Allow ESC to be binded to custom action, when not in tab complete, at least when nothing being inputed

[guyuming76]

I am using reedline in my rfm file manager, to let user manipulate files shown in GUI with commands in terminal emulator. But i cannot keybind ESC to my custom code, it's said that ESC is used by reedline. I see that when i use tab completion and menu, ESC can cancel the menu. But at least when i start a new readline call and nothing has being inputted, i see nothing happens with ESC. I just need ESC for my custom action here: I want to use ESC to cancel the file selection in file manager GUI. Without this, i have to switch focus to the GUI window, ESC to cancel file selection and switch focus back. Currently, i am using ALT+E keybinding as an alternative, but it's not easy to remember as ESC.

[fdncred]

It seems to work in nushell. I've had this set as a keybinding for a very long time. ESC clears the command line buffer.

  {
    name: clear
    modifier: none
    keycode: esc
    mode: [emacs vi_normal vi_insert]
    event: { edit: clear }
  }

[guyuming76]

i use something like what follows, ESC key works with my custom host command. But, when i use tab complete, and after the menu show up, i cannot use ESC key to cancel the completion menu. I don't want my ESC keybinding to override its default behavior in completion menu.

...
    keybindings.add_binding(KeyModifiers::NONE, KeyCode::Esc,                                                             
        ReedlineEvent::ExecuteHostCommand("esc".to_string())); 
...
    let engine = match history_result {                                                                                   
        Ok(history) => Reedline::create().use_bracketed_paste(true)                                                       
            .with_completer(Box::new(CombinedCompleter::new(CCompleter::new(rfm_functions, None)))) 
				       .with_menu(ReedlineMenu::EngineCompleter(completion_menu))                        
                                        .with_history(Box::new(history))                                                  
                                        .with_validator(Box::new(AlwaysIncompleteValidator))   
                                        .with_edit_mode(Box::new(Emacs::new(keybindings)))            
                                        .with_quick_completions(true) 
                                        .with_hinter(Box::new(CwdAwareHinter::default().with_style(Style::new().italic().\
fg(Color::LightGray)).with_min_chars(2))),                                                                                
        Err(e) => {                                                                                                       
            warn!("History load error: {}", e);                                                                           
            Reedline::create().with_completer(Box::new(CombinedCompleter::new(CCompleter::new(rfm_functions, None)))) 
                                        .with_menu(ReedlineMenu::EngineCompleter(completion_menu))                        
                                        .with_validator(Box::new(AlwaysIncompleteValidator)) 
                                        .with_edit_mode(Box::new(Emacs::new(keybindings)))  
                                        .with_quick_completions(true) 
        }                                                                                                                 
    };