A possible way to write presentations in Halk could be using procedural Perl:

   title 'About Foos And Bars';
   author 'The author';
   theme 'clean';
   pretty_printer 'source_highlight_wrapper.sh';
   
   section 'Section title';
   subsection 'Subsection Title';
   
   slide 'Slide Title', <<'BODY';
   This slide introduces foo, which is further detailed
   <a href="[% halk.link_to_sref('bar') %]">later</a>.
   BODY

That would be simply do()ed, and does not require to know Perl, but to know the syntax of the config file, which can be documented. Recursive file inclusion is trivial. It has the drawback that its flexibility is limited however, but what we want to configure might not be that complicated.