Model, Update, View. Three pieces, one loop, zero surprises. We explain The Elm Architecture from scratch with side-by-side examples in Rust and Scala, trace where the pattern came from, why it keeps showing up in TUIs and functional codebases, and when it stops being the right tool.
Move, borrow, clone, Rc, Arc, Cow. Rust gives you six lightsaber forms for ownership. Each one counters a specific threat. Using the wrong form against the wrong opponent is not just inelegant, it is fatal. We map each strategy to the situations where it excels and where it fails catastrophically.
In this part we model the heart of the project: the Task entity, its immutable transitions, and a taxonomy of errors by layers. Less magic, more explicit rules, and fewer surprise bugs.
We kick off the series by building a To-Do CLI in Rust from CodeCrafters’ Project #1, but without turning it into a giant script. We cover architecture decisions, layer boundaries, and why a small project can also teach you serious design.
Reading guide for the Todo CLI in Rust series, featuring the repository’s technical map, recommended reading order, and direct links to files and commits to follow each decision step by step.