001    package org.hackystat.telemetry.analyzer.language.ast;
002    
003    /**
004     * The interface for expression in telemetry language. Expression participates in arithmetic
005     * operation and function calls to form more complex expression.
006     * <p>
007     * This is a tag interface, there is no method to implement.
008     * 
009     * @author (Cedric) Qin ZHANG
010     * @version $Id$
011     */
012    public interface Expression {
013    }