isRdrDataCon, isUnqual, getRdrName, isQual,
setRdrNameSpace )
import BasicTypes ( maxPrecedence, Activation, InlineSpec(..), alwaysInlineSpec, neverInlineSpec )
-import Lexer ( P, failSpanMsgP )
+import Lexer ( P, failSpanMsgP, extension, bangPatEnabled )
import TysWiredIn ( unitTyCon )
import ForeignCall ( CCallConv, Safety, CCallTarget(..), CExportSpec(..),
DNCallSpec(..), DNKind(..), CLabelString )
checkPat :: SrcSpan -> LHsExpr RdrName -> [LPat RdrName] -> P (LPat RdrName)
checkPat loc (L l (HsVar c)) args
| isRdrDataCon c = return (L loc (ConPatIn (L l c) (PrefixCon args)))
-checkPat loc (L _ (HsApp f x)) args = do
- x <- checkLPat x
- checkPat loc f (x:args)
-checkPat loc (L _ e) [] = do
- p <- checkAPat loc e
- return (L loc p)
+checkPat loc e args -- OK to let this happen even if bang-patterns
+ -- are not enabled, because there is no valid
+ -- non-bang-pattern parse of (C ! e)
+ | Just (e', args') <- splitBang e
+ = do { args'' <- checkPatterns args'
+ ; checkPat loc e' (args'' ++ args) }
+checkPat loc (L _ (HsApp f x)) args
+ = do { x <- checkLPat x; checkPat loc f (x:args) }
+checkPat loc (L _ e) []
+ = do { p <- checkAPat loc e; return (L loc p) }
checkPat loc pat _some_args
= patFail loc
NegApp (L _ (HsOverLit pos_lit)) _
-> return (mkNPat pos_lit (Just noSyntaxExpr))
- ELazyPat e -> checkLPat e >>= (return . LazyPat)
- EAsPat n e -> checkLPat e >>= (return . AsPat n)
+ SectionR (L _ (HsVar bang)) e
+ | bang == bang_RDR -> checkLPat e >>= (return . BangPat)
+ ELazyPat e -> checkLPat e >>= (return . LazyPat)
+ EAsPat n e -> checkLPat e >>= (return . AsPat n)
ExprWithTySig e t -> checkLPat e >>= \e ->
-- Pattern signatures are parsed as sigtypes,
-- but they aren't explicit forall points. Hence
(L _ (HsOverLit lit@(HsIntegral _ _)))
| plus == plus_RDR
-> return (mkNPlusKPat (L nloc n) lit)
- where
- plus_RDR = mkUnqual varName FSLIT("+") -- Hack
OpApp l op fix r -> checkLPat l >>= \l ->
checkLPat r >>= \r ->
HsType ty -> return (TypePat ty)
_ -> patFail loc
+plus_RDR, bang_RDR :: RdrName
+plus_RDR = mkUnqual varName FSLIT("+") -- Hack
+bang_RDR = mkUnqual varName FSLIT("!") -- Hack
+
checkPatField :: (Located RdrName, LHsExpr RdrName) -> P (Located RdrName, LPat RdrName)
checkPatField (n,e) = do
p <- checkLPat e
---------------------------------------------------------------------------
-- Check Equation Syntax
-checkValDef
- :: LHsExpr RdrName
- -> Maybe (LHsType RdrName)
- -> Located (GRHSs RdrName)
- -> P (HsBind RdrName)
-
-checkValDef lhs opt_sig (L rhs_span grhss)
- | Just (f,inf,es) <- isFunLhs lhs
- = if isQual (unLoc f)
- then parseError (getLoc f) ("Qualified name in function definition: " ++
- showRdrName (unLoc f))
- else do ps <- checkPatterns es
- let match_span = combineSrcSpans (getLoc lhs) rhs_span
- matches = mkMatchGroup [L match_span (Match ps opt_sig grhss)]
- return (FunBind { fun_id = f, fun_infix = inf, fun_matches = matches,
- fun_co_fn = idCoercion, bind_fvs = placeHolderNames })
+checkValDef :: LHsExpr RdrName
+ -> Maybe (LHsType RdrName)
+ -> Located (GRHSs RdrName)
+ -> P (HsBind RdrName)
+
+checkValDef lhs opt_sig grhss
+ = do { mb_fun <- isFunLhs lhs
+ ; case mb_fun of
+ Just (fun, is_infix, pats) -> checkFunBind (getLoc lhs)
+ fun is_infix pats opt_sig grhss
+ Nothing -> checkPatBind lhs grhss }
+
+checkFunBind lhs_loc fun is_infix pats opt_sig (L rhs_span grhss)
+ | isQual (unLoc fun)
+ = parseError (getLoc fun) ("Qualified name in function definition: " ++
+ showRdrName (unLoc fun))
+ | otherwise
+ = do ps <- checkPatterns pats
+ let match_span = combineSrcSpans lhs_loc rhs_span
+ matches = mkMatchGroup [L match_span (Match ps opt_sig grhss)]
+ return (FunBind { fun_id = fun, fun_infix = is_infix, fun_matches = matches,
+ fun_co_fn = idCoercion, bind_fvs = placeHolderNames })
-- The span of the match covers the entire equation.
