package cobalt.lang;

import java.util.List;

abstract class Expr {
    interface Visitor<R> {
        R visitBinaryExpr(Binary expr);
        R visitGroupingExpr(Grouping expr);
        R visitLiteralExpr(Literal expr);
        R visitUnaryExpr(Unary expr);
        R visitVarExpr(Variable expr);
        R visitAssignExpr(Assign expr);
    }


    static class Binary extends Expr {
        Binary(Expr left, Token operator, Expr right) {
            this.left = left;
            this.operator = operator;
            this.right = right;
        }

        <R> R accept(Visitor<R> visitor) {
            return visitor.visitBinaryExpr(this);
        }

        final Expr left;
        final Token operator;
        final Expr right;
    }


    static class Grouping extends Expr {
        Grouping(Expr expression) {
            this.expression = expression;
        }

        <R> R accept(Visitor<R> visitor) {
            return visitor.visitGroupingExpr(this);
        }

        final Expr expression;
    }


    static class Literal extends Expr {
        Literal(Object value) {
            this.value = value;
        }

        <R> R accept(Visitor<R> visitor) {
            return visitor.visitLiteralExpr(this);
        }

        final Object value;
    }

    
    static class Unary extends Expr {
        Unary(Token operator, Expr right) {
            this.operator = operator;
            this.right = right;
        }

        <R> R accept(Visitor<R> visitor) {
            return visitor.visitUnaryExpr(this);
        }

        final Token operator;
        final Expr right;
    }

    static class Variable extends Expr {
        Variable(Token name, boolean nullable) {
            this.name = name;
            this.nullable = nullable;
        }

        <R> R accept(Visitor<R> visitor) {
            return visitor.visitVarExpr(this);
        }

        final Token name;
        final boolean nullable;
    }

    static class Assign extends Expr {
        Assign(Token name, Expr value) {
            this.name = name;
            this.value = value;
        }

        <R> R accept(Visitor<R> visitor) {
            return visitor.visitAssignExpr(this);
        }

        final Token name;
        final Expr value;
    }

    abstract <R> R accept(Visitor<R> visitor);
}