public static NodeType Neighbour <NodeType, EdgeType>(this IHas <INodeLogic <NodeType, EdgeType> > node, IHas <IEdgeLogic <NodeType, EdgeType> > edge)
where NodeType : IHas <INodeLogic <NodeType, EdgeType> >
where EdgeType : IHas <IEdgeLogic <NodeType, EdgeType> >
{
if (edge.Head().Equals(node))
{
return(edge.Foot());
}
if (edge.Foot().Equals(node))
{
return(edge.Head());
}
return(default(NodeType));
}