I found that with-meta applied to a function returns an instance of RestFn.
However, I know that invoking a function through applyTo is much slower than through invoke.
The benchmarks in :thread: confirm this.
Is it a problem that a function with metadata is slower than it could be?
If so, I could propose a solution - to proxy all methods like invoke to the original function, not just applyTo.
https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/AFunction.java#L31-L33
(require '[criterium.core :as c])
(defn f [x]
x)
(c/quick-bench
(f 1))
;; Execution time mean : 1,642094 ns
(defn wrapper [f]
(fn [y]
(f y)))
(let [f' (wrapper f)]
(c/quick-bench (f' 1)))
;; Execution time mean : 5,016630 ns
(let [f'' (with-meta f {:foo :bar})]
(c/quick-bench (f'' 1)))
;; Execution time mean : 31,332965 ns
(defn wrapper' [f]
(fn [& args]
(apply f args)))
(let [f''' (wrapper' f)]
(c/quick-bench (f''' 1)))
;; Execution time mean : 41,983970 ns
Additional links:
- https://clojurians.slack.com/archives/C03S1KBA2/p1740750168290999
- https://github.com/camsaul/methodical/pull/150
