title: Which is best $this or self or static when referencing const variable?
body: <p>I learned that <strong>static</strong> is better than <strong>self</strong> because self does late static binding.</p>
  
  <p>But I wonder which would be best at referencing <strong>const</strong> variable.</p>
  
  <pre><code>class Black
  {
      const color = 'black';
  
      public function byThis()
      {
          return $this::color;
      }
  
      public function bySelf()
      {
          return self::color;
      }
  
      public function byStatic()
      {
          return static::color;
      }
  }
  </code></pre>
  
  <p>I checked all of three getters work well. Which is the best choice? (I use PHP 7.0)</p>