Re: Feature request: italic style in region_highlight

[Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>]

Bart Schaefer wrote on Thu, Jan 02, 2020 at 18:30:17 -0800:
> On Thu, Jan 2, 2020 at 1:06 PM Roman Perepelitsa
> <roman.perepelitsa@xxxxxxxxx> wrote:
> >
> > > %O/%o (for "oblique") would be available. I realise that an oblique font
> > > is not strictly the same as italic.
> >
> > Perfect timing. I wanted to ask which alternative letter to use as %a
> > is taken by something (watch, perhaps?). %O/%o sounds good.
> 
> Agree.  (However, the only use of %a I could find is in the zstyle
> formats for VCS, which didn't seem to conflict.

In vcs_info one can always double the percent sign if needed.  Well, %a for one
is used in both patch-format and actionformats, so it's possible it'd have to be
doubled twice if someone wanted to use %a in its prompt meaning in patch-format.

> > With %A{...} we would have to
> > explain how it interacts with the other sequences. E.g., does %u
> > cancel %A{4}?
> 
> I think if we created %A{4} (which BTW I would recommend requiring at
> least two digits, e.g. %A{04}) then we would have to document the
> existing escapes as being shorthands for the corresponding %A forms,
> so yes, %u would cancel %A{04}.

Why would we create either %A{4} or %A{04}?  The API to script writers should
use symbolic names; the API between us and the terminal should use terminfo
rather than hardcoded escape sequences.  If anything, something like «%X{foo}»
that does the equivalent of «%{`tput foo`%}» might be worthwhile?  We could
still add an %Y/%y pair of escapes for italics but they'd be syntactic sugar
for %X{sitm} and %X{ritm} respectively.

(X, Y, and y are metasyntactic variables for the actual letters we'd use.)

Cheers,

Daniel