I think this kind of control mechanism is not a great idea and could lead to easy bugs. I think it's a better idea to write a function that applies a function

I think this kind of control mechanism is not a great idea and could lead to easy bugs. I think it's a better idea to write a function that applies a function to the elements of a tree. Ideally you'd make a function for each traversal order. This makes it obvious what is happening. map_tree_pre(my_tree, my_func); map_tree_in(my_tree, my_func); map_tree_post(my_tree, my_func); map_tree_bfs(my_tree, my_func);