Fix a performance issue in the UI.

2 files changed, 40 insertions, 13 deletions

diff --git a/src/eval.rs b/src/eval.rs
index e07bec2..470bae6 100644
--- a/src/eval.rs
+++ b/src/eval.rs
@@ -194,19 +194,41 @@ impl Num {
     }
 }
 
-fn format_float(f: f64) -> String {
-    let mut s = format!("{f:.7}");
-    while let Some(b'0') = s.as_bytes().get(s.len() - 1) {
-        s.truncate(s.len() - 1);
-    }
-    s
-}
-
 impl Display for Num {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
         match self {
-            Num::Int(n) => write!(f, "{n}"),
-            Num::Float(n) => write!(f, "{}", format_float(*n)),
+            Num::Int(n) => {
+                if n.bits() < 100 {
+                    return write!(f, "{n}");
+                }
+                let buf = format!("{n}");
+                let rounding_factor = BigInt::from(10).pow(buf.len() - 8);
+                let (mut rounded, rem) = n.div_mod_floor(&rounding_factor);
+                match rem.cmp(&(rounding_factor / 2)) {
+                    Ordering::Greater => rounded += 1,
+                    Ordering::Equal if rounded.is_odd() => rounded += 1,
+                    _ => (),
+                }
+                let rounded_str = format!("{rounded}");
+                write!(
+                    f,
+                    "{}.{}e{}",
+                    &rounded_str[..1],
+                    &rounded_str[1..],
+                    buf.len() - 1
+                )
+            }
+            Num::Float(n) => {
+                let n = *n;
+                if !(-1e30..=1e30).contains(&n) {
+                    return write!(f, "{n:.7e}");
+                }
+                let mut buf = format!("{n:.7}");
+                while let Some(b'0') = buf.as_bytes().get(buf.len() - 1) {
+                    buf.truncate(buf.len() - 1);
+                }
+                write!(f, "{buf}")
+            }
         }
     }
 }
diff --git a/src/main.rs b/src/main.rs
index 08c1ded..9fe62b3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -34,7 +34,7 @@ fn main() -> ExitCode {
         let grid = Grid::new();
         window.set_child(Some(&grid));
 
-        let input = Entry::new();
+        let input = Entry::builder().width_request(300).build();
         grid.attach(&input, 0, 0, 1, 1);
 
         let output = Entry::builder().editable(false).build();
@@ -59,6 +59,7 @@ fn main() -> ExitCode {
         window.add_controller(key_controller);
 
         glib::spawn_future_local(async move {
+            let mut prev_input = String::from("");
             loop {
                 if ping_recv.recv().await.is_err() {
                     break;
@@ -66,17 +67,21 @@ fn main() -> ExitCode {
                 let Some(input) = get_mail(mailbox.as_ref()) else {
                     continue;
                 };
+                if input == prev_input {
+                    continue;
+                }
+                prev_input = input.clone();
                 let (output_send, output_recv) = async_channel::bounded(1);
                 let thread_handle = gtk4::gio::spawn_blocking(move || {
                     if let Some(result) = parser::parse(&input) {
-                        output_send.send_blocking(result).unwrap();
+                        output_send.send_blocking(format!("{result}")).unwrap();
                     }
                 });
                 let _ = thread_handle.await;
                 let Ok(result) = output_recv.try_recv() else {
                     continue;
                 };
-                output.set_text(&format!("{result}"));
+                output.set_text(&result);
             }
         });