X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FCheck.lhs;h=9aac5ce777c04309f4d34bfc7982b5544c3a0bc8;hb=5d3051c66796dcf884b052f9e4afc3ed19b9f514;hp=dbbbea4742665a8daf1f1897f6975982e1ef193b;hpb=6d32951e5097e8e4e046af351299e1bbe64c442c;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/Check.lhs b/ghc/compiler/deSugar/Check.lhs index dbbbea4..9aac5ce 100644 --- a/ghc/compiler/deSugar/Check.lhs +++ b/ghc/compiler/deSugar/Check.lhs @@ -1,314 +1,338 @@ % -% (c) The GRASP/AQUA Project, Glasgow University, 1997 +% (c) The GRASP/AQUA Project, Glasgow University, 1997-1998 % -% Author: Juan J. Quintela +% Author: Juan J. Quintela +\section{Module @Check@ in @deSugar@} \begin{code} -#include "HsVersions.h" -module Check ( check , SYN_IE(ExhaustivePat), SYN_IE(WarningPat), BoxedString(..) ) where +module Check ( check , ExhaustivePat ) where -IMP_Ubiq() -#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 201 -IMPORT_DELOOPER(DsLoop) -- here for paranoia-checking reasons - -- and to break dsExpr/dsBinds-ish loop -#else -import {-# SOURCE #-} DsExpr ( dsExpr ) -import {-# SOURCE #-} DsBinds ( dsBinds ) -#endif import HsSyn -import TcHsSyn ( SYN_IE(TypecheckedPat), - SYN_IE(TypecheckedMatch), - SYN_IE(TypecheckedHsBinds), - SYN_IE(TypecheckedHsExpr) - ) -import DsHsSyn ( outPatType ) -import CoreSyn - -import DsMonad ( SYN_IE(DsM), DsMatchContext(..), - DsMatchKind(..) - ) -import DsUtils ( EquationInfo(..), - MatchResult(..), - SYN_IE(EqnNo), - SYN_IE(EqnSet), - CanItFail(..) - ) -import Id ( idType, - GenId{-instance-}, - SYN_IE(Id), - idName, - isTupleCon, - getIdArity - ) -import IdInfo ( ArityInfo(..) ) -import Lex ( isLexConSym ) -import Name ( occNameString, - Name, - getName, - nameUnique, - getOccName, - getOccString - ) -import Outputable ( PprStyle(..), - Outputable(..) - ) -import PprType ( GenType{-instance-}, - GenTyVar{-ditto-} - ) -import Pretty -import Type ( isPrimType, - eqTy, - SYN_IE(Type), - getAppTyCon - ) -import TyVar ( GenTyVar{-instance Eq-}, SYN_IE(TyVar) ) -import TysPrim ( intPrimTy, - charPrimTy, - floatPrimTy, - doublePrimTy, - addrPrimTy, - wordPrimTy - ) -import TysWiredIn ( nilDataCon, consDataCon, - mkTupleTy, tupleCon, - mkListTy, - charTy, charDataCon, - intTy, intDataCon, - floatTy, floatDataCon, - doubleTy, doubleDataCon, - addrTy, addrDataCon, - wordTy, wordDataCon - ) -import TyCon ( tyConDataCons ) +import TcHsSyn ( hsPatType, mkVanillaTuplePat ) +import TcType ( tcTyConAppTyCon ) +import DsUtils ( EquationInfo(..), MatchResult(..), + CanItFail(..), firstPat ) +import MatchLit ( tidyLitPat, tidyNPat ) +import Id ( Id, idType ) +import DataCon ( DataCon, dataConTyCon, dataConOrigArgTys, dataConFieldLabels ) +import Name ( Name, mkInternalName, getOccName, isDataSymOcc, + getName, mkVarOccFS ) +import TysWiredIn +import PrelNames ( unboundKey ) +import TyCon ( tyConDataCons, tupleTyConBoxity, isTupleTyCon ) +import BasicTypes ( Boxity(..) ) +import SrcLoc ( noSrcLoc, Located(..), unLoc, noLoc ) import UniqSet -import Unique ( Unique{-instance Eq-} ) -import Util ( pprTrace, - panic, - pprPanic - ) -\end{code} +import Util ( takeList, splitAtList, notNull ) +import Outputable +import FastString -This module perfoms checks about if one list of equations are: - - Overlapped - - Non exhaustive +#include "HsVersions.h" +\end{code} +This module performs checks about if one list of equations are: +\begin{itemize} +\item Overlapped +\item Non exhaustive +\end{itemize} To discover that we go through the list of equations in a tree-like fashion. -If you like theory, a similar algoritm is described in: - Two Tecniques for Compiling Lazy Pattern Matching - Luc Maranguet +If you like theory, a similar algorithm is described in: +\begin{quotation} + {\em Two Techniques for Compiling Lazy Pattern Matching}, + Luc Maranguet, INRIA Rocquencourt (RR-2385, 1994) - -The algorithm is based in the first Technique, but there are somo diferences: - - We don't generate code - - We have constructors and literals (not only literals as in the article) - - We don't use directions, we must select the columns from left-to-right - -(By the wat the second technique is really similar to the one used in MAtch.lhs to generate code) - +\end{quotation} +The algorithm is based on the first technique, but there are some differences: +\begin{itemize} +\item We don't generate code +\item We have constructors and literals (not only literals as in the + article) +\item We don't use directions, we must select the columns from + left-to-right +\end{itemize} +(By the way the second technique is really similar to the one used in + @Match.lhs@ to generate code) This function takes the equations of a pattern and returns: - - The patterns that are not recognized - - The equations that are not overlapped - -It symplify the patterns and then call check' (the same semantics),and it needs to -reconstruct the patterns again .... +\begin{itemize} +\item The patterns that are not recognized +\item The equations that are not overlapped +\end{itemize} +It simplify the patterns and then call @check'@ (the same semantics), and it +needs to reconstruct the