# demand
[
](https://crates.io/crates/demand)
[](https://docs.rs/demand)
[](./LICENSE)
[](https://github.com/jdx/demand/actions/workflows/test.yml)
[](http://github.com/jdx/demand/issues)
A prompt library for Rust. Based on [huh? for Go](https://github.com/charmbracelet/huh). Maintained by [@jdx](https://github.com/jdx) and [@roele](https://github.com/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`](./examples/input.rs).
```rust
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`](./examples/input-password.rs).
```rust
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");
}
```
## List
Shows a list of options. Run example with [`cargo run --example list`](./examples/list.rs).
```rust
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
Select from a list of options.
Run example with [`cargo run --example select`](./examples/select.rs).
```rust
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`](./examples/multiselect.rs).
```rust
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`](./examples/confirm.rs).
```rust
use demand::Confirm;
fn main() {
let ms = Confirm::new("Are you sure?")
.affirmative("Yes!")
.negative("No.");
let yes = ms.run().expect("error running confirm");
}
```
## Dialog
Show a dialog with multiple buttons.
Run example with [`cargo run --example dialog`](./examples/dialog.rs).
```rust
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");
}
```
## Spinner
Spinners are used to indicate that a process is running.
Run example with [`cargo run --example spinner`](./examples/spinner.rs).
```rust
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.
```rust
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](https://www.bbc.com/culture/article/20150202-the-greatest-mistranslations-ever)
that soured US-French relations in 1830. In French, the verb "demander" means "to ask".