parseResult.rs

enum ParseResult<T> {
  Success(T),
  Failure,
  Error
}

impl <T> ParseResult<T> {
  fn map<U, F: Fn(T) -> U>(&self, f: F) -> ParseResult<U> {
    match *self {
      ParseResult::Success(t) => ParseResult::Success(f(t)),
      ParseResult::Failure => ParseResult::Failure,
      ParseResult::Error => ParseResult::Error
    }
  }
}