[Haskell-beginners] Clearing Parsec error messages

Hi all, In a Parsec project I used the *fail* parser, wanting to show a message to the user and halt the parsing process. That's okay, but the error message showed included some other "unexpected" and "expecting" messages that did not seem related to the fail. My guess is that Parsec keeps these messages in an internal state, to use them whenever needed. My question is, how can I clear those error messages and only show the string I pass to fail? -- []'s Giuliano Vilela.