Re: Making a function than can only be used interactively

[Christopher Dimech]

> Sent: Tuesday, July 05, 2022 at 10:05 AM
> From: "Christopher Dimech" <dimech@gmx.com>
> To: "Stefan Monnier" <monnier@iro.umontreal.ca>
> Cc: tsdh@gnu.org, help-gnu-emacs@gnu.org
> Subject: Re: Making a function than can only be used interactively
>
>
>
> > Sent: Tuesday, July 05, 2022 at 9:45 AM
> > From: "Stefan Monnier" <monnier@iro.umontreal.ca>
> > To: "Christopher Dimech" <dimech@gmx.com>
> > Cc: tsdh@gnu.org, help-gnu-emacs@gnu.org
> > Subject: Re: Making a function than can only be used interactively
> >
> > >>    Indeed. It's usually discouraged because it's incompatible with
> > >>    non-interactive uses of the function, but in the case under discussion
> > >>    you don't care about that because you already have another function to
> > >>    use for non-interactive calls.
> > > It is indeed incompatible with non-interactive use.  A thing that can be 
> > > done
> > > is fire the warning even when Lisp Code in not transformed into byte-code.
> >
> > You could emit the warning/error during macro-expansion, indeed.
> > Something like:
> >
> >     (defun foo (a b c)
> >       (interactive ...)
> >       (declare (compiler-macro (lambda (_) (error "Called 
> > non-interactively"))))
> >       ...)
> >
> > Not sure what's the benefit, still.

I am not confident the declare command will always work.

Not for

(defun foo ()
(interactive)
(let ((a ...)
(b ...)
(c ...))
...))


> > > Although byte compilation in recommended, I wonder how often people 
> > > actually
> > > byte-compile every file.
> >
> > `flymake-mode` will run the compiler for you to get those warnings right
> > while you're writing the code.  If people don't see the warning because
> > they don't compile their files, then let's fix it by trying to convince
> > them to compile their files, which will come with a lot of other benefits.
> >
> > > Byte compiling will often tell you errors or warning in your elisp
> > > code that you normally wouldn't know, but I think that running an
> > > interactive-only function non-interactively is serious enough to
> > > insert the warning in the warnings buffer anyway.
> >
> > Usually calling an interactive-only function non-interactively is not
> > serious *at all* and very often it's The Right Thing to do.
> >
> >         Stefan
>
> Depends whether the person coding that function thinks it is.  What can he
> do then?  Issue warning as you suggested with `declare`?
>
>