title: How to access nested parameter values in Symfony2?
body: <p>I created a parameter in my <code>parameters.yml</code> file:</p>
  
  <pre><code>parameters:
      category:
          var: test
  </code></pre>
  
  <p>How can I access this parameter in my <code>config.yml</code>? For example, I want to pass this parameter to all my twig files as a global twig variable:</p>
  
  <pre><code>twig:
      globals:
          my_var: %category.var% # throws ParameterNotFoundException
  </code></pre>