4 · Wizard

wizard.wizard — wizard.clj, wizard_controller.clj.

State machine

stateDiagram-v2
  direction LR
  [*] --> editing
  state editing {
    direction LR
    [*] --> details
    details --> address : NEXT [name ok]
    address --> review : NEXT [address ok]
    address --> details : BACK
    review --> address : BACK
  }
  review --> saving : SUBMIT
  saving --> done : save! ok / keep receipt
  saving --> review : save! failed / keep error

What to look at

• :initial [:editing :details] — a nested start. The state is a vector all the way through: in ctx, in the store (["editing","details"]) and in the render fn, which branches on (last state).
• Inside :editing, :target :address is relative. :SUBMIT {:target [:saving]} leaves the parent with a full path.
• :RESET and :INIT sit in the machine-wide :on, so they work from every state; :INIT {} is the hatch.
• :saving has an :invoke. save! runs synchronously in the same request; its return value goes to :on-done's action, and (throw (ex-info …)) goes to :on-error, back to the review step with the message in :memory. Type fail as the name to see it.
• The receipt is dissoced on RESET, so the spec expects :receipt nil in the result — the removed-signal null.

Spec: block 4 in examples_test.clj.