Conclusion

This example demonstrated several advanced features of Transit:

• Automatic update function generation: When your state machine has no conditional transitions and preserves state payload types, you can use mkUpdateAuto to let the compiler generate the update function for you, eliminating boilerplate code.

• Manual layout control: Unlike the previous examples that used automatic layouts, we showed how to precisely position nodes using the Manual layout option, giving you complete control over the visual representation of your state machine.

• Graph analysis verification: We verified that this graph has an Eulerian trail using the same hasEulerTrail function from the previous example, demonstrating how Transit’s graph analysis capabilities work consistently across different state machines.

Together with the previous examples, we’ve seen how Transit provides a comprehensive solution for building type-safe state machines, generating documentation, and performing graph analysis — all from a single type-level specification.