public String combineStr(REPrimitiveFragment frag)
	{
		String ret = "[";
		for(int i = 0; i < chars.length; i++)
		{
			if(chars[i] && frag.chars[i])
			{
				if(i == 91 - 32 ) ret += "\\[";
				else if(i == 93 - 32) ret += "\\]";
				else if(i == 94 - 32) ret += "\\^";
				else if(i == 92 - 32) ret += "\\\\";
				else ret += String.valueOf((char)(i + 32));
			}
		}
		return ret + "]";	
	}