# Application

A minimal sauron application only need to implement the `Application` trait.

```rust
pub trait Application<MSG>{
    fn update(&mut self, msg: MSG) -> Cmd<Self, MSG>;
    fn view(&self) -> Node<MSG>;
}
```

```rust
impl Application<Msg> for Model {
    fn update(&mut self, msg: MSG) -> Cmd<Self, MSG>{
        // --snip--
    }
    fn view(&self) -> Node<MSG>{
        // --snip
    }
}
```
There are only 2 methods that you are required to implement in an Application.
The `update` function describes how it update the models based on the `MSG` that
is coming from UI events. Update can return a `Cmd` which in turn further update the
Application model in the subsequent update loop.
The `view` function describes how to present the application in the screen.


## Cmd
Sauron has a runtime system where it executes commands.
A `Cmd` is a way of telling Sauron, "Hey, I want you to do this thing!".
So if you want to send an HTTP request, you would need to command Sauron to do it.

Every `Cmd` specifis which effects you need to do the application and the type of messages that will come back into your application.