3
下面是update-in
的源代码:元数Clojure中的源代码超载
(defn update-in
([m [k & ks] f]
(if ks
(assoc m k (update-in (get m k) ks f))
(assoc m k (f (get m k)))))
([m [k & ks] f a]
(if ks
(assoc m k (update-in (get m k) ks f a))
(assoc m k (f (get m k) a))))
([m [k & ks] f a b]
(if ks
(assoc m k (update-in (get m k) ks f a b))
(assoc m k (f (get m k) a b))))
([m [k & ks] f a b c]
(if ks
(assoc m k (update-in (get m k) ks f a b c))
(assoc m k (f (get m k) a b c))))
([m [k & ks] f a b c & args]
(if ks
(assoc m k (apply update-in (get m k) ks f a b c args))
(assoc m k (apply f (get m k) a b c args)))))
据我知道(我现在不太多),这总是给相同的结果:
(defn my-update-in2
([m [k & ks ] f & args]
(if ks
(assoc m k (apply update-in (get m k) ks f args))
(assoc m k (apply f (get m k) args)))))
我的问题:为什么不是update-in
(和许多其他Clojure函数)以这种方式实现?我猜想有性能问题,即。不使用apply
更快。