/*
 * Exp.java 1.0 2006-02-14
 *
 * Copyright (C) 2006 by Ifi, UiO
 */

import antlr.collections.AST;

/**
 * Simple AST class for an expression.
 *
 * @version $Revision:$
 * @author Sven-Jørgen Karlsen <svenjok@ifi.uio.no>
 * @since 1.0
 */
public interface Exp extends AST {

    // Cumbersom hack to avoid collision with Antlr AST libraries's toString()
    // abuse.
    public String toLispString();

    public enum Operator {
        PLUS("+"), MINUS("-"), MULT("*"), DIV("/");
        
        private final String strValue;
        
        Operator(String value) {
            this.strValue = value;
        }
        
        public String toString() {
            return strValue;
        }
        
        public static Operator fromString(String strValue) {
            for (Operator op : Operator.values()) {
                if (op.strValue.equals(strValue)) {
                    return op;
                }
            }
            return null;
        }
    }

}

/* Exp.java ends here */