Re: Smarter M-x that filters on major-mode

[Alan Mackenzie]

Hello, Stefan.

On Sun, Feb 14, 2021 at 17:33:30 -0600, Stefan Kangas wrote:
> Alan Mackenzie <acm@muc.de> writes:

> >> - This is a clean and natural expansion of `interactive'.

> > How can you say this?  The new stuff going into `interactive' has
> > nothing to do with its current function.  See above.  Please answer this
> > point.

> Well, what is `interactive'?  According to the ELisp Manual:

>  -- Special Form: interactive arg-descriptor
>      This special form declares that a function is a command, and that
>      it may therefore be called interactively (via ‘M-x’ or by entering
>      a key sequence bound to it).

> So `interactive' is exactly about showing it on `M-x'.  Now we add an
> extension to that which says _in which modes_ `M-x' will show it (by
> default).  That feels very natural to me.

No, it's not about "showing" the command.  It's about executing it.
Surely you see there's a difference, a substantial difference, between
searching for a command, or choosing one, and then executing it?  At the
very least, the new stuff proposed for `interactive' is MUCH more
loosely connected with the current stuff, than the current stuff with
itself.

I would further say that the new stuff for `interactive' isn't anything
to do the the command it's going into - it's to do with that command's
relationship with other entities.  So this change to `interactive' is
suboptimal from a software engineering viewpoint - when these
relationships change, lots of functions will need changing rather than
just the forms expressing those relationships.

I'm worried that Lars hasn't chosen to answer my post from yesterday
afternoon, and that he may be ploughing ahead with this, despite the
reservations expressed by several people.

Just to be entirely clear, I'm in favour of this new functionality for
M-x (provided, of course, that it is optional).  But the degree of
disruption caused to Emacs by the proposed way of implementation seems
quite out of proportion to what will be gained, and also seems quite
unnecessary.

> >> - I'm not sure what it means to turn things upside down.

> > Sorry, that's a bit of English idiom.  It means moving things around
> > a lot, changing lots of things, usually with the implication that
> > the result won't have justified the extent of the required effort.

> OK, that is approximately what I understood.  But I put it in a bit
> more blunt language that you did not intend to use.  I apologize if
> this misrepresented your position, as that was not my intention.

No problem!  If I use idiomatic English, I shouldn't expect it to be
understood all the time.

-- 
Alan Mackenzie (Nuremberg, Germany).