Initial data commit

Task/Queue-Definition/PHP/queue-definition-1.php

@@ -0,0 +1,21 @@
+class Fifo {
+  private $data = array();
+  public function push($element){
+    array_push($this->data, $element);
+  }
+  public function pop(){
+    if ($this->isEmpty()){
+      throw new Exception('Attempt to pop from an empty queue');
+    }
+    return array_shift($this->data);
+  }
+
+  //Alias functions
+  public function enqueue($element) { $this->push($element); }
+  public function dequeue() { return $this->pop(); }
+
+  //Note: PHP prevents a method name of 'empty'
+  public function isEmpty(){
+    return empty($this->data);
+  }
+}