Re: emacs rendering comparisson between emacs23 and emacs26.3

[Stefan Monnier]

> This is in jit-lock-register, which is not called from jit-lock.el.
> Does this mean that non-nil, non-t value of jit-lock-contextually is
> like nil, unless the major mode calls jit-lock-register with its 2nd
> argument non-nil?

Yes.

> And if so, why does the doc string mention font-lock-keywords-only and
> doesn't mention jit-lock-register?

I think that's because that's written for the end-user rather than for
the programmer: the end user doesn't know `jit-lock-register`, but it
may know `font-lock-keywords-only`.

But maybe it's really just an artifact of history (originally, jit-lock
and font-lock were more tightly linked).

> They seem to be at least theoretically independent?  If not, where's
> their connection?

`font-lock-keywords-only` ends up passed by font-lock as
2nd arg to `jit-lock-register`.


        Stefan


PS: BTW, maybe `jit-lock-contextually` should really be part of
font-lock rather than jit-lock.