLambda ty pa b `thenDs` \(clam,_) -> - dePArrComp qs pa (mkApps (Var filterP) [Type ty, clam, cea]) + dePArrComp qs body pa (mkApps (Var filterP) [Type ty, clam, cea]) -- -- <<[:e' | p <- e, qs:]>> pa ea = -- let ef = filterP (\x -> case x of {p -> True; _ -> False}) e -- in -- <<[:e' | qs:]>> (pa, p) (crossP ea ef) -- -dePArrComp (BindStmt p e : qs) pa cea = +dePArrComp (BindStmt p e _ _ : qs) body pa cea = dsLookupGlobalId filterPName `thenDs` \filterP -> dsLookupGlobalId crossPName `thenDs` \crossP -> dsLExpr e `thenDs` \ce -> @@ -406,7 +410,7 @@ dePArrComp (BindStmt p e : qs) pa cea = ty'cef = ty'ce -- filterP preserves the type pa' = mkTuplePat [pa, p] in - dePArrComp qs pa' (mkApps (Var crossP) [Type ty'cea, Type ty'cef, cea, cef]) + dePArrComp qs body pa' (mkApps (Var crossP) [Type ty'cea, Type ty'cef, cea, cef]) -- -- <<[:e' | let ds, qs:]>> pa ea = -- <<[:e' | qs:]>> (pa, (x_1, ..., x_n)) @@ -414,7 +418,7 @@ dePArrComp (BindStmt p e : qs) pa cea = -- where -- {x_1, ..., x_n} = DV (ds) -- Defined Variables -- -dePArrComp (LetStmt ds : qs) pa cea = +dePArrComp (LetStmt ds : qs) body pa cea = dsLookupGlobalId mapPName `thenDs` \mapP -> let xs = map unLoc (collectGroupBinders ds) ty'cea = parrElemType cea @@ -432,7 +436,7 @@ dePArrComp (LetStmt ds : qs) pa cea = let pa' = mkTuplePat [pa, mkTuplePat (map nlVarPat xs)] proj = mkLams [v] ccase in - dePArrComp qs pa' (mkApps (Var mapP) [Type ty'cea, proj, cea]) + dePArrComp qs body pa' (mkApps (Var mapP) [Type ty'cea, proj, cea]) -- -- <<[:e' | qs | qss:]>> pa ea = -- <<[:e' | qss:]>> (pa, (x_1, ..., x_n)) @@ -440,7 +444,7 @@ dePArrComp (LetStmt ds : qs) pa cea = -- where -- {x_1, ..., x_n} = DV (qs) -- -dePArrComp (ParStmt qss : qs) pa cea = +dePArrComp (ParStmt qss : qs) body pa cea = dsLookupGlobalId crossPName `thenDs` \crossP -> deParStmt qss `thenDs` \(pQss, ceQss) -> @@ -448,26 +452,26 @@ dePArrComp (ParStmt qss : qs) pa cea = ty'ceQss = parrElemType ceQss pa' = mkTuplePat [pa, pQss] in - dePArrComp qs pa' (mkApps (Var crossP) [Type ty'cea, Type ty'ceQss, - cea, ceQss]) + dePArrComp qs body pa' (mkApps (Var crossP) [Type ty'cea, Type ty'ceQss, + cea, ceQss]) where deParStmt [] = -- empty parallel statement lists have not source representation panic "DsListComp.dePArrComp: Empty parallel list comprehension" deParStmt ((qs, xs):qss) = -- first statement - let resStmt = ResultStmt $ mkExplicitTuple (map nlHsVar xs) + let res_expr = mkExplicitTuple (map nlHsVar xs) in - dsPArrComp (map unLoc qs ++ [resStmt]) undefined `thenDs` \cqs -> + dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs -> parStmts qss (mkTuplePat (map nlVarPat xs)) cqs --- parStmts [] pa cea = return (pa, cea) parStmts ((qs, xs):qss) pa cea = -- subsequent statements (zip'ed) dsLookupGlobalId zipPName `thenDs` \zipP -> - let pa' = mkTuplePat [pa, mkTuplePat (map nlVarPat xs)] - ty'cea = parrElemType cea - resStmt = ResultStmt $ mkExplicitTuple (map nlHsVar xs) + let pa' = mkTuplePat [pa, mkTuplePat (map nlVarPat xs)] + ty'cea = parrElemType cea + res_expr = mkExplicitTuple (map nlHsVar xs) in - dsPArrComp (map unLoc qs ++ [resStmt]) undefined `thenDs` \cqs -> + dsPArrComp (map unLoc qs) res_expr undefined `thenDs` \cqs -> let ty'cqs = parrElemType cqs cea' = mkApps (Var zipP) [Type ty'cea, Type ty'cqs, cea, cqs] in |