dprint-plugin-zig

Wrapper for Zig's formatter (zig fmt) for use as a formatting plugin in dprint. It formats Zig (.zig) and ZON (.zon) files exactly like zig fmt does, since it's the parser and renderer of Zig's own std (std.zig.Ast) compiled to Wasm.

Install

Install and setup dprint.

Then in your project's directory with a dprint.json file, run:

dprint add zig

Note: You do not need Zig installed globally as dprint will run the formatter from the .wasm file in a sandboxed environment.

Configuration

There's nothing to configure, since zig fmt has no formatting options. The "zig" key in your dprint.json is only there for consistency with other plugins, and any property in it is reported as unknown:

{
  "zig": {},
  "plugins": [
    // ...etc...
  ],
}

The global configuration doesn't apply either. Like zig fmt, the plugin always indents with four spaces, has no line width, and outputs LF newlines, so a file with CRLF newlines is formatted to LF regardless of newLineKind. Range formatting isn't supported, so a request to format part of a file leaves it as it is.

Like zig fmt, a .zon file is formatted as ZON, a UTF-16 little endian file is formatted to UTF-8, and a file that doesn't parse is an error with the same message zig fmt gives (without the file path, since dprint already says which file it is). The plugin doesn't run zig fmt --ast-check's extra checks.

JS Formatting API

• JS Formatter - Browser/Deno and Node
• npm package

Versioning

This repo automatically upgrades to the latest stable release of Zig once a day. You can check which version of Zig is being used by looking at minimum_zig_version in the build.zig.zon file in this repo:

https://github.com/dprint/dprint-plugin-zig/blob/main/build.zig.zon

At the moment, the version of this plugin does not reflect the version of Zig.

Development

The plugin is written in Zig and builds with the Zig version in build.zig.zon, which build.zig requires exactly, since the formatter is part of Zig's std. It's a wasm32-freestanding module with no imports, so it doesn't rely on the dprint CLI providing WASI.

zig build test --summary all # unit tests, plus spec tests comparing against `zig fmt`
zig build # outputs zig-out/plugin.wasm

The spec tests format each file in tests/specs with the plugin and with zig fmt of the Zig running the tests, and check that the output (or the parse error) is the same.

Credits

• Zig by the Zig contributors, under the MIT license.

License

This project is licensed under the MIT License - see the LICENSE file for details. See third_party for the license of the Zig code it includes.