X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FdeSugar%2FMatch.lhs;h=a28eb844bdd1798ca5515086735f53e8a1dba3c3;hb=e79c9ce01d0ce4412bd4bcd99c8c728a6a2ec569;hp=3f3a1272bbb7298ec93cedb8c05cdb568d501130;hpb=6a05ec5ef5373f61b7f9f5bdc344483417fa801b;p=ghc-hetmet.git diff --git a/compiler/deSugar/Match.lhs b/compiler/deSugar/Match.lhs index 3f3a127..a28eb84 100644 --- a/compiler/deSugar/Match.lhs +++ b/compiler/deSugar/Match.lhs @@ -6,7 +6,7 @@ The @match@ function \begin{code} -{-# OPTIONS -w #-} +{-# 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 @@ -26,6 +26,7 @@ import Check import CoreSyn import Literal import CoreUtils +import MkCore import DsMonad import DsBinds import DsGRHSs @@ -37,13 +38,13 @@ import MatchLit import PrelInfo import Type import TysWiredIn -import BasicTypes import ListSetOps import SrcLoc import Maybes import Util import Name import Outputable +import FastString \end{code} This function is a wrapper of @match@, it must be called from all the parts where @@ -60,20 +61,26 @@ matchCheck :: DsMatchContext -> [EquationInfo] -- Info about patterns, etc. (type synonym below) -> DsM MatchResult -- Desugared result! -matchCheck ctx vars ty qs - = getDOptsDs `thenDs` \ dflags -> - matchCheck_really dflags ctx vars ty qs +matchCheck ctx vars ty qs = do + dflags <- getDOptsDs + matchCheck_really dflags ctx vars ty qs +matchCheck_really :: DynFlags + -> DsMatchContext + -> [Id] + -> Type + -> [EquationInfo] + -> DsM MatchResult matchCheck_really dflags ctx vars ty qs - | incomplete && shadow = - dsShadowWarn ctx eqns_shadow `thenDs` \ () -> - dsIncompleteWarn ctx pats `thenDs` \ () -> + | incomplete && shadow = do + dsShadowWarn ctx eqns_shadow + dsIncompleteWarn ctx pats match vars ty qs - | incomplete = - dsIncompleteWarn ctx pats `thenDs` \ () -> + | incomplete = do + dsIncompleteWarn ctx pats match vars ty qs - | shadow = - dsShadowWarn ctx eqns_shadow `thenDs` \ () -> + | shadow = do + dsShadowWarn ctx eqns_shadow match vars ty qs | otherwise = match vars ty qs @@ -94,6 +101,7 @@ It will limit the number of patterns/equations displayed to@ maximum_output@. (ToDo: add command-line option?) \begin{code} +maximum_output :: Int maximum_output = 4 \end{code} @@ -105,11 +113,11 @@ dsShadowWarn ctx@(DsMatchContext kind loc) qs = putSrcSpanDs loc (warnDs warn) where warn | qs `lengthExceeds` maximum_output - = pp_context ctx (ptext SLIT("are overlapped")) + = pp_context ctx (ptext (sLit "are overlapped")) (\ f -> vcat (map (ppr_eqn f kind) (take maximum_output qs)) $$ - ptext SLIT("...")) + ptext (sLit "...")) | otherwise - = pp_context ctx (ptext SLIT("are overlapped")) + = pp_context ctx (ptext (sLit "are overlapped")) (\ f -> vcat $ map (ppr_eqn f kind) qs) @@ -117,37 +125,42 @@ dsIncompleteWarn :: DsMatchContext -> [ExhaustivePat] -> DsM () dsIncompleteWarn ctx@(DsMatchContext kind loc) pats = putSrcSpanDs loc (warnDs warn) where - warn = pp_context ctx (ptext SLIT("are non-exhaustive")) - (\f -> hang (ptext SLIT("Patterns not matched:")) + warn = pp_context ctx (ptext (sLit "are non-exhaustive")) + (\_ -> hang (ptext (sLit "Patterns not matched:")) 4 ((vcat $ map (ppr_incomplete_pats kind) (take maximum_output pats)) $$ dots)) - dots | pats `lengthExceeds` maximum_output = ptext SLIT("...") + dots | pats `lengthExceeds` maximum_output = ptext (sLit "...") | otherwise = empty +pp_context :: DsMatchContext -> SDoc -> ((SDoc -> SDoc) -> SDoc) -> SDoc pp_context (DsMatchContext kind _loc) msg rest_of_msg_fun - = vcat [ptext SLIT("Pattern match(es)") <+> msg, - sep [ptext