Yichus

Yichus is a Bosatsu application for Bosatsu developers. Build provenance-aware interactive demos and simulations that let you ask “why did this value happen?” and explore alternate paths instantly.

No Virtual DOM Direct DOM Updates Why? Explanations What-If Analysis Sweep Charts Explorer IO Graph Export

Featured

Benchmarks Performance

Playground

Write Bosatsu simulation code and compile it entirely in your browser — no server required. Edit, run, and explore results with full Why-provenance tracing.

Open Playground Powered by Scala.js

Learn and verify

UI demos No Virtual DOM

Counter

Minimal state updates with deterministic event-to-output behavior.

Todo List

List state operations with predictable add/remove update paths.

Form Input

Controlled inputs and state synchronization without hidden effects.

Particles

Large animated state updates using incremental runtime updates.

Simulation demos Why? + What if?

Investment

Run portfolio assumptions and compare outcomes across scenarios.

Game demos Grid + Replay

Time Travel Puzzle

Program a move loop, predict future-self collisions, and verify the replay on the full game surface.

Time Travel Stepper

Step the deterministic rules fixture tick by tick to inspect collisions, rewinds, and win conditions.

Grid Smoke Test

Validate the reusable grid renderer, tile palette, and entity drawing primitives that power the game.