title: Un-define constants with define/apc_define_constants in PHP
body: <p>I'm using constants for output messages in different languages.
  For example, if a user chooses "English", a file with this constant would be required:</p>
  
  <pre><code>define('welcomeMessage','Welcome!');
  </code></pre>
  
  <p>If she chooses "Spanish": </p>
  
  <pre><code>define('welcomeMessage','Bien Venidos!');
  </code></pre>
  
  <p>etc etc...</p>
  
  <p>The problem occurs when a user iterates through languages. I can't redefine constants with either define/apc_define_constants (as far as I know). Can I delete and redefine them?</p>
  
  <p>Is there a good solution for this?</p>