Hi Zhenhua,

> a. The parser fetch and parse one command per loop. The prefix is
> the command prefix without parameter. For example, the prefix of
> "AT+CLIP=1" is "+CLIP".
> 
> b. Search registered notification node in command_list. Invoke the
> callback if found.
> 
> c. Termiate the execution if the result is an error. Otherwise,
> parse next command.

I applied this patch but refactored it heavily afterwards.  Thanks.

Regards,
-Denis