topic.clj

(defmacro topic
  ([t] nil)
  ([t form] form)
  ([t form & more]
    `(let [~t ~form] (topic ~t ~@more))) )

(def topic-ex1
  (topic % 1
    (+ 1 %)
    (/ % 2) ) )

(def topic-ex2
  [
    '(->>
      (map vector (range) coll)
      (filter (fn [[f & args]] (apply f args)))
      (map first) )

    '(topic coll
      (map vector (range) coll)
      (filter (fn [[f & args]] (apply f args)) coll)
      (map first coll) ) ] )