title: Defining lists in prolog scripts
body: <p>I am new to prolog programming and have been told in a tutorial to define a list of structures (in a script) so that I can query it as a database. However I find it impossible to define this list as a variable in a script. When I define a list such as</p>
  
  <pre><code>X=[a,b,c].
  </code></pre>
  
  <p>I just receive an error saying </p>
  
  <pre><code>No permission to modify static_procedure `(=)/2'
  </code></pre>
  
  <p>Does prolog not support defining variables such as this? I am using SWI-Prolog under linux.</p>