clojure中的合并cond参数(cl样式)

my-cond cond :else

(defmacro my-cond
  [& others]
  (if others
    (let [more# (next others)
          extra-clauses# (if more# `(my-cond ~@more#))
          clause# (first others)]
      (if (= 2 (count clause#))
        `(if ~(first clause#) ~(second clause#) ~extra-clauses#)
        `(if ~(first clause#) ~(first clause#)  ~extra-clauses#)))))


(deftest my-cond-works
  (is (= 3 (my-cond (false 1) (false 2) (3))))
  (is (= "otherwise" (my-cond (false "don't care") ("otherwise"))))
  (is (= nil (my-cond (:one nil) ("otherwise"))))
  (is (= "care" (my-cond (1 "care") ("otherwise"))))
  (is (= "otherwise" (my-cond (false "care") ("otherwise") (true "true"))))
  (is (= "silly" (my-cond (nil "no") (nil) ("yes" "silly")))))

(defmacro my-cond [[if1 then1] & others]
  (when (or if1 then1 others)
    (let [extra-clauses# (if others `(my-cond ~@others))]
      (if then1
        `(if ~if1 ~then1 ~extra-clauses#)
        `(if ~if1 ~if1  ~extra-clauses#)))))

user> (my-cond (false "first") (nil nil) ("otherwise"))
"otherwise"

(defmacro my-cond [[if1 then1] & others]
  (if others 
    `(if ~if1 ~then1 (my-cond ~@others))
    `(if ~if1 ~then1)))

(my-cond (false 1) (false 2) (3 3))   ; results in 3