go2 =>
  println("Test 2"),
  queue_test2,
  nl.

empty2() = [].
push2(Queue, Value) = Q2 =>
  Q2 = [Value] ++ Queue.
pop2(Q,_) = _, Q==[] ; var(Q) =>
   throw $error(empty_queue,pop,'Q'=Q).
pop2(Queue,V) = [Queue[I] : I in 1..Queue.len-1] =>
   V = Queue.last().

queue_test2 =>
    % create an empty queue
    Q = empty2(),
    printf("Create queue %w%n%n", Q),

    % add numbers 1 and 2
    println("Add numbers 1 and 2 : "),
    Q := Q.push2(1).push2(2),

    % display queue
    printf("Q: %w\n\n", Q),

    % pop element
    Q := Q.pop2(V),

    % display results
    printf("Pop : Value: %w Queue: %w\n\n", V, Q),

    % test the queue
    print("Test of the queue: "),
    ( Q.empty() -> println("Queue empty"); println("Queue not empty") ),
    nl,

    % pop the elements
    print("Pop the queue : "),
    Q := Q.pop2(V2),
    printf("Value %w Queue : %w%n%n", V2, Q),

    println("Pop empty queue:"),
    catch(_ = Q.pop2(_V),Exception,println(Exception)),

    % command chaining
    println("\nCommand chaining: "),
    Q := Q.push2(3).push2(4),
    Q := Q.pop2(V3).pop2(V4),
    printf("V3: %w V4: %w\n", V3, V4),
    nl,
    println(q=Q).