June 2018 Update

Task/Queue-Definition/Elena/queue-definition.elena

@@ -0,0 +1,62 @@
+import extensions.
+
+template queue :: type
+{
+    array<type> theArray.
+    int         theTop.
+    int         theTale.
+
+    explicit
+    [
+        theArray := type<>(8).
+        theTop := 0.
+        theTale := 0.
+    ]
+
+    bool empty
+        = theTop == theTale.
+
+    push type:anObject
+    [
+        if (theTale > theArray length)
+        [
+            theArray := theArray reallocate(theTale).
+        ].
+
+        theArray[theTale] := anObject.
+
+        theTale += 1.
+    ]
+
+    type pop
+    [
+        if (theTale == theTop)
+            [ InvalidOperationException new:"Queue is empty"; raise ].
+
+        type item := theArray[theTop].
+
+        theTop += 1.
+
+        ^ item
+    ]
+}
+
+program =
+[
+    queue<int> q := queue<int>().
+    q push(1).
+    q push(2).
+    q push(3).
+    console printLine(q pop).
+    console printLine(q pop).
+    console printLine(q pop).
+    console printLine("a queue is ", q empty; iif("empty","not empty")).
+    console print("Trying to pop:").
+    try(q pop)
+    {
+        on(Exception e)
+        [
+            console printLine(e message)
+        ]
+    }
+].

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;                          # ->