Moonbit

MoonBit Action Handbook

This is the fast entry point for MoonBit work.

Use this file for common tasks, then jump to skills/ or references/ only when the task needs more depth.

Start Here

Use these commands to validate the local toolchain and start a project:

moon --version
moon new my-app
moon check
moon test
moon build
moon fmt

If the user asked for a specific target, verify the target in the relevant sub-skill before choosing build flags.

Minimal Code Shapes

Function

fn greet(name: String) -> String {
  "Hello, \{name}!"
}

Main

fn main {
  println(greet("MoonBit"))
}

Struct and enum

struct Point {
  x: Int
  y: Int
}

enum Color {
  Red
  Green
  Blue
}

Trait and impl

pub(open) trait Show {
  fn to_string(self) -> String
}

impl Show for Point with to_string(self) -> String {
  "Point(\{self.x}, \{self.y})"
}

Error handling

suberror NotFound

fn lookup(id: Int) -> String raise NotFound {
  if id <= 0 {
    raise NotFound
  }
  "ok"
}

Task Router

Reference Map

Execution Checklist

Use this checklist before handing work back:

1. Run moon check.
2. Run moon test.
3. Run moon fmt.
4. Build the target the user cares about.
5. If the task touches public API, verify the route to skills/8-architecture-decisions/.

Guidance

• Prefer the sub-skill when the task is focused and specific.
• Prefer references/ when you need deeper detail or a second example.
• Avoid hard-coded claims about exact MoonBit syntax or release dates unless they are verified against the installed toolchain.
• Keep examples minimal in this file; put specialized patterns in the child skills and references.

Notes

• This skill is a router and handbook, not a full tutorial.
• If a user reports a compiler error, route to skills/3-debug-errors/ first and then confirm with references/error-codes.md if needed.
• If a user asks for performance advice, route to skills/5-optimize/ and measure before changing code.
• If a user asks for a new project, route to skills/1-create-project/ and choose the template before writing code.