Variable.java

/**
 *  Copyright (C) 2010 dennis zhuang (killme2008@gmail.com)
 *
 *  This library is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published
 *  by the Free Software Foundation; either version 2.1 of the License, or
 *  (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 **/
package com.googlecode.aviator.lexer.token;

import java.util.Map;


/**
 * Variable token
 * 
 * @author dennis
 * 
 */
public class Variable extends AbstractToken<Object> {

    /**
     * Boolean value true
     */
    public static final Variable TRUE = new Variable("true", -1) {

        @Override
        public Object getValue(Map<String, Object> env) {
            return true;
        }

    };

    /**
     * Boolean value false
     */
    public static final Variable FALSE = new Variable("false", -1) {

        @Override
        public Object getValue(Map<String, Object> env) {
            return false;
        }

    };

    /**
     * Boolean value false
     */
    public static final Variable NIL = new Variable("nil", -1) {

        @Override
        public Object getValue(Map<String, Object> env) {
            return null;
        }

    };


    public com.googlecode.aviator.lexer.token.Token.TokenType getType() {
        return TokenType.Variable;
    }


    public Object getValue(Map<String, Object> env) {
        if (env != null) {
            return env.get(this.lexeme);
        }
        else {
            return this.lexeme;
        }
    }


    public Variable(String name, int startIndex) {
        super(startIndex, name);
    }

}