title: Constraint programming in SWI-Prolog
body: <p>I want to have a list L with three elements A,B, and C with the following constraint, </p>
  
  <pre><code>:- use_module(library(clpfd)).
  L[A,B,C], L ins 1..3, A#=B+C.
  </code></pre>
  
  <p>But, it gives an error - <code>Syntax error: Operator expected.</code></p>