ANTLR.kt

import org.antlr.v4.runtime.CharStreams
import org.antlr.v4.runtime.CommonTokenStream

// Implement visitor

fun main(args: Array<String>) {
    val stream = CharStreams.fromStream("1 + 1".byteInputStream())
    val lexer = GrammarLexer(stream)
    val tokens = CommonTokenStream(lexer)
    val parser = GrammarParser(tokens)
    val cst = parser.start()

    val visitor = // ...
    println(cst.accept(visitor))
}