Clojure，方面，defprotocol，defrecord

Question

(defprotocol IAnimal "IAnimal"
  (report [o]
    (println (type o) " reporting.\n")
    (inner-report o)
    (println (type o) " out.\n")))

(defrecord Dog [] IAnimal
  (inner-report [o]
    (println "Woof Woof.\n")))

(defrecord Cat [] IAnimal
  (inner-report [o]
    (println "Meow Meow.\n")))

(defrecord Vampire [] IAnimal
  (inner-report [o]
    (println "I don't sparkle.\n")))

现在，我希望它输出：

Dog reporting.
Woof Woof.
Dog out.
Cat reporting.
Meow Meow.
Cat out.
Vampire reporting.
I don't sparkle.
Vampire out.

不幸的是，由于上述代码未编译，因此不会发生这种情况。实现“这个”的最佳方法是什么？

我所说的“此”是指我想成为某个协议的一部分的功能，我想为所有记录提供一个实现，并且我希望该功能可以访问记录实现的专用功能。

（这样做的Clojure方法是什么？）

Answer 1

协议就像Java接口一样，它们无法为其方法提供实现。但这有效：

(defn report [o]
  (println (type o) " reporting.\n")
  (inner-report o)
  (println (type o) " out.\n"))

(defprotocol IAnimal
  "the animal protocol"
  (inner-report [o] "a report"))

(defrecord Dog []
  IAnimal
  (inner-report [o]
    (println "Woof Woof.\n")))

(defrecord Cat []
  IAnimal
  (inner-report [o]
    (println "Meow Meow.\n")))

(defrecord Vampire []
  IAnimal
  (inner-report [o]
    (println "I don't sparkle.\n")))

(report (new Cat))
;; user.Cat reporting.
;; Meow Meow.
;; user.Cat out.