package fr.celticinfo.lox

interface ExprVisitor<R> {
    fun visitBinary(binary: Binary): R
    fun visitGrouping(grouping: Grouping): R
    fun visitLiteral(literal: Literal): R
    fun visitUnary(unary: Unary): R

}

/**
 * The Expr class represents the different types of expressions that can be parsed by the Parser.
 */
sealed class Expr {
    abstract fun <R> accept(visitor: ExprVisitor<R>): R
}

data class Binary(
    val left: Expr, val operator: Token, val right: Expr
) : Expr() {
    override fun <R> accept(visitor: ExprVisitor<R>): R {
        return visitor.visitBinary(this)
    }
}

data class Grouping(
    val expression: Expr
) : Expr() {
    override fun <R> accept(visitor: ExprVisitor<R>): R {
        return visitor.visitGrouping(this)
    }
}

data class Literal(
    val value: Any
) : Expr() {
    override fun <R> accept(visitor: ExprVisitor<R>): R {
        return visitor.visitLiteral(this)
    }
}

data class Unary(
    val operator: Token, val right: Expr
) : Expr() {
    override fun <R> accept(visitor: ExprVisitor<R>): R {
        return visitor.visitUnary(this)
    }
}