#MoonBit Labeler

#Build from source

#Prerequisites

• MoonBit — moon 0.1.20261104 is the toolchain this release is built and tested with, and it is the minimum. try? was removed in that toolchain, so the pinned riantr/moonbit_image@0.3.9 (the release that replaced try? with an explicit match) does not compile on anything older. Newer toolchains are expected to work but are not what CI runs.
• Node.js ≥ 18 with npm on PATH (for the Vite frontend)
• Proton CLI — proton_cli is the wrapper that drives the native AOT compile, downloads the CEF runtime, and assembles the exe. It is a mooncakes binary package and is installed with:

  moon install moonbit-community/proton_cli@0.9.0

  which drops it in ~/.moon/bin. Pin the version to the one in moon.mod: all published Proton modules use one lockstep version, so an unpinned install floats to the newest release and silently drifts out of lockstep. See https://github.com/moonbit-community/proton.
• PowerShell 5.1 on PATH (Windows-only; the native folder picker spawns powershell.exe -NoProfile -NonInteractive -EncodedCommand)
• ~850 MB of disk for the first CEF download (proton_cli setup)

#One-time setup

# From the project root:
moon install moonbit-community/proton_cli@0.9.0  # the CLI itself
moon update                                     # sync moon.mod deps
proton_cli setup                                 # download the CEF runtime
cd frontend && npm install && cd ..             # Vite + frontend deps

#Build the native executable

proton_cli build -- --release
# output: target/proton-dist/moonbit-labeler/moonbit-labeler.exe

proton_cli package --format app
# output: target/proton-dist/moonbit-labeler/moonbit-labeler.exe
#         plus the CEF runtime beside it (libcef.dll, *.pak, ...)

cd target/proton-dist
tar -a -cf moonbit-labeler-0.2.16.zip moonbit-labeler

#Verify a build

moon test --target native           # 85 tests (blackbox + unit)
node frontend/qa/webkit_picker_blackbox.test.mjs   # frontend blackbox

# The async half of the IPC (the class rename and the video path) is
# covered by Node scripts that drive the real --stdio bridge. They need an
# executable with the CEF runtime beside it, i.e. the packaged app:
node tests/stdio/class_revision_stdio_blackbox.test.mjs \
     target/proton-dist/moonbit-labeler/moonbit-labeler.exe
node tests/stdio/video_stdio_blackbox.test.mjs \
     target/proton-dist/moonbit-labeler/moonbit-labeler.exe --expect-ffmpeg

#Run

# launch the packaged exe (it picks CEF mode if libcef.dll is present,
# --stdio mode if not — see _build/run.bat for the full wrapper):
_build/run.bat

# OR drive the labeler backend over JSON-RPC without launching CEF:
target/proton-dist/moonbit-labeler/moonbit-labeler.exe --stdio
# ...then send one JSON object per line on stdin, read responses on stdout.

#Project layout (high-level)

.
├── app/                            # runnable entry (CEF + stdio)
├── extensions/labeler/             # 27 IPC ops + label/VOC/YOLO/COCO pipeline
├── frontend/                       # Vite + vanilla-JS UI (built into the exe at pack time)
├── moon.mod                        # deps: proton@0.9.0, proton_contract@0.9.0, moonbit_image@0.3.9 (async comes from the builtin moonbitlang/core)
├── proton.project.json             # identifier, frontend, package (output dir, formats, version)
└── AGENTS.md                       # setup + commands + smoke-test recipe (read first)

#Embedding the backend without CEF

pub async fn dispatch_op(op : String, payload : Json) -> Json

#Consuming it from another MoonBit project

moon add riantr/moonbit_labeler@0.2.16

import {
  "riantr/moonbit_labeler@0.2.16",
}

• The published module is native-only. It declares supported_targets = "+native", so the consuming package has to declare supported_targets = "native" as well.
• The async runtime must be declared. dispatch_op is an async function, so an async fn main needs moonbitlang/core/async in the package's moon.pkg, together with options("allow-experimental-packages": ["moonbitlang/core/async"]) — that package is still flagged experimental upstream.
• The package goes in moon.pkg, and nowhere else. The moon.pkg import block is what makes @labeler resolvable. There is no file-level import line, and adding one is a parse error in this toolchain (import <bare path> is not valid syntax — the path form belongs in moon.pkg, and the file refers to the package as @labeler).

# cmd/main/moon.pkg
import {
  "riantr/moonbit_labeler/extensions/labeler",
  "moonbitlang/core/async",
  "moonbitlang/core/json",
}

supported_targets = "native"

pkgtype(kind: "executable")

options(
  "allow-experimental-packages": [ "moonbitlang/core/async" ],
)

// cmd/main/main.mbt

///|
async fn main {
  let ops = @labeler.dispatch_op_list()
  println("op count = " + ops.length().to_string())

  // `dispatch_op` is async and raises, so the error is handled here rather
  // than letting `main` raise.
  let text = @labeler.dispatch_op(
    "list_images",
    @json.parse("{\"path\":\"C:/some/images\"}"),
  ).stringify() catch {
    _ => "dispatch failed"
  }
  println(text)
}

#License