for http://aan.io/timing-clojure-macros/

timing-clojure-macros-1.clj

λ: (time (+ 2 2))
"Elapsed time: 0.02675 msecs"
4

timing-clojure-macros-10.clj

λ: (timed (+ 2 2))
"Timed +: 0.066662 msecs"
4

timing-clojure-macros-2.clj

λ: (source time)
(defmacro time
  "Evaluates expr and prints the time it took.  Returns the value of
 expr."
  {:added "1.0"}
  [expr]
  `(let [start# (. System (nanoTime))
         ret# ~expr]
     (prn (str "Elapsed time: " (/ (double (- (. System (nanoTime)) start#)) 1000000.0) " msecs"))
     ret#))
nil

timing-clojure-macros-3.clj

(defmacro get-funtion-name 
  [expr] 
  (prn (:name (meta (resolve expr)))))

timing-clojure-macros-4.clj

λ: (get-funtion-name +)
+
nil

timing-clojure-macros-5.clj

λ: (get-funtion-name (+ 2 2))
λ: ClassCastException clojure.lang.PersistentList cannot be cast to clojure.lang.Symbol  clojure.core/ns-resolve

timing-clojure-macros-6.clj

(defmacro better-get-funtion-name 
  [expr] 
  (let [sym (= (type expr) clojure.lang.Symbol)]
    (prn (:name (meta (if sym  
                        (resolve expr)  
                        (resolve (first expr))))))))

timing-clojure-macros-7.clj

λ: (better-get-funtion-name +)
+
nil

timing-clojure-macros-8.clj

λ: (better-get-funtion-name (+ 2 2))
+
nil

timing-clojure-macros-9.clj

(defmacro timed [expr]
  (let [sym (= (type expr) clojure.lang.Symbol)]
    `(let [start# (. System (nanoTime))
           return# ~expr
           res# (if ~sym  
                    (resolve '~expr)  
                    (resolve (first '~expr)))]
       (prn (str "Timed "
           (:name (meta res#))
           ": " (/ (double (- (. System (nanoTime)) start#)) 1000000.0) " msecs"))
       return#)))