Some Clojure Tidbits

tidbits.clj

;; CLOJURE STM USING REFS
;; this is just an immutable declaration
(def some-numbers #{1 2 3})

;;if you want to make the above mutable, you can use "refs"
(def some-numbers (ref #{1 2 3 }))

;; @ is used to dereference data
(def current-some-numbers @some-numbers)

;; the set is already dereferenced, so 23 is added to that set
;; the some-numbers remains unchanged
(@some-numbers conj 23)

;; dosync is required when modifying the references
;; alter ref func args => applies the func on the ref "in-place"
(dosync (alter @some-numbers conj 23))

;;how to setting some-numbers to a vector?
;;meaning changing it completely 
(dosync (ref-set @some-numbers [1 2 3 4 5]))