X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FMatchLit.lhs;h=287d730f7d5283178f1e50f850600aa87f3a6d38;hb=fa9c9782a4e66d7af52f4e1ef8ddf2445741dd44;hp=f3e10ff5c03181469d728ec064f45a3b4d75097d;hpb=111cee3f1ad93816cb828e38b38521d85c3bcebb;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/MatchLit.lhs b/ghc/compiler/deSugar/MatchLit.lhs index f3e10ff..287d730 100644 --- a/ghc/compiler/deSugar/MatchLit.lhs +++ b/ghc/compiler/deSugar/MatchLit.lhs @@ -4,28 +4,90 @@ \section[MatchLit]{Pattern-matching literal patterns} \begin{code} -module MatchLit ( matchLiterals ) where +module MatchLit ( dsLit, matchLiterals ) where #include "HsVersions.h" import {-# SOURCE #-} Match ( match ) import {-# SOURCE #-} DsExpr ( dsExpr ) -import HsSyn ( HsLit(..), OutPat(..), HsExpr(..) ) -import TcHsSyn ( TypecheckedHsExpr, TypecheckedPat ) -import CoreSyn ( Expr(..), Bind(..) ) -import Id ( Id ) - import DsMonad +import DsCCall ( resultWrapper ) import DsUtils +import HsSyn ( HsLit(..), Pat(..), HsExpr(..) ) +import TcHsSyn ( TypecheckedPat ) +import Id ( Id ) +import CoreSyn +import TyCon ( tyConDataCons ) +import TcType ( tcSplitTyConApp, isIntegerTy ) + +import PrelNames ( ratioTyConKey ) +import Unique ( hasKey ) import Literal ( mkMachInt, Literal(..) ) -import PrimRep ( PrimRep(IntRep) ) import Maybes ( catMaybes ) -import Type ( Type, isUnLiftedType ) +import Type ( isUnLiftedType ) import Panic ( panic, assertPanic ) +import Maybe ( isJust ) +import Ratio ( numerator, denominator ) \end{code} +%************************************************************************ +%* * + Desugaring literals + [used to be in DsExpr, but DsMeta needs it, + and it's nice to avoid a loop] +%* * +%************************************************************************ + +We give int/float literals type @Integer@ and @Rational@, respectively. +The typechecker will (presumably) have put \tr{from{Integer,Rational}s} +around them. + +ToDo: put in range checks for when converting ``@i@'' +(or should that be in the typechecker?) + +For numeric literals, we try to detect there use at a standard type +(@Int@, @Float@, etc.) are directly put in the right constructor. +[NB: down with the @App@ conversion.] + +See also below where we look for @DictApps@ for \tr{plusInt}, etc. + +\begin{code} +dsLit :: HsLit -> DsM CoreExpr +dsLit (HsChar c) = returnDs (mkCharExpr c) +dsLit (HsCharPrim c) = returnDs (mkLit (MachChar c)) +dsLit (HsString str) = mkStringLitFS str +dsLit (HsStringPrim s) = returnDs (mkLit (MachStr s)) +dsLit (HsInteger i) = mkIntegerExpr i +dsLit (HsInt i) = returnDs (mkIntExpr i) +dsLit (HsIntPrim i) = returnDs (mkIntLit i) +dsLit (HsFloatPrim f) = returnDs (mkLit (MachFloat f)) +dsLit (HsDoublePrim d) = returnDs (mkLit (MachDouble d)) +dsLit (HsLitLit str ty) + = ASSERT( isJust maybe_ty ) + returnDs (wrap_fn (mkLit (MachLitLit str rep_ty))) + where + (maybe_ty, wrap_fn) = resultWrapper ty + Just rep_ty = maybe_ty + +dsLit (HsRat r ty) + = mkIntegerExpr (numerator r) `thenDs` \ num -> + mkIntegerExpr (denominator r) `thenDs` \ denom -> + returnDs (mkConApp ratio_data_con [Type integer_ty, num, denom]) + where + (ratio_data_con, integer_ty) + = case tcSplitTyConApp ty of + (tycon, [i_ty]) -> ASSERT(isIntegerTy i_ty && tycon `hasKey` ratioTyConKey) + (head (tyConDataCons tycon), i_ty) +\end{code} + +%************************************************************************ +%* * + Pattern matching on literals +%* * +%************************************************************************ + \begin{code} matchLiterals :: [Id] -> [EquationInfo] @@ -40,7 +102,7 @@ is much like @matchConFamily@, which uses @match_cons_used@ to create the alts---here we use @match_prims_used@. \begin{code} -matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal lit_ty : ps1) _ : eqns) +matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal : ps1) _ : eqns) = -- GENERATE THE ALTS match_prims_used vars eqns_info `thenDs` \ prim_alts -> @@ -49,10 +111,10 @@ matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal lit_t where match_prims_used _ [{-no more eqns-}] = returnDs [] - match_prims_used vars eqns_info@(EqnInfo n ctx ((LitPat literal lit_ty):ps1) _ : eqns) + match_prims_used vars eqns_info@(EqnInfo n ctx (pat@(LitPat literal):ps1) _ : eqns) = let (shifted_eqns_for_this_lit, eqns_not_for_this_lit) - = partitionEqnsByLit Nothing literal eqns_info + = partitionEqnsByLit pat eqns_info in -- recursive call to make other alts... match_prims_used vars eqns_not_for_this_lit `thenDs` \ rest_of_alts -> @@ -61,28 +123,28 @@ matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (LitPat literal lit_t -- now do the business to make the alt for _this_ LitPat ... match vars shifted_eqns_for_this_lit `thenDs` \ match_result -> returnDs ( - (mk_core_lit lit_ty literal, match_result) + (mk_core_lit literal, match_result) : rest_of_alts ) where - mk_core_lit :: Type -> HsLit -> Literal - - mk_core_lit ty (HsIntPrim i) = mkMachInt i - mk_core_lit ty (HsCharPrim c) = MachChar c - mk_core_lit ty (HsStringPrim s) = MachStr s - mk_core_lit ty (HsFloatPrim f) = MachFloat f - mk_core_lit ty (HsDoublePrim d) = MachDouble d - mk_core_lit ty (HsLitLit s) = ASSERT(isUnLiftedType ty) - MachLitLit s ty - mk_core_lit ty other = panic "matchLiterals:mk_core_lit:unhandled" + mk_core_lit :: HsLit -> Literal + + mk_core_lit (HsIntPrim i) = mkMachInt i + mk_core_lit (HsCharPrim c) = MachChar c + mk_core_lit (HsStringPrim s) = MachStr s + mk_core_lit (HsFloatPrim f) = MachFloat f + mk_core_lit (HsDoublePrim d) = MachDouble d + mk_core_lit (HsLitLit s ty) = ASSERT(isUnLiftedType ty) + MachLitLit s ty + mk_core_lit other = panic "matchLiterals:mk_core_lit:unhandled" \end{code} \begin{code} matchLiterals all_vars@(var:vars) - eqns_info@(EqnInfo n ctx ((NPat literal lit_ty eq_chk):ps1) _ : eqns) + eqns_info@(EqnInfo n ctx (pat@(NPatOut literal lit_ty eq_chk):ps1) _ : eqns) = let (shifted_eqns_for_this_lit, eqns_not_for_this_lit) - = partitionEqnsByLit Nothing literal eqns_info + = partitionEqnsByLit pat eqns_info in dsExpr (HsApp eq_chk (HsVar var)) `thenDs` \ pred_expr -> match vars shifted_eqns_for_this_lit `thenDs` \ inner_match_result -> @@ -109,10 +171,10 @@ We generate: \begin{code} -matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx ((NPlusKPat master_n k ty ge sub):ps1) _ : eqns) +matchLiterals all_vars@(var:vars) eqns_info@(EqnInfo n ctx (pat@(NPlusKPatOut master_n k ge sub):ps1) _ : eqns) = let (shifted_eqns_for_this_lit, eqns_not_for_this_lit) - = partitionEqnsByLit (Just master_n) k eqns_info + = partitionEqnsByLit pat eqns_info in match vars shifted_eqns_for_this_lit `thenDs` \ inner_match_result -> @@ -137,10 +199,7 @@ that are ``same''/different as one we are looking at. We need to know whether we're looking at