X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FMatch.lhs;h=d7c3bdb4c1c130dca3e5247afe05cb03d13d25e2;hb=7caedc52dde9fb7f773fb3a1d5fc0f7b2d8de848;hp=e63d55930e7d8ec662b4c76611c9020281523707;hpb=26741ec416bae2c502ef00a2ba0e79050a32cb67;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/Match.lhs b/ghc/compiler/deSugar/Match.lhs index e63d559..d7c3bdb 100644 --- a/ghc/compiler/deSugar/Match.lhs +++ b/ghc/compiler/deSugar/Match.lhs @@ -1,55 +1,185 @@ + % % (c) The GRASP/AQUA Project, Glasgow University, 1992-1996 % \section[Main_match]{The @match@ function} \begin{code} -#include "HsVersions.h" +module Match ( match, matchExport, matchWrapper, matchSimply ) where -module Match ( match, matchWrapper, matchSimply ) where - -IMP_Ubiq() -IMPORT_DELOOPER(DsLoop) -- here for paranoia-checking reasons - -- and to break dsExpr/dsBinds-ish loop +#include "HsVersions.h" -import HsSyn hiding ( collectBinders{-also from CoreSyn-} ) -import TcHsSyn ( TypecheckedPat(..), TypecheckedMatch(..), - TypecheckedHsBinds(..), TypecheckedHsExpr(..) ) -import DsHsSyn ( outPatType, collectTypedPatBinders ) +import {-# SOURCE #-} DsExpr ( dsExpr ) +import {-# SOURCE #-} DsBinds ( dsBinds ) + +import CmdLineOpts ( opt_WarnIncompletePatterns, opt_WarnOverlappingPatterns, + opt_WarnSimplePatterns + ) +import HsSyn +import TcHsSyn ( TypecheckedPat, TypecheckedMatch, + TypecheckedHsBinds, TypecheckedHsExpr ) +import DsHsSyn ( outPatType ) +import Check ( check, ExhaustivePat, WarningPat, BoxedString ) import CoreSyn - import CoreUtils ( coreExprType ) import DsMonad import DsGRHSs ( dsGRHSs ) import DsUtils -import MatchCon ( matchConFamily ) -import MatchLit ( matchLiterals ) - -import FieldLabel ( allFieldLabelTags, fieldLabelTag ) -import Id ( idType, mkTupleCon, +import Id ( idType, dataConFieldLabels, dataConArgTys, recordSelectorFieldLabel, - GenId{-instance-} + Id ) -import PprStyle ( PprStyle(..) ) -import PprType ( GenType{-instance-}, GenTyVar{-ditto-} ) +import MatchCon ( matchConFamily ) +import MatchLit ( matchLiterals ) +import Name ( Name {--O only-} ) import PrelVals ( pAT_ERROR_ID ) -import Type ( isPrimType, eqTy, getAppDataTyConExpandingDicts, - instantiateTauTy +import Type ( isUnpointedType, splitAlgTyConApp, + Type ) -import TyVar ( GenTyVar{-instance Eq-} ) +import TyVar ( TyVar ) import TysPrim ( intPrimTy, charPrimTy, floatPrimTy, doublePrimTy, addrPrimTy, wordPrimTy ) import TysWiredIn ( nilDataCon, consDataCon, mkTupleTy, mkListTy, charTy, charDataCon, intTy, intDataCon, - floatTy, floatDataCon, doubleTy, - doubleDataCon, stringTy, addrTy, + floatTy, floatDataCon, doubleTy, tupleCon, + doubleDataCon, addrTy, addrDataCon, wordTy, wordDataCon ) -import Unique ( Unique{-instance Eq-} ) -import Util ( panic, pprPanic, assertPanic ) +import UniqSet +import Outputable +\end{code} + +This function is a wrapper of @match@, it must be called from all the parts where +it was called match, but only substitutes the firs call, .... +if the associated flags are declared, warnings will be issued. +It can not be called matchWrapper because this name already exists :-( + +JJCQ 30-Nov-1997 + +\begin{code} +matchExport :: [Id] -- Vars rep'ing the exprs we're matching with + -> [EquationInfo] -- Info about patterns, etc. (type synonym below) + -> DsM MatchResult -- Desugared result! + +matchExport vars qs@((EqnInfo _ ctx _ (MatchResult _ _ _)) : _) + | incomplete && shadow = + dsShadowWarn ctx eqns_shadow `thenDs` \ () -> + dsIncompleteWarn ctx pats `thenDs` \ () -> + match vars qs + | incomplete = + dsIncompleteWarn ctx pats `thenDs` \ () -> + match vars qs + | shadow = + dsShadowWarn ctx eqns_shadow `thenDs` \ () -> + match vars qs + | otherwise = + match vars qs + where (pats,indexs) = check qs + incomplete = opt_WarnIncompletePatterns && (length pats /= 0) + shadow = opt_WarnOverlappingPatterns && sizeUniqSet indexs < no_eqns + no_eqns = length qs + unused_eqns = uniqSetToList (mkUniqSet [1..no_eqns] `minusUniqSet` indexs) + eqns_shadow = map (\n -> qs!!