patterns again .... The problem appear with things like: +\begin{verbatim} f [x,y] = .... f (x:xs) = ..... - -We want to put the two patterns with the same syntax, (prefix form) and then all the -constructors are equal: +\end{verbatim} +We want to put the two patterns with the same syntax, (prefix form) and +then all the constructors are equal: +\begin{verbatim} f (: x (: y [])) = .... f (: x xs) = ..... +\end{verbatim} +(more about that in @simplify_eqns@) -(more about that in symplify_eqns) - -We would preffer to have a WarningPat of type String, but Strings and the +We would prefer to have a @WarningPat@ of type @String@, but Strings and the Pretty Printer are not friends. - -\begin{code} -data BoxedString = BS String +We use @InPat@ in @WarningPat@ instead of @OutPat@ +because we need to print the +warning messages in the same way they are introduced, i.e. if the user +wrote: +\begin{verbatim} + f [x,y] = .. +\end{verbatim} +He don't want a warning message written: +\begin{verbatim} + f (: x (: y [])) ........ +\end{verbatim} +Then we need to use InPats. +\begin{quotation} + Juan Quintela 5 JUL 1998\\ + User-friendliness and compiler writers are no friends. +\end{quotation} -type WarningPat = InPat BoxedString --Name --String -type ExhaustivePat = ([WarningPat], [(BoxedString, [HsLit])]) +\begin{code} +type WarningPat = InPat Name +type ExhaustivePat = ([WarningPat], [(Name, [HsLit])]) +type EqnNo = Int +type EqnSet = UniqSet EqnNo + + +check :: [EquationInfo] -> ([ExhaustivePat], [EquationInfo]) + -- Second result is the shadowed equations +check qs = (untidy_warns, shadowed_eqns) + where + (warns, used_nos) = check' ([1..] `zip` map simplify_eqn qs) + untidy_warns = map untidy_exhaustive warns + shadowed_eqns = [eqn | (eqn,i) <- qs `zip` [1..], + not (i `elementOfUniqSet` used_nos)] + +untidy_exhaustive :: ExhaustivePat -> ExhaustivePat +untidy_exhaustive ([pat], messages) = + ([untidy_no_pars pat], map untidy_message messages) +untidy_exhaustive (pats, messages) = + (map untidy_pars pats, map untidy_message messages) + +untidy_message :: (Name, [HsLit]) -> (Name, [HsLit]) +untidy_message (string, lits) = (string, map untidy_lit lits) +\end{code} +The function @untidy@ does the reverse work of the @simplify_pat@ funcion. + +\begin{code} -instance Outputable BoxedString where - ppr sty (BS s) = text s +type NeedPars = Bool +untidy_no_pars :: WarningPat -> WarningPat +untidy_no_pars p = untidy False p -check :: [EquationInfo] -> ([ExhaustivePat],EqnSet) -check qs = check' (simplify_eqns qs) +untidy_pars :: WarningPat -> WarningPat +untidy_pars p = untidy True p +untidy :: NeedPars -> WarningPat -> WarningPat +untidy b (L loc p) = L loc (untidy' b p) + where + untidy' _ p@(WildPat _) = p + untidy' _ p@(VarPat name) = p + untidy' _ (LitPat lit) = LitPat (untidy_lit lit) + untidy' _ p@(ConPatIn name (PrefixCon [])) = p + untidy' b (ConPatIn name ps) = pars b (L loc (ConPatIn name (untidy_con ps))) + untidy' _ (ListPat pats ty) = ListPat (map untidy_no_pars pats) ty + untidy' _ (TuplePat pats box ty) = TuplePat (map untidy_no_pars pats) box ty + untidy' _ (PArrPat _ _) = panic "Check.untidy: Shouldn't get a parallel array here!" + untidy' _ (SigPatIn _ _) = panic "Check.untidy: SigPat" + +untidy_con (PrefixCon pats) = PrefixCon (map untidy_pars pats) +untidy_con (InfixCon p1 p2) = InfixCon (untidy_pars p1) (untidy_pars p2) +untidy_con (RecCon bs) = RecCon [(f,untidy_pars p) | (f,p) <- bs] + +pars :: NeedPars -> WarningPat -> Pat Name +pars True p = ParPat p +pars _ p = unLoc p + +untidy_lit :: HsLit -> HsLit +untidy_lit (HsCharPrim c) = HsChar c +untidy_lit lit = lit \end{code} This equation is the same that check, the only difference is that the -boring work is done, that woprk needs to be done only once, this is -the reason top have two funtions, check is the external interface, -check' is called recursively. +boring work is done, that work needs to be done only once, this is +the reason top have two functions, check is the external interface, +@check'@ is called recursively. There are several cases: -\begin{item} -\item There are no equations: Everything is okey. +\begin{itemize} +\item There are no equations: Everything is OK. \item There are only one equation, that can fail, and all the patterns are variables. Then that equation is used and the same equation is - nonexhaustive. -\item All the patterns are variables, and the match can fail,therr are more equations - then the results is the result of the rest of equations and this equation is used also. + non-exhaustive. +\item All the patterns are variables, and the match can fail, there are + more equations then the results is the result of the rest of equations + and this equation is used also. -\item The general case, if all the patterns are variables (here the match can't fail) - then the result is that this equation is used and this equation doesn't generate - non-exustive cases. +\item The general case, if all the patterns are variables (here the match + can't fail) then the result is that this equation is used and this + equation doesn't generate non-exhaustive cases. -\item