org.nutz.el.parse.StringParse Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of nutz Show documentation

Nutz, which is a collections of lightweight frameworks, each of them can be used independently

There is a newer version: 1.r.72

package org.nutz.el.parse;

import org.nutz.el.ElException;
import org.nutz.el.Parse;

/**
 * 字符串转换器
 * @author juqkai([email protected])
 *
 */
public class StringParse implements Parse {
	public Object fetchItem(CharQueue exp) {
		//@ JKTODO 添加转意字符
		switch(exp.peek()){
		case '\'':
		case '"':
			StringBuilder sb = new StringBuilder();
			char end = exp.poll();
//			while(!exp.isEmpty() && !exp.peek().equals(end)){
			while(!exp.isEmpty() && exp.peek() != end){
				if(exp.peek() == '\\') {//转义字符?
					parseSp(exp, sb);
				}else{
					sb.append(exp.poll());
				}
			}
			exp.poll();
			return sb.toString();
		}
		return nullobj;
	}
	
	private void parseSp(CharQueue exp, StringBuilder sb){
		switch (exp.poll()) {
		case 'n':
			sb.append('\n');
			break;
		case 'r':
			sb.append('\r');
			break;
		case 't':
			sb.append('\t');
			break;
		case '\\':
			sb.append('\\');
			break;
		case '\'':
			sb.append('\'');
			break;
		case '\"':
			sb.append('\"');
			break;
		case 'u':
			char[] hex = new char[4];
			for (int i = 0; i < 4; i++)
				hex[i] = exp.poll();
			sb.append((char)Integer.valueOf(new String(hex), 16).intValue());
			break;
		case 'b': //这个支持一下又何妨?
			sb.append(' ');//空格
			break;
		case 'f':
			sb.append('\f');//这个支持一下又何妨?
			break;
		default:
			throw new ElException("Unexpected char");	//1.b.37及之前的版本,会忽略非法的转义字符
		}
	}

	public static void main(String args[]){
		double x = .1 + 5;
		System.out.println(x);
	}
}