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 BTW, should it be (eval-after-load 'org '(require 'ob-prolog)) or (eval-after-load "org" '(require 'ob-prolog)) . . . org in quotes? 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 wrote: > > > > On Thu, May 14, 2015 at 11:41 PM, Lawrence Bottorff > 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