Re: delete-selection-mode as default (WAS: Some developement questions)

[Alan Mackenzie]

Hello, Drew.

On Sun, Sep 09, 2018 at 15:24:30 -0700, Drew Adams wrote:
> I agree that a poll of this list is not a great guide (for this question
> and many others).

> > Two questions should be considered: a) "Would leaving it off scare
> > away potential new users?" and b) "Would turning it on obscure an
> > option that is potentially useful to at least a subset of new users?"

> I must have missed what that potentially useful option is.

The option is having delete-selection-mode turned off, which is a useful
option in itself.

Actually, I'm not sure what the use of d-s-mode actually is.  I don't
recall anyone here advocating it on some intrinsic merits, only "because
everybody else does it", which I've never found a convincing argument for
anything in Emacs.

> > On the other hand, if `delete-selection-mode` is on by default,
> > most, if not all, new users will never even consider the
> > possibility that Emacs has the option to disable it and that
> > that might actually fit their workflow better.

> This too hints at some advantage to having it off.

> The only argument I saw here (unless I've forgotten already)
> in favor of it being off (by default or not) is that when it is on
> a user (new or old) can too easily accidentally delete text.

> (Some added "irretrievably", but I haven't seen that claim
> supported yet.)

That was me, the complete phrase was "irretrievably lost" and I carefully
outlined what was being lost and where.  In summary, it was a carefully
and painstakingly constructed region, and what was being lost by a
careless movement key without <shift> was the point and mark of the
highlighted region, not its contents.  Furthermore it was in programs
which aren't Emacs.

> That advantage would seem to be something that would
> most benefit new users, no? But the claim has been that
> new users are more used to the on, not the off, behavior.

> So again, what's the advantage to it being off? (It's not a
> rhetorical question.) Is there really some useful "option"
> that its being off offers? Does that give you additional
> choice or control?

Yes.  It enables you to type onto the end of a (highlighted) region
without being distracted by first having to do something to remove the
highlighting, or more likely without first having to use `undo' to get
your region back again, followed by unhighlighting it followed by typing
the character you want to append.

Personally, it scarcely affects me because I run with transient-mark-mode
disabled, but I still occasionally get unwanted highlighting of regions
for some reason.

-- 
Alan Mackenzie (Nuremberg, Germany).