title: Scala/Play Framework: How to modify fields in Form object before validation
body: <p>One of the simples things in a web app should be to read fields from HTML forms. The play framework offers the Form class to validate and map those answers. It works fine as long as you don't want to do special things.</p>
  
  <p>I found out that with</p>
  
  <pre><code>   val newform = user.copy(errors = user.errors++Seq(FormError("email", "Already registered")), data = user.data + ("username"-&gt;"correctedName")
  </code></pre>
  
  <p>I can modify errors and fields before redisplaying the form.</p>
  
  <p>But how is it possible to modify fields <strong>before</strong> they get validated?
  It would be nice to remove unwanted white spaces, transform "11.05.2014" into "11-May-2014" and such things.</p>