I don't think this example reads very clearly. Visually you have to parse until you see the next => and then back track one word to figure out the key.
> move( from=> $x, $y, delta=> $up, $right ); Personally I'd write that as either move(from => [$x, $y], delta => [$up, $right]); OR assuming I has a Position object and a vector object move(from => $pos1, delta => $vec1); The original example just seems difficult to parse. Paul