Re: Making vertical-border char defcustom?

[Eli Zaretskii]

> From: "Paul W. Rankin" <address@hidden>
> Date: Tue, 21 Jan 2020 16:25:52 +1000
> Cc: address@hidden
> 
> On 21 Jan 2020, at 4:08 am, Eli Zaretskii <address@hidden> wrote:
> > We don't offer customization of the display tables via defcustom, most
> > probably because it is "tricky" (as you yourself discovered).  I
> > hesitate to offer just this one slot of the display table, and the
> > fact that it only affects TTY frames and requires UTF-8 capable
> > terminal on top of that doesn't provide additional motivation...
> 
> Do you mean tricky from an implementation or user perspective?

The former.  This is a low-level facility that Emacs itself uses on a
very low level.  Naïvely customizing it will have global session-wide
effect, something many users won't want, and then they will want to
have user-level access to buffer- and window-local display tables,
something that is not trivial to get right.

> > display-fill-column-indicator-character is an entirely different
> > matter, it's a minor mode which lets users specify an indicator glyph.
> 
> This I mean more from a user perspective, as in, "Oh I see I can customise 
> this vertical line but I can't customise this vertical line next to it..."

The other one was never meant to be customized, not really.