List<Node> EdgesFor(Node node)
{
List<Node> value;
if (edges.TryGetValue(node, out value))
return value;
return edges[node] = new List<Node>();
}
public void Connect(Node from, Node to)
{
var fromEdges = EdgesFor(from);
if (fromEdges.Contains(to))
return;
fromEdges.Add(to);
}
void Append(Node node)
{
if(node.IsEmpty)
return;
Append(node.ToString());
}