Re: `*' interactive spec in some text-killing functions

[David Kastrup]

"Juanma Barranquero" <address@hidden> writes:

> On 6/28/07, David Kastrup <address@hidden> wrote:
>
>> But _why_ wouldn't it be "smart"?  The command _is_ executed, it has
>> the normal effect (which may become relevant if the buffer-read-only
>> state changes), and it does _absolutely_ no harm to the buffer
>> contents or anything else.
>
> Neither does any harm to PgUp at the beginning of a buffer.

If the command would get executed, the screen would be blank.  Emacs
can't execute the command, however.

> What is the message for? To alert me that I cannot go up?

To alert you that Emacs is _not_ executing the command.

> Well, my overwrite message is to alert me that I cannot overwrite
> even if I just changed to overwrite,

So WHAT?  Emacs _does_ change to overwrite mode.  It _completes_ the
command _properly_.  And it _will_ alert you if you actually try
inserting or overwriting any characters.

> and that I shouldn't expect most normal keys to act differently just
> because I changed to overwrite.

There are _billions_ of prospective variables you can change or toggle
that won't make a difference in particular modes or other stuff.  So
_WHAT_?  _Why_ should Emacs warn you whenever you do something that
_might_ not have an effect later unless certain other conditions are
changed?

Why?  How does it help the user?  How does it keep harm from him?

>> You still have not presented a single case where a notice would be
>> of any use at all, even if just to prevent the user from wasting
>> time or energy.
>
> Do you mean that the PgUp case is better because it prevents the
> user from endlessly looping doing PgUp without noticing that he's at
> the beginning of the buffer (which is also displayed in the mode
> line, at least on the default line-number-mode configuration) and
> that nothing is moving?

Page-Up is _not_ being executed.  Emacs tells the user why it can't do
his demand.  But overwrite-mode _is_ toggled, and the toggling _will_
show an effect when the buffer gets changed to read-write, or when
inhibit-read-only gets temporarily enabled, or when you do C-x C-w to
a different file or a number of other things.  Emacs _executes_ your
command, and there are a number of cases where executing it will make
a difference.  And even if it didn't: I don't want Emacs to alert me
whenever it executes a command that may not make a difference.

>> I don't get it, and you are not exactly making a convincing, or
>> even any case for it.
>
> I stopped trying to convince you around the "angels on a pin's head"
> message, if not earlier. But you are unable to accept that I'm
> saying that I would find it convenient: you try to convince me that
> I wouldn't. That's ridiculous.

WHY?!?!?  WHY would it be convenient?  PLEASE, PLEASE, PLEASE, explain
in what respect it would help you at all save time, confusion or
whatever.  _Why_ can't you explain what gains you would draw from such
a message?

-- 
David Kastrup