Here it is an example: If we oversimplify json parsing consist of 2 parts.

1. JSON parsing to Jansson data structures
2. Converting Jasson data structures to lisp data structures.

If we assume that 1 is taking most of the time then we could write the
following code:

start(string, callback) -> convert string to char* -> post it to worker
thread -> worker thread does the parsing
-> worker thread post to main loop -> main loop converts Jansson ds to lisp
ds -> main loop
calls the callback passed on start

The same strategy probably could be applied to Font locking with
TreeSitter.

Thanks,
Ivan

On Wed, Jun 24, 2020 at 7:29 PM Eli Zaretskii <eliz@gnu.org> wrote:

> > From: yyoncho <yyoncho@gmail.com>
> > Date: Wed, 24 Jun 2020 19:17:30 +0300
> > Cc: 42028@debbugs.gnu.org
> >
> > As a side note, this feature will be useful even for the core C part for
> anything
> > that wants to perform async processing not including LispObject.
>
> How will it help that?  The event queue is processed synchronously.
>