//! The Rush shell.

pub mod env;
pub mod exec;
pub mod eval;

use env::job;

/// Attempt to execute a program, rush expression or builtin.
pub fn exec (prog: impl exec::Exec) -> Result<job::Job<job::Running>> {
    todo!()
}

pub use err::{
    Error,
    Result,
};

mod err {

    /// A global union type of errors produced anywhere within the Rush shell.
    #[derive(Debug)]
    pub enum Error {
        Io (std::io::Error)
    }

    impl From<std::io::Error> for Error {
        fn from (err: std::io::Error) -> Self {
            Error::Io (err)
        }
    }

    /// A less verbose way to use the [`Result`](std::result::Result) type with
    /// an [`Error`].
    pub type Result<T, E = Error> = std::result::Result<T, E>;

}