X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FhsSyn%2FHsPat.lhs;h=7fb5f725334fdb03e2b45c64a93a5b86e9e6edcf;hp=84eadb77946b21e84bad43e09ed8bbf089fd9a5e;hb=c0687066474aa4ce4912f31a5c09c1bcd673fb06;hpb=9504390ca8d82e3cb9618e44baea124ce27b9bde diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs index 84eadb7..7fb5f72 100644 --- a/compiler/hsSyn/HsPat.lhs +++ b/compiler/hsSyn/HsPat.lhs @@ -11,6 +11,7 @@ -- any warnings in the module. See -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings -- for details +{-# LANGUAGE DeriveDataTypeable #-} module HsPat ( Pat(..), InPat, OutPat, LPat, @@ -19,13 +20,13 @@ module HsPat ( HsConPatDetails, hsConPatArgs, HsRecFields(..), HsRecField(..), hsRecFields, - HsQuasiQuote(..), + mkPrefixConPat, mkCharLitPat, mkNilPat, - mkPrefixConPat, mkCharLitPat, mkNilPat, mkCoPat, mkCoPatCoI, + isBangHsBind, isLiftedPatBind, + isBangLPat, hsPatNeedsParens, + isIrrefutableHsPat, - isBangHsBind, hsPatNeedsParens, - patsAreAllCons, isConPat, isSigPat, isWildPat, - patsAreAllLits, isLitPat, isIrrefutableHsPat + pprParendLPat ) where import {-# SOURCE #-} HsExpr (SyntaxExpr, LHsExpr, pprLExpr) @@ -36,7 +37,6 @@ import HsLit import HsTypes import BasicTypes -- others: -import Coercion import PprCore ( {- instance OutputableBndr TyVar -} ) import TysWiredIn import Var @@ -46,6 +46,9 @@ import Outputable import Type import SrcLoc import FastString +-- libraries: +import Data.Data hiding (TyCon) +import Data.Maybe \end{code} @@ -62,9 +65,7 @@ data Pat id -- support hsPatType :: Pat Id -> Type | VarPat id -- Variable - | VarPatOut id (DictBinds id) -- Used only for overloaded Ids; the - -- bindings give its overloaded instances - | LazyPat (LPat id) -- Lazy pattern + | LazyPat (LPat id) -- Lazy pattern | AsPat (Located id) (LPat id) -- As pattern | ParPat (LPat id) -- Parenthesised pattern | BangPat (LPat id) -- Bang pattern @@ -98,10 +99,10 @@ data Pat id | ConPatOut { pat_con :: Located DataCon, pat_tvs :: [TyVar], -- Existentially bound type variables (tyvars only) - pat_dicts :: [id], -- Ditto *coercion variables* and *dictionaries* + pat_dicts :: [EvVar], -- Ditto *coercion variables* and *dictionaries* -- One reason for putting coercion variable here, I think, -- is to ensure their kinds are zonked - pat_binds :: DictBinds id, -- Bindings involving those dictionaries + pat_binds :: TcEvBinds, -- Bindings involving those dictionaries pat_args :: HsConPatDetails id, pat_ty :: Type -- The type of the pattern } @@ -121,7 +122,9 @@ data Pat id | LitPat HsLit -- Used for *non-overloaded* literal patterns: -- Int#, Char#, Int, Char, String, etc. - | NPat (HsOverLit id) -- ALWAYS positive + | NPat -- Used for all overloaded literals, + -- including overloaded strings with -XOverloadedStrings + (HsOverLit id) -- ALWAYS positive (Maybe (SyntaxExpr id)) -- Just (Name of 'negate') for negative -- patterns, Nothing otherwise (SyntaxExpr id) -- Equality checker, of type t->t->Bool @@ -131,12 +134,6 @@ data Pat id (SyntaxExpr id) -- (>=) function, of type t->t->Bool (SyntaxExpr id) -- Name of '-' (see RnEnv.lookupSyntaxName) - ------------ Generics --------------- - | TypePat (LHsType id) -- Type pattern for generic definitions - -- e.g f{| a+b |} = ... - -- These show up only in class declarations, - -- and should be a top-level pattern - ------------ Pattern type signatures --------------- | SigPatIn (LPat id) -- Pattern with a type signature (LHsType id) @@ -145,12 +142,13 @@ data Pat id Type ------------ Pattern coercions (translation only) --------------- - | CoPat HsWrapper -- If co::t1 -> t2, p::t2, + | CoPat HsWrapper -- If co :: t1 ~ t2, p :: t2, -- then (CoPat co p) :: t1 (Pat id) -- Why not LPat? Ans: existing locn will do Type -- Type of whole pattern, t1 -- During desugaring a (CoPat co pat) turns into a cast with 'co' on -- the scrutinee, followed by a match on 'pat' + deriving (Data, Typeable) \end{code} HsConDetails is use for patterns/expressions *and* for data type declarations @@ -160,6 +158,7 @@ data HsConDetails arg rec = PrefixCon [arg] -- C p1 p2 p3 | RecCon rec -- C { x = p1, y = p2 } | InfixCon arg arg -- p1 `C` p2 + deriving (Data, Typeable) type HsConPatDetails id = HsConDetails (LPat id) (HsRecFields id (LPat id)) @@ -177,51 +176,45 @@ data HsRecFields id arg -- A bunch of record fields -- { x = 3, y = True } -- Used for both expressions and patterns = HsRecFields { rec_flds :: [HsRecField id arg], - rec_dotdot :: Maybe Int } - -- Nothing => the normal case - -- Just n => the group uses ".." notation, - -- and the first n elts of rec_flds - -- were the user-written ones - -- (In the latter case, the remaining elts of - -- rec_flds are the non-user-written ones) + rec_dotdot :: Maybe Int } -- Note [DotDot fields] + deriving (Data, Typeable) + +-- Note [DotDot fields] +-- ~~~~~~~~~~~~~~~~~~~~ +-- The rec_dotdot field means this: +-- Nothing => the normal case +-- Just n => the group uses ".." notation, +-- +-- In the latter case: +-- +-- *before* renamer: rec_flds are exactly the n user-written fields +-- +-- *after* renamer: rec_flds includes *all* fields, with +-- the first 'n' being the user-written ones +-- and the remainder being 'filled in' implicitly data HsRecField id arg = HsRecField { hsRecFieldId :: Located id, - hsRecFieldArg :: arg, + hsRecFieldArg :: arg, -- Filled in by renamer hsRecPun :: Bool -- Note [Punning] - } + } deriving (Data, Typeable) -- Note [Punning] -- ~~~~~~~~~~~~~~ -- If you write T { x, y = v+1 }, the HsRecFields will be -- HsRecField x x True ... -- HsRecField y (v+1) False ... --- That is, for "punned" field x is immediately expanded to x=x --- but with a punning flag so we can detect it later +-- That is, for "punned" field x is expanded (in the renamer) +-- to x=x; but with a punning flag so we can detect it later -- (e.g. when pretty printing) +-- +-- If the original field was qualified, we un-qualify it, thus +-- T { A.x } means T { A.x = x } hsRecFields :: HsRecFields id arg -> [id] hsRecFields rbinds = map (unLoc . hsRecFieldId) (rec_flds rbinds) \end{code} -\begin{code} -data HsQuasiQuote id = HsQuasiQuote - id - id - SrcSpan - FastString - -instance OutputableBndr id => Outputable (HsQuasiQuote id) where - ppr = ppr_qq - -ppr_qq :: OutputableBndr id => HsQuasiQuote id -> SDoc -ppr_qq (HsQuasiQuote name quoter _ quote) = - char '$' <> brackets (ppr name) <> - ptext (sLit "[:") <> ppr quoter <> ptext (sLit "|") <> - ppr quote <> ptext (sLit "|]") -\end{code} - - %************************************************************************ %* * %* Printing patterns @@ -241,14 +234,29 @@ pprPatBndr var -- Print with type info if -dppr-debug is on else ppr var +pprParendLPat :: (OutputableBndr name) => LPat name -> SDoc +pprParendLPat (L _ p) = pprParendPat p + +pprParendPat :: (OutputableBndr name) => Pat name -> SDoc +pprParendPat p | patNeedsParens p = parens (pprPat p) + | otherwise = pprPat p + +patNeedsParens :: Pat name -> Bool +patNeedsParens (ConPatIn _ d) = not (null (hsConPatArgs d)) +patNeedsParens (ConPatOut { pat_args = d }) = not (null (hsConPatArgs d)) +patNeedsParens (SigPatIn {}) = True +patNeedsParens (SigPatOut {}) = True +patNeedsParens (ViewPat {}) = True +patNeedsParens (CoPat {}) = True +patNeedsParens _ = False + pprPat :: (OutputableBndr name) => Pat name -> SDoc