RE: CUA-mode features and documenation

[Drew Adams]

>     What cua-selection-mode provides is the:
>     - transient-mark-mode
>     - delete-selection-mode

Delete selection mode already provides (uses) transient mark mode. So CUA
selection mode apparently adds only this:

>     - S-ARROW_KEY extends the region 

And maybe this (?):

>     (Probably some more, but this is the main functionality).

> This might be a superior for Delete Selection mode.

What do you mean by "a superior [?] for D S mode"? Do you mean that it would
be good to add those S-<arrowkey> bindings to D S mode or to replace D S
mode by CUA selection mode?

If so, I disagree. I use D S mode, and I don't want the S-<arrowkey>
bindings.

Anyway, in D S mode, you can already use S-<arrowkey>s the same way, but
only when the region is active. I think Kim should have said that in CUA
selection mode S-<arrowkey> *activates the region* and extends it, whereas
in delete selection mode it extends the active region.

IOW, AFAICT, CUA selection mode just lets you skip hitting C-SPC before
using S-<arrowkey>. I prefer the D S behavior, myself: S-<arrowkey> extends
the active region, but doesn't also set mark. (You can then use S-<arrowkey>
for something else when the region is not active.)

I think we need to keep giving users a choice about this (having
S-<arrowkey> set mark if the region is inactive). That could be done by
keeping both D S mode and CUA selection mode, or (simpler?) by adding a user
option and keeping only one of them.

I don't know about the "probably some more" stuff - perhaps we should look
into that. If there is in fact no more, then just adding an option to D S
mode for S-<arrowkey> to set mark (if inactive) would be sufficient. We
could then drop CUA selection mode.

Question (not proposal): Assuming we keep CUA selection mode, would it be
clearer to change its name, to avoid confusion with CUA mode? I imagine that
CUA selection mode is a perfectly accurate name, in that it presumably
implements the selection part of IBM's Common User Access
(http://en.wikipedia.org/wiki/Common_User_Access).

Even so, (1) the name might lead to some confusion with CUA mode, and (2)
it's not obvious to most people what "CUA" is. That ignorance is probably OK
for CUA mode, since you need to read the doc anyway to find out what it's
all about (lots of features), and "Common User Access" refers to more than
just selection. But for CUA selection mode, we might look for a better name.

Note that "delete selection" mode is also not the ideal name for what it
does. It is really a "replace selection" mode. You can type to replace the
active region, and deletion is just replacement by nothing. But then, even
"replace selection" doesn't convey the ability to extend the active region
using S-<arrowkey>.

Looking at various Emacs Wiki entries, I suspect there is a fair amount of
confusion for newbies among (1) transient mark mode, (2) delete selection
mode, (3) PC selection mode, and (4) CUA selection mode. But I guess that's
the nature of the beast - Emacs provides a world of optional behaviors, even
out of the box. Vive la difference !

> If we want to promote it that way, we should choose a better
> name that CUA Selection mode, because most people won't know
> what "CUA" means.

Ah, what I asked.

> But I don't think it should be the default, any more than
> Delete Selection mode should be.

(I have no strong opinion about the default, but I think either CUA
selection mode or delete selection mode behavior would be a good default
behavior for newbies.)

To move forward, perhaps someone can speak to the "probably some more", and
we can then discuss how we might combine CUA selection mode and delete
selection mode (with options, so we don't lose existing behavior).