Re: Major modes using `widen' is a good, even essential, programming practice.

[Gregory Heytings]

> I'm also working on a bigger change that will push the 
> narrowing/limiting mechanics down to font-lock, but I'm yet to find the 
> best place to put that logic.

You may have seen that this has already been tried, and found 
insufficient.

> And the problem with working on a feature like that is that it will be 
> fixing performance problems I don't really have. And, as such, cannot 
> evaluate different tradeoffs. And neither you nor Gregory want to give 
> me feedback by actually trying that tiny patch.

Sorry, I cannot reply to all posts in a few hours.

I hope you realize how... local that patch it.  Sure, it makes the 18 MB 
json file example (and only that example) slightly better.  But on my 
machine I still see Emacs stuttering when leaning on C-v, I still see 
delays when searching through the file with C-s, and so forth.  And of 
course with larger files the delays become more and more significant. 
With a 300 MB json file I have to wait about 30 s after pressing M->.