{def queue.add
 {lambda {:v :q}
  {let { {_ {A.addlast! :v :q}}}
       } ok}}
-> queue.add

{def queue.get
 {lambda {:q}
  {let { {:v {A.first :q}}
         {_ {A.subfirst! :q}}
       } :v}}}
-> queue.get

{def queue.empty?
 {lambda {:q}
  {A.empty? :q}}}
-> queue.empty?

{def Q {A.new}}    -> Q      []
{queue.add 1 {Q}}  ->  ok    [1]
{queue.add 2 {Q}}  ->  ok    [1,2]
{queue.add 3 {Q}}  ->  ok    [1,2,3]
{queue.get {Q}}    -> 1      [2,3]
{queue.add 4 {Q}}  ->  ok    [2,3,4]
{queue.empty? {Q}} -> false
{queue.get {Q}}    -> 2      [3,4]
{queue.get {Q}}    -> 3      [4]
{queue.get {Q}}    -> 4      []
{queue.get {Q}}    -> undefined
{queue.empty? {Q}} -> true