[PING] Add a way to invoke redefined (overridden) GDB commands

[Marco Barisione <mbarisione@undo.io>]

Ping for the patch series at https://sourceware.org/pipermail/gdb-patches/2020-September/171829.html.

Thanks!


> On 14 Sep 2020, at 10:39, Marco Barisione <mbarisione@undo.io> wrote:
> 
> Currently, when a GDB command is redefined, the original implementation is not
> available any more.  This makes it difficult to build features on top of
> existing commands.
> 
> Last year I submitted a patch to fix this but I ran out of time to address the
> review comments (the original patch was sent on the 28th of October 2019).
> These patches restart that work and should address all the comments I got last
> time.  As the patchea are very different and a long time passed, I'm
> submitting as a new series.
> 
> My patches add a new "uplevel" command and a new gdb.Command.invoke_uplevel
> method inspired by TCL (as initially suggested by Andrew Burgess) so you can
> do this:
> 
>    (gdb) define run
>    echo Will run!\n
>    uplevel 0 run
>    end
>    (gdb) run
>    Will run!
>    [... normal output of run ...]
> 
> 
> There are a couple of other things which could be added to make the "uplevel"
> command more helpful, but I think they are out of scope and my patches are
> already useful as they are.
> 
> The first thing is adding a way of accessing the untokenised arguments to a
> command via something like "$arg@" (Andrew Burgess suggested "$argv", but
> Pedro Alves pointed out that would look like an argument vector).
> 
> Another thing which could be added is the ability to do "uplevel -1 ..." to
> access the directly redefined command.
> This is implemented in Python but I couldn't find an obvious way of doing that
> for the "uplevel" command as there's no way of knowing which command you are
> currently executing (at least from what I could see).
> Maybe it could be implemented in a similar way to how command arguments are
> kept around with scoped_user_args_level, so we could keep a stack of all (user
> and non-user) commands which are being executed.  By checking the latest one
> you can know what "uplevel -1" would apply to.
> 

-- 
Marco Barisione