Given a traversal with the structure:
Strategies are applied in the order:
This prevents strategies from performing global operations across the traversal and all decedents effectively as children will not have been processed by preceding strategies yet.
Say you want a strategy that compresses the entire traversal in to a string for sending over the wire, you want this to happen after everything else, but traversals with children will not have had their children processed.
Ideally strategy application would be as follows:
That way strategy B can check if it is being applied to the root traversal and if it is it knows that A has been applied globally.