[jackhill/mal.git] / impls / lib / trivial.mal

;; Trivial but convenient functions.

;; Integer predecessor (number -> number)
(def! inc (fn* [a] (+ a 1)))

;; Integer predecessor (number -> number)
(def! dec (fn* (a) (- a 1)))

;; Integer nullity test (number -> boolean)
(def! zero? (fn* (n) (= 0 n)))

;; Returns the unchanged argument.
(def! identity (fn* (x) x))

;; Generate a hopefully unique symbol. See section "Plugging the Leaks"
;; of http://www.gigamonkeys.com/book/macros-defining-your-own.html
(def! gensym
  (let* [counter (atom 0)]
    (fn* []
      (symbol (str "G__" (swap! counter inc))))))
Commit	Line	Data
dcdb6c02 NB	1	;; Trivial but convenient functions.
dcdb6c02 NB	2
26ced15b NB	3	;; Integer predecessor (number -> number)
	4	(def! inc (fn* [a] (+ a 1)))
	5
dcdb6c02 NB	6	;; Integer predecessor (number -> number)
	7	(def! dec (fn* (a) (- a 1)))
	8
	9	;; Integer nullity test (number -> boolean)
	10	(def! zero? (fn* (n) (= 0 n)))
	11
	12	;; Returns the unchanged argument.
	13	(def! identity (fn* (x) x))
	14
e748a37d NB	15	;; Generate a hopefully unique symbol. See section "Plugging the Leaks"
e748a37d NB	16	;; of http://www.gigamonkeys.com/book/macros-defining-your-own.html
26ced15b NB	17	(def! gensym
	18	(let* [counter (atom 0)]
	19	(fn* []
	20	(symbol (str "G__" (swap! counter inc))))))