Hashes changed the way we program

        sub handle_article {
            my ($path, $category, $article_body) = @_;
            ...
            # lots of stuff
            ...
            
            # also, generate a count
            # of the number of articles
            # in each category
            # ???
        }

• In C / Fortran / etc, a big pain in the butt

• We'll see later what a big pain