Re: Making a function than can only be used interactively

[Christopher Dimech <dimech@gmx.com>]

> 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.
>
> > 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`?