package visitor.typecase;
import enumeration.Op;

public interface Expr { }

class Const implements Expr {
	public final int c;
	public Const(int c) {
		this.c = c;
	}
}

class BinOp implements Expr {
	public final Expr l;
	public final Expr r;
	public final Op op;

	public BinOp(Expr l, Op op, Expr r) {
		if ((l == null) || (op == null) || (r == null)) {
			throw new IllegalArgumentException();
		}
		this.op = op;
		this.l = l;
		this.r = r;
	}
}