title: Syntax Error: Operator expected in SWI Prolog
body: <p>I keep getting a syntax error every time I try to compile this buffer. I've gone through the ordinary steps of removing all spaces, but still I keep getting the same error every time.</p>
  
  <pre><code>solve_puzzle(Swimmers):-
      Swimmers=[_Girl1,_Girl2,_Girl3],
      [girl(_,_,_,first),girl(_,_,_,second),girl(_,_,_,third)]=Swimmers,
      is_faster(girl(claudia,_,_,_),(_,_,cheltenham_girls,_),Swimmers),
      is_faster(girl(mary,_,_,_),girl(_,table_tennis,_,_),Swimmers),
      member(girl(_,weightlifting,_,first),Swimmers),
      member(girl(mary,_,sydney_girls_high_school,_),Swimmers),
      member(girl(claudia,ballroom_dancing,_,_),Swimmers),
      member(girl(_,_,hornsby_girls_high_school,_),Swimmers).
  
  is_faster(F,S,[F|[S|_]]).
  is_faster(F,S,[F,S,[_|Rest]]):- is_faster[F,S,Rest).
  </code></pre>
  
  <p>Whats doing this? I seem to run into this every time I attempt prolog.</p>