bug#6774: Cut and paste with C-w/mouse-2 not working?

[Eli Zaretskii]

> Date: Tue, 17 Aug 2010 10:24:16 +0200
> From: Jan Djärv <jan.h.d@swipnet.se>
> CC: handa@m17n.org, cyd@stupidchicken.com, 6774@debbugs.gnu.org, 
>  angelo.graziosi@alice.it
> 
> 1. The region is different from previous redisplay.
> 2. The region is not empty.
> 3. The region is hightlighted.

2 and 3 are trivial, but 1 is slightly harder: we don't currently
track whether region beginning and end changed.

> > And why a hook? do we want to do in that hook anything except set some
> > selection, like PRIMARY?  If we only want to set a selection, we can
> > do that directly.
> 
> Yes, but given all the variables that can influence what to do, I just 
> thought 
> it better to hand it off out of redisplay.

Accessing a Lisp variable from C is hardly a concern.