package parser.grammars

import com.github.h0tk3y.betterParse.combinators.use
import com.github.h0tk3y.betterParse.grammar.Grammar
import com.github.h0tk3y.betterParse.lexer.Token
import com.github.h0tk3y.betterParse.lexer.literalToken
import com.github.h0tk3y.betterParse.lexer.regexToken
import com.github.h0tk3y.betterParse.lexer.token

abstract class Tokens : Grammar<Any>() {
    // Prolog tokens
    protected val nameToken: Token by regexToken("[a-z][a-zA-Z0-9_]*")
    protected val variableToken: Token by regexToken("[A-Z][a-zA-Z0-9_]*")

    // Arithmetic tokens
    protected val floatToken: Token by regexToken("-?[1-9][0-9]*\\.[0-9]+")
    protected val integerToken: Token by regexToken("-?([1-9][0-9]*|0)")

    // Special tokens
    protected val neck by literalToken(":-")
    protected val comma: Token by literalToken(",")
    protected val leftParenthesis: Token by literalToken("(")
    protected val rightParenthesis: Token by literalToken(")")
    protected val dot by literalToken(".")

    // Ignored tokens
    protected val whitespace: Token by regexToken("\\s+", ignore = true)
    protected val singleLineComment: Token by regexToken("%[^\\n]*", ignore = true)
    protected val multiLineComment: Token by regexToken("/\\*.*?\\*/", ignore = true)

    protected val dummy by token { _, _ -> -1 } use { throw IllegalStateException("This parser should not be used") }
}