X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FdeSugar%2FDsListComp.lhs;h=63cae938d083cf5b061ccd87a272e3fc69999801;hp=1ecab67e10fbc580e8e79d854152c004db1b2b8d;hb=d76d9636aeebe933d160157331b8c8c0087e73ac;hpb=4ac2bb39dffb4b825ece73b349ff0d56d79092d7 diff --git a/compiler/deSugar/DsListComp.lhs b/compiler/deSugar/DsListComp.lhs index 1ecab67..63cae93 100644 --- a/compiler/deSugar/DsListComp.lhs +++ b/compiler/deSugar/DsListComp.lhs @@ -54,7 +54,9 @@ dsListComp :: [LStmt Id] dsListComp lquals res_ty = do dflags <- getDOptsDs let quals = map unLoc lquals - [elt_ty] = tcTyConAppArgs res_ty + elt_ty = case tcTyConAppArgs res_ty of + [elt_ty] -> elt_ty + _ -> pprPanic "dsListComp" (ppr res_ty $$ ppr lquals) if not (dopt Opt_EnableRewriteRules dflags) || dopt Opt_IgnoreInterfacePragmas dflags -- Either rules are switched off, or we are ignoring what there are; @@ -82,9 +84,9 @@ dsListComp lquals res_ty = do -- of that comprehension that we need in the outer comprehension into such an expression -- and the type of the elements that it outputs (tuples of binders) dsInnerListComp :: ([LStmt Id], [Id]) -> DsM (CoreExpr, Type) -dsInnerListComp (stmts, bndrs) = do +dsInnerListComp (stmts, bndrs) = do { expr <- dsListComp (stmts ++ [noLoc $ mkLastStmt (mkBigLHsVarTup bndrs)]) - bndrs_tuple_type + (mkListTy bndrs_tuple_type) ; return (expr, bndrs_tuple_type) } where bndrs_tuple_type = mkBigCoreVarTupTy bndrs @@ -117,7 +119,8 @@ dsTransformStmt (TransformStmt stmts binders usingExpr maybeByExpr _ _) -- Given such a statement it gives you back an expression representing how to compute the transformed -- list and the tuple that you need to bind from that list in order to proceed with your desugaring dsGroupStmt :: Stmt Id -> DsM (CoreExpr, LPat Id) -dsGroupStmt (GroupStmt stmts binderMap by using _ _ _) = do +dsGroupStmt (GroupStmt { grpS_stmts = stmts, grpS_bndrs = binderMap + , grpS_by = by, grpS_using = using }) = do let (fromBinders, toBinders) = unzip binderMap fromBindersTypes = map idType fromBinders @@ -130,7 +133,7 @@ dsGroupStmt (GroupStmt stmts binderMap by using _ _ _) = do -- Work out what arguments should be supplied to that expression: i.e. is an extraction -- function required? If so, create that desugared function and add to arguments - usingExpr' <- dsLExpr (either id noLoc using) + usingExpr' <- dsLExpr using usingArgs <- case by of Nothing -> return [expr] Just by_e -> do { by_e' <- dsLExpr by_e @@ -688,45 +691,15 @@ parrElemType e = Translation for monad comprehensions \begin{code} - --- | Keep the "context" of a monad comprehension in a small data type to avoid --- some boilerplate... -data DsMonadComp = DsMonadComp - { mc_return :: Either (SyntaxExpr Id) (Expr CoreBndr) - , mc_body :: LHsExpr Id - , mc_m_ty :: Type - } - --- -- Entry point for monad comprehension desugaring --- -dsMonadComp :: [LStmt Id] -- the statements - -> Type -- the final type - -> DsM CoreExpr -dsMonadComp stmts res_ty - = dsMcStmts stmts (DsMonadComp (Left return_op) body m_ty) - where - (m_ty, _) = tcSplitAppTy res_ty - - -dsMcStmts :: [LStmt Id] - -> DsMonadComp - -> DsM CoreExpr - --- No statements left for desugaring. Desugar the body after calling "return" --- on it. -dsMcStmts [] DsMonadComp { mc_return, mc_body } - = case mc_return of - Left ret -> dsLExpr $ noLoc ret `nlHsApp` mc_body - Right ret' -> do - { body' <- dsLExpr