//! Build interactive programs using The Elm Architecture.
use crate::{Command, Element, Renderer};
mod state;
pub use state::State;
/// The core of a user interface application following The Elm Architecture.
pub trait Program: Sized {
/// The graphics backend to use to draw the [`Program`].
type Renderer: Renderer;
/// The type of __messages__ your [`Program`] will produce.
type Message: std::fmt::Debug + Send;
/// Handles a __message__ and updates the state of the [`Program`].
///
/// This is where you define your __update logic__. All the __messages__,
/// produced by either user interactions or commands, will be handled by
/// this method.
///
/// Any [`Command`] returned will be executed immediately in the
/// background by shells.
fn update(&mut self, message: Self::Message) -> Command<Self::Message>;
/// Returns the widgets to display in the [`Program`].
///
/// These widgets can produce __messages__ based on user interaction.
fn view(&self) -> Element<'_, Self::Message, Self::Renderer>;
}