In the general case, there can exist literals ,constructors or only vars in the - first column, we actuate in consecuence. +\item In the general case, there can exist literals ,constructors or only + vars in the first column, we actuate in consequence. -\end{item} +\end{itemize} \begin{code} -check' :: [EquationInfo] -> ([ExhaustivePat],EqnSet) -check' [] = ([([],[])],emptyUniqSet) +check' :: [(EqnNo, EquationInfo)] + -> ([ExhaustivePat], -- Pattern scheme that might not be matched at all + EqnSet) -- Eqns that are used (others are overlapped) + +check' [] = ([([],[])],emptyUniqSet) -check' [EqnInfo n ctx ps (MatchResult CanFail _ _)] - | all_vars ps = ([(take (length ps) (repeat new_wild_pat),[])], unitUniqSet n) +check' ((n, EqnInfo { eqn_pats = ps, eqn_rhs = MatchResult can_fail _ }) : rs) + | first_eqn_all_vars && case can_fail of { CantFail -> True; CanFail -> False } + = ([], unitUniqSet n) -- One eqn, which can't fail -check' qs@((EqnInfo n ctx ps (MatchResult CanFail _ _)):_) - | all_vars ps = (pats, addOneToUniqSet indexs n) + | first_eqn_all_vars && null rs -- One eqn, but it can fail + = ([(takeList ps (repeat nlWildPat),[])], unitUniqSet n) + + | first_eqn_all_vars -- Several eqns, first can fail + = (pats, addOneToUniqSet indexs n) where - (pats,indexs) = check' (tail qs) + first_eqn_all_vars = all_vars ps + (pats,indexs) = check' rs -check' qs@((EqnInfo n ctx ps result):_) - | all_vars ps = ([], unitUniqSet n) --- | nplusk = panic "Check.check': Work in progress: nplusk" --- | npat = panic "Check.check': Work in progress: npat ?????" +check' qs | literals = split_by_literals qs | constructors = split_by_constructor qs | only_vars = first_column_only_vars qs - | otherwise = panic "Check.check': Not implemented :-(" + | otherwise = pprPanic "Check.check': Not implemented :-(" (ppr first_pats) where - constructors = or (map is_con qs) - literals = or (map is_lit qs) --- npat = or (map is_npat qs) --- nplusk = or (map is_nplusk qs) - only_vars = and (map is_var qs) + -- Note: RecPats will have been simplified to ConPats + -- at this stage. + first_pats = ASSERT2( okGroup qs, pprGroup qs ) map firstPatN qs + constructors = any is_con first_pats + literals = any is_lit first_pats + only_vars = all is_var first_pats \end{code} -Here begins the code to deal with literals, we need to split the matrix in diferent matrix -begining by each literal and a last matrix with the rest of values. +Here begins the code to deal with literals, we need to split the matrix +in different matrix beginning by each literal and a last matrix with the +rest of values. \begin{code} -split_by_literals :: [EquationInfo] -> ([ExhaustivePat],EqnSet) +split_by_literals :: [(EqnNo, EquationInfo)] -> ([ExhaustivePat], EqnSet) split_by_literals qs = process_literals used_lits qs where used_lits = get_used_lits qs \end{code} -process_explicit_literals is a funtion taht process each literal that appears in -the column of the matrix. +@process_explicit_literals@ is a function that process each literal that appears +in the column of the matrix. \begin{code} -process_explicit_literals :: [HsLit] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +process_explicit_literals :: [HsLit] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) process_explicit_literals lits qs = (concat pats, unionManyUniqSets indexs) where pats_indexs = map (\x -> construct_literal_matrix x qs) lits (pats,indexs) = unzip pats_indexs - \end{code} -Process_literals calls process_explicit_literals to deal with the literals taht apears in -the matrix and deal also sith ther rest of the cases. It must be one Variable to be complete. +@process_literals@ calls @process_explicit_literals@ to deal with the literals +that appears in the matrix and deal also with the rest of the cases. It +must be one Variable to be complete. \begin{code} -process_literals :: [HsLit] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +process_literals :: [HsLit] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) process_literals used_lits qs - | length default_eqns == 0 = ([make_row_vars used_lits (head qs)]++pats,indexs) - | otherwise = (pats_default,indexs_default) + | null default_eqns = ([make_row_vars used_lits (head qs)] ++ pats,indexs) + | otherwise = (pats_default,indexs_default) where (pats,indexs) = process_explicit_literals used_lits qs - default_eqns = (map remove_var (filter is_var qs)) + default_eqns = ASSERT2( okGroup qs, pprGroup qs ) + [remove_var q | q <- qs, is_var (firstPatN q)] (pats',indexs') = check' default_eqns - pats_default = [(new_wild_pat:ps,constraints) | (ps,constraints) <- (pats')] ++ pats + pats_default = [(nlWildPat:ps,constraints) | (ps,constraints) <- (pats')] ++ pats indexs_default = unionUniqSets indexs' indexs \end{code} -Here we have selected the literal and we will select all the equations that begins for that -literal and create a new matrix. +Here we have selected the literal and we will select all the equations that +begins for that literal and create a new matrix. \begin{code} -construct_literal_matrix :: HsLit -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +construct_literal_matrix :: HsLit -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) construct_literal_matrix lit qs = (map (\ (xs,ys) -> (new_lit:xs,ys)) pats,indexs) where (pats,indexs) = (check' (remove_first_column_lit lit qs)) - new_lit = LitPatIn lit + new_lit = nlLitPat lit remove_first_column_lit :: HsLit - -> [EquationInfo] - -> [EquationInfo] -remove_first_column_lit lit qs = - map shift_pat (filter (is_var_lit lit) qs) + -> [(EqnNo, EquationInfo)] + -> [(EqnNo, EquationInfo)] +remove_first_column_lit lit qs + = ASSERT2( okGroup qs, pprGroup qs ) + [(n, shift_pat eqn) | q@(n,eqn) <- qs, is_var_lit lit (firstPatN q)] where - shift_pat (EqnInfo n ctx [] result) = panic "Check.shift_var: no patterns" - shift_pat (EqnInfo n ctx (_:ps) result) = EqnInfo n ctx ps result - + shift_pat eqn@(EqnInfo { eqn_pats = _:ps}) = eqn { eqn_pats = ps } + shift_pat eqn@(EqnInfo { eqn_pats = []}) = panic "Check.shift_var: no patterns" \end{code} -This function splits the equations @qs@ in groups that deal with the same constructor +This function splits the equations @qs@ in groups that deal with the +same constructor. \begin{code} - -split_by_constructor :: [EquationInfo] -> ([ExhaustivePat],EqnSet) - -split_by_constructor qs | length unused_cons /= 0 = need_default_case used_cons unused_cons qs - | otherwise = no_need_default_case used_cons qs +split_by_constructor :: [(EqnNo, EquationInfo)] -> ([ExhaustivePat], EqnSet) +split_by_constructor qs + | notNull unused_cons = need_default_case used_cons unused_cons qs + | otherwise = no_need_default_case used_cons qs where used_cons = get_used_cons qs unused_cons = get_unused_cons used_cons - \end{code} -The first column of the patterns matrix only have vars, then there is nothing to do. +The first column of the patterns matrix only have vars, then there is +nothing to do. \begin{code} -first_column_only_vars :: [EquationInfo] -> ([ExhaustivePat],EqnSet) -first_column_only_vars qs = (map (\ (xs,ys) -> (WildPatIn:xs,ys)) pats,indexs) +first_column_only_vars :: [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) +first_column_only_vars qs = (map (\ (xs,ys) -> (nlWildPat:xs,ys)) pats,indexs) where - (pats,indexs) = check' (map remove_var qs) - + (pats, indexs) = check' (map remove_var qs) \end{code} -This equation takes a matrix of patterns and split the equations by constructor, using all -the constructors that appears in the first column of the pattern matching. +This equation takes a matrix of patterns and split the equations by +constructor, using all the constructors that appears in the first column +of the pattern matching. -We can need a default clause or not ...., it depends if we used all the constructors or not -explicitily. The reasoning is similar to process_literals, the difference is that here -the default case is not allways needed. +We can need a default clause or not ...., it depends if we used all the +constructors or not explicitly. The reasoning is similar to @process_literals@, +the difference is that here the default case is not always needed. \begin{code} -no_need_default_case :: [TypecheckedPat] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +no_need_default_case :: [Pat Id] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) no_need_default_case cons qs = (concat pats, unionManyUniqSets indexs) where pats_indexs = map (\x -> construct_matrix x qs) cons (pats,indexs) = unzip pats_indexs -need_default_case :: [TypecheckedPat] -> [Id] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +need_default_case :: [Pat Id] -> [DataCon] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) need_default_case used_cons unused_cons qs - | length default_eqns == 0 = (pats_default_no_eqns,indexs) - | otherwise = (pats_default,indexs_default) + | null default_eqns = (pats_default_no_eqns,indexs) + | otherwise = (pats_default,indexs_default) where (pats,indexs) = no_need_default_case used_cons qs - default_eqns = (map remove_var (filter is_var qs)) + default_eqns = ASSERT2( okGroup qs, pprGroup qs ) + [remove_var q | q <- qs, is_var (firstPatN q)] (pats',indexs') = check' default_eqns pats_default = [(make_whole_con c:ps,constraints) | c <- unused_cons, (ps,constraints) <- pats'] ++ pats @@ -316,60 +340,70 @@ need_default_case used_cons unused_cons qs pats_default_no_eqns = [(make_whole_con c:new_wilds,[]) | c <- unused_cons] ++ pats indexs_default = unionUniqSets indexs' indexs -construct_matrix :: TypecheckedPat -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +construct_matrix :: Pat Id -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) construct_matrix con qs = - (map (make_con con) pats,indexs) where (pats,indexs) = (check' (remove_first_column con qs)) \end{code} -Here remove first column is more difficult that with literals due to the fact that -constructors can have arguments. - -for instance, the matrix +Here remove first column is more difficult that with literals due to the fact +that constructors can have arguments. +For instance, the matrix +\begin{verbatim} (: x xs) y z y - +\end{verbatim} is transformed in: - +\begin{verbatim} x xs y _ _ y - +\end{verbatim} \begin{code} -remove_first_column :: TypecheckedPat -- Constructor - -> [EquationInfo] - -> [EquationInfo] -remove_first_column (ConPat con _ con_pats) qs = - map shift_var (filter (is_var_con con) qs) +remove_first_column :: Pat Id -- Constructor + -> [(EqnNo, EquationInfo)] + -> [(EqnNo, EquationInfo)] +remove_first_column (ConPatOut (L _ con) _ _ _ (PrefixCon con_pats) _) qs + = ASSERT2( okGroup qs, pprGroup qs ) + [(n, shift_var eqn) | q@(n, eqn) <- qs, is_var_con con (firstPatN q)] where - new_wilds = [WildPat (outPatType arg_pat) | arg_pat <- con_pats] - shift_var (EqnInfo n ctx (ConPat _ _ ps':ps) result) = - EqnInfo n ctx (ps'++ps) result - shift_var (EqnInfo n ctx (WildPat _ :ps) result) = - EqnInfo n ctx (new_wilds ++ ps) result - shift_var _ = panic "Check.Shift_var:No done" - -make_row_vars :: [HsLit] -> EquationInfo -> ExhaustivePat -make_row_vars used_lits (EqnInfo _ _ pats _ ) = - (VarPatIn new_var:take (length (tail pats)) (repeat WildPatIn),[(new_var,used_lits)]) - where new_var = BS "#x" - -make_row_vars_for_constructor :: EquationInfo -> [WarningPat] -make_row_vars_for_constructor (EqnInfo _ _ pats _ ) = take (length (tail pats)) (repeat WildPatIn) - -compare_cons :: TypecheckedPat -> TypecheckedPat -> Bool -compare_cons (ConPat id1 _ _) (ConPat id2 _ _) = id1 == id2 - -remove_dups :: [TypecheckedPat] -> [TypecheckedPat] + new_wilds = [WildPat (hsPatType arg_pat) | arg_pat <- con_pats] + shift_var eqn@(EqnInfo { eqn_pats = ConPatOut _ _ _ _ (PrefixCon ps') _ : ps}) + = eqn { eqn_pats = map unLoc ps' ++ ps } + shift_var eqn@(EqnInfo { eqn_pats = WildPat _ : ps }) + = eqn { eqn_pats = new_wilds ++ ps } + shift_var _ = panic "Check.Shift_var:No done" + +make_row_vars :: [HsLit] -> (EqnNo, EquationInfo) -> ExhaustivePat +make_row_vars used_lits (_, EqnInfo { eqn_pats = pats}) + = (nlVarPat new_var:takeList (tail pats) (repeat nlWildPat),[(new_var,used_lits)]) + where + new_var = hash_x + +hash_x = mkInternalName unboundKey {- doesn't matter much -} + (mkVarOccFS FSLIT("#x")) + noSrcLoc + +make_row_vars_for_constructor :: (EqnNo, EquationInfo) -> [WarningPat] +make_row_vars_for_constructor (_, EqnInfo { eqn_pats = pats}) + = takeList (tail pats) (repeat nlWildPat) + +compare_cons :: Pat Id -> Pat Id -> Bool +compare_cons (ConPatOut (L _ id1) _ _ _ _ _) (ConPatOut (L _ id2) _ _ _ _ _) = id1 == id2 + +remove_dups :: [Pat Id] -> [Pat Id] remove_dups [] = [] remove_dups (x:xs) | or (map (\y -> compare_cons x y) xs) = remove_dups xs | otherwise = x : remove_dups xs -get_used_cons :: [EquationInfo] -> [TypecheckedPat] -get_used_cons qs = remove_dups [con | (EqnInfo _ _ (con@(ConPat _ _ _):_) _) <- qs] +get_used_cons :: [(EqnNo, EquationInfo)] -> [Pat Id] +get_used_cons qs = remove_dups [pat | q <- qs, let pat = firstPatN q, + isConPatOut pat] + +isConPatOut (ConPatOut {}) = True +isConPatOut other = False remove_dups' :: [HsLit] -> [HsLit] remove_dups' [] = [] @@ -377,246 +411,288 @@ remove_dups' (x:xs) | x `elem` xs = remove_dups' xs | otherwise = x : remove_dups' xs -get_used_lits :: [EquationInfo] -> [HsLit] -get_used_lits qs = remove_dups' (get_used_lits' qs) +get_used_lits :: [(EqnNo, EquationInfo)] -> [HsLit] +get_used_lits qs = remove_dups' all_literals + where + all_literals = get_used_lits' qs + +get_used_lits' :: [(EqnNo, EquationInfo)] -> [HsLit] +get_used_lits' [] = [] +get_used_lits' (q:qs) + | Just lit <- get_lit (firstPatN q) = lit : get_used_lits' qs + | otherwise = get_used_lits qs -get_used_lits' :: [EquationInfo] -> [HsLit] -get_used_lits' [] = [] -get_used_lits' ((EqnInfo _ _ ((LitPat lit _):_) _):qs) = lit : get_used_lits qs -get_used_lits' ((EqnInfo _ _ ((NPat lit _ _):_) _):qs) = lit : get_used_lits qs -get_used_lits' (q:qs) = get_used_lits qs +get_lit :: Pat id -> Maybe HsLit +-- Get a representative HsLit to stand for the OverLit +-- It doesn't matter which one, because they will only be compared +-- with other HsLits gotten in the same way +get_lit (LitPat lit) = Just lit +get_lit (NPat (HsIntegral i _) mb _ _) = Just (HsIntPrim (mb_neg mb i)) +get_lit (NPat (HsFractional f _) mb _ _) = Just (HsFloatPrim (mb_neg mb f)) +get_lit other_pat = Nothing -get_unused_cons :: [TypecheckedPat] -> [Id] +mb_neg :: Num a => Maybe b -> a -> a +mb_neg Nothing v = v +mb_neg (Just _) v = -v + +get_unused_cons :: [Pat Id] -> [DataCon] get_unused_cons used_cons = unused_cons where - (ConPat _ ty _) = head used_cons - (ty_con,_) = getAppTyCon ty - all_cons = tyConDataCons ty_con - used_cons_as_id = map (\ (ConPat id _ _) -> id) used_cons - unused_cons = uniqSetToList (mkUniqSet all_cons `minusUniqSet` mkUniqSet used_cons_as_id) - -all_vars :: [TypecheckedPat] -> Bool -all_vars [] = True -all_vars (WildPat _:ps) = all_vars ps -all_vars _ = False - -remove_var :: EquationInfo -> EquationInfo -remove_var (EqnInfo n ctx (WildPat _:ps) result) = EqnInfo n ctx ps result -remove_var _ = panic "Check:remove_var: equation not begin with a variable" - -is_con :: EquationInfo -> Bool -is_con (EqnInfo _ _ ((ConPat _ _ _):_) _) = True -is_con _ = False - -is_lit :: EquationInfo -> Bool -is_lit (EqnInfo _ _ ((LitPat _ _):_) _) = True -is_lit (EqnInfo _ _ ((NPat _ _ _):_) _) = True -is_lit _ = False - -is_npat :: EquationInfo -> Bool -is_npat (EqnInfo _ _ ((NPat _ _ _):_) _) = True -is_npat _ = False - -is_nplusk :: EquationInfo -> Bool -is_nplusk (EqnInfo _ _ ((NPlusKPat _ _ _ _ _):_) _) = True -is_nplusk _ = False - -is_var :: EquationInfo -> Bool -is_var (EqnInfo _ _ ((WildPat _):_) _) = True -is_var _ = False - -is_var_con :: Id -> EquationInfo -> Bool -is_var_con con (EqnInfo _ _ ((WildPat _):_) _) = True -is_var_con con (EqnInfo _ _ ((ConPat id _ _):_) _) | id == con = True -is_var_con con _ = False - -is_var_lit :: HsLit -> EquationInfo -> Bool -is_var_lit lit (EqnInfo _ _ ((WildPat _):_) _) = True -is_var_lit lit (EqnInfo _ _ ((LitPat lit' _):_) _) | lit == lit' = True -is_var_lit lit (EqnInfo _ _ ((NPat lit' _ _):_) _) | lit == lit' = True -is_var_lit lit _ = False + (ConPatOut _ _ _ _ _ ty) = head used_cons + ty_con = tcTyConAppTyCon ty -- Newtype observable + all_cons = tyConDataCons ty_con + used_cons_as_id = map (\ (ConPatOut (L _ d) _ _ _ _ _) -> d) used_cons + unused_cons = uniqSetToList + (mkUniqSet all_cons `minusUniqSet` mkUniqSet used_cons_as_id) + +all_vars :: [Pat Id] -> Bool +all_vars [] = True +all_vars (WildPat _:ps) = all_vars ps +all_vars _ = False + +remove_var :: (EqnNo, EquationInfo) -> (EqnNo, EquationInfo) +remove_var (n, eqn@(EqnInfo { eqn_pats = WildPat _ : ps})) = (n, eqn { eqn_pats = ps }) +remove_var _ = panic "Check.remove_var: equation does not begin with a variable" + +----------------------- +eqnPats :: (EqnNo, EquationInfo) -> [Pat Id] +eqnPats (_, eqn) = eqn_pats eqn + +okGroup :: [(EqnNo, EquationInfo)] -> Bool +-- True if all equations have at least one pattern, and +-- all have the same number of patterns +okGroup [] = True +okGroup (e:es) = n_pats > 0 && and [length (eqnPats e) == n_pats | e <- es] + where + n_pats = length (eqnPats e) + +-- Half-baked print +pprGroup es = vcat (map pprEqnInfo es) +pprEqnInfo e = ppr (eqnPats e) + + +firstPatN :: (EqnNo, EquationInfo) -> Pat Id +firstPatN (_, eqn) = firstPat eqn + +is_con :: Pat Id -> Bool +is_con (ConPatOut _ _ _ _ _ _) = True +is_con _ = False + +is_lit :: Pat Id -> Bool +is_lit (LitPat _) = True +is_lit (NPat _ _ _ _) = True +is_lit _ = False + +is_var :: Pat Id -> Bool +is_var (WildPat _) = True +is_var _ = False + +is_var_con :: DataCon -> Pat Id -> Bool +is_var_con con (WildPat _) = True +is_var_con con (ConPatOut (L _ id) _ _ _ _ _) | id == con = True +is_var_con con _ = False + +is_var_lit :: HsLit -> Pat Id -> Bool +is_var_lit lit (WildPat _) = True +is_var_lit lit pat + | Just lit' <- get_lit pat = lit == lit' + | otherwise = False \end{code} -The difference beteewn make_con and make_whole_con is that make_wole_con creates a new -constructor with all their arguments, and make_Con takes a list of argumntes, creates -the contructor geting thir argumnts from the list. See where are used for details. +The difference beteewn @make_con@ and @make_whole_con@ is that +@make_wole_con@ creates a new constructor with all their arguments, and +@make_con@ takes a list of argumntes, creates the contructor getting their +arguments from the list. See where \fbox{\ ???\ } are used for details. -We need to reconstruct the patterns (make the constructors infix and similar) at the -same time that we create the constructors. +We need to reconstruct the patterns (make the constructors infix and +similar) at the same time that we create the constructors. You can tell tuple constructors using - +\begin{verbatim} Id.isTupleCon - -You can see if one contructur is infix with this clearer code :-)))))))))) - +\end{verbatim} +You can see if one constructor is infix with this clearer code :-)))))))))) +\begin{verbatim} Lex.isLexConSym (Name.occNameString (Name.getOccName con)) +\end{verbatim} Rather clumsy but it works. (Simon Peyton Jones) -We con't mind the nilDataCon because it doesn't change the way to print the messsage, -we are searching only for things like: [1,2,3], not x:xs .... - +We don't mind the @nilDataCon@ because it doesn't change the way to +print the messsage, we are searching only for things like: @[1,2,3]@, +not @x:xs@ .... -In recontruct_pat we want to "undo" the work taht we have done in simplify_pat +In @reconstruct_pat@ we want to ``undo'' the work +that we have done in @simplify_pat@. In particular: - ((,) x y) returns to be (x, y) - ((:) x xs) returns to be (x:xs) - (x:(...:[]) returns to be [x,...] - -The dificult case is the third one becouse we need to follow all the contructors until the [] -to know taht we need to use the second case, not the second. - +\begin{tabular}{lll} + @((,) x y)@ & returns to be & @(x, y)@ +\\ @((:) x xs)@ & returns to be & @(x:xs)@ +\\ @(x:(...:[])@ & returns to be & @[x,...]@ +\end{tabular} +% +The difficult case is the third one becouse we need to follow all the +contructors until the @[]@ to know that we need to use the second case, +not the second. \fbox{\ ???