Re: [RFA] PR python/13598 - add before_prompt event

[Phil Muldoon <pmuldoon@redhat.com>]

On 22/07/16 11:01, Yao Qi wrote:
> Hi Tom,
> 
> On Sat, May 21, 2016 at 6:00 AM, Tom Tromey <tom@tromey.com> wrote:
>> This adds an event that is emitted just before GDB presents a prompt
>> to the user.  This provides Python code a way to react to whatever
>> changes might have been made by the previous command.  For example, in
>> my GUI I use this to track changes to the selected frame and reflect
>> them in the UI.
> 
> I read this patch multiple times, but don't know the motivation of adding this
> event.  In PR python/13598, you mentioned you want to get event when
> something is changed.  If so, why don't you add the python event for the changes
> you are interested in?  What is your use case of using python code in GDB?

The use-case seems clear to me. 

Old workflow:

gdb-prompt -> command entered -> gdb does something -> gdb finishes ->
gdb displays prompt

New workflow:

gdb-prompt -> command entered -> gdb does something -> gdb finishes ->
notifies interested observers -> gdb displays prompt

I think it would be useful to know the time when GDB is done
processing the event queue and before it displays the prompt and waits
on user input.

Cheers

Phil