title: PHP abstract properties
body: <p>Is there any way to define abstract class properties in PHP?</p>
  
  <pre><code>abstract class Foo_Abstract {
      abstract public $tablename;
  }
  
  class Foo extends Foo_Abstract {
      //Foo must 'implement' $property
      public $tablename = 'users';   
  }
  </code></pre>