Rust bindings for kson-lib API

Example usage

Add the library to your dependencies:

cargo add kson-rs

Write some code:

use kson_rs::Kson;

fn main() {
    let json = Kson::to_json("key: [1, 2, 3, 4]")
        .map_err(|_| "unreachable: kson input is guaranteed to be valid!")
        .unwrap();
    println!("{}", json.output());
}

Running this with cargo run should print the following to stdout:

{
  "key": [
    1,
    2,
    3,
    4
  ]
}

Obtaining kson-lib binaries

The kson-sys crate requires linking to the kson-lib binary. Our build.rs automatically downloads a suitable binary from the kson-binaries repository, if it can be found. In case no pre-built binary is available for your platform, you need to manually specify how to obtain it through one of the following environment variables:

• KSON_ROOT_SOURCE_DIR: if set to the root of a KSON source tree, we will attempt to build and use the necessary binaries from there.
• KSON_PREBUILT_BIN_DIR: use pre-built KSON binaries from the specified directory.

A note on Windows and dynamic linking

By default we use static linking under the hood, which means you can use the kson crate without further setup. On Windows, however, we have no choice but to use dynamic linking (due to limitations in kotlin-native). This requires extra work from your side so the operating system can find kson.dll when your program runs. Unfold the section below if you'd like to know more.

// build.rs
use std::path::Path;
use std::{env, fs};

fn main() {
    let lib_bin_path = env::var("DEP_KSON_LIB_BINARY").expect("DEP_KSON_LIB_BINARY not set");
    let lib_bin_path = Path::new(&lib_bin_path);

    let profile = env::var("PROFILE").unwrap();
    let target_root = Path::new(&env::var("CARGO_MANIFEST_DIR").unwrap()).join("target");
    let dest_dir = target_root.join(&profile);

    fs::create_dir_all(&dest_dir).unwrap();
    fs::copy(
        lib_bin_path,
        dest_dir.join(lib_bin_path.file_name().unwrap()),
    )
    .expect("failed to copy kson binary");

    // Re-run if the source library changes
    println!("cargo:rerun-if-changed={}", lib_bin_path.display());
}