Re: Making a function than can only be used interactively

[Stefan Monnier <monnier@iro.umontreal.ca>]

>>    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