Machines examples

Worked, runnable apps — the machine features you read about, running.

New to machines? Build one yourself first — the Tutorial walks you through a login machine step by step — then skim Concepts for the whole model. After that, work through the apps below in order: each adds a little more machinery than the last.

• state_machine_walkthrough — your first machine, end to end. The Concepts login flow as runnable code: a self-contained transition table, with guards and actions living with the spec rather than in a global registry, driven headlessly to show the pure-transition + drain testing story. Read first: Concepts. → source
• nine_states — parallel regions and tags. One :type :parallel machine with three orthogonal regions (:data / :form / :mode) and :tags; a render-priority table over the tag union collapses all nine canonical UI states into a single case in the root view. Read first: Parallel states and Tags. → source
• long_running_work — spawning workers, and cancelling them cleanly. Cancellable long-running work via :spawn-all: one parent coordinator spawns N parallel worker children, with per-step progress as an internal self-transition and a cooperative cancellation cascade that fires on every exit path — including unmount. Read first: Actors. → source
• websocket — the lot, in one machine. The canonical connection machine: a hierarchical compound :active state parenting connect/auth/connected, a :spawn'd socket actor bound to that state, :after exponential backoff, :always queue-flush on reconnect, and connection-epoch staleness against the live socket id. Read first: Hierarchical states, Actors, and Automatic transitions. → source

One more — not a machine, included only for substrate variety:

• process_monitor_helix — a Helix two-pane process monitor. It shows Helix consuming subs via use-subscribe and a live :dispatch-later tick loop, but has no state machine. Reach for it to see the ideas under another substrate, not as a machine example. → source