The MoonBit Update——1023

Announcement
1

In October 2023, MoonBit underwent Alpha testing. This post aims to introduce recent updates to MoonBit’s language and toolchain, along with applications developed using MoonBit.

Changes in MoonBit Language

1. According to community feedback, the keyword for top-level functions has been changed from func to fn, unifying it with local functions. This change also helps to prevent unnecessary confusion for developers.

Before:

func fib(num : Int) -> Int {
  fn aux(n, acc1, acc2) {
    match n {
      0 => acc1
      1 => acc2
      _ => aux(n - 1, acc2, acc1 + acc2)
    }
  }
  aux(num, 0, 1)
}

func init {
  println(fib(46))
}

After:

fn fib(num : Int) -> Int {
  fn aux(n, acc1, acc2) {
    match n {
      0 => acc1
      1 => acc2
      _ => aux(n - 1, acc2, acc1 + acc2)
    }
  }
  aux(num, 0, 1)
}

fn init {
  println(fib(46))
}

2. Based on feedback from the community, the Float64 type name has been changed to Double.

Before

let pi : Float64 = 3.14

After

let pi : Double = 3.14
  1. The MoonBit’s toolchain download for Intel-based Mac is now supported. MoonBit

1280X1280
1280X12801280×217 38.7 KB

Additionally, support for Windows is expected to be available by the next few weeks.

Build System

1. moon.pkg and moon.mod have been changed to JSON format

moon.pkg and moon.mod have been changed to JSON format moon.pkg.json and moon.mod.json. The transition from a custom format to JSON is due to the rapid evolution of toolchains. Using JSON reduces maintenance overhead and simplifies integration with other tools, making it a more efficient choice as the toolchain continues to evolve quickly.

Before

moon.mod

module hello

After

moon.mod.json

{
  "name": "hello"
}

Before

moon.pkg

package main

import "hello/lib"

After

moon.pkg.json

{
  "name": "main",
  "import": {
    "hello/lib": ""
  }
}