clojure-reader 0.6.0

use clojure_reader::parse::{self, NodeKind, SourceReader};

fn underline(column: usize, width: usize) -> String {
  let mut out = " ".repeat(column.saturating_sub(1));
  out.push_str(&"^".repeat(width.max(1)));
  out
}

fn main() {
  let source = "(def foo-bar (+ 猫gatoキャット 42))";

  let mut reader = SourceReader::new(source);
  let parsed = parse::parse(&mut reader).expect("failed to parse example input");

  let NodeKind::List(items, _) = parsed.kind else {
    panic!("expected outer list");
  };
  let NodeKind::List(inner, _) = &items[2].kind else {
    panic!("expected inner list");
  };
  let cat = &inner[1];
  let span = cat.span();
  let width = source[span.0.ptr..span.1.ptr]
    .chars()
    .map(|ch| if ch.is_ascii() { 1 } else { 2 })
    .sum::<usize>();

  println!("{source}");
  println!("{} symbol not found", underline(span.0.column, width));
  println!(
    "\nspan: start=(line {}, column {}, ptr {}) end=(line {}, column {}, ptr {})",
    span.0.line, span.0.column, span.0.ptr, span.1.line, span.1.column, span.1.ptr,
  );
}

#[test]
fn run() {
  main();
}