a @LitPat@/@NPat@, and what literal we're after. \begin{code} -partitionEqnsByLit :: Maybe Id -- (Just v) for N-plus-K patterns, where v - -- is the "master" variable; - -- Nothing for NPats and LitPats - -> HsLit +partitionEqnsByLit :: TypecheckedPat -> [EquationInfo] -> ([EquationInfo], -- These ones are for this lit, AND -- they've been "shifted" by stripping @@ -149,51 +208,35 @@ partitionEqnsByLit :: Maybe Id -- (Just v) for N-plus-K patterns, where v -- are exactly as fed in. ) -partitionEqnsByLit nPlusK lit eqns +partitionEqnsByLit master_pat eqns = ( \ (xs,ys) -> (catMaybes xs, catMaybes ys)) - (unzip (map (partition_eqn nPlusK lit) eqns)) + (unzip (map (partition_eqn master_pat) eqns)) where - partition_eqn :: Maybe Id -> HsLit -> EquationInfo -> - (Maybe EquationInfo, Maybe EquationInfo) + partition_eqn :: TypecheckedPat -> EquationInfo -> (Maybe EquationInfo, Maybe EquationInfo) - partition_eqn Nothing lit (EqnInfo n ctx (LitPat k _ : remaining_pats) match_result) - | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats match_result), Nothing) + partition_eqn (LitPat k1) (EqnInfo n ctx (LitPat k2 : remaining_pats) match_result) + | k1 == k2 = (Just (EqnInfo n ctx remaining_pats match_result), Nothing) -- NB the pattern is stripped off the EquationInfo - partition_eqn Nothing lit (EqnInfo n ctx (NPat k _ _ : remaining_pats) match_result) - | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats match_result), Nothing) + partition_eqn (NPatOut k1 _ _) (EqnInfo n ctx (NPatOut k2 _ _ : remaining_pats) match_result) + | k1 == k2 = (Just (EqnInfo n ctx remaining_pats match_result), Nothing) -- NB the pattern is stripped off the EquationInfo - partition_eqn (Just master_n) lit - (EqnInfo n ctx (NPlusKPat n' k _ _ _ : remaining_pats) match_result) - | lit `eq_lit` k = (Just (EqnInfo n ctx remaining_pats new_match_result), Nothing) + partition_eqn (NPlusKPatOut master_n k1 _ _) + (EqnInfo n ctx (NPlusKPatOut n' k2 _ _ : remaining_pats) match_result) + | k1 == k2 = (Just (EqnInfo n ctx remaining_pats new_match_result), Nothing) -- NB the pattern is stripped off the EquationInfo where new_match_result | master_n == n' = match_result | otherwise = mkCoLetsMatchResult - [NonRec n' (Var master_n)] match_result + [NonRec n' (Var master_n)] match_result -- Wild-card patterns, which will only show up in the shadows, -- go into both groups - partition_eqn nPlusK lit - eqn@(EqnInfo n ctx (WildPat _ : remaining_pats) match_result) + partition_eqn master_pat eqn@(EqnInfo n ctx (WildPat _ : remaining_pats) match_result) = (Just (EqnInfo n ctx remaining_pats match_result), Just eqn) -- Default case; not for this pattern - partition_eqn nPlusK lit eqn = (Nothing, Just eqn) - --- ToDo: meditate about this equality business... - -eq_lit (HsInt i1) (HsInt i2) = i1 == i2 -eq_lit (HsFrac f1) (HsFrac f2) = f1 == f2 - -eq_lit (HsIntPrim i1) (HsIntPrim i2) = i1 == i2 -eq_lit (HsFloatPrim f1) (HsFloatPrim f2) = f1 == f2 -eq_lit (HsDoublePrim d1) (HsDoublePrim d2) = d1 == d2 -eq_lit (HsChar c1) (HsChar c2) = c1 == c2 -eq_lit (HsCharPrim c1) (HsCharPrim c2) = c1 == c2 -eq_lit (HsString s1) (HsString s2) = s1 == s2 -eq_lit (HsStringPrim s1) (HsStringPrim s2) = s1 == s2 -eq_lit (HsLitLit s1) (HsLitLit s2) = s1 == s2 -- ToDo: ??? (dubious) -eq_lit other1 other2 = panic "matchLiterals:eq_lit" + partition_eqn master_pat eqn = (Nothing, Just eqn) \end{code} +