A model for this must provide:

bool fo.operator() ( Kernel::Point_2 p, Kernel::Point_2 q, Kernel::Point_2 r)
returns true iff the three points p, q and r form a left turn or if they are collinear and the distance of q to p is larger than the distance of r to p, where p is the point passed to the object at construction.
Precondition: p does not lie in the interior of the segment rq, i.e. p is an extreme point with respect to {p,q,r}.


AdaptableFunctor (with three arguments)