Re: [RFC 3/8] Add output styles to gdb

[Simon Marchi <simark at simark dot ca>]

On 2018-09-06 5:12 p.m., Tom Tromey wrote:
> This adds some output styling to the CLI.
> 
> A style is currently a foreground color, a background color, and an
> intensity (dim or bold).  (This list could be expanded depending on
> terminal capabilities.)
> 
> A style can be applied while printing.  This patch changes cli-out.c
> to apply styles just to certain fields, recognized by name.  In
> particular, function names and file names are stylized.
> 
> This seemed like a reasonable approach, because the names are fixed
> due to their use in MI.  That is, the CLI is just as exposed to future
> changes as MI is.
> 
> Users can control the style via a number of new set/show commands.  In
> the interest of not typing many nearly-identical documentation
> strings, I automated this.  On the down side, this is not very
> i18n-friendly.
> 
> I've chose some default colors to use.  I think it would be good to
> enable this by default, so that when users start the new gdb, they
> will see the new feature.
> 
> Stylizing is done if TERM is set and is not "dumb".  This could be
> improved when the TUI is available by using the curses has_colors
> call.  That is, the lowest layer could call this without committing to
> using curses everywhere; see my other patch for TUI colorizing.
> 
> I considered adding a new "set_style" method to ui_file.  However,
> because the implementation had to interact with the pager code, I
> didn't take this approach.  But, one idea might be to put the isatty
> check there and then have it defer to the lower layers.

Hi Tom,

Overall this looks great.  I'm not too worried about internationalization.
I think in this case for example:

  _("The \"%s\" display intensity is: %s\n"), name, value

If "name" corresponds to a field name or sub-command name (like "filename"),
it's probably better to leave it in english.  If it refers to the concept
of a filename, then we would want to translate it.

In the latter case, I guess we could do it in two steps, and also pass the value
through gettext:

  std::string tmpl = string_printf ("The %s display intensity is: %%s\n", name);
  printf (_(tmpl.c_str ()), _(value));

So tmpl would contain "The filename display intensity is: %s\n", which could be
looked up by gettext to something that has the proper translation for "filename".
Then, the color name would be translated too.

Or maybe I don't understand how gettext works.


I'm just not sure about choosing styles using the field name.  For a filename, you could
have a bunch of different field names, file filename, original_filename, absolute_filename,
etc.  So it can quickly become a bit crowded here.

Could we pass an additional enum parameter to do_field_string to indicate the type of
element this field represents?  If this parameter has a default value of "NOTHING",
then we can add then incrementally.  Or it can even be an hybrid approach, where we
try to match field names, which works 95% of the time, and then have this enum parameter
to override the auto-detection if needed.

Simon