\ } +% \begin{code} +isInfixCon con = isDataSymOcc (getOccName con) -isInfixCon con = isLexConSym (occNameString (getOccName con)) - -is_nil (ConPatIn (BS con) []) = con == getOccString nilDataCon -is_nil _ = False +is_nil (ConPatIn con (PrefixCon [])) = unLoc con == getName nilDataCon +is_nil _ = False -is_list (ListPatIn _) = True +is_list (ListPat _ _) = True is_list _ = False return_list id q = id == consDataCon && (is_nil q || is_list q) -make_list p q | is_nil q = ListPatIn [p] -make_list p (ListPatIn ps) = ListPatIn (p:ps) -make_list _ _ = panic "Check.make_list: Invalid argument" - -make_con :: TypecheckedPat -> ExhaustivePat -> ExhaustivePat -make_con (ConPat id ty pats) (p:q:ps, constraints) - | return_list id q = (make_list p q : ps, constraints) - | isInfixCon id = (ParPatIn (ConOpPatIn p name fixity q) : ps, constraints) - where name = BS (getOccString id) - fixity = panic "Check.make_con: Guessing fixity" -make_con (ConPat id ty pats) (ps,constraints) - | isTupleCon id = (TuplePatIn pats_con : rest_pats, constraints) - | otherwise = (ConPatIn name pats_con : rest_pats, constraints) - where num_args = length pats - name = BS (getOccString id) - pats_con = (take num_args ps) - rest_pats = drop num_args ps - -make_whole_con :: Id -> WarningPat -make_whole_con con | isInfixCon con = ParPatIn(ConOpPatIn new_wild_pat name fixity new_wild_pat) - | otherwise = ConPatIn name pats +make_list p q | is_nil q = ListPat [p] placeHolderType +make_list p (ListPat ps ty) = ListPat (p:ps) ty +make_list _ _ = panic "Check.make_list: Invalid argument" + +make_con :: Pat Id -> ExhaustivePat -> ExhaustivePat +make_con (ConPatOut (L _ id) _ _ _ _ _) (lp:lq:ps, constraints) + | return_list id q = (noLoc (make_list lp q) : ps, constraints) + | isInfixCon id = (nlInfixConPat (getName id) lp lq : ps, constraints) + where q = unLoc lq + +make_con (ConPatOut (L _ id) _ _ _ (PrefixCon pats) ty) (ps, constraints) + | isTupleTyCon tc = (noLoc (TuplePat pats_con (tupleTyConBoxity tc) ty) : rest_pats, constraints) + | isPArrFakeCon id = (noLoc (PArrPat pats_con placeHolderType) : rest_pats, constraints) + | otherwise = (nlConPat name pats_con : rest_pats, constraints) + where + name = getName id + (pats_con, rest_pats) = splitAtList pats ps + tc = dataConTyCon id + +-- reconstruct parallel array pattern +-- +-- * don't check for the type only; we need to make sure that we are really +-- dealing with one of the fake constructors and not with the real +-- representation + +make_whole_con :: DataCon -> WarningPat +make_whole_con con | isInfixCon con = nlInfixConPat name nlWildPat nlWildPat + | otherwise = nlConPat name pats where - fixity = panic "Check.make_whole_con: Guessing fixity" - name = BS (getOccString con) - arity = get_int_arity con - pats = take arity (repeat new_wild_pat) - - -new_wild_pat :: WarningPat -new_wild_pat = WildPatIn - -get_int_arity :: Id -> Int -get_int_arity id = arity_to_int (getIdArity id) - where - arity_to_int (ArityExactly n) = n - arity_to_int _ = panic "getIntArity: Unknown arity" - + name = getName con + pats = [nlWildPat | t <- dataConOrigArgTys con] \end{code} -This equation makes the same thing that tidy in Match.lhs, the -diference is that here we can do all the tidy in one place and in the -Match tidy it must be done one column each time due to bookeping +This equation makes the same thing as @tidy@ in @Match.lhs@, the +difference is that here we can do all the tidy in one place and in the +@Match@ tidy it must be done one column each time due to bookkeeping constraints. \begin{code} -simplify_eqns :: [EquationInfo] -> [EquationInfo] -simplify_eqns [] = [] -simplify_eqns ((EqnInfo n ctx pats result):qs) = - (EqnInfo n ctx(map simplify_pat pats) result) : - simplify_eqns qs - -simplify_pat :: TypecheckedPat -> TypecheckedPat -simplify_pat (WildPat gt ) = WildPat gt - -simplify_pat (VarPat id) = WildPat (idType id) - -simplify_pat (LazyPat p) = simplify_pat p - -simplify_pat (AsPat id p) = simplify_pat p - -simplify_pat (ConPat id ty ps) = ConPat id ty (map simplify_pat ps) - -simplify_pat (ConOpPat p1 id p2 ty) = ConPat id ty (map simplify_pat [p1,p2]) - -simplify_pat (ListPat ty ps) = foldr (\ x -> \y -> ConPat consDataCon list_ty [x, y]) - (ConPat nilDataCon list_ty []) - (map simplify_pat ps) - where list_ty = mkListTy ty - - -simplify_pat (TuplePat ps) = ConPat (tupleCon arity) - (mkTupleTy arity (map outPatType ps)) - (map simplify_pat ps) - where - arity = length ps - -simplify_pat (RecPat id ty idps) = ConPat id ty pats - where - pats = map (\ (id,p,_)-> simplify_pat p) idps - -simplify_pat pat@(LitPat lit lit_ty) - | isPrimType lit_ty = LitPat lit lit_ty - - | lit_ty `eqTy` charTy = ConPat charDataCon charTy [LitPat (mk_char lit) charPrimTy] - - | otherwise = pprPanic "tidy1:LitPat:" (ppr PprDebug pat) +simplify_eqn :: EquationInfo -> EquationInfo +simplify_eqn eqn = eqn { eqn_pats = map simplify_pat (eqn_pats eqn), + eqn_rhs = simplify_rhs (eqn_rhs eqn) } where - mk_char (HsChar c) = HsCharPrim c - -simplify_pat (NPat lit lit_ty hsexpr) = better_pat + -- Horrible hack. The simplify_pat stuff converts NPlusK pats to WildPats + -- which of course loses the info that they can fail to match. So we + -- stick in a CanFail as if it were a guard. + -- The Right Thing to do is for