Re: Refer to the directory of the currently being loaded elisp script from within the Emacs lisp file itself.

[Hongyi Zhao]

On Fri, Jun 11, 2021 at 9:15 AM Óscar Fuentes <ofv@wanadoo.es> wrote:
>
> Hongyi Zhao <hongyi.zhao@gmail.com> writes:
>
> > On Thu, Jun 10, 2021 at 11:40 PM Óscar Fuentes <ofv@wanadoo.es> wrote:
> >>
> >> Hongyi Zhao <hongyi.zhao@gmail.com> writes:
> >>
> >> >> BTW, the correct method for concatenating a directory and a file name is
> >> >>
> >> >> (load-file
> >> >>   (concat
> >> >>     (file-name-as-directory (file-name-directory load-file-name))
> >> >>     "auth.el.gpg"))
> >> >
> >> > I tried you above code, it still doesn't work with the following info:
> >> >
> >> > file-name-as-directory: Wrong type argument: stringp, nil [2 times]
> >> > Mark set
> >>
> >> load-file-name is defined while the file is being loaded, after that it
> >> is nil. So if you tried with `C-x C-e' or some other interactive command
> >> it wont work.
> >>
> >> Once the code above is in the correct file, save it, start Emacs and
> >> report back what happens.
> >
> > See my current usage on
> > <https://github.com/hongyi-zhao/screen2latex.el/blob/bd820184a29158c14de1afaf564f9e2898dd88ac/screen2latex.el#L45>
> > according to the instructions here.
> >
> > After I start Emacs and tried with `M-x screenlatex RET', I will see
> > the following info in *Messages* buffer:
> >
> > expand-file-name: Wrong type argument: stringp, nil
>
> As explained previously, load-file-name is only defined when the file is
> being loaded, otherwise it is nil.
>
> You can put the directory name on a variable at load time and use that
> variable on your command:
>
> (setq my-directory (file-name-directory load-file-name)

It really does the trick. Thank you for pointing this out. BTW, It should be:

 (setq my-directory (file-name-directory load-file-name))

What about the following according to the tutorial at
<http://ergoemacs.org/emacs/elisp_relative_path.html>?:

(setq my-directory (file-name-directory (or load-file-name buffer-file-name)))

>
> (defun screen2latex ()
> ...
>   (load-file (expand-file-name "auth.el.gpg" my-directory))
>
>

Regards
-- 
Assoc. Prof. Hongyi Zhao <hongyi.zhao@gmail.com>
Theory and Simulation of Materials
Hebei Vocational University of Technology and Engineering
NO. 552 North Gangtie Road, Xingtai, China