eddyb · February 24, 2020 16:11 · eddyb · Aug 26, 2017
diff --git a/errfilt.rs b/errfilt.rs
 use std::io;
 use std::io::prelude::*;

 fn main() {
    let stdin = io::stdin();
    let mut stderr = io::stderr();
    let mut last_message = String::new();
    let mut last_loc = String::new();
    for line in stdin.lock().lines() {
        let line = line.unwrap();
        let trimmed = line.trim();
        if trimmed.starts_with("Finished ") {
            continue;
        }

        let message = std::mem::replace(&mut last_message, String::new());

        let loc_prefix = "--> ";
        if trimmed.starts_with(loc_prefix) {
            last_loc = trimmed[loc_prefix.len()..].to_string();
            if !message.is_empty() {
                writeln!(stderr, "{}: {}", last_loc, message).unwrap();
            }
            continue;
        }

        if !message.is_empty() {
            writeln!(stderr, "{}", message).unwrap();
        }

        if line.starts_with("error") || line.starts_with("warn") {
            let after = line.trim_left_matches(char::is_alphabetic);
            if after.starts_with("[") || after.starts_with(":") {
                last_message.push_str(&line);
                continue;
            }
        }

        // Empty line, reset location.
        if line.is_empty() {
            last_loc.clear();
        }

        // Source snippet.
        if trimmed.starts_with(|c: char| c.is_digit(10)) {
            continue;
        }

        // Weird thing in a source snippet.
        if trimmed.starts_with("::: ") {
            continue;
        }

        // Empty line.
        if trimmed == "|" {
            continue;
        }

        // Extra messages.
        if line.starts_with("  ") && !last_loc.is_empty() {
            let message = trimmed.trim_left_matches(&[' ', '|', '=', '_', '-', '^'][..]);
            if !message.is_empty() {
                writeln!(stderr, "{}: {}", last_loc, message).unwrap();
            }
            continue;
        }

        writeln!(stderr, "{}", line).unwrap();
    }
 }
	use std::io;
	use std::io::prelude::*;

	fn main() {
	let stdin = io::stdin();
	let mut stderr = io::stderr();
	let mut last_message = String::new();
	let mut last_loc = String::new();
	for line in stdin.lock().lines() {
	let line = line.unwrap();
	let trimmed = line.trim();
	if trimmed.starts_with("Finished ") {
	continue;
	}

	let message = std::mem::replace(&mut last_message, String::new());

	let loc_prefix = "--> ";
	if trimmed.starts_with(loc_prefix) {
	last_loc = trimmed[loc_prefix.len()..].to_string();
	if !message.is_empty() {
	writeln!(stderr, "{}: {}", last_loc, message).unwrap();
	}
	continue;
	}

	if !message.is_empty() {
	writeln!(stderr, "{}", message).unwrap();
	}

	if line.starts_with("error") \|\| line.starts_with("warn") {
	let after = line.trim_left_matches(char::is_alphabetic);
	if after.starts_with("[") \|\| after.starts_with(":") {
	last_message.push_str(&line);
	continue;
	}
	}

	// Empty line, reset location.
	if line.is_empty() {
	last_loc.clear();
	}

	// Source snippet.
	if trimmed.starts_with(\|c: char\| c.is_digit(10)) {
	continue;
	}

	// Weird thing in a source snippet.
	if trimmed.starts_with("::: ") {
	continue;
	}

	// Empty line.
	if trimmed == "\|" {
	continue;
	}

	// Extra messages.
	if line.starts_with(" ") && !last_loc.is_empty() {
	let message = trimmed.trim_left_matches(&[' ', '\|', '=', '_', '-', '^'][..]);
	if !message.is_empty() {
	writeln!(stderr, "{}: {}", last_loc, message).unwrap();
	}
	continue;
	}

	writeln!(stderr, "{}", line).unwrap();
	}
	}