4 patches for repository http://code.haskell.org/parsec3:

Sun Feb 20 18:24:22 EET 2011  Roman Cheplyaka <roma@ro-che.info>
  * Choose the longest match when merging error messages

Sun Feb 20 18:24:49 EET 2011  Roman Cheplyaka <roma@ro-che.info>
  * try: do not reset the error position

Sun Feb 20 18:29:20 EET 2011  Roman Cheplyaka <roma@ro-che.info>
  * lookAhead: do not consume input on success; update documentation

Sun Feb 20 19:30:26 EET 2011  Roman Cheplyaka <roma@ro-che.info>
  * Improve <?>

New patches:

[Choose the longest match when merging error messages
Roman Cheplyaka <roma@ro-che.info>**20110220162422
 Ignore-this: 54e2733159a1574abb229e09ff6935c1
] hunk ./Text/Parsec/Error.hs 137
     = ParseError pos (msg : filter (msg /=) msgs)
 
 mergeError :: ParseError -> ParseError -> ParseError
-mergeError (ParseError pos msgs1) (ParseError _ msgs2)
-    = ParseError pos (msgs1 ++ msgs2)
+mergeError (ParseError pos1 msgs1) (ParseError pos2 msgs2)
+    = case pos1 `compare` pos2 of
+        -- select the longest match
+        EQ -> ParseError pos1 (msgs1 ++ msgs2)
+        GT -> ParseError pos1 msgs1
+        LT -> ParseError pos2 msgs2
 
 instance Show ParseError where
     show err
[try: do not reset the error position
Roman Cheplyaka <roma@ro-che.info>**20110220162449
 Ignore-this: 8508bc41fc6dcd9b7c06aac762f12c71
] hunk ./Text/Parsec/Prim.hs 435
 
 try :: ParsecT s u m a -> ParsecT s u m a
 try p =
-    ParsecT $ \s@(State _ pos _) cok _ eok eerr ->
-    let pcerr parseError = eerr $ setErrorPos pos parseError 
-    in unParser p s cok pcerr eok eerr
+    ParsecT $ \s cok _ eok eerr ->
+    unParser p s cok eerr eok eerr
 
 -- | The parser @tokenPrim showTok posFromTok testTok@ accepts a token @t@
 -- with result @x@ when the function @testTok t@ returns @'Just' x@. The
[lookAhead: do not consume input on success; update documentation
Roman Cheplyaka <roma@ro-che.info>**20110220162920
 Ignore-this: e884771490209b93e9fec044543a18ef
] {
hunk ./Text/Parsec/Combinator.hs 279
                             <|>
                               do{ x <- p; xs <- scan; return (x:xs) }
 
--- | @lookAhead p@ parses @p@ without consuming any input.
-
-lookAhead :: (Stream s m t) => ParsecT s u m a -> ParsecT s u m a
-lookAhead p         = do{ state <- getParserState
-                        ; x <- p
-                        ; setParserState state
-                        ; return x
-                        }
-
hunk ./Text/Parsec/Prim.hs 40
     , (<|>)
     , label
     , labels
+    , lookAhead
     , Stream(..)
     , tokens
     , try
hunk ./Text/Parsec/Prim.hs 439
     ParsecT $ \s cok _ eok eerr ->
     unParser p s cok eerr eok eerr
 
+-- | @lookAhead p@ parses @p@ without consuming any input.
+--
+-- If @p@ fails and consumes some input, so does @lookAhead@. Combine with 'try'
+-- if this is undesirable.
+
+lookAhead :: (Stream s m t) => ParsecT s u m a -> ParsecT s u m a
+lookAhead p         = do{ state <- getParserState
+                        ; x <- p'
+                        ; setParserState state
+                        ; return x
+                        }
+    where
+    p' = ParsecT $ \s cok cerr eok eerr ->
+         unParser p s eok cerr eok eerr
+
 -- | The parser @tokenPrim showTok posFromTok testTok@ accepts a token @t@
 -- with result @x@ when the function @testTok t@ returns @'Just' x@. The
 -- source position of the @t@ should be returned by @posFromTok t@ and
}
[Improve <?>
Roman Cheplyaka <roma@ro-che.info>**20110220173026
 Ignore-this: b147dad8729f0a8f22b7149559d6b243
] hunk ./Text/Parsec/Prim.hs 315
 -- letter', which is less friendly.
 
 (<?>) :: (ParsecT s u m a) -> String -> (ParsecT s u m a)
-p <?> msg = label p msg
+p <?> msg = ParsecT $ \s cok cerr eok eerr ->
+    let parseError = newErrorMessage (Expect msg) (statePos s)
+        eok' x s' _ = eok x s' parseError
+        eerr' _ = eerr parseError
+    in unParser p s cok cerr eok' eerr'
 
 -- | This combinator implements choice. The parser @p \<|> q@ first
 -- applies @p@. If it succeeds, the value of @p@ is returned. If @p@

Context:

[TAG 3.1.1
Antoine Latter <aslatter@gmail.com>**20110129160030
 Ignore-this: 42ddc9e7316d68945c2c1260c2acd403
] 
Patch bundle hash:
52077d12002c2820c33c39701e01ead8de62c61e