Re: cc-mode fontification feels random

[João Távora]

On Fri, Jun 4, 2021 at 11:59 AM Philipp <p.stephani2@gmail.com> wrote:

> > Am 04.06.2021 um 12:39 schrieb Eli Zaretskii <eliz@gnu.org>:
> >
> >> From: João Távora <joaotavora@gmail.com>
> >> Cc: Eli Zaretskii <eliz@gnu.org>,  Daniel Colascione <dancol@dancol.org>,
> >>  emacs-devel@gnu.org,  ubolonton@gmail.com
> >> Date: Fri, 04 Jun 2021 11:08:48 +0100
> >>
> >> - However, LSP support for fontification seems like it's potentially
> >>  _less_ efficient than integrating something like tree-sitter as a C
> >>  module in Emacs.  That's because the contents of the buffer and
> >>  fontification results are continually transmitted back and forth via
> >>  pipes and JSON format.
> >
> > The communication of buffer contents to these agents/servers is indeed
> > one aspect of the existing packages (those I had time to look at) that
> > I personally am unhappy about.  Sending the whole buffer or its large
> > chunks down the wire as buffer-substring (which requires encoding to
> > be correct) is non-scalable, especially if it also requires conversion
> > to JSON.
>
> How bad is is actually; are there good numbers on this?

Not from me.  Only gut feeling.  But I have seen latency from servers before.
That just depends on the server and its architecture, I guess.

 However there are reports of enormous latency on Emacs side when JSON
messages get very long and complex. Part of this related simply to JSON
parsing and allocation of lots of lisp objects.  My hunch is that
fontification of
a big and complex buffer would give rise to one of these big and complex
JSON messages.

João