MoonBit and Zig

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This is an experimental project exploring interoperability between MoonBit and modern systems programming languages.

Project Goals

This project started as an effort to implement an HTTP client in MoonBit. Instead of relying on traditional libcurl-based solutions, this project takes a more exploratory approach with the following goals:

1. Achieve complete independence from libcurl.
2. Implement the HTTP client using Zig's standard library.
3. Explore integration patterns between MoonBit and C/Zig.

Rationale for Technical Choices

Zig was chosen over C for the underlying implementation due to several advantages:

1. Dependency Management

• The C ecosystem often involves complex dependency management.
• This typically requires manual configuration of compilers (like GCC), library paths, and linking.
• In contrast, Zig offers a modern build system and a comprehensive standard library.

2. Standard Library Capabilities

• Zig's standard library includes a built-in HTTP client implementation.
• This eliminates the need for external dependencies for core HTTP functionality.

3. Interoperability

• Interoperability is achieved via the C ABI (Phase 1).
• Direct MoonBit - Zig interoperability (Phase 2) (Implemented).

Architecture Evolution

The key components are:

• MoonBit: The primary language for application development.
• Zig: Implements the underlying HTTP client logic.
• C: Acts as the intermediate bridge (in Phase 1).

Past Architecture (Phase 1)

21e56bb

MoonBit -> C ABI -> Zig

Current Architecture (Phase 2)

MoonBit -> Zig

Usage Example

fn main {
  // GET request
  println(@http.curl_get("https://api.example.com"))
  
  // POST request
  println(@http.curl_post("https://api.example.com", "{'data': 'test'}"))
}

CLI

> ./zig-out/bin/moonbit_zig
 No request url.

 Usage:
  moonbit_zig <url>

> ./zig-out/bin/moonbit_zig https://jsonplaceholder.typicode.com/todos/1
It Works! You've requested: https://jsonplaceholder.typicode.com/todos/1
{
  "userId": 1,
  "id": 1,
  "title": "delectus aut autem",
  "completed": false
}

Build

The project uses Zig build system, controlled by moon command:

moon build --target native

Notes

1. Requires Zig 0.11.0 or higher
2. Ensure MoonBit runtime environment is properly set up
3. Currently supports macOS/aarch64 platform only

Limitations and Known Issues

The current implementation has a significant limitation: the exception handling mechanism is incomplete. While direct function calls from MoonBit to Zig have been implemented, there are issues when handling exceptions thrown from the Zig side. Specifically, Zig's errors cannot currently be gracefully converted into MoonBit's exception handling mechanism.