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Date: Fri, 05 Aug 2011 11:51:02 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH] monitor: HMP: fix consecutive integer
 expression parsing
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To: Alon Levy <alevy@redhat.com>
Cc: qemu-devel@nongnu.org

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?

Regards,

Anthony Liguori