error.java

语法分析器

/**
 * this class handle the error problem
 * @author:贺静
 * @version :1.2
 */

import java.io.IOException;

public class Error {
	public String getError(int errorCon) throws IOException {
		String s = "";
		switch (errorCon) {
		// case -1 to -4 is the parse error
		case -1:
			s = " 程序必须以 'class' 开始 \n";
			break;
		case -2:
			s = " 程序体必须以 '{' 开始 \n ";
			break;
		case -3:
			s = " 'Class' 只能是程序开始标识符 \n";
			break;
		case -4:
			s = " unwanted input: the program should already end \n";
			break;
		// case -30 to -35 is the lex error
		case -30:
			s = "   注释不匹配" + "\n";
			break;
		case -31:
			s = "  标识符不能以 '_' 结束" + "\n";
			break;
		case -32:
			s = "'" + "'  标识符不能以数字开头" + "\n";
			break;
		case -33:
			s = "'" + "'   数字不能以 '.' 结束" + "\n";
			break;
		case -34:
			s = "   invalid input " + "\n";
			break;
		case -35:
			s = "  数字的输入格式错误" + "\n";
			break;
		default:
			break;
		}
		return s;
	}
}