title: How to 'validate' a Symfony form in steps - instead of calling $form->isValid()
body: <p>I am using Symfony 1.3.6 on Ubuntu.</p>
  
  <p>I have a form with a lot of fields on it - rather than showing all the fields in one go (which may intimidate the user), I want to break up the form into stages, so that a user can fill in only the fields displayed, at each step/stage (kinda like a wizard).</p>
  
  <p>In order to do that, I need to write custom methods for the form, e.g.:</p>
  
  <pre><code>validateStep1();
  validateStep2();
  ...
  validate StepN();
  </code></pre>
  
  <p>Where in each of the functions above, I only validate a subset of the available widgets - i.e. I validate only the widgets displayed to the user in that step.</p>
  
  <p>In order to do that, it would be useful if I could call an isValid() method on widgets, however, I have looked at the sfWidget classes and there is no such isValid() method at the widget level.</p>
  
  <p>I don't want to hard code validation for each widget I am using, since this is not <strong>DRY</strong></p>
  
  <p>Does anyone know how I can check  individual widgets in a form to see whether the user entered value(s) are valid?</p>