Cannot edit "Prolog Program Name" on SWI-Prolog with GNU-Emacs (trying to setup inferior Prolog process)

Question

I am on Windows 8, I like Emacs and wish to use it for Prolog programming. I am trying to set up an inferior Prolog process from which to query Prolog programs.

I am following this installation. I have successfully followed steps 1 (saved on C:\Users\Username\Emacs-24.3\site-lisp), 2, 3, and some of 4. But I cannot

Go to "Prolog Inferior" group and edit "Prolog Program Name", to insert SWI Prolog's command pathname as there is no edit option to be found.

My question:

• how to edit prolog-program-name, or
• how to insert SWI Prolog's command pathname, or
• how to set up an inferior Prolog process on emacs ?

Thank you!

Answer 1

If swipl is in your $PATH, you don't need any customization at all. But otherwise, just use the built-in prolog-mode and add something like (setq prolog-program-name "c:/Users/Username/SWI-Prolog/swipl"). Note the use of forward slashes instead of backslashes.

Answer 2

Somehow this is what worked for me. This is on Emacs 26.3. After upgrading all my packages, C-c C-b in Prolog buffers had changed its behaviour into running GNU Prolog by default. Under Prolog Program Name, which appears to be a dictionary, there is a key t which was set to gprolog. So I set it to swipl as highlighted in the screenshot, and got back the previous/desired behaviour.