Re: Selection changes in revno 100822

[Eli Zaretskii]

> From: "Drew Adams" <address@hidden>
> Cc: <address@hidden>, <address@hidden>, <address@hidden>,
>         <address@hidden>, <address@hidden>
> Date: Sun, 15 Aug 2010 12:29:29 -0700
> 
> > > Emacs has traditionally associated mouse-2 pasting with yanking the
> > > head of the kill ring.
> > 
> > Drew, you make a convincing argument that you would like selecting
> > text to set the clipboard with that text.
> 
> I did not say that in what you quoted - read it again.

I was unable to quote a small part of your mail that said it all.
Nevertheless, please trust me that I read it all and understood what I
read.

> Does it say anything about mouse _selection_?  No.  It speaks about
> mouse-2 _pasting_ as yanking the kill-ring head.

If selecting text sets the clipboard, then mouse-2 will yank it.  You
also provided other use-cases which led me to the same conclusion:
that you want selected text to go to the clipboard.  For example:

> Yes, I did say that "I often use C-y to yank text that I have previously
> selected using the mouse.  And I often use mouse-2 to yank text that I have
> previously selected using the keyboard."  Both directions, for the mouse and 
> for
> the keyboard.  Just what Emacs has always offered.

These both will work like you want them to if selecting text puts it
into the clipboard.

> Express what will change for _users_, operationally, and why it is a good 
> thing.
> Don't just say that the change is good and the traditional behavior is 
> "bogus".

You seem to confuse me with Stephen.  I didn't say the old behavior
was bogus.

> State clearly what is to be gained by changing.

Consistency with other X apps, so it seems.  And I happen to agree
that consistency with widely accepted GUI standards is a Good Thing,
in general.

> And say clearly and completely what the change is.

That was said already.  Let me repeat it (quoting David with slight
changes):

  clipboards aren't overwritten when you merely select text.
  clipboards are overwritten when you cut/copy (C-w/M-w)
  clipboard text is not inserted (pasted) when you click mouse-2.
  clipboard text is inserted when you paste (C-y)

  primary selections are overwritten when you merely select text.
  primary selections are not overwritten when you cut/copy (C-w/M-w) (but 
    they've probably already just been overwritten because you selected
    text just before you cut/copied).
  primary selections are inserted when you click mouse-2.
  primary selections are not inserted when you paste (C-y)

> That's my point: Make clear what the stakes are for users: What will
> be changed _from a user point of view_.  And why it is a good thing:
> advantages, disadvantages.

See this URL:

   http://standards.freedesktop.org/clipboards-spec/clipboards-latest.txt

It makes good sense wrt apps other than Emacs.  When applied to Emacs,
IMO most of the reasons it gives for the above behavior are quite
lame, because Emacs has features this document doesn't consider.  But
there's one reason that made perfect sense to me even wrt Emacs,
namely, that the "traditional" Emacs behavior with setting PRIMARY on
C-w/M-w has this problem:

 - you should be able to select text, then paste the clipboard over
   it, but that doesn't work if the selection and clipboard are the
   same

IOW, if selecting text overwrites the clipboard, you cannot select and
then paste from the clipboard over the selection, because selecting
destroys the clipboard data.

(It is ironical that all the heated discussion regarding the reasons
why the new behavior is "right" never brought up this reason, which
IMO is the only one that hits the nail on the head.)

> It's amazing to me that we've gotten this far along with no proposal,
> discussion, and argument about pros & cons for users.

FWIW, the above URL was posted here long ago.  All the info you are
looking for is there.