(defmacro do1 [expr1 & exprs]
  "Evaluates expr1 and then exprs and returns the value of expr1.
   Similar to Common Lisp's prog1."
  `(let [first-form-val# ~first-form]
     (do ~@forms) first-form-val#))

(defn make-counter [init]
  (let [count (atom init)]
    (fn [n] (do1 @count (swap! count + n)))))