// Real world r13

Multi-step form

Wizard, checkout, onboarding. Forward and back navigation, with the submit button only legal on the last step.

Code

wizard.fsl

const wizard = sm`
  account  'next'    → profile;
  profile  'next'    → review;
  review   'submit'  → done;

  profile  'back'    → account;
  review   'back'    → profile;
`;

// 'submit' is only legal on 'review' — the button literally cannot fire elsewhere

Notes

The disabled-state for the submit button comes for free: wizard.valid_action('submit') tells you whether to grey it out, and you wired no logic to make that work.