bun[c/h]

bun[c/h] (pronounced "bunch") is a bun plugin that allows you to automatically import and link C/C++ libraries via C header files.

Installation

Bun[c/h] depends on clang for parsing C/C++ header files. clang must be in your path for bun[c/h] to work.

On linux, install clang with your distribution's package manager.

# Debian/Ubuntu
sudo apt install clang
# Arch
sudo pacman -S clang
# etc. you're smart enough to figure it out

On macOS, clang is provided by the xcode command line tools.

xcode-select --install

On windows, you can grab clang from LLVM's releases page. Make sure to add its directory to your PATH.

Then, add bun[c/h] to your project

bun add @kodicraft/bunch

Usage

Loading the plugin

To use bun[c/h] in your project, create a file to store plugin configuration. If you don't have one already, create a file called plugins.ts or plugins.js in your project's root directory. Then, add the following to the file:

import bunch from "bunch";
import { plugin } from "bun";

plugin(bunch({
    // Where to find libraries. Bun[c/h] will search for a library with the same name as the header in each directory in order. Defaults to ["/usr/lib", "/usr/local/lib""]
    lib_dirs: ["path/to/libraries"],

    // Whether to honor the LD_PRELOAD environment variable. If true, bun[c/h] will take libraries mentionned by the path here before looking at any other directories. Defaults to true.
    honor_ld_preload: true,

    // Whether to honor the LD_LIBRARY_PATH environment variable. If true, bun[c/h] will add the directories mentioned by the path here to the list of directories to search for libraries. Defaults to true.
    honor_ld_library_path: true,

    // If set, force bun[c/h] to use a specific file extension for libraries instead of using your OS's default. Defaults to undefined.
    lib_ext: "so",

    // Directory in which to store persistent data related to bun[c/h]. Defaults to "./.bunch".
    bunch_dir: "./.bunch",

    // Whether or not to create type declarations for libraries. Recommended when using bun[c/h] with TypeScript. Defaults to true.
    create_d_ts: true,

    // Whether or not to use a cache to avoid re-parsing unchanged header files. Defaults to true.
    use_cache: true,
}));

You may play around with the config to get something that works for you.

Then, add plugins.ts/plugins.js to your bunfig.toml file:

preload = ["plugins.ts"]

[test]
preload = ["plugins.ts"]

Importing libraries

To import a library, simply import the library's header file like you would any other module:

import { function } from "simple.h";

Functions defined in simple.h are now available to call. Bun will automatically handle linking the library and loading the functions.

Note that there is do default export yet, but plans are in the works to add one.

Issues

Bun[c/h], while technically feature-complete and functional, still provides a couple of drawbacks which may make its usage more difficult (especially when using TypeScript) than I'd like to to be.

Loaders and LSP

Currently, bun's loaders have no way to tie into your LSP. This means that although bun[c/h] generates valid TypeScript, intellisense will not be able to provide proper suggestions. Even worse, your LSP will actually report errors when trying to import header files.

Because of this, bun[c/h] will require you to tinker with your tsconfig.json file for a bit to get everything to work properly. You will need to add the following to your tsconfig.json file:

{
    "compilerOptions": {
        "typeRoots": ["node_modules/", ".bunch/types/"]
    },

    "paths": {
        "example_library.h": ["./relative/path/to/example_library.h"]
        // ^ This needs to just be the exact name of your header file
        // You will be able to import it directly with the name you specify here
    }
}

For this to work, you will have to run your project (and import the header files) at least once before you can get intellisense to work. This is because bun[c/h] needs to generate the TypeScript bindings before you can use them.

Import arguments and multi-header libraries

A common pattern with large libraries is allowing you to include multiple different headers that provide different functionality. For example, the SDL2 library provides a header called SDL.h that provides the core functionality of the library, but also provides headers like SDL_image.h and SDL_ttf.h that provide additional functionality. All of these files have different names but you are only meant to import libSDL2.so once.

You might also notice that it is a bit weird for bun[c/h] to expect your header file and library to have the same name save for the extension. Ideally, they should be separate, however, that is not currently possible to achieve in bun.

Bun custom loaders are not able, to my knowledge, of getting any extra information other than the file name of the file being imported. This means that bun[c/h] has no way of knowing what library to link to when you import SDL_image.h or SDL_ttf.h.

An idea I considered was to allow you to specify the library to link to in the import statement, like so:

import { /* ... */ } from "SDL_image.h:libSDL2";

However, due to the way bun has to handle modules, it is not possible to do this. Bun needs imported file names to be real file names, meaning we can't "smuggle" in extra data in the file name.

Contributing

For information on contributing, see CONTRIBUTING.md. This file will describe how to set up your development environment, run and write tests, and submit a pull request.

License

Bun[c/h] is licensed under the MIT, similarly to Bun. LLVM (including clang) which this project depends on is licensed under the Apache 2.0 license.