X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FhsSyn%2FHsPat.lhs;h=ea59e8827eade9dc485d489011b6ef60e7d93fa7;hb=e4c8d2b11b4be71885532cb14434511b6c47866c;hp=953d228942a0c85da06b8035a72c430609819740;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1;p=ghc-hetmet.git diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs index 953d228..ea59e88 100644 --- a/compiler/hsSyn/HsPat.lhs +++ b/compiler/hsSyn/HsPat.lhs @@ -1,15 +1,17 @@ % +% (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[PatSyntax]{Abstract Haskell syntax---patterns} \begin{code} module HsPat ( - Pat(..), InPat, OutPat, LPat, + Pat(..), InPat, OutPat, LPat, HsConDetails(..), hsConArgs, + HsRecField(..), mkRecField, - mkPrefixConPat, mkCharLitPat, mkNilPat, + mkPrefixConPat, mkCharLitPat, mkNilPat, mkCoPat, isBangHsBind, patsAreAllCons, isConPat, isSigPat, isWildPat, @@ -22,19 +24,20 @@ module HsPat ( import {-# SOURCE #-} HsExpr ( SyntaxExpr ) -- friends: -import HsBinds ( DictBinds, HsBind(..), emptyLHsBinds, pprLHsBinds ) -import HsLit ( HsLit(HsCharPrim), HsOverLit ) -import HsTypes ( LHsType, PostTcType ) -import BasicTypes ( Boxity, tupleParens ) +import HsBinds +import HsLit +import HsTypes +import HsDoc +import BasicTypes -- others: import PprCore ( {- instance OutputableBndr TyVar -} ) -import TysWiredIn ( nilDataCon, charDataCon, charTy ) -import Var ( TyVar ) -import DataCon ( DataCon, dataConTyCon ) -import TyCon ( isProductTyCon ) +import TysWiredIn +import Var +import DataCon +import TyCon import Outputable -import Type ( Type ) -import SrcLoc ( Located(..), unLoc, noLoc ) +import Type +import SrcLoc \end{code} @@ -81,12 +84,15 @@ data Pat id | ConPatIn (Located id) (HsConDetails id (LPat id)) - | ConPatOut (Located DataCon) - [TyVar] -- Existentially bound type variables - [id] -- Ditto dictionaries - (DictBinds id) -- Bindings involving those dictionaries - (HsConDetails id (LPat id)) - Type -- The type of the pattern + | ConPatOut { + pat_con :: Located DataCon, + pat_tvs :: [TyVar], -- Existentially bound type variables + -- including any bound coercion variables + pat_dicts :: [id], -- Ditto dictionaries + pat_binds :: DictBinds id, -- Bindings involving those dictionaries + pat_args :: HsConDetails id (LPat id), + pat_ty :: Type -- The type of the pattern + } ------------ Literal and n+k patterns --------------- | LitPat HsLit -- Used for *non-overloaded* literal patterns: @@ -118,21 +124,37 @@ data Pat id ------------ Dictionary patterns (translation only) --------------- | DictPat -- Used when destructing Dictionaries with an explicit case - [id] -- superclass dicts - [id] -- methods + [id] -- Superclass dicts + [id] -- Methods + + ------------ Pattern coercions (translation only) --------------- + | CoPat HsWrapper -- If co::t1 -> t2, p::t2, + -- then (CoPat co p) :: t1 + (Pat id) -- Why not LPat? Ans: existing locn will do + Type + -- During desugaring a (CoPat co pat) turns into a cast with 'co' on + -- the scrutinee, followed by a match on 'pat' \end{code} HsConDetails is use both for patterns and for data type declarations \begin{code} data HsConDetails id arg - = PrefixCon [arg] -- C p1 p2 p3 - | RecCon [(Located id, arg)] -- C { x = p1, y = p2 } - | InfixCon arg arg -- p1 `C` p2 + = PrefixCon [arg] -- C p1 p2 p3 + | RecCon [HsRecField id arg] -- C { x = p1, y = p2 } + | InfixCon arg arg -- p1 `C` p2 + +data HsRecField id arg = HsRecField { + hsRecFieldId :: Located id, + hsRecFieldArg :: arg, + hsRecFieldDoc :: Maybe (LHsDoc id) +} + +mkRecField id arg = HsRecField id arg Nothing hsConArgs :: HsConDetails id arg -> [arg] hsConArgs (PrefixCon ps) = ps -hsConArgs (RecCon fs) = map snd fs +hsConArgs (RecCon fs) = map hsRecFieldArg fs hsConArgs (InfixCon p1 p2) = [p1,p2] \end{code} @@ -169,7 +191,8 @@ pprPat (PArrPat pats _) = pabrackets (interpp'SP pats) pprPat (TuplePat pats bx _) = tupleParens bx (interpp'SP pats) pprPat (ConPatIn con details) = pprUserCon con details -pprPat (ConPatOut con tvs dicts binds details _) +pprPat (ConPatOut { pat_con = con, pat_tvs = tvs, pat_dicts = dicts, + pat_binds = binds, pat_args = details }) = getPprStyle $ \ sty -> -- Tiresome; in TcBinds.tcRhs we print out a if debugStyle sty then -- typechecked Pat in an error message, -- and we want to make sure it prints nicely @@ -182,6 +205,7 @@ pprPat (NPat l Nothing _ _) = ppr l pprPat (NPat l (Just _) _ _) = char '-' <> ppr l pprPat (NPlusKPat n k _ _) = hcat [ppr n, char '+', ppr k] pprPat (TypePat ty) = ptext SLIT("{|") <> ppr ty <> ptext SLIT("|}") +pprPat (CoPat co pat _) = parens (pprHsWrapper (ppr pat) co) pprPat (SigPatIn pat ty) = ppr pat <+> dcolon <+> ppr ty pprPat (SigPatOut pat ty) = ppr pat <+> dcolon <+> ppr ty pprPat (DictPat ds ms) = parens (sep [ptext SLIT("{-dict-}"), @@ -195,13 +219,17 @@ pprConArgs (PrefixCon pats) = interppSP pats pprConArgs (InfixCon p1 p2) = interppSP [p1,p2] pprConArgs (RecCon rpats) = braces (hsep (punctuate comma (map (pp_rpat) rpats))) where - pp_rpat (v, p) = hsep [ppr v, char '=', ppr p] - + pp_rpat (HsRecField v p _d) = + hsep [ppr v, char '=', ppr p] -- add parallel array brackets around a document -- pabrackets :: SDoc -> SDoc pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") + +instance (OutputableBndr id, Outputable arg) => + Outputable (HsRecField id arg) where + ppr (HsRecField n ty doc) = ppr n <+> dcolon <+> ppr ty <+> ppr_mbDoc doc \end{code} @@ -214,13 +242,21 @@ pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") \begin{code} mkPrefixConPat :: DataCon -> [OutPat id] -> Type -> OutPat id -- Make a vanilla Prefix constructor pattern -mkPrefixConPat dc pats ty = noLoc $ ConPatOut (noLoc dc) [] [] emptyLHsBinds (PrefixCon pats) ty +mkPrefixConPat dc pats ty + = noLoc $ ConPatOut { pat_con = noLoc dc, pat_tvs = [], pat_dicts = [], + pat_binds = emptyLHsBinds, pat_args = PrefixCon pats, + pat_ty = ty } mkNilPat :: Type -> OutPat id mkNilPat ty = mkPrefixConPat nilDataCon [] ty mkCharLitPat :: Char -> OutPat id mkCharLitPat c = mkPrefixConPat charDataCon [noLoc $ LitPat (HsCharPrim c)] charTy + +mkCoPat :: HsWrapper -> OutPat id -> Type -> OutPat id +mkCoPat co lpat@(L loc pat) ty + | isIdHsWrapper co = lpat + | otherwise = L loc (CoPat co pat ty) \end{code} @@ -260,14 +296,14 @@ isWildPat other = False patsAreAllCons :: [Pat id] -> Bool patsAreAllCons pat_list = all isConPat pat_list -isConPat (AsPat _ pat) = isConPat (unLoc pat) -isConPat (ConPatIn _ _) = True -isConPat (ConPatOut _ _ _ _ _ _) = True -isConPat (ListPat _ _) = True -isConPat (PArrPat _ _) = True -isConPat (TuplePat _ _ _) = True -isConPat (DictPat ds ms) = (length ds + length ms) > 1 -isConPat other = False +isConPat (AsPat _ pat) = isConPat (unLoc pat) +isConPat (ConPatIn {}) = True +isConPat (ConPatOut {}) = True +isConPat (ListPat {}) = True +isConPat (PArrPat {}) = True +isConPat (TuplePat {}) = True +isConPat (DictPat ds ms) = (length ds + length ms) > 1 +isConPat other = False isSigPat (SigPatIn _ _) = True isSigPat (SigPatOut _ _) = True @@ -301,6 +337,7 @@ isIrrefutableHsPat pat go1 (VarPatOut _ _) = True go1 (LazyPat pat) = True go1 (BangPat pat) = go pat + go1 (CoPat _ pat _) = go1 pat go1 (ParPat pat) = go pat go1 (AsPat _ pat) = go pat go1 (SigPatIn pat _) = go pat @@ -310,7 +347,7 @@ isIrrefutableHsPat pat go1 (PArrPat pats _) = False -- ? go1 (ConPatIn _ _) = False -- Conservative - go1 (ConPatOut (L _ con) _ _ _ details _) + go1 (ConPatOut{ pat_con = L _ con, pat_args = details }) = isProductTyCon (dataConTyCon con) && all go (hsConArgs details)