demand

A prompt library for Rust. Based on huh? for Go. Maintained by @jdx and @roele.

Input

• Single-line text input with variable prompt and placeholder
• Auto-complete suggestions with TAB
• Validate input with a custom closure

Run example with cargo run --example input.

use demand::Input;

fn main() {
    let notempty_minlen = |s: &str| {
        if s.is_empty() {
            return Err("Name cannot be empty");
        }
        if s.len() < 8 {
            return Err("Name must be at least 8 characters");
        }
        Ok(())
    };

    let t = Input::new("What's your name?")
        .description("We'll use this to personalize your experience.")
        .placeholder("Enter your name")
        .prompt("Name: ")
        .suggestions(vec![
            "Adam Grant",
            "Danielle Steel",
            "Eveline Widmer-Schlumpf",
            "Robert De Niro",
            "Ronaldo Rodrigues de Jesus",
            "Sarah Michelle Gellar",
            "Yael Naim",
            "Zack Snyder",
        ])
        .validation(notempty_minlen);
    let i = t.run().expect("error running input");
}

Password

Run example with cargo run --example input-password.

use demand::Input;

fn main() {
    let t = Input::new("Set a password")
        .placeholder("Enter password")
        .prompt("Password: ")
        .password(true);
    let i = t.run().expect("error running input");
}

Select

Select from a list of options.

Run example with cargo run --example select.

use demand::{DemandOption, Select};

fn main() {
    let ms = Select::new("Toppings")
        .description("Select your topping")
        .filterable(true)
        .option(DemandOption::new("Lettuce"))
        .option(DemandOption::new("Tomatoes"))
        .option(DemandOption::new("Charm Sauce"))
        .option(DemandOption::new("Jalapenos").label("Jalapeños"))
        .option(DemandOption::new("Cheese"))
        .option(DemandOption::new("Vegan Cheese"))
        .option(DemandOption::new("Nutella"));
    ms.run().expect("error running select");
}

Multiselect

Select multiple options from a list. Run example with cargo run --example multiselect.

use demand::{DemandOption, MultiSelect};

fn main() {
    let ms = MultiSelect::new("Toppings")
        .description("Select your toppings")
        .min(1)
        .max(4)
        .filterable(true)
        .option(DemandOption::new("Lettuce").selected(true))
        .option(DemandOption::new("Tomatoes").selected(true))
        .option(DemandOption::new("Charm Sauce"))
        .option(DemandOption::new("Jalapenos").label("Jalapeños"))
        .option(DemandOption::new("Cheese"))
        .option(DemandOption::new("Vegan Cheese"))
        .option(DemandOption::new("Nutella"));
    ms.run().expect("error running multi select");
}

Confirm

Confirm a question with a yes or no. Run example with cargo run --example confirm.

use demand::Confirm;

fn main() {
    let ms = Confirm::new("Are you sure?")
        .affirmative("Yes!")
        .negative("No.");
    let yes = ms.run().expect("error running confirm");
}

Spinner

Spinners are used to indicate that a process is running. Run example with cargo run --example spinner.

use std::{thread::sleep, time::Duration};

use demand::{Spinner, SpinnerStyle};

fn main() {
    Spinner::new("Loading Data...")
        .style(SpinnerStyle::line())
        .run(|| {
            sleep(Duration::from_secs(2));
        })
        .expect("error running spinner");
}

Themes

Supply your own custom theme or choose from one of the predefined themes:

Derive a custom theme from the default theme.

let theme = Theme {
    selected_prefix: String::from(" •"),
    selected_prefix_fg: Theme::color_rgb(2, 191, 135),
    unselected_prefix: String::from("  "),
    ..Theme::default()
};

Input::new("What's your e-mail?")
        .description("Please enter your e-mail address.")
        .placeholder("name@domain.com")
        .theme(&theme)
        .run()
        .expect("error running input")?;

Base 16

Charm

Default if colors are enabled in the console.

Catppuccin

Dracula

New

Default if colors are NOT enabled in the console.

"demand"

The name of this library is inspired by a great mistranslation that soured US-French relations in 1830. In French, the verb "demander" means "to ask".