tabdisp.rs

use std::fmt::{self, Display, Formatter};
use std::io::{self, Write};

use tabwriter::TabWriter;

struct Table([[usize; 2]; 2]);

impl Display for Table {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        let write_table = || -> io::Result<Vec<u8>> {
            let table = Vec::new();
            let mut tf = TabWriter::new(table).padding(1);

            for r in self.0.iter() {
                let mut ci = r.iter();
                if let Some(c0) = ci.next() {
                    write!(tf, "{}", c0)?;
                    for c in ci {
                        write!(tf, "\t{}", c)?;
                    }
                }
                writeln!(tf)?;
            }

            tf.flush().unwrap();
            Ok(tf.into_inner().unwrap())
        };

        let table = write_table().or(Err(fmt::Error))?;
        write!(f, "{}", std::str::from_utf8(&table).unwrap())
    }
}

fn main() {
    let table = Table([[0, 1], [2, 3]]);
    print!("{}", table);
}