A prompt library for Rust. Based on huh? for Go. Maintained by @jdx and @roele.
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Run any example from the repository with cargo run --example <name>.
Start with grid_select, input, select, or multiselect; use themes -- dracula
to try a different theme. The animations below show the actual examples.
See the recording guide to regenerate them.
- Single-line text input with variable prompt and placeholder
- Complete suggestions with
TAB - Auto-complete API for custom suggestions
- 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");
}Input supports the common emacs-style (GNU Readline default) bindings:
| Keys | Action |
|---|---|
| ←/→, ctrl-b/ctrl-f | move one character |
| alt-b/alt-f | move one word |
| home/end, ctrl-a/ctrl-e | move to start/end of line |
| backspace | delete the character before the cursor |
| delete, ctrl-d | delete the character under the cursor |
| ctrl-w, alt-backspace | delete the word before the cursor |
| alt-d | delete the word after the cursor |
| ctrl-u/ctrl-k | delete to the start/end of the line |
| ctrl-y | paste the text last deleted with the above |
| ctrl-t | swap the two characters around the cursor |
In password inputs, word commands act on the whole line so they don't reveal where the spaces are.
Run example with cargo run --example autocomplete_basic.
Run example with cargo run --example input-password.
Multi-line text, entered in the user's $VISUAL / $EDITOR. Press e to open the editor and enter to submit.
Run example with cargo run --example editor.
use demand::Editor;
fn main() {
let notes = Editor::new("Release notes")
.description("Summarize what changed in this release.")
.default_value("## Changes\n\n- \n")
.extension("md")
.run()
.expect("error running editor");
}Shows a list of options. Run example with cargo run --example list.
use demand::List;
fn main() {
let list = List::new("Toppings")
.description("List of available toppings")
.item("Lettuce")
.item("Tomatoes")
.item("Charm Sauce")
.item("Jalapenos")
.item("Cheese")
.item("Vegan Cheese")
.item("Nutella")
.item("Peanut Butter")
.item("Banana")
.filterable(true);
list.run().expect("error running list")
}Select from a list of options.
Run example with cargo run --example select.
The abbreviated example below shows a few countries; the runnable demo includes more options to demonstrate pagination.
use demand::{DemandOption, Select};
fn main() {
let select = Select::new("Country")
.description("Pick a country")
.filterable(true)
.option(DemandOption::new("US").label("United States"))
.option(DemandOption::new("DE").label("Germany"))
.option(DemandOption::new("BR").label("Brazil").selected(true))
.option(DemandOption::new("CA").label("Canada"))
.option(DemandOption::new("GB").label("United Kingdom"));
select.run().expect("error running select");
}Select::handle returns a PromptHandle that another thread can use to change the title or description while the select is waiting for input.
On Windows, a change is shown at the next keypress rather than right away.
Run example with cargo run --example select_dynamic.
let mut select = Select::new("Coins inserted: 0")
.option(DemandOption::new("Complete payment"))
.option(DemandOption::new("Quit"));
let handle = select.handle();
std::thread::spawn(move || handle.set_title("Coins inserted: 50"));
let choice = select.run()?;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");
}Pick one column for each row of a table, e.g. which version to upgrade each package to. ↑/↓ move between rows, ←/→ move the row's choice between its cells. Empty cells aren't selectable.
Run example with cargo run --example grid_select.
use demand::{GridRow, GridSelect};
fn main() {
let columns = ["Current", "Range", "Latest"];
let grid = GridSelect::new("Pick the packages you want to upgrade")
.columns(columns)
.filterable(true)
.row(GridRow::new("react").cell("^18.2.0").cell("^18.3.1").cell("^19.0.0"))
.row(GridRow::new("chalk").cell("^4.1.2").empty_cell().cell("^5.0.0"))
.row(GridRow::new("jest").cell("^27.4.7").cell("^27.5.1"));
for (package, column) in grid.run().expect("error running grid select") {
println!("{package}: {}", columns[column]);
}
}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");
}Show a dialog with multiple buttons.
Run example with cargo run --example dialog.
use demand::{Dialog, DialogButton};
fn main() {
let ms = Dialog::new("Are you sure?")
.description("This will do a thing.")
.buttons(vec![
DialogButton::new("Ok"),
DialogButton::new("Not sure"),
DialogButton::new("Cancel"),
])
.selected_button(1);
ms.run().expect("error running confirm");
}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");
}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")?;
Default if colors are enabled in the console.
Default if colors are NOT enabled in the console.
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".
