shrust

Rust library to create interactive command line shells

Documentation

Copyright © 2019 Pierre-Henri Symoneaux

THIS SOFTWARE IS DISTRIBUTED WITHOUT ANY WARRANTY
Check LICENSE.txt file for more information.

This is currently a work in progress, and the API should be consider unstable. I'll start documenting and releasing to crates.io once a first level of stability has been reached

How to use

Including

More often, you will include the library as a dependency to your project. In order to do this, add the following lines to your Cargo.toml file :

[dependencies]
shrust = "0.0.7"

Basic usage

Let's have a look at example dummy.rs :

extern crate shrust;
use shrust::{Shell, ShellIO};
use std::io::prelude::*;

fn main() {
    let mut shell = Shell::new(());
    shell.new_command_noargs("hello", "Say 'hello' to the world", |io, _| {
        writeln!(io, "Hello World !!!")?;
        Ok(())
    });

    shell.run_loop(&mut ShellIO::default());
}

The output of this program would be

λ cargo run --example dummy
     Running `target\debug\examples\dummy.exe`
>help
 hello    :  Say 'hello' to the world
 help     :  Print this help
 history  :  Print commands history or run a command from it
 quit     :  Quit
>hello
Hello World !!!
>quit

Attaching data

You can attach data to the shell for usage by commands as seen in data.rs:

let v = Vec::new();
let mut shell = Shell::new(v);
shell.new_command("push", "Add string to the list", 1, |io, v, s| {
    writeln!(io, "Pushing {}", s[0])?;
    v.push(s[0].to_string());
    Ok(())
});
shell.new_command_noargs("list", "List strings", |io, v| {
    for s in v {
        writeln!(io, "{}", s)?;
    }
    Ok(())
});

shell.run_loop(&mut ShellIO::default());

Output:

λ cargo run --example dummy
     Running `target\debug\examples\dummy.exe`
>help
 help     :  Print this help
 history  :  Print commands history or run a command from it
 list     :  List strings
 push     :  Add string to the list
 quit     :  Quit
>push foo
Pushing foo
>push bar
Pushing bar
>list
foo
bar
>quit

Using custom I/O

In previous examples, the shell's loop was run the following way:

shell.run_loop(&mut ShellIO::default());

ShellIO::default() returns an stdin/stdout IO.

It's possible to create a ShellIO instance around user-defined I/O. For example to connect a Shell on a socket, the ShellIO would be created with

let mut io = ShellIO::new_io(sock);

where sock is the socket, then the shell can be started with

shell.run_loop(&mut io);

This is applied in example socket.rs.

Default handler

By default, when a command is not found, the evaluation returns an UnknownCommand error. This behavior can be customized by providing a custom default handler to be invoked on not found command.

let mut shell = Shell::new(());
shell.set_default(|io, _, cmd| {
    writeln!(io, "Hello from default handler !!! Received: {}", cmd)?;
    Ok(())
});
shell.run_loop(&mut ShellIO::default());

Output:

λ cargo run --example default
     Running `target\debug\examples\default.exe`
>foo
Hello from default handler !!! Received: foo
>quit

This is applied in example default.rs.

Multithreading

A shell instance itself cannot be shared across threads, it needs to be cloned. A shell is clonable only if the wrapped data is clonable too. However, the wrapped data can be easily shared if (for example) it's an Arc around a Sync+Send value.

TBD...

Additional examples are provided in documentation and in examples directory