reedline/examples/completions.rs

// Create a reedline object with tab completions support
// cargo run --example completions
//
// "t" [Tab] will allow you to select the completions "test" and "this is the reedline crate"
// [Enter] to select the chosen alternative

use reedline::{
    default_emacs_keybindings, ColumnarMenu, DefaultCompleter, DefaultPrompt, EditCommand, Emacs,
    KeyCode, KeyModifiers, Keybindings, Reedline, ReedlineEvent, ReedlineMenu, Signal,
};
use std::io;

fn add_menu_keybindings(keybindings: &mut Keybindings) {
    keybindings.add_binding(
        KeyModifiers::NONE,
        KeyCode::Tab,
        ReedlineEvent::UntilFound(vec![
            ReedlineEvent::Menu("completion_menu".to_string()),
            ReedlineEvent::MenuNext,
        ]),
    );
    keybindings.add_binding(
        KeyModifiers::ALT,
        KeyCode::Enter,
        ReedlineEvent::Edit(vec![EditCommand::InsertNewline]),
    );
}

fn main() -> io::Result<()> {
    // Number of columns
    let columns: u16 = 4;
    // Column width
    let col_width: Option<usize> = None;
    // Column padding
    let col_padding: usize = 2;

    let commands = vec![
        "test".into(),
        "hello world".into(),
        "hello world reedline".into(),
        "this is the reedline crate".into(),
    ];
    let completer = Box::new(DefaultCompleter::new_with_wordlen(commands, 2));

    // Use the interactive menu to select options from the completer
    let columnar_menu = ColumnarMenu::default()
        .with_name("completion_menu")
        .with_columns(columns)
        .with_column_width(col_width)
        .with_column_padding(col_padding);

    let completion_menu = Box::new(columnar_menu);

    let mut keybindings = default_emacs_keybindings();
    add_menu_keybindings(&mut keybindings);

    let edit_mode = Box::new(Emacs::new(keybindings));

    let mut line_editor = Reedline::create()
        .with_completer(completer)
        .with_menu(ReedlineMenu::EngineCompleter(completion_menu))
        .with_edit_mode(edit_mode);

    let prompt = DefaultPrompt::default();

    loop {
        let sig = line_editor.read_line(&prompt)?;
        match sig {
            Signal::Success(buffer) => {
                println!("We processed: {buffer}");
            }
            Signal::CtrlD | Signal::CtrlC => {
                println!("\nAborted!");
                break Ok(());
            }
        }
    }
}