the whole system to treat NPlusK pats properly + simplify_rhs (MatchResult can_fail body) + | any has_nplusk_pat (eqn_pats eqn) = MatchResult CanFail body + | otherwise = MatchResult can_fail body + +has_nplusk_lpat :: LPat Id -> Bool +has_nplusk_lpat (L _ p) = has_nplusk_pat p + +has_nplusk_pat :: Pat Id -> Bool +has_nplusk_pat (NPlusKPat _ _ _ _) = True +has_nplusk_pat (ParPat p) = has_nplusk_lpat p +has_nplusk_pat (AsPat _ p) = has_nplusk_lpat p +has_nplusk_pat (SigPatOut p _ ) = has_nplusk_lpat p +has_nplusk_pat (ConPatOut _ _ _ _ ps ty) = any has_nplusk_lpat (hsConArgs ps) +has_nplusk_pat (ListPat ps _) = any has_nplusk_lpat ps +has_nplusk_pat (TuplePat ps _ _) = any has_nplusk_lpat ps +has_nplusk_pat (PArrPat ps _) = any has_nplusk_lpat ps +has_nplusk_pat (LazyPat p) = False -- Why? +has_nplusk_pat (BangPat p) = has_nplusk_lpat p -- I think +has_nplusk_pat p = False -- VarPat, VarPatOut, WildPat, LitPat, NPat, TypePat, DictPat + +simplify_lpat :: LPat Id -> LPat Id +simplify_lpat p = fmap simplify_pat p + +simplify_pat :: Pat Id -> Pat Id +simplify_pat pat@(WildPat gt) = pat +simplify_pat (VarPat id) = WildPat (idType id) +simplify_pat (VarPatOut id _) = WildPat (idType id) -- Ignore the bindings +simplify_pat (ParPat p) = unLoc (simplify_lpat p) +simplify_pat (LazyPat p) = unLoc (simplify_lpat p) +simplify_pat (BangPat p) = unLoc (simplify_lpat p) +simplify_pat (AsPat id p) = unLoc (simplify_lpat p) +simplify_pat (SigPatOut p _) = unLoc (simplify_lpat p) -- I'm not sure this is right + +simplify_pat (ConPatOut (L loc id) tvs dicts binds ps ty) + = ConPatOut (L loc id) tvs dicts binds (simplify_con id ps) ty + +simplify_pat (ListPat ps ty) = + unLoc $ foldr (\ x y -> mkPrefixConPat consDataCon [x,y] list_ty) + (mkNilPat list_ty) + (map simplify_lpat ps) + where list_ty = mkListTy ty + +-- introduce fake parallel array constructors to be able to handle parallel +-- arrays with the existing machinery for constructor pattern +-- +simplify_pat (PArrPat ps ty) + = mk_simple_con_pat (parrFakeCon (length ps)) + (PrefixCon (map simplify_lpat ps)) + (mkPArrTy ty) + +simplify_pat (TuplePat ps boxity ty) + = mk_simple_con_pat (tupleCon boxity arity) + (PrefixCon (map simplify_lpat ps)) + ty 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] - - -- Convert the literal pattern "" to the constructor pattern []. - | null_str_lit lit = ConPat nilDataCon lit_ty [] + arity = length ps - | otherwise = NPat lit lit_ty hsexpr - - mk_int (HsInt i) = HsIntPrim i - mk_int l@(HsLitLit s) = l - - mk_char (HsChar c) = HsCharPrim c - mk_char l@(HsLitLit s) = l - - mk_word l@(HsLitLit s) = l - - mk_addr l@(HsLitLit s) = l - - mk_float (HsInt i) = HsFloatPrim (fromInteger i) - mk_float (HsFrac f) = HsFloatPrim f - mk_float l@(HsLitLit s) = l +-- unpack string patterns fully, so we can see when they overlap with +-- each other, or even explicit lists of Chars. +simplify_pat pat@(LitPat (HsString s)) = + foldr (\c pat -> mk_simple_con_pat consDataCon (PrefixCon [mk_char_lit c,noLoc pat]) stringTy) + (mk_simple_con_pat nilDataCon (PrefixCon []) stringTy) (unpackFS s) + where + mk_char_lit c = noLoc (mk_simple_con_pat charDataCon (PrefixCon [nlLitPat (HsCharPrim c)]) charTy) - mk_double (HsInt i) = HsDoublePrim (fromInteger i) - mk_double (HsFrac f) = HsDoublePrim f - mk_double l@(HsLitLit s) = l +simplify_pat pat@(LitPat lit) = unLoc (tidyLitPat lit (noLoc pat)) - null_str_lit (HsString s) = _NULL_ s - null_str_lit other_lit = False +simplify_pat pat@(NPat lit mb_neg _ lit_ty) = unLoc (tidyNPat lit mb_neg lit_ty (noLoc pat)) -simplify_pat (NPlusKPat id hslit ty hsexpr1 hsexpr2) = --NPlusKPat id hslit ty hsexpr1 hsexpr2 - WildPat ty - where ty = panic "Check.simplify_pat: Never used" +simplify_pat (NPlusKPat id hslit hsexpr1 hsexpr2) + = WildPat (idType (unLoc id)) -simplify_pat (DictPat dicts methods) = - case num_of_d_and_ms of - 0 -> simplify_pat (TuplePat []) +simplify_pat (DictPat dicts methods) + = case num_of_d_and_ms of + 0 -> simplify_pat (TuplePat [] Boxed unitTy) 1 -> simplify_pat (head dict_and_method_pats) - _ -> simplify_pat (TuplePat dict_and_method_pats) + _ -> simplify_pat (mkVanillaTuplePat (map noLoc dict_and_method_pats) Boxed) where num_of_d_and_ms = length dicts + length methods dict_and_method_pats = map VarPat (dicts ++ methods) +mk_simple_con_pat con args ty = ConPatOut (noLoc con) [] [] emptyLHsBinds args ty + +----------------- +simplify_con con (PrefixCon ps) = PrefixCon (map simplify_lpat ps) +simplify_con con (InfixCon p1 p2) = PrefixCon [simplify_lpat p1, simplify_lpat p2] +simplify_con con (RecCon fs) + | null fs = PrefixCon [nlWildPat | t <- dataConOrigArgTys con] + -- Special case for null patterns; maybe not a record at all + | otherwise = PrefixCon (map (simplify_lpat.snd) all_pats) + where + -- pad out all the missing fields with WildPats. + field_pats = map (\ f -> (f, nlWildPat)) (dataConFieldLabels con) + all_pats = foldr (\ (id,p) acc -> insertNm (getName (unLoc id)) p acc) + field_pats fs + + insertNm nm p [] = [(nm,p)] + insertNm nm p (x@(n,_):xs) + | nm == n = (nm,p):xs + | otherwise = x : insertNm nm p xs \end{code}