RecognizerBase.kt

class Recognizer(private val scanner: Scanner) {
    private var last: Token? = null

    fun recognizeStart(): Boolean {
        last = scanner.getToken()
        val result = // recognize...(); 
        return when(last?.symbol) {
            Symbol.EOF -> result
            else -> false
        }
    }

    private fun recognizeTerminal(symbol: Symbol): Boolean =
        if (last?.symbol == symbol) {
            last = scanner.getToken()
            true
        } else {
            false
        }
}

fun main() {
    val result = Recognizer(Scanner(Automaton, "input".byteInputStream())).recognizeStart()
}