pprPat (VarPat var) = pprPatBndr var -pprPat (VarPatOut var bs) = parens (pprPatBndr var <+> braces (ppr bs)) pprPat (WildPat _) = char '_' -pprPat (LazyPat pat) = char '~' <> ppr pat -pprPat (BangPat pat) = char '!' <> ppr pat -pprPat (AsPat name pat) = parens (hcat [ppr name, char '@', ppr pat]) -pprPat (ViewPat expr pat _) = parens (hcat [pprLExpr expr, text " -> ", ppr pat]) +pprPat (LazyPat pat) = char '~' <> pprParendLPat pat +pprPat (BangPat pat) = char '!' <> pprParendLPat pat +pprPat (AsPat name pat) = hcat [ppr name, char '@', pprParendLPat pat] +pprPat (ViewPat expr pat _) = hcat [pprLExpr expr, text " -> ", ppr pat] pprPat (ParPat pat) = parens (ppr pat) pprPat (ListPat pats _) = brackets (interpp'SP pats) pprPat (PArrPat pats _) = pabrackets (interpp'SP pats) @@ -261,29 +269,25 @@ pprPat (ConPatOut { pat_con = con, pat_tvs = tvs, pat_dicts = dicts, if debugStyle sty then -- typechecked Pat in an error message, -- and we want to make sure it prints nicely ppr con <+> sep [ hsep (map pprPatBndr tvs) <+> hsep (map pprPatBndr dicts), - pprLHsBinds binds, pprConArgs details] + ppr binds, pprConArgs details] else pprUserCon con details -pprPat (LitPat s) = ppr s +pprPat (LitPat s) = ppr s pprPat (NPat l Nothing _) = ppr l pprPat (NPat l (Just _) _) = char '-' <> ppr l -pprPat (NPlusKPat n k _ _) = hcat [ppr n, char '+', ppr k] -pprPat (QuasiQuotePat (HsQuasiQuote name quoter _ quote)) - = char '$' <> brackets (ppr name) <> - ptext (sLit "[:") <> ppr quoter <> ptext (sLit "|") <> - ppr quote <> ptext (sLit "|]") -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 (NPlusKPat n k _ _) = hcat [ppr n, char '+', ppr k] +pprPat (QuasiQuotePat qq) = ppr qq +pprPat (CoPat co pat _) = pprHsWrapper (ppr pat) co +pprPat (SigPatIn pat ty) = ppr pat <+> dcolon <+> ppr ty +pprPat (SigPatOut pat ty) = ppr pat <+> dcolon <+> ppr ty pprUserCon :: (Outputable con, OutputableBndr id) => con -> HsConPatDetails id -> SDoc pprUserCon c (InfixCon p1 p2) = ppr p1 <+> ppr c <+> ppr p2 pprUserCon c details = ppr c <+> pprConArgs details pprConArgs :: OutputableBndr id => HsConPatDetails id -> SDoc -pprConArgs (PrefixCon pats) = interppSP pats -pprConArgs (InfixCon p1 p2) = interppSP [p1,p2] +pprConArgs (PrefixCon pats) = sep (map pprParendLPat pats) +pprConArgs (InfixCon p1 p2) = sep [pprParendLPat p1, pprParendLPat p2] pprConArgs (RecCon rpats) = ppr rpats instance (OutputableBndr id, Outputable arg) @@ -299,7 +303,7 @@ instance (OutputableBndr id, Outputable arg) => Outputable (HsRecField id arg) where ppr (HsRecField { hsRecFieldId = f, hsRecFieldArg = arg, hsRecPun = pun }) - = ppr f <+> (if pun then empty else equals <+> ppr arg) + = ppr f <+> (ppUnless pun $ equals <+> ppr arg) -- add parallel array brackets around a document -- @@ -319,7 +323,7 @@ mkPrefixConPat :: DataCon -> [OutPat id] -> Type -> OutPat id -- Make a vanilla Prefix constructor pattern mkPrefixConPat dc pats ty = noLoc $ ConPatOut { pat_con = noLoc dc, pat_tvs = [], pat_dicts = [], - pat_binds = emptyLHsBinds, pat_args = PrefixCon pats, + pat_binds = emptyTcEvBinds, pat_args = PrefixCon pats, pat_ty = ty } mkNilPat :: Type -> OutPat id @@ -327,15 +331,6 @@ mkNilPat ty = mkPrefixConPat nilDataCon [] ty mkCharLitPat :: Char -> OutPat id mkCharLitPat c = mkPrefixConPat charDataCon [noLoc $ LitPat (HsCharPrim c)] charTy - -mkCoPat :: HsWrapper -> Pat id -> Type -> Pat id -mkCoPat co pat ty - | isIdHsWrapper co = pat - | otherwise = CoPat co pat ty - -mkCoPatCoI :: CoercionI -> Pat id -> Type -> Pat id -mkCoPatCoI IdCo pat _ = pat -mkCoPatCoI (ACo co) pat ty = mkCoPat (WpCast co) pat ty \end{code} @@ -369,41 +364,34 @@ patterns