(n - 1)) unused_eqns +\end{code} + +This variable shows the maximun number of lines of output generated for warnings. +It will limit the number of patterns/equations displayed to maximum_output. + +(ToDo: add command-line option?) + +\begin{code} +maximum_output = 4 +\end{code} + +The next two functions creates the warning message. + +\begin{code} +dsShadowWarn :: DsMatchContext -> [EquationInfo] -> DsM () +dsShadowWarn ctx@(DsMatchContext kind _ _) qs = dsWarn warn + where + warn | length qs > maximum_output + = hang (pp_context ctx (ptext SLIT("are overlapped"))) + 12 ((vcat $ map (ppr_eqn kind) (take maximum_output qs)) + $$ ptext SLIT("...")) + | otherwise + = hang (pp_context ctx (ptext SLIT("are overlapped"))) + 12 (vcat $ map (ppr_eqn kind) qs) + +dsIncompleteWarn :: DsMatchContext -> [ExhaustivePat] -> DsM () +dsIncompleteWarn ctx@(DsMatchContext kind _ _) pats = dsWarn warn + where + warn | length pats > maximum_output + = hang (pp_context ctx (ptext SLIT("are non-exhaustive"))) + 12 (hang (ptext SLIT("Patterns not recognized:")) + 4 ((vcat $ map (ppr_incomplete_pats kind) (take maximum_output pats)) + $$ ptext SLIT("..."))) + | otherwise + = hang (pp_context ctx (ptext SLIT("are non-exhaustive"))) + 12 (hang (ptext SLIT("Patterns not recognized:")) + 4 (vcat $ map (ppr_incomplete_pats kind) pats)) + +pp_context NoMatchContext msg = ptext SLIT("Some match(es)") <+> msg + +pp_context (DsMatchContext kind pats loc) msg + = hang (hcat [ppr loc, ptext SLIT(": ")]) + 4 (hang message + 4 (pp_match kind pats)) + where + message = ptext SLIT("Pattern match(es)") <+> msg + + pp_match (FunMatch fun) pats + = hsep [ptext SLIT("in the definition of function"), quotes (ppr fun)] + + pp_match CaseMatch pats + = hang (ptext SLIT("in a group of case alternatives beginning:")) + 4 (ppr_pats pats) + + pp_match PatBindMatch pats + = hang (ptext SLIT("in a pattern binding:")) + 4 (ppr_pats pats) + + pp_match LambdaMatch pats + = hang (ptext SLIT("in a lambda abstraction:")) + 4 (ppr_pats pats) + + pp_match DoBindMatch pats + = hang (ptext SLIT("in a `do' pattern binding:")) + 4 (ppr_pats pats) + + pp_match ListCompMatch pats + = hang (ptext SLIT("in a `list comprension' pattern binding:")) + 4 (ppr_pats pats) + + pp_match LetMatch pats + = hang (ptext SLIT("in a `let' pattern binding:")) + 4 (ppr_pats pats) + +ppr_pats pats = sep (map ppr pats) + +separator (FunMatch _) = SLIT("=") +separator (CaseMatch) = SLIT("->") +separator (LambdaMatch) = SLIT("->") +separator (PatBindMatch) = panic "When is this used?" +separator (DoBindMatch) = SLIT("<-") +separator (ListCompMatch) = SLIT("<-") +separator (LetMatch) = SLIT("=") + +ppr_shadow_pats kind pats = sep [ppr_pats pats, ptext (separator 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 (map ppr_constraint constraints)] + + +ppr_constraint (var,pats) = sep [ppr var, ptext SLIT("`not_elem`"), ppr pats] + +ppr_eqn kind (EqnInfo _ _ pats _) = ppr_shadow_pats kind pats + \end{code} + The function @match@ is basically the same as in the Wadler chapter, except it is monadised, to carry around the name supply, info about annotations, etc. @@ -104,7 +234,6 @@ So, the full type signature: \begin{code} match :: [Id] -- Variables rep'ing the exprs we're matching with -> [EquationInfo] -- Info about patterns, etc. (type synonym below) - -> [EquationInfo] -- Potentially shadowing equations above this one -> DsM MatchResult -- Desugared result! \end{code} @@ -151,32 +280,19 @@ than the Wadler-chapter code for @match@ (p.