X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FhsSyn%2FHsPat.lhs;h=7fb5f725334fdb03e2b45c64a93a5b86e9e6edcf;hp=5572f62a74a22ea386be4283e346eba3b917a9b7;hb=1b381af863d64aaa0a4dd9c816170c58e6131a9e;hpb=ad94d40948668032189ad22a0ad741ac1f645f50 diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs index 5572f62..7fb5f72 100644 --- a/compiler/hsSyn/HsPat.lhs +++ b/compiler/hsSyn/HsPat.lhs @@ -5,12 +5,13 @@ \section[PatSyntax]{Abstract Haskell syntax---patterns} \begin{code} -{-# OPTIONS -w #-} +{-# OPTIONS -fno-warn-incomplete-patterns #-} -- The above warning supression flag is a temporary kludge. -- While working on this module you are encouraged to remove it and fix -- any warnings in the module. See --- http://hackage.haskell.org/trac/ghc/wiki/CodingStyle#Warnings +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings -- for details +{-# LANGUAGE DeriveDataTypeable #-} module HsPat ( Pat(..), InPat, OutPat, LPat, @@ -19,17 +20,16 @@ module HsPat ( HsConPatDetails, hsConPatArgs, HsRecFields(..), HsRecField(..), hsRecFields, - mkPrefixConPat, mkCharLitPat, mkNilPat, mkCoPat, + mkPrefixConPat, mkCharLitPat, mkNilPat, - isBangHsBind, - patsAreAllCons, isConPat, isSigPat, isWildPat, - patsAreAllLits, isLitPat, isIrrefutableHsPat - ) where - -#include "HsVersions.h" + isBangHsBind, isLiftedPatBind, + isBangLPat, hsPatNeedsParens, + isIrrefutableHsPat, + pprParendLPat + ) where -import {-# SOURCE #-} HsExpr ( SyntaxExpr ) +import {-# SOURCE #-} HsExpr (SyntaxExpr, LHsExpr, pprLExpr) -- friends: import HsBinds @@ -45,6 +45,10 @@ import TyCon import Outputable import Type import SrcLoc +import FastString +-- libraries: +import Data.Data hiding (TyCon) +import Data.Maybe \end{code} @@ -61,12 +65,10 @@ 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 patterng + | BangPat (LPat id) -- Bang pattern ------------ Lists, tuples, arrays --------------- | ListPat [LPat id] -- Syntactic list @@ -96,35 +98,42 @@ data Pat id | 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_tvs :: [TyVar], -- Existentially bound type variables (tyvars only) + 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 :: TcEvBinds, -- Bindings involving those dictionaries pat_args :: HsConPatDetails id, pat_ty :: Type -- The type of the pattern } + ------------ View patterns --------------- + | ViewPat (LHsExpr id) + (LPat id) + PostTcType -- The overall type of the pattern + -- (= the argument type of the view function) + -- for hsPatType. + + ------------ Quasiquoted patterns --------------- + -- See Note [Quasi-quote overview] in TcSplice + | QuasiQuotePat (HsQuasiQuote id) + ------------ Literal and n+k patterns --------------- | 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 - PostTcType -- Type of the pattern | NPlusKPat (Located id) -- n+k pattern (HsOverLit id) -- It'll always be an HsIntegral (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) @@ -133,12 +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 @@ -148,6 +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)) @@ -163,36 +174,47 @@ However HsRecFields is used only for patterns and expressions \begin{code} data HsRecFields id arg -- A bunch of record fields -- { x = 3, y = True } - -- Used for both expressiona and patterns + -- 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} - %************************************************************************ %* * %* Printing patterns @@ -212,14 +234,30 @@ 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 (ParPat pat) = parens (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) pprPat (TuplePat pats bx _) = tupleParens bx (interpp'SP pats) @@ -231,23 +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 (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 (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 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 (PrefixCon pats) = interppSP pats -pprConArgs (InfixCon p1 p2) = interppSP [p1,p2] +pprConArgs :: OutputableBndr id => HsConPatDetails id -> SDoc +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) @@ -257,18 +297,18 @@ instance (OutputableBndr id, Outputable arg) ppr (HsRecFields { rec_flds = flds, rec_dotdot = Just n }) = braces (fsep (punctuate comma (map ppr (take n flds) ++ [dotdot]))) where - dotdot = ptext SLIT("..") <+> ifPprDebug (ppr (drop n flds)) + dotdot = ptext (sLit "..") <+> ifPprDebug (ppr (drop n flds)) 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 -- pabrackets :: SDoc -> SDoc -pabrackets p = ptext SLIT("[:") <> p <> ptext SLIT(":]") +pabrackets p = ptext (sLit "[:") <> p <> ptext (sLit ":]") \end{code} @@ -283,7 +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 @@ -291,11 +331,6 @@ 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} @@ -329,70 +364,103 @@ patterns are treated specially, of course. The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are. \begin{code} -isWildPat (WildPat _) = True -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 other = False - -isSigPat (SigPatIn _ _) = True -isSigPat (SigPatOut _ _) = True -isSigPat other = False - -patsAreAllLits :: [Pat id] -> Bool -patsAreAllLits pat_list = all isLitPat pat_list - -isLitPat (AsPat _ pat) = isLitPat (unLoc pat) -isLitPat (LitPat _) = True -isLitPat (NPat _ _ _ _) = True -isLitPat (NPlusKPat _ _ _ _) = True -isLitPat other = 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 p) }) = True -isBangHsBind bind = False - -isIrrefutableHsPat :: LPat id -> Bool --- This function returns False if it's in doubt; specifically +-- 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, +-- in the sense of falling through to the next pattern. +-- (NB: this is not quite the same as the (silly) defn +-- in 3.17.2 of the Haskell 98 report.) +-- +-- isIrrefutableHsPat returns False if it's in doubt; specifically -- on a ConPatIn it doesn't know the size of the constructor family -- But if it returns True, the pattern is definitely irrefutable isIrrefutableHsPat pat = go pat where - go (L _ pat) = go1 pat + go (L _ pat) = go1 pat - go1 (WildPat _) = True - go1 (VarPat _) = True - go1 (VarPatOut _ _) = True - go1 (LazyPat pat) = True + go1 (WildPat {}) = True + go1 (VarPat {}) = True + go1 (LazyPat {}) = True go1 (BangPat pat) = go pat go1 (CoPat _ pat _) = go1 pat go1 (ParPat pat) = go pat go1 (AsPat _ pat) = go pat + go1 (ViewPat _ pat _) = go pat go1 (SigPatIn pat _) = go pat go1 (SigPatOut pat _) = go pat go1 (TuplePat pats _ _) = all go pats - go1 (ListPat pats _) = False - go1 (PArrPat pats _) = False -- ? + go1 (ListPat {}) = False + go1 (PArrPat {}) = False -- ? - go1 (ConPatIn _ _) = False -- Conservative + 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 - go1 (NPat _ _ _ _) = False - go1 (NPlusKPat _ _ _ _) = False - - go1 (TypePat _) = panic "isIrrefutableHsPat: type pattern" + go1 (LitPat {}) = False + go1 (NPat {}) = False + go1 (NPlusKPat {}) = False + + go1 (QuasiQuotePat {}) = urk pat -- Gotten rid of by renamer, before + -- isIrrefutablePat is called + + urk pat = pprPanic "isIrrefutableHsPat:" (ppr pat) + +hsPatNeedsParens :: Pat a -> Bool +hsPatNeedsParens (WildPat {}) = False +hsPatNeedsParens (VarPat {}) = False +hsPatNeedsParens (LazyPat {}) = False +hsPatNeedsParens (BangPat {}) = False +hsPatNeedsParens (CoPat {}) = True +hsPatNeedsParens (ParPat {}) = False +hsPatNeedsParens (AsPat {}) = False +hsPatNeedsParens (ViewPat {}) = True +hsPatNeedsParens (SigPatIn {}) = True +hsPatNeedsParens (SigPatOut {}) = True +hsPatNeedsParens (TuplePat {}) = False +hsPatNeedsParens (ListPat {}) = False +hsPatNeedsParens (PArrPat {}) = False +hsPatNeedsParens (ConPatIn _ ds) = conPatNeedsParens ds +hsPatNeedsParens (ConPatOut {}) = True +hsPatNeedsParens (LitPat {}) = False +hsPatNeedsParens (NPat {}) = False +hsPatNeedsParens (NPlusKPat {}) = True +hsPatNeedsParens (QuasiQuotePat {}) = True + +conPatNeedsParens :: HsConDetails a b -> Bool +conPatNeedsParens (PrefixCon args) = not (null args) +conPatNeedsParens (InfixCon {}) = False +conPatNeedsParens (RecCon {}) = False \end{code}