title: How to use optional parameters at zend routing
body: <p>I want to set a similar routing to the standard-router with optional parameters, e.g.:</p>
  
  <pre><code>intranet.route = 'intranet/:controller/:action/:title/:id'
  </code></pre>
  
  <p>only the id-parameter doesn't need a value. 
  i tried giving it an default value like <em>null</em> - but then the variable is still set, but i don't want it to exist at all when the user does not give it any value</p>
  
  <p>also, how can i set up a route with dynamic values, just like this:</p>
  
  <p><em>intranet/index/index/Front%20Page/123/foo/bar</em></p>
  
  <p>then the variable $foo exists with the value "bar"</p>