~93, first @match@ clause). And gluing the ``success expressions'' together isn't quite so pretty. \begin{code} -match [] eqns_info shadows - = pin_eqns eqns_info `thenDs` \ match_result@(MatchResult _ _ _ cxt) -> - - -- If at this stage we find that at least one of the shadowing - -- equations is guaranteed not to fail, then warn of an overlapping pattern - if not (all shadow_can_fail shadows) then - dsShadowError cxt `thenDs` \ _ -> - returnDs match_result - else - returnDs match_result - +match [] eqns_info + = complete_matches eqns_info where - pin_eqns [EqnInfo [] match_result] = returnDs match_result - -- Last eqn... can't have pats ... - - pin_eqns (EqnInfo [] match_result1 : more_eqns) - = pin_eqns more_eqns `thenDs` \ match_result2 -> - combineMatchResults match_result1 match_result2 - - pin_eqns other_pat = panic "match: pin_eqns" - - shadow_can_fail :: EquationInfo -> Bool - - shadow_can_fail (EqnInfo [] (MatchResult CanFail _ _ _)) = True - shadow_can_fail (EqnInfo [] (MatchResult CantFail _ _ _)) = False - shadow_can_fail other = panic "match:shadow_can_fail" + complete_matches [eqn] + = complete_match eqn + + complete_matches (eqn:eqns) + = complete_match eqn `thenDs` \ match_result1 -> + complete_matches eqns `thenDs` \ match_result2 -> + combineMatchResults match_result1 match_result2 + + complete_match (EqnInfo _ _ [] match_result@(MatchResult _ _ _)) + = returnDs match_result \end{code} %************************************************************************ @@ -198,17 +314,16 @@ Wadler-chapter @match@ (p.~93, last clause), and @match_unmixed_blk@ corresponds roughly to @matchVarCon@. \begin{code} -match vars@(v:vs) eqns_info shadows +match vars@(v:vs) eqns_info = mapDs (tidyEqnInfo v) eqns_info `thenDs` \ tidy_eqns_info -> - mapDs (tidyEqnInfo v) shadows `thenDs` \ tidy_shadows -> let tidy_eqns_blks = unmix_eqns tidy_eqns_info in - match_unmixed_eqn_blks vars tidy_eqns_blks tidy_shadows + match_unmixed_eqn_blks vars tidy_eqns_blks where unmix_eqns [] = [] unmix_eqns [eqn] = [ [eqn] ] - unmix_eqns (eq1@(EqnInfo (p1:p1s) _) : eq2@(EqnInfo (p2:p2s) _) : eqs) + unmix_eqns (eq1@(EqnInfo _ _ (p1:p1s) _) : eq2@(EqnInfo _ _ (p2:p2s) _) : eqs) = if ( (irrefutablePat p1 && irrefutablePat p2) || (isConPat p1 && isConPat p2) || (isLitPat p1 && isLitPat p2) ) then @@ -225,19 +340,16 @@ match vars@(v:vs) eqns_info shadows -- subsequent blocks create a "fail expr" for the first one... match_unmixed_eqn_blks :: [Id] -> [ [EquationInfo] ] -- List of eqn BLOCKS - -> [EquationInfo] -- Shadows -> DsM MatchResult - match_unmixed_eqn_blks vars [] shadows = panic "match_unmixed_eqn_blks" + match_unmixed_eqn_blks vars [] = panic "match_unmixed_eqn_blks" - match_unmixed_eqn_blks vars [eqn_blk] shadows = matchUnmixedEqns vars eqn_blk shadows + match_unmixed_eqn_blks vars [eqn_blk] = matchUnmixedEqns vars eqn_blk - match_unmixed_eqn_blks vars (eqn_blk:eqn_blks) shadows - = matchUnmixedEqns vars eqn_blk shadows `thenDs` \ match_result1 -> -- try to match with first blk - match_unmixed_eqn_blks vars eqn_blks shadows' `thenDs` \ match_result2 -> + match_unmixed_eqn_blks vars (eqn_blk:eqn_blks) + = matchUnmixedEqns vars eqn_blk `thenDs` \ match_result1 -> -- try to match with first blk + match_unmixed_eqn_blks vars eqn_blks `thenDs` \ match_result2 -> combineMatchResults match_result1 match_result2 - where - shadows' = eqn_blk ++ shadows \end{code} Tidy up the leftmost pattern in an @EquationInfo@, given the variable @v@ @@ -252,6 +364,8 @@ Replace the `as' pattern @x@@p@ with the pattern p and a binding @x = v@. Removing lazy (irrefutable) patterns (you don't want to know...). \item Converting explicit tuple- and list-pats into ordinary @ConPats@. +\item +Convert the literal pat "" to []. \end{itemize} The result of this tidying is that the column of patterns will include @@ -277,9 +391,9 @@ tidyEqnInfo :: Id -> EquationInfo -> DsM EquationInfo -- DsM'd because of internal call to "match". -- "tidy1" does the interesting stuff, looking at -- one pattern and fiddling the list of bindings. -tidyEqnInfo v (EqnInfo (pat : pats) match_result) +tidyEqnInfo v (EqnInfo n ctx (pat : pats) match_result) = tidy1 v pat match_result `thenDs` \ (pat', match_result') -> - returnDs (EqnInfo (pat' : pats) match_result') + returnDs (EqnInfo n ctx (pat' : pats) match_result') tidy1 :: Id -- The Id being scrutinised -> TypecheckedPat -- The pattern against which it is to be matched @@ -317,12 +431,9 @@ tidy1 v (WildPat ty) match_result -} tidy1 v (LazyPat pat) match_result - = mkSelectorBinds [] pat l_to_l (Var v) `thenDs` \ sel_binds -> + = mkSelectorBinds pat (Var v) `thenDs` \ sel_binds -> returnDs (WildPat (idType v), mkCoLetsMatchResult [NonRec b rhs | (b,rhs) <- sel_binds] match_result) - where - l_to_l = binders `zip` binders -- Boring - binders = collectTypedPatBinders pat -- re-express as (ConPat ...) [directly] @@ -335,14 +446,14 @@ tidy1 v (RecPat con_id pat_ty rpats) match_result pats = map mk_pat tagged_arg_tys -- Boring stuff to find the arg-tys of the constructor - (_, inst_tys, _) = {-trace "Match.getAppDataTyConExpandingDicts" $-} getAppDataTyConExpandingDicts pat_ty + (_, inst_tys, _) = splitAlgTyConApp pat_ty con_arg_tys' = dataConArgTys con_id inst_tys - tagged_arg_tys = con_arg_tys' `zip` allFieldLabelTags + tagged_arg_tys = con_arg_tys' `zip` (dataConFieldLabels con_id) -- mk_pat picks a WildPat of the appropriate type for absent fields, -- and the specified pattern for present fields - mk_pat (arg_ty, tag) = case [pat | (sel_id,pat,_) <- rpats, - fieldLabelTag (recordSelectorFieldLabel sel_id) == tag + mk_pat (arg_ty, lbl) = case [pat | (sel_id,pat,_) <- rpats, + recordSelectorFieldLabel sel_id == lbl ] of (pat:pats) -> ASSERT( null pats ) pat @@ -362,7 +473,7 @@ tidy1 v (TuplePat pats) match_result where arity = length pats tuple_ConPat - = ConPat (mkTupleCon arity) + = ConPat (tupleCon arity) (mkTupleTy arity (map outPatType pats)) pats @@ -381,29 +492,34 @@ tidy1 v (DictPat dicts methods) match_result -- LitPats: the desugarer only sees these at well-known types tidy1 v pat@(LitPat lit lit_ty) match_result - | isPrimType lit_ty + | isUnpointedType lit_ty = returnDs (pat, match_result) - | lit_ty `eqTy` charTy + | lit_ty == charTy = returnDs (ConPat charDataCon charTy [LitPat (mk_char lit) charPrimTy], match_result) - | otherwise = pprPanic "tidy1:LitPat:" (ppr PprDebug pat) + | otherwise = pprPanic "tidy1:LitPat:" (ppr pat) where mk_char (HsChar c) = HsCharPrim c -- NPats: we *might* be able to replace these w/ a simpler form + tidy1 v pat@(NPat lit lit_ty _) match_result = returnDs (better_pat, match_result) where better_pat - | lit_ty `eqTy` charTy = ConPat charDataCon lit_ty [LitPat (mk_char lit) charPrimTy] - | lit_ty `eqTy` intTy = ConPat intDataCon lit_ty [LitPat (mk_int lit) intPrimTy] - | lit_ty `eqTy` wordTy = ConPat wordDataCon lit_ty [LitPat (mk_word lit) wordPrimTy] - | lit_ty `eqTy` addrTy = ConPat addrDataCon lit_ty [LitPat (mk_addr lit) addrPrimTy] - | lit_ty `eqTy` floatTy = ConPat floatDataCon lit_ty [LitPat (mk_float lit) floatPrimTy] - | lit_ty `eqTy` doubleTy = ConPat doubleDataCon lit_ty [LitPat (mk_double lit) doublePrimTy] + | lit_ty == charTy = ConPat charDataCon lit_ty [LitPat (mk_char lit) charPrimTy] + | lit_ty == intTy = ConPat intDataCon lit_ty [LitPat (mk_int lit) intPrimTy] + | lit_ty == wordTy = ConPat wordDataCon lit_ty [LitPat (mk_word lit) wordPrimTy] + | lit_ty == addrTy = ConPat addrDataCon lit_ty [LitPat (mk_addr lit) addrPrimTy] + | lit_ty == floatTy = ConPat floatDataCon lit_ty [LitPat (mk_float lit) floatPrimTy] + | lit_ty == doubleTy = ConPat doubleDataCon lit_ty [LitPat (mk_double lit) doublePrimTy] + + -- Convert the literal pattern "" to the constructor pattern []. + | null_str_lit lit = ConPat nilDataCon lit_ty [] + | otherwise = pat mk_int (HsInt i) = HsIntPrim i @@ -424,6 +540,9 @@ tidy1 v pat@(NPat lit lit_ty _) match_result mk_double (HsFrac f) = HsDoublePrim f mk_double l@(HsLitLit s) = l + null_str_lit (HsString s) = _NULL_ s + null_str_lit other_lit = False + -- and everything else goes through unchanged... tidy1 v non_interesting_pat match_result @@ -508,36 +627,31 @@ Its arguments and results are the same as for the ``top-level'' @match@. \begin{code} matchUnmixedEqns :: [Id] -> [EquationInfo] - -> [EquationInfo] -- Shadows -> DsM MatchResult -matchUnmixedEqns [] _ _ = panic "matchUnmixedEqns: no names" +matchUnmixedEqns [] _ = panic "matchUnmixedEqns: no names" -matchUnmixedEqns all_vars@(var:vars) eqns_info shadows +matchUnmixedEqns all_vars@(var:vars) eqns_info | irrefutablePat first_pat = ASSERT( irrefutablePats column_1_pats ) -- Sanity check -- Real true variables, just like in matchVar, SLPJ p 94 - match vars remaining_eqns_info remaining_shadows + match vars remaining_eqns_info | isConPat first_pat = ASSERT( patsAreAllCons column_1_pats ) - matchConFamily all_vars eqns_info shadows + matchConFamily all_vars eqns_info | isLitPat first_pat = ASSERT( patsAreAllLits column_1_pats ) -- see notes in MatchLiteral -- not worried about the same literal more than once in a column -- (ToDo: sort this out later) - matchLiterals all_vars eqns_info shadows + matchLiterals all_vars eqns_info where first_pat = head column_1_pats - column_1_pats = [pat | EqnInfo (pat:_) _ <- eqns_info] - remaining_eqns_info = [EqnInfo pats match_result | EqnInfo (_:pats) match_result <- eqns_info] - remaining_shadows = [EqnInfo pats match_result | EqnInfo (pat:pats) match_result <- shadows, - irrefutablePat pat ] - -- Discard shadows which can be refuted, since they don't shadow - -- a variable + column_1_pats = [pat | EqnInfo _ _ (pat:_) _ <- eqns_info] + remaining_eqns_info = [EqnInfo n ctx pats match_result | EqnInfo n ctx (_:pats) match_result <- eqns_info] \end{code} %************************************************************************ @@ -589,41 +703,70 @@ matchWrapper :: DsMatchKind -- For shadowing warning messages -> [TypecheckedMatch] -- Matches being desugared -> String -- Error message if the match fails -> DsM ([Id], CoreExpr) -- Results +\end{code} --- a special case for the common ...: --- just one Match --- lots of (all?) unfailable pats --- e.g., --- f x y z = .... - + a special case for the common ...: + just one Match + lots of (all?) unfailable pats + e.g., + f x y z = .... + + This