why-clojure#2.clj

why-clojure#2.clj

;; refs are never mutated
;; equality is value-based, not identity based
;; but you can still compare identity
(let [a [1 2 3]
      b (conj a 4)]
  (prn a) ;; [1 2 3]
  (prn b) ;; [1 2 3 4]
  (= a b) ;; false
  (= a (drop-last b)) ;; true
  (identical? a (drop-last b)) ;; false
  )

why-clojure#2.js

var a = [1, 2, 3]
var b = a.push(4)
console.log(a) // [1, 2, 3, 4]
console.log(b) // 4, heh
b = [1, 2, 3, 4]
console.log(a == b) // false
console.log(a === b) // false
;[1,2,3] == [1,2,3] // false