-- That isn't quite right, but it'll do for now.
- | otherwise = do
- lhs <- checkPattern lhs
- return (PatBind lhs grhss placeHolderType placeHolderNames)
+
+checkPatBind lhs (L _ grhss)
+ = do { lhs <- checkPattern lhs
+ ; return (PatBind lhs grhss placeHolderType placeHolderNames) }
checkValSig
:: LHsExpr RdrName
-- A variable binding is parsed as a FunBind.
-isFunLhs :: LHsExpr RdrName
- -> Maybe (Located RdrName, Bool, [LHsExpr RdrName])
+
+ -- The parser left-associates, so there should
+ -- not be any OpApps inside the e's
+splitBang :: LHsExpr RdrName -> Maybe (LHsExpr RdrName, [LHsExpr RdrName])
+-- Splits (f ! g a b) into (f, [(! g), a, g])
+splitBang (L loc (OpApp l_arg bang@(L loc' (HsVar op)) _ r_arg))
+ | op == bang_RDR = Just (l_arg, L loc (SectionR bang arg1) : argns)
+ where
+ (arg1,argns) = split_bang r_arg []
+ split_bang (L _ (HsApp f e)) es = split_bang f (e:es)
+ split_bang e es = (e,es)
+splitBang other = Nothing
+
+isFunLhs :: LHsExpr RdrName
+ -> P (Maybe (Located RdrName, Bool, [LHsExpr RdrName]))
+-- Just (fun, is_infix, arg_pats) if e is a function LHS
isFunLhs e = go e []
where
go (L loc (HsVar f)) es
- | not (isRdrDataCon f) = Just (L loc f, False, es)
+ | not (isRdrDataCon f) = return (Just (L loc f, False, es))
go (L _ (HsApp f e)) es = go f (e:es)
go (L _ (HsPar e)) es@(_:_) = go e es
- go (L loc (OpApp l (L loc' (HsVar op)) fix r)) es
- | not (isRdrDataCon op) = Just (L loc' op, True, (l:r:es))
- | otherwise =
- case go l es of
- Just (op', True, j : k : es') ->
- Just (op', True,
- j : L loc (OpApp k (L loc' (HsVar op)) fix r) : es')
- _ -> Nothing
- go _ _ = Nothing
+ go e@(L loc (OpApp l (L loc' (HsVar op)) fix r)) es
+ | Just (e',es') <- splitBang e
+ = do { bang_on <- extension bangPatEnabled
+ ; if bang_on then go e' (es' ++ es)
+ else return (Just (L loc' op, True, (l:r:es))) }
+ -- No bangs; behave just like the next case
+ | not (isRdrDataCon op)
+ = return (Just (L loc' op, True, (l:r:es)))
+ | otherwise
+ = do { mb_l <- go l es
+ ; case mb_l of
+ Just (op', True, j : k : es')
+ -> return (Just (op', True, j : op_app : es'))
+ where
+ op_app = L loc (OpApp k (L loc' (HsVar op)) fix r)
+ _ -> return Nothing }
+ go _ _ = return Nothing
---------------------------------------------------------------------------
-- Miscellaneous utilities
projects / ghc-hetmet.git / blobdiff