wall of code

*XmlParser> parse (predicate (== "banana") matchIdentifier) "hey"
case parse (MkParser (\s =>
                        case s of
                          "" => parseFailure ""
                          s => if isAlpha (strHead s)
                                 then case span isAlphaNumOrDash s of
                                        (parsed, rest) => parseSuccess rest parsed
                                 else parseFailure s))
           "hey" of
  Right (s, a) => if f a then r else Left s
  Left fail => r : Either String (String, String)
*XmlParser> :let bleh = parse (predicate (== "banana") matchIdentifier) "hey"
*XmlParser> bleh
Left "" : Either String (String, String)