elo: improve UX on live updating leaderboard

src/elo.rs

@@ -5,7 +5,7 @@ use crate::{
     logic::{ChildrenEvalMethod, FutureMoveConfig},
     repr::{Board, Piece, Winner},
 };
-use indicatif::{ParallelProgressIterator, ProgressStyle};
+use indicatif::{ParallelProgressIterator, ProgressStyle, TermLike};
 use rand::seq::SliceRandom;
 use rayon::iter::{IntoParallelIterator, ParallelIterator};
 use skillratings::{
@@ -164,6 +164,7 @@ impl PlayerArena {
         // Immediately drop our copy of the sender so the channel closes properly
         drop(sender);
 
+        let term = console::Term::stdout();
         // Process results on main thread as they arrive
         let mut received_num = 0;
         while let Ok((i, j, o)) = receiver.recv() {
@@ -172,7 +173,11 @@ impl PlayerArena {
 
             // print the leaderboard every 5 steps
             if received_num % 5 == 0 {
-                println!("{}", self);
+                term.clear_last_lines(num)
+                    .expect("unable to clear prev lines");
+                let formatted_self = format!("{}", self);
+                term.write_str(&formatted_self)
+                    .expect("unable to write leaderboard");
             }
 
             // break if all pairs were recieved