title: Custom date format (callback with php logic)
body: <p><strong>I want to create a dynamic php date format. Example: show the time of the node if it was published today and only the day/month when older then today. I want this format to be available throughout Drupal like the other predefined date formats in Drupal (not just on theme level)</strong>.</p>
  
  <p>I found the (D7 only) hook for hook_date_format_types but even that one doesn't seem to allow for a callback where I could define this PHP logic.</p>
  
  <p>Does anyone know which hook would make this possible? Or a module which does this?</p>