Crystal API

trait for declaring an application, pretty much just create a struct and implement the trait, the main function should be async as in the trait.

• you will also need to import Box and async_trait for any struct implementing async trait to work otherwise you'll get a compile error

#[async_trait]
pub trait Application {
    fn new() -> Self;

    async fn run(&mut self, _: Vec<String>) -> Result<(), Error> {
        Ok(())
    }
}

#[derive(Debug)]
pub enum Error {
    UnknownCommand(String),
    CommandFailed(String),
    ApplicationError(String),
    EmptyCommand,
}