Subject: Re: bug#56682: Fix the long lines font locking related slowdowns

From: Dmitry Gutov <[email-masked]>
Date: Fri, 12 Aug 2022 21:09:33 +0300

20:58, August 12, 2022, Eli Zaretskii <[email-masked]>:

From: Dmitry Gutov <[email-masked]>
Cc: Eli Zaretskii <[email-masked]>,
"[email-masked]" <[email-masked]>,
"[email-masked]" <[email-masked]>
Date: Fri, 12 Aug 2022 19:35:57 +0300

I have eliminated two performance problems frim js-json-mode that are uncharacteristic for font-lock in
general. One used a pathological matcher (simply removed), and another uses the "frameworks" facility
which simply always rescans the full buffer from the beginning. That one can/should be fixed later, but I have
disabled it for JSON (where it doesn't make sense anyway).

You should know that the rest of js-mode's font-lock keywords are still there. I experimented with leaving just
the bare minimum needed for JSON, but the effect was very minimal (like 20% improvement).

I didn't yet have time to try the branch, but what you say begs a
question: does the branch attempt to solve the problems of JSON files
only, or does it attempt to solve a more general problem?

There is nothing json-specific in the branch.

All the js/json stuff is on master already.