title: What does the / slash mean in this Prolog Predicate
body: <p>Would anyone be able to explain to me what the forward slash '/' means in the context of this Prolog predicate. I've tried Googling it, reviewing other questions but I can't find a definitive answer, or at least one that makes sense to me. I'm aware of what arity is but I'm not sure this is related.</p>
  <pre><code>move_astar([Square | Path] / G / _, [NextSquare, Square | Path] / SumG / NewH) :-
       square(Square, NextSquare, Distance),
       not(member(NextSquare, Path)),
       SumG is G + Distance,
       heuristic(NextSquare, NewH).
  </code></pre>