special case have been ``undone'' due to problems with the new warnings + messages (Check.lhs.check). We need there the name of the variables to be able to + print later the equation. JJQC 30-11-97 + +\begin{old_code} matchWrapper kind [(PatMatch (VarPat var) match)] error_string = matchWrapper kind [match] error_string `thenDs` \ (vars, core_expr) -> returnDs (var:vars, core_expr) matchWrapper kind [(PatMatch (WildPat ty) match)] error_string - = newSysLocalDs ty `thenDs` \ var -> + = newSysLocalDs ty `thenDs` \ var -> matchWrapper kind [match] error_string `thenDs` \ (vars, core_expr) -> returnDs (var:vars, core_expr) matchWrapper kind [(GRHSMatch - (GRHSsAndBindsOut [OtherwiseGRHS expr _] binds _))] error_string - = dsBinds False binds `thenDs` \ core_binds -> - dsExpr expr `thenDs` \ core_expr -> + (GRHSsAndBindsOut [GRHS [] expr _] binds _))] error_string + = dsBinds False{-don't auto-scc-} binds `thenDs` \ core_binds -> + dsExpr expr `thenDs` \ core_expr -> returnDs ([], mkCoLetsAny core_binds core_expr) +\end{old_code} ----------------------------------------------------------------------------- --- and all the rest... (general case) + And all the rest... (general case) + + + There is one small problem with the Lambda Patterns, when somebody + writes something similar to: + (\ (x:xs) -> ...) + he/she don't want a warning about incomplete patterns, that is done with + the flag opt_WarnSimplePatterns. + This problem also appears in the : + do patterns, but if the do can fail it creates another equation if the match can + fail (see DsExpr.doDo function) + let patterns, are treated by matchSimply + List Comprension Patterns, are treated by matchSimply also + +We can't call matchSimply with Lambda patterns, due to lambda patterns can have more than +one pattern, and match simply only accepts one pattern. + +JJQC 30-Nov-1997 + +\begin{code} matchWrapper kind matches error_string - = flattenMatches kind matches `thenDs` \ eqns_info@(EqnInfo arg_pats (MatchResult _ result_ty _ _) : _) -> + = flattenMatches kind 1 matches `thenDs` \ eqns_info@(EqnInfo _ _ arg_pats (MatchResult _ result_ty _) : _) -> selectMatchVars arg_pats `thenDs` \ new_vars -> - match new_vars eqns_info [] `thenDs` \ match_result -> + match_fun new_vars eqns_info `thenDs` \ match_result -> mkErrorAppDs pAT_ERROR_ID result_ty error_string `thenDs` \ fail_expr -> - extractMatchResult match_result fail_expr `thenDs` \ result_expr -> + extractMatchResult match_result fail_expr `thenDs` \ result_expr -> returnDs (new_vars, result_expr) + where match_fun = case kind of + LambdaMatch | opt_WarnSimplePatterns -> matchExport + | otherwise -> match + _ -> matchExport \end{code} %************************************************************************ @@ -638,33 +781,38 @@ pattern. It returns an expression. \begin{code} matchSimply :: CoreExpr -- Scrutinee - -> TypecheckedPat -- Pattern it should match - -> Type -- Type of result + -> DsMatchKind -- Match kind + -> TypecheckedPat -- Pattern it should match + -> Type -- Type of result -> CoreExpr -- Return this if it matches -> CoreExpr -- Return this if it does -> DsM CoreExpr -matchSimply (Var var) pat result_ty result_expr fail_expr - = match [var] [eqn_info] [] `thenDs` \ match_result -> - extractMatchResult match_result fail_expr +matchSimply (Var var) kind pat result_ty result_expr fail_expr + = getSrcLocDs `thenDs` \ locn -> + let + ctx = DsMatchContext kind [pat] locn + eqn_info = EqnInfo 1 ctx [pat] initial_match_result + in + match_fun [var] [eqn_info] `thenDs` \ match_result -> + extractMatchResult