Re: [Haskell-cafe] How to use notFollowedBy function in Parsec

Am Dienstag, 22. November 2005 15:58 schrieben Sie:

Hello, I run as follows:

simple::Parser String simple = do manyTill anyToken (semi <|> eof)

run:: Show a => Parser a -> String -> IO()

run p input

= case (parse p "" input) of

Left err -> do {putStr "parse error at " ;print err}

Right x -> print x

ParsecLanguage> :load Test.hs Type checking ERROR "Test.hs":21 - Type error in application *** Expression : semi <|> eof *** Term : semi *** Type : GenParser Char () String *** Does not match : GenParser a b ()

Do you know what happens? Thank you.

Aye, <|> takes two parsers of the same type, so we'd need manyTill anyToken ((semi >> return () ) <|> eof) or manyTill anyToken (semi <|> (eof >> return "dummy String")) Cheers, Daniel