Proof of concept: S-expressions for HTML templating in clojure

sexpr-html-templating.clj

(defprotocol ToHtml
  (to-html [x]))

(extend-protocol ToHtml
  String
  (to-html [s]
    (clojure.string/escape s {\< "&lt;" \> "&gt;" \" "&quot;" \& "&amp;"}))

  clojure.lang.IPersistentMap
  (to-html [attrs]
    (clojure.string/join
     " " (for [[k v] attrs]
           (str (name k) "=\"" (to-html (str v)) "\""))))

  clojure.lang.ISeq
  (to-html [[tag attrs-or-more & more]]
    (if (map? attrs-or-more)
      (str
       "<" tag " " (to-html attrs-or-more) ">"
       (apply str (map to-html more))
       "</" tag ">")
      (str "<" tag ">"
       (apply str (map to-html (cons attrs-or-more more)))
       "</" tag ">"))))

(to-html (div {:class "foo" :id "bar"}
           (h1 "Hello")
           (p "Some text" (i "Italic"))))

(println (to-html '(div {:class "foo" :id "bar"}
                     (h1 "Hello")
                     (p "Some text" (i "Italic")))))

; => <div class="foo" id="bar"><h1>Hello</h1><p>Some text<i>Italic</i></p></div>


;; Then in combination with https://github.com/brandonbloom/backtick, you can do templating via syntax-quote:

  (template (ul {:class "foo-list"} ~@items))