defmacro-example.clj

(ns otca.shorts)

(defn wait-return [s r]
  (Thread/sleep (* s 1000))
  r)



#_(defn time-taken [expr]
    (let [start (. System (nanoTime))
          result (expr)
          end (. System (nanoTime))
          total-time (/ (double (- end start)) 100000.0)]
      (println "Took " total-time " to eval")
      result))

(defmacro time-taken [& expr]
  `(let [start# (. System (nanoTime))
         result# (do
                   ~@expr)
         end# (. System (nanoTime))
         total-time# (/ (double (- end# start#)) 100000.0)]
     (println '~expr " took " total-time# " to eval")
     result#))

(comment
  (def var1 "one")
  `(list ~var1 2 3)
  (wait-return 2 "hey")
  (time-taken (+ 1 1))
  (time-taken (+ 1 1) (wait-return 2 "hey"))
  (macroexpand-1 '(time-taken (+ 1 1) (wait-return 2 "hey"))))

100,000??

Nanoseconds are 10^-9 seconds.

Thanks for linking to this code though.