fb_console: only allow backspace to delete user input

user/fb_console/src/main.rs

@@ -93,39 +93,50 @@ fn spawn_framebuffer(
  if let Some(event) = console.input_events.recv().await {
  match event {
  InputEvent::KeyPressed(key) => {
- write!(console.console.lock(), "{}", key).unwrap();
- needs_redraw = true;
+ // TODO: `noline` is a no-std REPL impl crate thingy that could be useful
+ // for improving this experience
+ match key {
+ '\n' => {
+ let mut stmts = Parser::new(&current_line).parse().unwrap();
+ current_line.clear();
+
+ for mut statement in &mut stmts {
+ resolver.resolve_bindings(&mut statement);
+ }
 
- if key == '\n' {
- let mut stmts = Parser::new(&current_line).parse().unwrap();
- current_line.clear();
+ let mut result = None;
+ for statement in stmts {
+ if let Some(value) = interpreter.eval_stmt(statement) {
+ result = Some(value);
+ }
+ }
 
- for mut statement in &mut stmts {
- resolver.resolve_bindings(&mut statement);
- }
+ write!(console.console.lock(), "{}", key);
+ while let Ok(output) = output_receiver.try_recv() {
+ writeln!(console.console.lock(), "Output: {}", output).unwrap();
+ }
 
- let mut result = None;
- for statement in stmts {
- if let Some(value) = interpreter.eval_stmt(statement) {
- result = Some(value);
+ if let Some(result) = result {
+ writeln!(console.console.lock(), "Result: {}", result).unwrap();
  }
- }
 
- while let Ok(output) = output_receiver.try_recv() {
- writeln!(console.console.lock(), "Output: {}", output).unwrap();
+  write!(console.console.lock(), "\n> ").unwrap();
+ needs_redraw = true;
  }
 
- if let Some(result) = result {
- writeln!(console.console.lock(), "Result: {}", result).unwrap();
+ // ASCII `DEL` is produced by backspace
+ '\x7f' => {
+ // Only allow the user to delete characters they've typed.
+ if current_line.pop().is_some() {
+ write!(console.console.lock(), "{}", key).unwrap();
+ needs_redraw = true;
+ }
  }
 
- write!(console.console.lock(), "\n> ").unwrap();
- } else {
- // Handle backspace (ASCII `DEL`) to delete the last char
- if key == '\x7f' {
- current_line.pop();
- } else {
+ other => {
+ write!(console.console.lock(), "{}", key).unwrap();
  current_line.push(key);
+ needs_redraw = true;
  }
  }
  }