Implementing a queue

We can implement a queue using Tarsana and the built-in functions for list operations. We will use the array for queue representation as well using this code:

require __DIR__ . '/vendor/autoload.php'; 

use Tarsana\Functional as F; 

$queue = []; 

$enqueue = F\append(F\__(), F\__()); 
$head = F\head(F\__()); 
$dequeue = F\tail(F\__()); 

$queue = $enqueue(1, $queue); 
$queue = $enqueue(2, $queue); 
$queue = $enqueue(3, $queue); 

echo "Queue is ".F\toString($queue)."\n"; 

$item = $head($queue); 
$queue = $dequeue($queue); 

echo "Dequeue-ed item: ".$item."\n"; 
echo "Queue is ".F\toString($queue)."\n"; 

$queue = $enqueue(4, $queue); 

echo "Queue is ".F\toString($queue)."\n"; 

Here, we use the append function to perform enqueue, and the head and tail functions for the first item in the queue...