Re: Unbalanced change hooks (part 2) [Documentation fix still remaining]

[Alan Mackenzie <acm@muc.de>]

Hello, Eli.

On Mon, Aug 29, 2016 at 05:50:11PM +0300, Eli Zaretskii wrote:
> > From: Daniel Colascione <dancol@dancol.org>
> > Date: Sun, 28 Aug 2016 20:18:32 -0700

> >     Please trust me that the documentation misleads.

> You are welcome to suggest more accurate wording that describes the
> current implementation.

I think it's only fair to point out that I did precisly this almost
three weeks ago (on 2016-08-10) and the welcome my efforts got was
somewhat less than wholeheartedly warm.

The current documentation misleads in asserting that b-c-f and a-c-f
cannot be used together in balanced pairs.  They most assuredly can,
with the exception of a tiny number of rarely occurring cases.  If this
were not true, CC Mode would not work at all.

Using b-c-f and a-c-f together is an essential technique - there are
things that cannot be done without it, or at least not in any reasonable
manner.  In this sense, maintaining a duplicate shadow buffer, or
scanning from BOB at every buffer change, or maintaining a separate
record of all text properties on a buffer, don't fall into the category
of reasonable, from my point of view.

Eliminating this technique from Emacs, whether by "polluting" the source
to stop it working altogether (as suggested by Stefan), or by forbidding
it in the documentation, has the effect of making Emacs a less powerful
programming system.  I don't think this is what any of us should want.

[ .... ]

-- 
Alan Mackenzie (Nuremberg, Germany).