Re: Making a function than can only be used interactively

[carlmarcos--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

Jul 3, 2022, 19:53 by tsdh@gnu.org:

> carlmarcos--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org> writes:
>
>>>> Is it possible to make an interactive function than can only be used
>>>> interactively?
>>>>
>>>
>>> I'm not sure I understand your question. A function, that may be
>>> called interactively, is called a "command" in Emacs.  And a command
>>> can definitely be called interactively, either by using it's name
>>> (using M-x) or binding it to a key.
>>>
>> I do not want people to use the function non-interactively.
>>
>
> How restrictive is that! :-)
>
> --8<---------------cut here---------------start------------->8---
> (defun only-interactive ()
>  (interactive)
>  (if (called-interactively-p 'interactive)
>  42
>  (error "You may not call me")))
>
> (only-interactive)
> ;;=> Debugger entered--Lisp error: (error "You may not call me")
>

Focusing on the former two `(if (called-interactively-p 'interactive)` and
`(only-interactive)`.  I would need some meatier examples.  

Using `(if (called-interactively-p 'interactive)`, would I need to put the entire 
implementations inside the if `statement`?


> (call-interactively 'only-interactive)
> ;;=> 42
>
> (cl-letf (((symbol-function 'called-interactively-p)
>  (lambda (&rest _args) t)))
>  (only-interactive))
> ;;=> 42
> --8<---------------cut here---------------end--------------->8---
>
> So as you see, there are many ways around it.
>
> Bye,
> Tassilo
>