match_result fail_expr where - eqn_info = EqnInfo [pat] initial_match_result - initial_match_result = MatchResult CantFail - result_ty - (\ ignore -> result_expr) - NoMatchContext - -matchSimply scrut_expr pat result_ty result_expr msg - = newSysLocalDs (outPatType pat) `thenDs` \ scrut_var -> - matchSimply (Var scrut_var) pat result_ty result_expr msg `thenDs` \ expr -> + initial_match_result = MatchResult CantFail result_ty (\ ignore -> result_expr) + match_fun = if opt_WarnSimplePatterns + then matchExport + else match + +matchSimply scrut_expr kind pat result_ty result_expr msg + = newSysLocalDs (outPatType pat) `thenDs` \ scrut_var -> + matchSimply (Var scrut_var) kind pat result_ty result_expr msg `thenDs` \ expr -> returnDs (Let (NonRec scrut_var scrut_expr) expr) -extractMatchResult (MatchResult CantFail _ match_fn _) fail_expr +extractMatchResult (MatchResult CantFail _ match_fn) fail_expr = returnDs (match_fn (error "It can't fail!")) -extractMatchResult (MatchResult CanFail result_ty match_fn _) fail_expr - = mkFailurePair result_ty `thenDs` \ (fail_bind_fn, if_it_fails) -> +extractMatchResult (MatchResult CanFail result_ty match_fn) fail_expr + = mkFailurePair result_ty `thenDs` \ (fail_bind_fn, if_it_fails) -> returnDs (Let (fail_bind_fn fail_expr) (match_fn if_it_fails)) \end{code} @@ -680,38 +828,44 @@ This is actually local to @matchWrapper@. \begin{code} flattenMatches :: DsMatchKind + -> EqnNo -> [TypecheckedMatch] -> DsM [EquationInfo] -flattenMatches kind [] = returnDs [] +flattenMatches kind n [] = returnDs [] -flattenMatches kind (match : matches) - = flatten_match [] match `thenDs` \ eqn_info -> - flattenMatches kind matches `thenDs` \ eqn_infos -> +flattenMatches kind n (match : matches) + = flatten_match [] n match `thenDs` \ eqn_info -> + flattenMatches kind (n+1) matches `thenDs` \ eqn_infos -> returnDs (eqn_info : eqn_infos) where flatten_match :: [TypecheckedPat] -- Reversed list of patterns encountered so far + -> EqnNo -> TypecheckedMatch -> DsM EquationInfo - flatten_match pats_so_far (PatMatch pat match) - = flatten_match (pat:pats_so_far) match + flatten_match pats_so_far n (PatMatch pat match) + = flatten_match (pat:pats_so_far) n match - flatten_match pats_so_far (GRHSMatch (GRHSsAndBindsOut grhss binds ty)) - = dsBinds False binds `thenDs` \ core_binds -> + flatten_match pats_so_far n (GRHSMatch (GRHSsAndBindsOut grhss binds ty)) + = dsBinds False{-don't auto-scc-} binds `thenDs` \ core_binds -> dsGRHSs ty kind pats grhss `thenDs` \ match_result -> - returnDs (EqnInfo pats (mkCoLetsMatchResult core_binds match_result)) + getSrcLocDs `thenDs` \ locn -> + returnDs (EqnInfo n (DsMatchContext kind pats locn) pats + (mkCoLetsMatchResult core_binds match_result)) where pats = reverse pats_so_far -- They've accumulated in reverse order - flatten_match pats_so_far (SimpleMatch expr) + flatten_match pats_so_far n (SimpleMatch expr) = dsExpr expr `thenDs` \ core_expr -> - returnDs (EqnInfo pats + getSrcLocDs `thenDs` \ locn -> + returnDs (EqnInfo n (DsMatchContext kind pats locn) pats (MatchResult CantFail (coreExprType core_expr) - (\ ignore -> core_expr) - NoMatchContext)) - -- The NoMatchContext is just a place holder. In a simple match, - -- the matching can't fail, so we won't generate an error message. - where - pats = reverse pats_so_far -- They've accumulated in reverse order + (\ ignore -> core_expr))) + + -- the matching can't fail, so we won't generate an error message. + where + pats = reverse pats_so_far -- They've accumulated in reverse order + \end{code} +