How to set executable path for a package on a configuration file on Emacs?

Question

I want to use "ediprolog" package on Emacs. I followed installation and usage instruction here https://www.metalevel.at/ediprolog/ and he says:

The two most important configuration options are:

ediprolog-system, either scryer (default) or swi

ediprolog-program, the path of the Prolog executable.

So I tried C-X , customize-group , ediprolog and checked the configuration file. The files looks like this:

To be honest I have no idea how, where can I edit to add the prolog executable path ~/.cargo/bin/scryer-prolog. In addition, Emacs says You can't edit this part of the Custom buffer when I tried to type something on the file.

And as I can expected, when I run ediprolog-dwim, "view-echo" says ediprolog-run-prolog: No prompt from: scryer-prolog, probably because I don't set the path on a configuration file.

I'm noob to Emacs and the package also, sorry about that, but I'm really struggling to achieve this step. Your comments must be really helpful for me. Thanks.

Answer 1

Try adding the path to the exec-path variable in emacs: when emacs forks off a subshell, this variable is added to the PATH that is passed to the subshell:

(add-to-list 'exec-path (expand-file-name (substitute-in-file-name "$HOME/.cargo/bin")))