lexicalanalysis.java

来自「<算法导论>第二版大部分算法实现. 1. 各类排序和顺序统计学相关」· Java 代码 · 共 57 行

/*
 * Copyright (C) 2003-2008 Wang Pengcheng <[e-mail]>
 * Permission is granted to copy, distribute and/or modify this
 * document under the terms of the GNU Free Documentation License,
 * Version 2.0 or any later version published by the Free Software Foundation;
 * with no Invariant Sections.
 * You may obtain a copy of the License at
 *   http://www.gnu.org/licenses/lgpl.txt
 */
//26 Feb 2008
package cn.edu.whu.iss.algorithm.unit10.expression.lexical;

/**
 * The expression lexical analysis.
 * It translate the support bracket to the aim bracket("(",")").
 * It can delete the error chars. The permit char is in the array of the 
 * PERMIT_CHAR.
 * @author wpc
 * @version 0.0.1
 */
public interface LexicalAnalysis {
	/**
	 * The permit char list
	 */
	char[] PERMIT_CHAR = {
		'0','1','2','3','4','5','6','7','8','9','.','^','*','/','+','-','(',')'	
	};
	
	/**
	 * The support brackets
	 */
	String[] SUPPORT_BRACKET = {
			"\\{","\\}","\\[","\\]"
	};
	/**
	 * Translate the support brackets to the aim brackets
	 */
	String[] AIM_BRACKET = {
		"\\(","\\)","\\(","\\)"	
	};
	
	/**
	 * Translate the brackets to the aim brackets.
	 * @param expr the expression
	 * @return the translated expression
	 */
	String translateBracket(String expr);
	
	/**
	 * Analyse the expression it delete the error chars.
	 * @param expr the expression
	 * @return the analysed expression.
	 */
	String analyseExpr(String expr);

}