title: Prolog: how to convert string to integer?
body: <p>So as the title says - how do you convert a string into an integer?
  the idea is something like this:</p>
  
  <pre><code>convert(String,Integer).
  
  examples:
  convert('1',1).
  convert('33',33).
  </code></pre>
  
  <p>I'm using <code>swi prolog</code></p>