public LabeledTree <N, E> TransformTopDown(Func <N, E, N, N> fn)
{
var edges = from edge in Edges
let newTarget = fn(Label, edge.Label, edge.Target.Label)
select LabeledTree.Edge(edge.Label, LabeledTree.Node(newTarget, edge.Target.Edges).TransformTopDown(fn));
return(LabeledTree.Node(Label, edges));
}
private LabeledTree <NodeLabel, EdgeLabel> ToTree(Node rootNode, ISet <NodeLabel> visitedNodes,
Func <NodeLabel, EdgeLabel, NodeLabel, bool> edgeFilter)
{
if (visitedNodes.Contains(rootNode.Label))
{
return(LabeledTree.Node <NodeLabel, EdgeLabel>(rootNode.Label));
}
else
{
visitedNodes.Add(rootNode.Label);
var edges = from e in rootNode.Edges
where edgeFilter(rootNode.Label, e.Label, e.TargetLabel)
from target in Nodes.FirstOption(n => NodeComparer.Equals(n.Label, e.TargetLabel))
select LabeledTree.Edge(e.Label, ToTree(target, visitedNodes, edgeFilter));
return(LabeledTree.Node(rootNode.Label, edges));
}
}