build.rs

#![feature(exit_status_error)]
use std::env;
use std::error::Error;
use std::process::Command;

fn main() {
    gen_for_grammar().unwrap();

    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-changed=src/parser/Cb.g4");
}

fn gen_for_grammar() -> Result<(), Box<dyn Error>> {
    let input = env::current_dir().unwrap().join("src").join("parser");
    let file_name = "Cb.g4";
    let antlr_path = env::current_dir().unwrap().join("bin").join("antlr.jar");

    Command::new("java")
        .current_dir(input)
        .env("CLASSPATH", antlr_path)
        .arg("org.antlr.v4.Tool")
        .arg("-Dlanguage=Rust")
        .arg("-visitor")
        .arg(&file_name)
        .stdout(std::process::Stdio::inherit())
        .stderr(std::process::Stdio::inherit())
        .spawn()
        .expect("antlr tool failed to start")
        .wait()?
        .exit_ok()
        .unwrap();

    // let _ = Command::new("cargo")
    //     .current_dir(env::current_dir()?)
    //     .arg("fmt")
    //     .spawn()
    //     .expect("failed to format antlr code")
    //     .wait_with_output()?;

    // .unwrap()
    // .stdout;
    // eprintln!("xx{}",String::from_utf8(x).unwrap());
    Ok(())
}