June 2018 Update

Task/Queue-Definition/Perl-6/queue-definition.pl6

@@ -0,0 +1,31 @@
+role FIFO {
+    method enqueue ( *@values ) { # Add values to queue, returns the number of values added.
+        self.push: @values;
+        return @values.elems;
+    }
+    method dequeue ( ) {         # Remove and return the first value from the queue.
+                                 # Return Nil if queue is empty.
+        return self.elems ?? self.shift !! Nil;
+    }
+    method is-empty ( ) {        # Check to see if queue is empty. Returns Boolean value.
+        return self.elems == 0;
+    }
+}
+
+# Example usage:
+
+my @queue does FIFO;
+
+say @queue.is-empty;                         # -> Bool::True
+for <A B C> -> $i { say @queue.enqueue: $i } # 1 \n 1 \n 1
+say @queue.enqueue: Any;                     # -> 1
+say @queue.enqueue: 7, 8;                    # -> 2
+say @queue.is-empty;                         # -> Bool::False
+say @queue.dequeue;                          # -> A
+say @queue.elems;                            # -> 4
+say @queue.dequeue;                          # -> B
+say @queue.is-empty;                         # -> Bool::False
+say @queue.enqueue('OHAI!');                 # -> 1
+say @queue.dequeue until @queue.is-empty;    # -> C \n Any() \n [7 8] \n OHAI!
+say @queue.is-empty;                         # -> Bool::True
+say @queue.dequeue;                          # ->