The Complete Rust Programming Reference Guide

Finding all devices

Walking a tree and executing a callback when visiting each node can be done in three ways:

• Pre-order, executing the callback before descending
• In-order, which executes the callback after descending left, but before descending into the right subtree
• Post-order, where the callback is executed after descending

Each of these traversal strategies yields a different order of tree elements, with in-order producing a sorted output, while pre- and post-order create a more structurally oriented sorting. For our users, the in-order walk will provide the best experience, since it also lets them reason better regarding the expected outcome, and, if displayed in a list, it's easier to navigate.

While implementing this walk is very ...