private double parseUnaryOperator() throws Exception{
		double result;	//
		String op;		//
		op="";
		//ǰΪָҷֵָΪ+-
		if((this.tokenType==DELIMITER_TOKEN)&&this.token.equals("+")||this.token.equals("-")){
			op=this.token;
			this.getToken();
		}
		//㵱ǰӱʽֵ
		result=this.parseBracket();
		if(op.equals("-")){
			//Ϊ-ʾӱʽֵΪ
			result=-result;
		}
		return result;
	}