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authorsimonmar <unknown>2002-05-06 12:32:32 +0000
committersimonmar <unknown>2002-05-06 12:32:32 +0000
commit687e68fa7bd127d6f01d5847182863ed302be99f (patch)
tree071e816864bc9aaca98948eae08cd6df34cca8b2 /src/HsParser.ly
parentcd0e300d6751a515bba168d84174ebd64ca66709 (diff)
[haddock @ 2002-05-06 12:32:32 by simonmar]
Allow empty data declarations (another GHC extension).
Diffstat (limited to 'src/HsParser.ly')
-rw-r--r--src/HsParser.ly12
1 files changed, 8 insertions, 4 deletions
diff --git a/src/HsParser.ly b/src/HsParser.ly
index fa0059b8..5a254ec1 100644
--- a/src/HsParser.ly
+++ b/src/HsParser.ly
@@ -1,5 +1,5 @@
-----------------------------------------------------------------------------
-$Id: HsParser.ly,v 1.6 2002/04/29 15:28:54 simonmar Exp $
+$Id: HsParser.ly,v 1.7 2002/05/06 12:32:32 simonmar Exp $
(c) Simon Marlow, Sven Panne 1997-2000
@@ -294,9 +294,9 @@ shift/reduce-conflict, so we don't handle this case here, but in bodyaux.
> topdecl :: { HsDecl }
> : 'type' simpletype srcloc '=' type
> { HsTypeDecl $3 (fst $2) (snd $2) $5 }
-> | 'data' ctype srcloc '=' constrs deriving
+> | 'data' ctype srcloc constrs deriving
> {% checkDataHeader $2 `thenP` \(cs,c,t) ->
-> returnP (HsDataDecl $3 cs c t (reverse $5) $6) }
+> returnP (HsDataDecl $3 cs c t (reverse $4) $5) }
> | 'newtype' ctype srcloc '=' constr deriving
> {% checkDataHeader $2 `thenP` \(cs,c,t) ->
> returnP (HsNewTypeDecl $3 cs c t $5 $6) }
@@ -439,7 +439,11 @@ C a, or (C1 a, C2 b, ... Cn z) and convert it into a context. Blaach!
Datatype declarations
> constrs :: { [HsConDecl] }
-> : constrs '|' constr { $3 : $1 }
+> : {- empty; a GHC extension -} { [] }
+> | '=' constrs1 { $2 }
+
+> constrs1 :: { [HsConDecl] }
+> : constrs1 '|' constr { $3 : $1 }
> | constr { [$1] }
> constr :: { HsConDecl }