On 16 May 2015, at 15:00, Lawrence Bottorff <borgauf@gmail.com> wrote:

I'm just a Prolog beginner, but this:

#+begin_src prolog

edge(a,b).

edge(a,e).

edge(b,d).

edge(b,c).

edge(c,a).

edge(e,b).

tedge(Node1,Node2) :-

        edge(Node1,SomeNode),

        edge(SomeNode,Node2).

#+end_src

keeps giving me this:

executing Prolog code block...

executing Prolog source code block

org-babel-execute:prolog: Wrong type argument: char-or-string-p, ni

Thank you for reporting a bug. I think I see what the problem is. You haven't defined a goal for the source block and ob-prolog doesn't guard for that. It should be easy to fix, but I am not sure if I will be able to do that before next week. If you want you can try to fix it yourself and send a PR on GitHub or a patch here. 

BTW, should it be

(eval-after-load 'org

  '(require 'ob-prolog))

or 

(eval-after-load "org"

  '(require 'ob-prolog))

. . . org in quotes?

I think both should work. I can't check right now as I only have my phone with me right now. 

On Thu, May 14, 2015 at 5:03 PM, Bjarte Johansen <bjarte.johansen@infomedia.uib.no> wrote:

> On 14 May 2015, at 20:22, Puneeth Chaganti <punchagan@gmail.com> wrote:
>
> On Thu, May 14, 2015 at 11:41 PM, Lawrence Bottorff <borgauf@gmail.com> wrote:
>>
>> Confused by the requirement:
>>
>> ;; To activate ob-prolog add the following to your init.el file:
>> ;;
>> ;;  (eval-after-load 'org
>> ;;    '(require 'org-prolog))
>
>
> I'm guessing its a typo and should be ob-prolog. The file provides ob-prolog.

Yes, I typed it wrong. Thank you for bringing it to my attention. I also discovered that it is better to use `org-babel-do-load-languages’ instead as well. I will change the recommendation tomorrow.

Regards,
Bjarte