Re: draft for DEL key poll

[Alan Mackenzie <acm@muc.de>]

On Mon, Sep 26, 2011 at 08:52:20PM -0400, Chong Yidong wrote:
> Richard Stallman <rms@gnu.org> writes:

> > In Emacs 24, now in pretest, a change is being considered for DEL
> > (often the Backspace key) and the Delete function key.  When there is
> > an active region, they would delete the region instead of just one
> > character.  This is enabled by default in the current pretest, so
> > building and using the pretest is a way to test it.

> This description fails to explain the underlying logic behind the
> change.

> If an active region is made with the mouse, and with shift-selection,
> the DEL key deletes it.  This behavior is non-negotiable as a default,
> as it is the standard behavior of graphical applications on modern GUI
> platforms and there is no good reason for Emacs to violate it.

There are several good reasons, otherwise Richard wouldn't be initiating
a poll about it.

I sincerely hope we won't be introducing too many more behaviours which
are "standard" in modern GUIs.

> Some Emacs commands perform a certain operation on the region when it is
> active.  In general, this "act on region" behavior does not draw a
> distinction between a region made with the mouse (or shift-selection)
> and a region made "normally" (e.g. by C-SPC followed by point motion).
> In previous Emacs releases, a special exception was made for the DEL and
> delete keys.  This exception has now been dropped.

I cannot let you get away with this epistemological conflation.  These
other commands do not act _ON_ the region.  They act _IN_ the region.
I.e., they do their normal thing in a portion of the buffer.  You've
utterly changed the meaning of `delete-character-forward', making it act
ON a region rather than on a character.  The behaviour of DEL and delete
was not previously an exception - they did their normal thing at the
boundary of the region.

> Anyone who argues that DEL ought not to delete a "normal" active region
> should provide a convincing explanation of why DEL should be treated
> differently from other Emacs commands that act on active regions.

See above.  DEL should keep its normal meaning in the presence of a
region, just like most other commands do.

As a matter of interest, in the proposed default configuration, how does
one delete a single character at a boundary of an "active" region?

-- 
Alan Mackenzie (Nuremberg, Germany).