bug#11361: 24.1.50; doc string of `yank-pop-change-selection'

[Eli Zaretskii <eliz@gnu.org>]

> From: "Drew Adams" <drew.adams@oracle.com>
> Cc: <11361@debbugs.gnu.org>
> Date: Fri, 27 Apr 2012 08:34:36 -0700
> 
> > > How is it changed by setting this to non-nil?  What do nil 
> > > and non-nil actually do?
> > 
> > The nil value doesn't do anything, obviously.
> 
> There must be a difference in behavior between nil and non-nil (or else it is
> not only the doc string that is problematic).  That's the point.

A non-nil value changes the default behavior in the way that is
documented.  A nil value does not make that change, that's all.  I see
no need to say obvious things like that; I wonder why you do.

> Instead of playing word games, try clarifying what this option does.  What does
> it mean to "change" the "window system selection"?  Change it how?  Change it to
> what?  From what?

I suggested to use "set" instead of "change", for that very reason.

> As I said:
> > See the Emacs manual, node Clipboard (presumably) for inspiration.

There's more than one way to cut a cake.  The issue here is why this
particular way is "useless".  I think it needs small improvements,
like I suggested, but that's all.

>  "if you change `yank-pop-change-selection' to `t', then `M-y'
>   saves the new yank to the clipboard."
> 
> That at least is clear.

Is it?  What is a "yank"? what is a "clipboard"?  And why an option is
called yank-pop-change-SELECTION when it affects the clipboard?  Etc.,
etc., ad nauseam.