Clojure: Expression Group

Sometimes you need to group several expressions together as one single expression. This can be done with do. (do is like lisp's progn)

(do
    (pr "a")
    (pr "b"))

;; is equivalent to

    (pr "a")
    (pr "b")

Most of the time it's used inside if .

For example:

(if something
    (do
  ; true body
        )
  (do
  ; else body
      ))

do returns the last expression in its body.

(do 3 4 ) ;  4