Re: [Qemu-devel] [PATCH] monitor: HMP: fix consecutive integer expression parsing

[Blue Swirl]

On Fri, Aug 5, 2011 at 4:51 PM, Anthony Liguori <address@hidden> wrote:
> On 08/03/2011 06:57 AM, Alon Levy wrote:
>>
>> Currently a command that takes two consecutive integer operations, like
>> client_migrate_info, will be incorrectly parsed by the human monitor if
>> the second expression begins with a minus ('-') or plus ('+') sign:
>>
>> client_migrate_info<protocol>  <hostname>  <port>  <tls-port>
>> client_migrate_info spice localhost 5900 -1
>> =>  port = 5899 = 5900 - 1
>>    tls-port = -1
>> But expected by the user to be:
>>    port = 5900
>>    tls-port = -1
>>
>> The fix is that for any required integer (ilM) expression followed by
>> another
>> integer expression (ilM) the first expression will be parsed by expr_unary
>> instead of expr_sum. So you can still use arithmetic, but you have to
>> enclose
>> it in parenthesis:
>>
>> Command line | Old parsed result | With patch result
>> (1+1) 2      | 2, 2              | 2, 2
>> 1 -1         | 0, -1             | 1, -1
>> The rest are bizarre but not any worse then before
>> 1+2+3        | 6, 5              | 1, 5
>> (1+2)+3      | 3, 3              | 3, 3
>
> I vote for just removing the expression parsing entirely.  It's incredibly
> non-intuitive and I don't think anyone really uses it.
>
> Does anyone strongly object?

I think the expressions would be useful with memory addresses, like
"xp/i $pc-4", but I usually start GDB in these cases. Can we disable
the expressions only for ports?