SLIT("In") <+> ppr_match <> char ':', nest 4 (rest_of_msg_fun pref)]] + = vcat [ptext (sLit "Pattern match(es)") <+> msg, + sep [ptext (sLit "In") <+> ppr_match <> char ':', nest 4 (rest_of_msg_fun pref)]] where (ppr_match, pref) = case kind of FunRhs fun _ -> (pprMatchContext kind, \ pp -> ppr fun <+> pp) - other -> (pprMatchContext kind, \ pp -> pp) + _ -> (pprMatchContext kind, \ pp -> pp) +ppr_pats :: Outputable a => [a] -> SDoc ppr_pats pats = sep (map ppr pats) +ppr_shadow_pats :: HsMatchContext Name -> [Pat Id] -> SDoc ppr_shadow_pats kind pats - = sep [ppr_pats pats, matchSeparator kind, ptext SLIT("...")] - -ppr_incomplete_pats kind (pats,[]) = ppr_pats pats -ppr_incomplete_pats kind (pats,constraints) = - sep [ppr_pats pats, ptext SLIT("with"), + = sep [ppr_pats pats, matchSeparator kind, ptext (sLit "...")] + +ppr_incomplete_pats :: HsMatchContext Name -> ExhaustivePat -> SDoc +ppr_incomplete_pats _ (pats,[]) = ppr_pats pats +ppr_incomplete_pats _ (pats,constraints) = + sep [ppr_pats pats, ptext (sLit "with"), sep (map ppr_constraint constraints)] - -ppr_constraint (var,pats) = sep [ppr var, ptext SLIT("`notElem`"), ppr pats] +ppr_constraint :: (Name,[HsLit]) -> SDoc +ppr_constraint (var,pats) = sep [ppr var, ptext (sLit "`notElem`"), ppr pats] +ppr_eqn :: (SDoc -> SDoc) -> HsMatchContext Name -> EquationInfo -> SDoc ppr_eqn prefixF kind eqn = prefixF (ppr_shadow_pats kind (eqn_pats eqn)) \end{code} @@ -230,7 +243,7 @@ Make all constructor patterns in column~1 into @ConPats@, notably Handle any irrefutable (or ``twiddle'') @LazyPats@. \end{itemize} \item -Now {\em unmix} the equations into {\em blocks} [w/ local function +Now {\em unmix} the equations into {\em blocks} [w\/ local function @unmix_eqns@], in which the equations in a block all have variable patterns in column~1, or they all have constructor patterns in ... (see ``the mixture rule'' in SLPJ). @@ -256,14 +269,14 @@ Wadler-chapter @match@ (p.~93, last clause), and @match_unmixed_blk@ corresponds roughly to @matchVarCon@. \begin{code} -match :: [Id] -- Variables rep'ing the exprs we're matching with +match :: [Id] -- Variables rep\'ing the exprs we\'re matching with -> Type -- Type of the case expression -> [EquationInfo] -- Info about patterns, etc. (type synonym below) -> DsM MatchResult -- Desugared result! match [] ty eqns = ASSERT2( not (null eqns), ppr ty ) - returnDs (foldr1 combineMatchResults match_results) + return (foldr1 combineMatchResults match_results) where match_results = [ ASSERT( null (eqn_pats eqn) ) eqn_rhs eqn @@ -280,7 +293,7 @@ match vars@(v:_) ty eqns ; let grouped = (groupEquations tidy_eqns) -- print the view patterns that are commoned up to help debug - ; ifOptDs Opt_D_dump_view_pattern_commoning (debug grouped) + ; ifOptM Opt_D_dump_view_pattern_commoning (debug grouped) ; match_results <- mapM match_group grouped ; return (adjustMatchResult (foldr1 (.) aux_binds) $ @@ -295,8 +308,8 @@ match vars@(v:_) ty eqns PgAny -> matchVariables vars ty (dropGroup eqns) PgCon _ -> matchConFamily vars ty (subGroups eqns) PgLit _ -> matchLiterals vars ty (subGroups eqns) - PgN lit -> matchNPats vars ty (subGroups eqns) - PgNpK lit -> matchNPlusKPats vars ty (dropGroup eqns) + PgN _ -> matchNPats vars ty (subGroups eqns) + PgNpK _ -> matchNPlusKPats vars ty (dropGroup eqns) PgBang -> matchBangs vars ty (dropGroup eqns) PgCo _ -> matchCoercion vars ty (dropGroup eqns) PgView _ _ -> matchView vars ty (dropGroup eqns) @@ -319,7 +332,7 @@ match vars@(v:_) ty eqns matchVariables :: [Id] -> Type -> [EquationInfo] -> DsM MatchResult -- Real true variables, just like in matchVar, SLPJ p 94 -- No binding to do: they'll all be wildcards by now (done in tidy) -matchVariables (var:vars) ty eqns = match vars ty (shiftEqns eqns) +matchVariables (_:vars) ty eqns = match vars ty (shiftEqns eqns) matchBangs :: [Id] -> Type -> [EquationInfo] -> DsM MatchResult matchBangs (var:vars) ty eqns @@ -350,9 +363,12 @@ matchView (var:vars) ty (eqns@(eqn1:_)) ; return (mkViewMatchResult var' viewExpr' var match_result) } -- decompose the first pattern and leave the rest alone +decomposeFirstPat :: (Pat Id -> Pat Id) -> EquationInfo -> EquationInfo decomposeFirstPat extractpat (eqn@(EqnInfo { eqn_pats = pat : pats })) = eqn { eqn_pats = extractpat pat : pats} +decomposeFirst_Coercion, decomposeFirst_Bang, decomposeFirst_View :: EquationInfo -> EquationInfo + decomposeFirst_Coercion = decomposeFirstPat (\ (CoPat _ pat _) -> pat) decomposeFirst_Bang = decomposeFirstPat (\ (BangPat pat ) -> unLoc pat) decomposeFirst_View = decomposeFirstPat (\ (ViewPat _ pat _) -> unLoc pat) @@ -416,9 +432,9 @@ tidyEqnInfo :: Id -> EquationInfo -- NPlusKPat -- but no other -tidyEqnInfo v eqn@(EqnInfo { eqn_pats = pat : pats }) - = tidy1 v pat `thenDs` \ (wrap, pat') -> - returnDs (wrap, eqn { eqn_pats = pat' : pats }) +tidyEqnInfo v eqn@(EqnInfo { eqn_pats = pat : pats }) = do + (wrap, pat') <- tidy1 v pat + return (wrap, eqn { eqn_pats = do pat' : pats }) tidy1 :: Id -- The Id being scrutinised -> Pat Id -- The pattern against which it is to be matched @@ -438,16 +454,16 @@ tidy1 :: Id -- The Id being scrutinised tidy1 v (ParPat pat) = tidy1 v (unLoc pat) tidy1 v (SigPatOut pat _) = tidy1 v (unLoc pat) -tidy1 v (WildPat ty) = returnDs (idDsWrapper, WildPat ty) +tidy1 _ (WildPat ty) = return (idDsWrapper, WildPat ty) -- case v of { x -> mr[] } -- = case v of { _ -> let x=v in mr[] } tidy1 v (VarPat var) - = returnDs (wrapBind var v, WildPat (idType var)) + = return (wrapBind var v, WildPat (idType var)) tidy1 v (VarPatOut var binds) = do { prs <- dsLHsBinds binds - ; return (wrapBind var v . mkDsLet (Rec prs), + ; return (wrapBind var v . mkCoreLet (Rec prs), WildPat (idType var)) } -- case v of { x@p -> mr[] } @@ -470,10 +486,10 @@ tidy1 v (AsPat (L _ var) pat) tidy1 v (LazyPat pat) = do { sel_prs <- mkSelectorBinds pat (Var v) ; let sel_binds = [NonRec b rhs | (b,rhs) <- sel_prs] - ; returnDs (mkDsLets sel_binds, WildPat (idType v)) } + ; return (mkCoreLets sel_binds, WildPat (idType v)) } -tidy1 v (ListPat pats ty) - = returnDs (idDsWrapper, unLoc list_ConPat) +tidy1 _ (ListPat pats ty) + = return (idDsWrapper, unLoc list_ConPat) where list_ty = mkListTy ty list_ConPat = foldr (\ x y -> mkPrefixConPat consDataCon [x, y] list_ty) @@ -482,30 +498,30 @@ tidy1 v (ListPat pats ty) -- Introduce fake parallel array constructors to be able to handle parallel -- arrays with the existing machinery for constructor pattern -tidy1 v (PArrPat pats ty) - = returnDs (idDsWrapper, unLoc parrConPat) +tidy1 _ (PArrPat pats ty) + = return (idDsWrapper, unLoc parrConPat) where arity = length pats parrConPat = mkPrefixConPat (parrFakeCon arity) pats (mkPArrTy ty) -tidy1 v (TuplePat pats boxity ty) - = returnDs (idDsWrapper, unLoc tuple_ConPat) +tidy1 _ (TuplePat pats boxity ty) + = return (idDsWrapper, unLoc tuple_ConPat) where arity = length pats tuple_ConPat = mkPrefixConPat (tupleCon boxity arity) pats ty -- LitPats: we *might* be able to replace these w/ a simpler form -tidy1 v (LitPat lit) - = returnDs (idDsWrapper, tidyLitPat lit) +tidy1 _ (LitPat lit) + = return (idDsWrapper, tidyLitPat lit) -- NPats: we *might* be able to replace these w/ a simpler form -tidy1 v (NPat lit mb_neg eq) - = returnDs (idDsWrapper, tidyNPat lit mb_neg eq) +tidy1 _ (NPat lit mb_neg eq) + = return (idDsWrapper, tidyNPat lit mb_neg eq) -- Everything else goes through unchanged... -tidy1 v non_interesting_pat - = returnDs (idDsWrapper, non_interesting_pat) +tidy1 _ non_interesting_pat + = return (idDsWrapper, non_interesting_pat) \end{code} \noindent @@ -702,34 +718,32 @@ matchSimply :: CoreExpr -- Scrutinee -> CoreExpr -- Return this if it doesn't -> DsM CoreExpr -matchSimply scrut hs_ctx pat result_expr fail_expr - = let +matchSimply scrut hs_ctx pat result_expr fail_expr = do + let match_result = cantFailMatchResult result_expr - rhs_ty = exprType fail_expr - -- Use exprType of fail_expr, because won't refine in the case of failure! - in - matchSinglePat scrut hs_ctx pat rhs_ty match_result `thenDs` \ match_result' -> + rhs_ty = exprType fail_expr + -- Use exprType of fail_expr, because won't refine in the case of failure! + match_result' <- matchSinglePat scrut hs_ctx pat rhs_ty match_result extractMatchResult match_result' fail_expr matchSinglePat :: CoreExpr -> HsMatchContext Name -> LPat Id -> Type -> MatchResult -> DsM MatchResult -matchSinglePat (Var var) hs_ctx (L _ pat) ty match_result - = getDOptsDs `thenDs` \ dflags -> - getSrcSpanDs `thenDs` \ locn -> +matchSinglePat (Var var) hs_ctx (L _ pat) ty match_result = do + dflags <- getDOptsDs + locn <- getSrcSpanDs let - match_fn dflags + match_fn dflags | dopt Opt_WarnSimplePatterns dflags = matchCheck ds_ctx - | otherwise = match - where - ds_ctx = DsMatchContext hs_ctx locn - in + | otherwise = match + where + ds_ctx = DsMatchContext hs_ctx locn match_fn dflags [var] ty [EqnInfo { eqn_pats = [pat], eqn_rhs = match_result }] -matchSinglePat scrut hs_ctx pat ty match_result - = selectSimpleMatchVarL pat `thenDs` \ var -> - matchSinglePat (Var var) hs_ctx pat ty match_result `thenDs` \ match_result' -> - returnDs (adjustMatchResult (bindNonRec var scrut) match_result') +matchSinglePat scrut hs_ctx pat ty match_result = do + var <- selectSimpleMatchVarL pat + match_result' <- matchSinglePat (Var var) hs_ctx pat ty match_result + return (adjustMatchResult (bindNonRec var scrut) match_result') \end{code} @@ -784,7 +798,7 @@ sameGroup PgAny PgAny = True sameGroup PgBang PgBang = True sameGroup (PgCon _) (PgCon _) = True -- One case expression sameGroup (PgLit _) (PgLit _) = True -- One case expression -sameGroup (PgN l1) (PgN l2) = True -- Needs conditionals +sameGroup (PgN _) (PgN _) = True -- Needs conditionals sameGroup (PgNpK l1) (PgNpK l2) = l1==l2 -- Order is significant -- See Note [Order of n+k] sameGroup (PgCo t1) (PgCo t2) = t1 `coreEqType` t2 @@ -810,7 +824,7 @@ sameGroup _ _ = False -- f (e1 -> True) = ... -- f (e2 -> "hi") = ... viewLExprEq :: (LHsExpr Id,Type) -> (LHsExpr Id,Type) -> Bool -viewLExprEq (e1,t1) (e2,t2) = +viewLExprEq (e1,_) (e2,_) = let -- short name for recursive call on unLoc lexp e e' = exp (unLoc e) (unLoc e') @@ -830,8 +844,8 @@ viewLExprEq (e1,t1) (e2,t2) = -- equating different ways of writing a coercion) wrap WpHole WpHole = True wrap (WpCompose w1 w2) (WpCompose w1' w2') = wrap w1 w1' && wrap w2 w2' - wrap (WpCo c) (WpCo c') = tcEqType c c' - wrap (WpApp d) (WpApp d') = d == d' + wrap (WpCast c) (WpCast c') = tcEqType c c' + wrap (WpApp d) (WpApp d') = d == d' wrap (WpTyApp t) (WpTyApp t') = tcEqType t t' -- Enhancement: could implement equality for more wrappers -- if it seems useful (lams and lets)