title: Simple Prolog factorial program loading
body: <p>I am learning Prolog using SWI-Prolog.
  Here is my practice code in file <code>fact.pl</code>:</p>
  
  <pre><code>factorial(N,F) :- N is 0, F is 1;
                N &gt; 0, M is N - 1, factorial(M,G), F is N*G.
  </code></pre>
  
  <p>While I was trying to load this file by using <code>[fact.pl]</code>, the interpreter gives me the following error:</p>
  
  <pre><code>?- [fact.pl].
  ERROR: Syntax error: Operator expected
  ERROR: [fact
  ERROR: ** here **
  ERROR: .pl] .
  </code></pre>
  
  <p>I am not sure how this happens, and I am pretty sure what I have done is the standard program loading command.</p>
  
  <p>Anyone has ever seen this please help, thank you. </p>