title: Symfony2 Use PHP Class Constant in YAML Config?
body: <p>I know this is probably not possible, but is there a clean way to use a PHP class constant within a YAML config/services/etc. file for Symfony2?</p>
  
  <p>For example, if I have this:</p>
  
  <pre><code>namespace My\Bundle\DependencyInjection;
  
  class MyClass
  {
      const MY_CONST = 'cookies';
  }
  </code></pre>
  
  <p>Is something like this possible (in a .yml file):</p>
  
  <pre><code>services:
      my_service:
          class: Some\Class
          arguments:
              - %My\Bundle\DependencyInjection\MyClass::MY_CONST%
  </code></pre>
  
  <p>That'd go a long way in helping maintain consistency between the two.</p>