clojure - Converting defmulti to defprotocol -


is possible convert below code uses defprotocol , defrecord instead of defmulti , defmethod? 

(defmulti test-multimethod (fn [keyword] keyword))  (defmethod test-multimethod :foo [a-map]   "foo-method called")  (defmethod test-multimethod :bar [a-map]   "bar-method called")  (defmulti perimeter (fn [shape] (:shape-name shape))) (defmethod perimeter :circle [circle]   (* 2 math/pi (:radius circle))) (defmethod perimeter :rectangle [rectangle]   (+ (* 2 (:width rectangle)) (* 2 (:height rectangle))))  (def some-shapes [{:shape-name :circle :radius 4}                    {:shape-name :rectangle :width 2 :height 2}])  (defmulti area (fn [shape] (:shape-name shape))) (defmethod area :circle [circle]   (* math/pi (:radius circle) (:radius circle))) (defmethod area :rectangle [rectangle]   (* (:width rectangle) (:height rectangle)))  (defmethod perimeter :square [square]   (* 4 (:side square))) (defmethod area :square [square]   (* (:side square) (:side square)))  (def more-shapes (conj some-shapes                        {:shape-name :square :side 4}))   (for [shape more-shapes] (perimeter shape)) (for [shape more-shapes] (area shape))

yes, declare functions in protocol definition shape, , define implementations in various record implementations square, circle, etc.

(defprotocol shape    (area [this])   (perimeter [this]))  (defrecord square [side] shape   (area [this] (* (:side this) (:side this)))   (perimeter [this] (* 4 (:side this))))  (defrecord rect [w l] shape   (area [this] (* (:l this) (:w this)))   (perimeter [this] (+ (:l this) (:l this) (:w this) (:w this))))  (def s (->square 4)) (def r (->rect 2 5))  (map area [s r]) ; '(16 10) (map :side [s r]) ; '(4 nil) (map :l [s r]) ; '(nil 5)

essentially oop (but immutable) if you're familiar that.

one nice thing defmulti implementation things though, can serialize , deserialize maps , use them as-is, without having reify them specific record class.


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