Y Combinator in Clojure

ycombinator.clj

(ns ycombinator)

;; Based on https://blog.klipse.tech/lambda/2016/08/07/pure-y-combinator-clojure.html

(defn factorial [n]
  (if (zero? n)
    1
    (* n (factorial (dec n)))))

(defn factorial-gen [func]
  (fn [n]
    (if (zero? n)
      1
      (* n (func (dec n))))))

(def Y-combinator (fn [f] ((fn [x] (x x))
                (fn [x] (f (fn [y]
                             ((x x) y)))))))
(defn Y [f]
  ((fn [x] (x x))
   (fn [x]
     (f (fn [y] ((x x) y)))
     )))
  
#_(
    ((Y factorial-gen) 19)
   121645100408832000
)