report.rs

struct Position { line: usize, col: usize }

fn report<P>(path: P, content: &str, pos: &Position, error: &str)
where
    P: AsRef<Path>,
{
    let Position { line, col } = pos;
    println!(
        "{}",
        format!("--> {}:{}:{}", path.as_ref().display(), line, col).dimmed()
    );
    for (idx, matched) in content.lines().enumerate().filter(|(idx, _)| (line-2..=*line).contains(idx)) {
        println!("{}{}", format!("{} |", idx).dimmed(), matched)
    }
    println!(
        "{}{}{}",
        format!("{}|", " ".repeat(line.to_string().len() + 1)).dimmed(),
        " ".repeat(*col),
        format!("^ error: {}", error).red()
    );
}

--> ../tests/data/example.json:12:6
10 |    {
11 |      "foo":"bye",
12 |      "bar":false
   |      ^ error: does not look good