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

[Dmitry Gutov]

On 06.08.2022 23:13, Alan Mackenzie wrote:
> Narrowing is primarily a user feature.  Users can arbitrarily narrow a
> buffer to ANY contiguous region of text.  So when a major mode needs to
> examine text even slightly distant from point, it MUST widen, to be sure
> that the text to be examined is within the visible region.

Now wouldn't it have been nice if user-level narrowing didn't create an 
*actual* narrowing but only some visual perception of it? IIRC there is 
a third-party package which implements this approach.

From what I've seen of feature requests related to narrowing in my 
packages, it's always along the lines of "please add (save-restriction 
(widen) ...) around the whole implementation".

Are there actually user-level commands which should not ignore 
narrowing? If not, it would be better if user-level narrowing was 
implemented as something else (e.g. two invisible overlays). Then all 
other code wouldn't have to bother with undoing it.