I am currently building a small library that has to traverse a tree of nodes and transform this tree into a document. This tree traversal and transformation is done in a recursive function. Now, it might happen, that the tree contains unsupported nodes. And I want to provide an option for the function, that either skips these unsupported nodes or returns an error tuple in this situation. So far, the easy part, the requirements.

What is the idiomatic Elixir way to stop processing a tree in a recursive function? I plan to handle this with one public function that is called by the user of my module, and the recursive processing is done in a private function. Normally, I would raise an exception and catch this in the public function, either return an ok or an error tuple.

But is this idiomatic?