MoonGridGym

MoonGridGym is a lightweight Gym-style environment suite written in MoonBit. It bundles a small set of classic grid environments behind one consistent API:

• GridWorld
• CliffWalking
• Maze
• FrozenLakeLike
• RandomMaze

Each environment exposes the same three operations:

• reset()
• step(action)
• render()

The suite also ships with a built-in shortest-path solver and rollout helpers for quick demos and evaluation.

The goal is to give MoonBit developers a clean, easy-to-test foundation for simulation, planning, search, and reinforcement-learning demos.

Why this is a good OSC2026 topic

• It is useful on its own, not just as a demo.
• It sits in a mature area, so the scope can grow without getting narrow.
• It is small enough to fit the contest’s reference code-size range.
• It gives you good README, tests, and example material for review.

Quick Start

moon check
moon test
moon run cmd/main

API

Create a scenario with one of the convenience constructors:

• new_grid_world(seed)
• new_cliff_walking(seed)
• new_maze(seed)
• new_frozen_lake_like(seed)
• new_random_maze(seed)

Then use the same interface everywhere:

let env = @moongridgym.new_grid_world(7)
let obs = env.reset()
println(env.summary())
println(obs.ascii)
let result = env.step(@moongridgym.Action::Right)
println(result.info)
println(result.observation.ascii)

Actions

• Up
• Down
• Left
• Right
• Stay

Scenarios

• GridWorld focuses on pathfinding with a simple obstacle layout.
• CliffWalking mirrors the classic control task with a harsh failure state.
• Maze is a fixed benchmark maze for deterministic examples.
• FrozenLakeLike adds slipping behavior and holes.
• RandomMaze generates a seeded maze for replayable experiments.

Solver Helpers

• shortest_path() returns a BFS plan from the current agent position.
• route_string() formats that plan as a readable action sequence.
• rollout(actions) runs a batch of actions and summarizes the episode.
• auto_solve() runs the shortest-path plan when one exists.

Repository policy

• MoonBit is the primary implementation language.
• The code in this repository is original and written from scratch.
• No upstream source code is copied into this project.
• If you later port or reference another project, list the upstream source, license, and scope of reuse here before submission.

Official Mirrors

• GitLink: https://gitlink.org.cn/zyjzyj78/MoonGridGym
• GitHub: https://github.com/zhaoyuanjuns/MoonGridGym

Contribution Rules

• The default branch is master.
• The commit history is authored by a single contributor account.
• No virtual or secondary contributors are included.

Contest readiness checklist

• Public repository
• Clear README
• MIT license
• Runnable example
• Automated tests
• GitHub Actions CI
• Mooncakes.io publication before final submission

Notes for submission

The OSC2026 guide requires the repository to be public, readable, and actively maintained. It also expects the acceptance materials to show the repository link, README, CI, tests, and Mooncakes publication.

If you publish this project to GitHub, replace the empty repository field in moon.mod with the final URL.