are treated specially, of course. The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are. \begin{code} -isWildPat :: Pat id -> Bool -isWildPat (WildPat _) = True -isWildPat _ = False - -patsAreAllCons :: [Pat id] -> Bool -patsAreAllCons pat_list = all isConPat pat_list - -isConPat :: Pat id -> Bool -isConPat (AsPat _ pat) = isConPat (unLoc pat) -isConPat (ConPatIn {}) = True -isConPat (ConPatOut {}) = True -isConPat (ListPat {}) = True -isConPat (PArrPat {}) = True -isConPat (TuplePat {}) = True -isConPat _ = False - -isSigPat :: Pat id -> Bool -isSigPat (SigPatIn _ _) = True -isSigPat (SigPatOut _ _) = True -isSigPat _ = False - -patsAreAllLits :: [Pat id] -> Bool -patsAreAllLits pat_list = all isLitPat pat_list - -isLitPat :: Pat id -> Bool -isLitPat (AsPat _ pat) = isLitPat (unLoc pat) -isLitPat (LitPat _) = True -isLitPat (NPat _ _ _) = True -isLitPat (NPlusKPat _ _ _ _) = True -isLitPat _ = False +isBangLPat :: LPat id -> Bool +isBangLPat (L _ (BangPat {})) = True +isBangLPat (L _ (ParPat p)) = isBangLPat p +isBangLPat _ = False isBangHsBind :: HsBind id -> Bool --- In this module because HsPat is above HsBinds in the import graph -isBangHsBind (PatBind { pat_lhs = L _ (BangPat _) }) = True -isBangHsBind _ = False +-- A pattern binding with an outermost bang +-- Defined in this module because HsPat is above HsBinds in the import graph +isBangHsBind (PatBind { pat_lhs = p }) = isBangLPat p +isBangHsBind _ = False + +isLiftedPatBind :: HsBind id -> Bool +-- A pattern binding with a compound pattern, not just a variable +-- (I# x) yes +-- (# a, b #) no, even if a::Int# +-- x no, even if x::Int# +-- We want to warn about a missing bang-pattern on the yes's +isLiftedPatBind (PatBind { pat_lhs = p }) = isLiftedLPat p +isLiftedPatBind _ = False + +isLiftedLPat :: LPat id -> Bool +isLiftedLPat (L _ (ParPat p)) = isLiftedLPat p +isLiftedLPat (L _ (BangPat p)) = isLiftedLPat p +isLiftedLPat (L _ (AsPat _ p)) = isLiftedLPat p +isLiftedLPat (L _ (TuplePat _ Unboxed _)) = False +isLiftedLPat (L _ (VarPat {})) = False +isLiftedLPat (L _ (WildPat {})) = False +isLiftedLPat _ = True isIrrefutableHsPat :: OutputableBndr id => LPat id -> Bool -- (isIrrefutableHsPat p) is true if matching against p cannot fail, @@ -421,7 +409,6 @@ isIrrefutableHsPat pat go1 (WildPat {}) = True go1 (VarPat {}) = True - go1 (VarPatOut {}) = True go1 (LazyPat {}) = True go1 (BangPat pat) = go pat go1 (CoPat _ pat _) = go1 pat @@ -436,7 +423,9 @@ isIrrefutableHsPat pat go1 (ConPatIn {}) = False -- Conservative go1 (ConPatOut{ pat_con = L _ con, pat_args = details }) - = isProductTyCon (dataConTyCon con) + = isJust (tyConSingleDataCon_maybe (dataConTyCon con)) + -- NB: tyConSingleDataCon_maybe, *not* isProductTyCon, because + -- the latter is false of existentials. See Trac #4439 && all go (hsConPatArgs details) go1 (LitPat {}) = False @@ -445,14 +434,12 @@ isIrrefutableHsPat pat go1 (QuasiQuotePat {}) = urk pat -- Gotten rid of by renamer, before -- isIrrefutablePat is called - go1 (TypePat {}) = urk pat urk pat = pprPanic "isIrrefutableHsPat:" (ppr pat) hsPatNeedsParens :: Pat a -> Bool hsPatNeedsParens (WildPat {}) = False hsPatNeedsParens (VarPat {}) = False -hsPatNeedsParens (VarPatOut {}) = True hsPatNeedsParens (LazyPat {}) = False hsPatNeedsParens (BangPat {}) = False hsPatNeedsParens (CoPat {}) = True @@ -470,7 +457,6 @@ hsPatNeedsParens (LitPat {}) = False hsPatNeedsParens (NPat {}) = False hsPatNeedsParens (NPlusKPat {}) = True hsPatNeedsParens (QuasiQuotePat {}) = True -hsPatNeedsParens (TypePat {}) = False conPatNeedsParens :: HsConDetails a b -> Bool conPatNeedsParens (PrefixCon args) = not (null args)