Complete doWork method

DoWorkCompleteSimple.kt

fun doWork(): Result<Unit> {
  return input() into
    ::parse elseIf
    {
      return Failure("Cannot parse email")
    } into
    ::validate elseIf
    {
      InvalidEmailAddress { message -> return Failure(message) }
      EmptySubject { message -> return Failure(message) }
      EmptyBody { message -> return Failure(message) }
    } into
    ::send elseIf
    {
      IOFailure { error -> return Failure(error.message ?: "") }
      Timeout { error -> return Failure(error.message ?: "") }
      UnAuthorized { error -> return Failure(error.message ?: "") }
    } into
    { Success(Unit) }
}

fun parse(input: String): Result<Email> = ...

fun validate(input: Success<Email>): ValidationResult = ...

fun send(input: ValidateSuccess): SendResult = ...