bug#39179: 27.0.50; [PATCH] Add filter to gdb-mi register buffer

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Fri, 31 Jan 2020 18:08:18 -0500
> Cc: 39179@debbugs.gnu.org
> 
> > I'm not sure it's a good idea to implement this as a button on the
> > header-line.  Such buttons are for frequent operations, and also have
> > the disadvantage of being unavailable on TTY frames.  What are the
> > chances users will need to redefine the register patters frequently
> > enough to justify the button?  Wouldn't it be much easier to have a
> > defcustom whose value users could interactively modify as needed?
> 
> I mainly use it to display only the registers I care about, say, all
> the *dx registers (rdx, edx, dx) or all the r** registers (rdx, rsi,
> etc).

I understand, but why wouldn't a simple defcustom do this job?  A list
of registers to display is a simple thing, no?

> And that depends on the program you are working on.

Really?  In what way?  I could only understand why you'd like to see
FP registers in some programs, but not in others.  But other than
that, why would you want to see this or that register?  Are you
frequently debugging on the machine language level?

> The main motivation behind this patch is that, currently the register buffer 
> simply displays all the possible registers (153 on my machine), and tracking 
> on some of them is very hard (scrolling back and forth, very annoying).

Then perhaps we should allow reordering the registers instead of
filtering their list, so that registers you want to see are at the
beginning?

> So this feather is a session-based quick filtering for interesting registers, 
> I don’t think defcustom makes it better.

Why don't you think a defcustom will do?

> +(defcustom gdb-registers-enable-filter nil
> +  "If t, enable register name filter in register buffer."
> +  :local t
> +  :type 'boolean
> +  :group 'gdb-buffers
> +  :version "27.1")

This should be "28.1", not "27.1".

> +(defcustom gdb-registers-filter-pattern-list nil
> +  "Registers that are displayed in register buffer.
> +
> +Should be a list.  Registers whose name can match
> +any of the regexps in the list is displayed."
                                  ^^
"are"

> +  :local t
> +  :type 'list
> +  :group 'gdb-buffers
> +  :version "28.1")
> +
>  (defvar gdb-debug-log nil
>    "List of commands sent to and replies received from GDB.
>  Most recent commands are listed first.  This list stores only the last
> @@ -4238,6 +4256,53 @@ gdb-frame-locals-buffer
>   'gdb-registers-mode
>   'gdb-invalidate-registers)
>  
> +(defun gdb-header-click-event-handler (function)
> +  "Return a function that handles clicking event on gdb header buttons.

This doesn't really return a function, it calls it, right?

But before we discuss the particular code, let's please first agree on
the design, OK?