mc_body - ; return $ mkApps ret' [body'] } - --- Otherwise desugar each statement step by step -dsMcStmts ((L loc stmt) : lstmts) mc - = putSrcSpanDs loc (dsMcStmt stmt lstmts mc) +dsMonadComp :: [LStmt Id] -> DsM CoreExpr +dsMonadComp stmts = dsMcStmts stmts +dsMcStmts :: [LStmt Id] -> DsM CoreExpr +dsMcStmts [] = panic "dsMcStmts" +dsMcStmts (L loc stmt : lstmts) = putSrcSpanDs loc (dsMcStmt stmt lstmts) +--------------- dsMcStmt :: Stmt Id -> [LStmt Id] -> DsM CoreExpr dsMcStmt (LastStmt body ret_op) stmts @@ -785,7 +758,7 @@ dsMcStmt (TransformStmt stmts binders usingExpr maybeByExpr return_op bind_op) s -- -- [| (q, then group by e using f); rest |] -- ---> f {qt} (\qv -> e) [| q; return qv |] >>= \ n_tup -> --- case unzip n_tup of qv -> [| rest |] +-- case unzip n_tup of qv' -> [| rest |] -- -- where variables (v1:t1, ..., vk:tk) are bound by q -- qv = (v1, ..., vk) @@ -794,61 +767,42 @@ dsMcStmt (TransformStmt stmts binders usingExpr maybeByExpr return_op bind_op) s -- f :: forall a. (a -> t) -> m1 a -> m2 (n a) -- n_tup :: n qt -- unzip :: n qt -> (n t1, ..., n tk) (needs Functor n) --- --- [| q, then group by e using f |] -> (f (\q_v -> e) [| q |]) >>= (return . (unzip q_v)) --- --- which is equal to --- --- [| q, then group by e using f |] -> liftM (unzip q_v) (f (\q_v -> e) [| q |]) --- --- where unzip is of the form --- --- unzip :: n (a,b,c,..) -> (n a,n b,n c,..) --- unzip m_tuple = ( fmap selN1 m_tuple --- , fmap selN2 m_tuple --- , .. ) --- where selN1 (a,b,c,..) = a --- selN2 (a,b,c,..) = b --- .. --- -dsMcStmt (GroupStmt stmts binderMap by using return_op bind_op fmap_op) stmts_rest - = do { let (fromBinders, toBinders) = unzip binderMap - fromBindersTypes = map idType fromBinders -- Types ty - fromBindersTupleTy = mkBigCoreTupTy fromBindersTypes - toBindersTypes = map idType toBinders -- Types (n ty) - toBindersTupleTy = mkBigCoreTupTy toBindersTypes + +dsMcStmt (GroupStmt { grpS_stmts = stmts, grpS_bndrs = bndrs + , grpS_by = by, grpS_using = using + , grpS_ret = return_op, grpS_bind = bind_op + , grpS_fmap = fmap_op }) stmts_rest + = do { let (from_bndrs, to_bndrs) = unzip bndrs + from_bndr_tys = map idType from_bndrs -- Types ty -- Desugar an inner comprehension which outputs a list of tuples of the "from" binders - ; expr <- dsInnerMonadComp stmts fromBinders return_op + ; expr <- dsInnerMonadComp stmts from_bndrs return_op -- Work out what arguments should be supplied to that expression: i.e. is an extraction -- function required? If so, create that desugared function and add to arguments - ; usingExpr' <- dsLExpr (either id noLoc using) + ; usingExpr' <- dsLExpr using ; usingArgs <- case by of Nothing -> return [expr] Just by_e -> do { by_e' <- dsLExpr by_e - ; lam <- matchTuple fromBinders by_e' + ; lam <- matchTuple from_bndrs by_e' ; return [lam, expr] } - -- Create an unzip function for the appropriate arity and element types - ; fmap_op' <- dsExpr fmap_op - ; (unzip_fn, unzip_rhs) <- mkMcUnzipM fmap_op' m_ty fromBindersTypes - -- Generate the expressions to build the grouped list -- Build a pattern that ensures the consumer binds into the NEW binders, -- which hold monads rather than single values + ; fmap_op' <- dsExpr fmap_op ; bind_op' <- dsExpr bind_op ; let bind_ty = exprType bind_op' -- m2 (n (a,b,c)) -> (n (a,b,c) -> r1) -> r2 - n_tup_ty = funArgTy $ funArgTy $ funResultTy bind_ty - - ; body <- dsMcStmts stmts_rest - ; n_tup_var <- newSysLocalDs n_tup_ty - ; tup_n_var <- newSysLocalDs (mkBigCoreVarTupTy toBinders) - ; us <- newUniqueSupply - ; let unzip_n_tup = Let (Rec [(unzip_fn, unzip_rhs)]) $ - App (Var unzip_fn) (Var n_tup_var) - -- unzip_n_tup :: (n a, n b, n c) - body' = mkTupleCase us toBinders body unzip_n_tup (Var tup_n_var) + n_tup_ty = funArgTy $ funArgTy $ funResultTy bind_ty -- n (a,b,c) + tup_n_ty = mkBigCoreVarTupTy to_bndrs + + ; body <- dsMcStmts stmts_rest + ; n_tup_var <- newSysLocalDs n_tup_ty + ; tup_n_var <- newSysLocalDs tup_n_ty + ; tup_n_expr <- mkMcUnzipM fmap_op' n_tup_var from_bndr_tys + ; us <- newUniqueSupply + ; let rhs' = mkApps usingExpr' usingArgs + body' = mkTupleCase us to_bndrs body tup_n_var tup_n_expr ; return (mkApps bind_op' [rhs', Lam n_tup_var body']) } @@ -864,23 +818,26 @@ dsMcStmt (GroupStmt stmts binderMap by using return_op bind_op fmap_op) stmts_re -- NB: we need a polymorphic mzip because we call it several times dsMcStmt (ParStmt pairs mzip_op bind_op return_op) stmts_rest - = do { exps <- mapM ds_inner pairs - ; let qual_tys = map (mkBigCoreVarTupTy . snd) pairs - ; mzip_op' <- dsExpr mzip_op - ; (zip_fn, zip_rhs) <- mkMcZipM mzip_op' (mc_m_ty mc) qual_tys + = do { exps_w_tys <- mapM ds_inner pairs -- Pairs (exp :: m ty, ty) + ; mzip_op' <- dsExpr mzip_op ; let -- The pattern variables - vars = map (mkBigLHsVarPatTup . snd) pairs + pats = map (mkBigLHsVarPatTup . snd) pairs -- Pattern with tuples of variables -- [v1,v2,v3] => (v1, (v2, v3)) - pat = foldr (\tn tm -> mkBigLHsPatTup [tn, tm]) (last vars) (init vars) - rhs = Let (Rec [(zip_fn, zip_rhs)]) (mkApps (Var zip_fn) exps) + pat = foldr1 (\p1 p2 -> mkLHsPatTup [p1, p2]) pats + (rhs, _) = foldr1 (\(e1,t1) (e2,t2) -> + (mkApps mzip_op' [Type t1, Type t2, e1, e2], + mkBoxedTupleTy [t1,t2])) + exps_w_tys ; dsMcBindStmt pat rhs bind_op noSyntaxExpr stmts_rest } where - ds_inner (stmts, bndrs) = dsInnerMonadComp stmts bndrs mono_ret_op + ds_inner (stmts, bndrs) = do { exp <- dsInnerMonadComp stmts bndrs mono_ret_op + ; return (exp, tup_ty) } where - mono_ret_op = HsWrap (WpTyApp (mkBigCoreVarTupTy bndrs)) return_op + mono_ret_op = HsWrap (WpTyApp tup_ty) return_op + tup_ty = mkBigCoreVarTupTy bndrs dsMcStmt stmt _ = pprPanic "dsMcStmt: unexpected stmt" (ppr stmt) @@ -891,10 +848,9 @@ matchTuple :: [Id] -> CoreExpr -> DsM CoreExpr -- \x. case x of (a,b,c) -> body matchTuple ids body = do { us <- newUniqueSupply - ; tup_id <- newSysLocalDs (mkBigLHsVarPatTup ids) + ; tup_id <- newSysLocalDs (mkBigCoreVarTupTy ids) ; return (Lam tup_id $ mkTupleCase us ids body tup_id (Var tup_id)) } - -- general `rhs' >>= \pat -> stmts` desugaring where `rhs'` is already a -- desugared `CoreExpr` dsMcBindStmt :: LPat Id @@ -936,10 +892,10 @@ dsMcBindStmt pat rhs' bind_op fail_op stmts dsInnerMonadComp :: [LStmt Id] -> [Id] -- Return a tuple of these variables - -> LHsExpr Id -- The monomorphic "return" operator + -> HsExpr Id -- The monomorphic "return" operator -> DsM CoreExpr dsInnerMonadComp stmts bndrs ret_op - = dsMcStmts (stmts ++ [noLoc (ReturnStmt (mkBigLHsVarTup bndrs) ret_op)]) + = dsMcStmts (stmts ++ [noLoc (LastStmt (mkBigLHsVarTup bndrs) ret_op)]) -- The `unzip` function for `GroupStmt` in a monad comprehensions -- @@ -948,85 +904,25 @@ dsInnerMonadComp stmts bndrs ret_op -- , liftM selN2 m_tuple -- , .. ) -- --- mkMcUnzipM m [t1, t2] --- = (unzip_fn, \ys :: m (t1, t2) -> --- ( liftM (selN1 :: (t1, t2) -> t1) ys --- , liftM (selN2 :: (t1, t2) -> t2) ys --- )) --- -mkMcUnzipM :: CoreExpr - -> Type -- m - -> [Type] -- [a,b,c,..] - -> DsM (Id, CoreExpr) -mkMcUnzipM liftM_op m_ty elt_tys - = do { ys <- newSysLocalDs monad_tuple_ty - ; xs <- mapM newSysLocalDs elt_tys - ; scrut <- newSysLocalDs tuple_tys - - ; unzip_fn <- newSysLocalDs unzip_fn_ty - - ; let -- Select one Id from our tuple - selectExpr n = mkLams [scrut] $ mkTupleSelector xs (xs !! n) scrut (Var scrut) - -- Apply 'selectVar' and 'ys' to 'liftM' - tupleElem n = mkApps liftM_op - -- Types (m is figured out by the type checker): - -- liftM :: forall a b. (a -> b) -> m a -> m b - [ Type tuple_tys, Type (elt_tys !! n) - -- Arguments: - , selectExpr n, Var ys ] - -- The final expression with the big tuple - unzip_body = mkBigCoreTup [ tupleElem n | n <- [0..length elt_tys - 1] ] - - ; return (unzip_fn, mkLams [ys] unzip_body) } - where monad_tys = map (m_ty `mkAppTy`) elt_tys -- [m a,m b,m c,..] - tuple_monad_tys = mkBigCoreTupTy monad_tys -- (m a,m b,m c,..) - tuple_tys = mkBigCoreTupTy elt_tys -- (a,b,c,..) - monad_tuple_ty = m_ty `mkAppTy` tuple_tys -- m (a,b,c,..) - unzip_fn_ty = monad_tuple_ty `mkFunTy` tuple_monad_tys -- m (a,b,c,..) -> (m a,m b,m c,..) - --- Generate the `mzip` function for `ParStmt` in monad comprehensions, for --- example: --- --- mzip :: m t1 --- -> (m t2 -> m t3 -> m (t2, t3)) --- -> m (t1, (t2, t3)) --- --- mkMcZipM m [t1, t2, t3] --- = (zip_fn, \(q1::t1) (q2::t2) (q3::t3) -> --- mzip q1 (mzip q2 q3)) --- -mkMcZipM :: CoreExpr - -> Type - -> [Type] - -> DsM (Id, CoreExpr) - -mkMcZipM mzip_op m_ty tys@(_:_:_) -- min. 2 types - = do { (ids, t1, tuple_ty, zip_body) <- loop tys - ; zip_fn <- newSysLocalDs $ - (m_ty `mkAppTy` t1) - `mkFunTy` - (m_ty `mkAppTy` tuple_ty) - `mkFunTy` - (m_ty `mkAppTy` mkBigCoreTupTy [t1, tuple_ty]) - ; return (zip_fn, mkLams ids zip_body) } - - where - -- loop :: [Type] -> DsM ([Id], Type, [Type], CoreExpr) - loop [t1, t2] = do -- last run of the `loop` - { ids@[a,b] <- newSysLocalsDs (map (m_ty `mkAppTy`) [t1,t2]) - ; let zip_body = mkApps mzip_op [ Type t1, Type t2 , Var a, Var b ] - ; return (ids, t1, t2, zip_body) } - - loop (t1:tr) = do - { -- Get ty, ids etc from the "inner" zip - (ids', t1', t2', zip_body') <- loop tr - - ; a <- newSysLocalDs $ m_ty `mkAppTy` t1 - ; let tuple_ty' = mkBigCoreTupTy [t1', t2'] - zip_body = mkApps mzip_op [ Type t1, Type tuple_ty', Var a, zip_body' ] - ; return ((a:ids'), t1, tuple_ty', zip_body) } - --- This case should never happen: -mkMcZipM _ _ tys = pprPanic "mkMcZipM: unexpected argument" (ppr tys) +-- mkMcUnzipM fmap ys [t1, t2] +-- = ( fmap (selN1 :: (t1, t2) -> t1) ys +-- , fmap (selN2 :: (t1, t2) -> t2) ys ) + +mkMcUnzipM :: CoreExpr -- fmap + -> Id -- Of type n (a,b,c) + -> [Type] -- [a,b,c] + -> DsM CoreExpr -- Of type (n a, n b, n c) +mkMcUnzipM fmap_op ys elt_tys + = do { xs <- mapM newSysLocalDs elt_tys + ; tup_xs <- newSysLocalDs (mkBigCoreTupTy elt_tys) + + ; let arg_ty = idType ys + mk_elt i = mkApps fmap_op -- fmap :: forall a b. (a -> b) -> n a -> n b + [ Type arg_ty, Type (elt_tys !! i) + , mk_sel i, Var ys] + + mk_sel n = Lam tup_xs $ + mkTupleSelector xs (xs !! n) tup_xs (Var tup_xs) + ; return (mkBigCoreTup (map mk_elt [0..length elt_tys - 1])) } \end{code}