title: Respect Validation for two fields
body: <p>I need to validate form data with Respect. At least one of these fields must have a value: <code>$vfname</code> and <code>$vlname</code>.  After some trial and error, I found that I can concatenate and test with <code>notEmpty()</code>:</p>
  
  <pre><code>v::StringType()-&gt;notEmpty()-&gt;assert($vfname . $vlname)
  </code></pre>
  
  <p>But this seems really hacky. Is there a better way to validate so that at least one of these fields has a value?</p>