ouped
  (->> pages
      (group-by (comp first keys :computer-of-the-future))
      (filter first)
      (into {})))
◊(def posts
  (-> grouped
    (update :tools #(conj % postmodern))
    (update-vals #(sort-by (comp first vals :computer-of-the-future) %))))
◊(def categories [:principles, :tools, :implementation])
◊(assert (= (set categories) (set (keys posts)))
         (keys posts))

◊(def n (atom 0))
◊(for [category categories])«
<hr>
<h2>◊(name category)</h2>

<ol class="post-list" start="