Tree::Binary::Search::Node is a node for a Tree::Binary::Search tree.
This is a subclass of Tree::Binary and is mostly used by Tree::Binary::Search.
new ($node_key, $node_value)
The constructor takes a $node_key and a $node_value. The key is used by Tree::Binary::Search to order the nodes in the tree. Both arguments are required, and exception is thrown if they are not present.
Returns the node key as set in the constructor. Node keys are write-once-read-only values, if you could change the node key, it would mess up the entire search tree.
This is used by Tree::Binary::Search when it need to re-root a tree due to a deletion.
Makes sure that the node key is cloned as well.