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# shrust
Rust library to create interactive command line shells
[Documentation](http://phsym.github.io/shrust)
*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 :
```toml
[dependencies]
shrust = "0.0.7"
```
## Basic usage
Let's have a look at example [dummy.rs](./examples/dummy.rs) :
```rust
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](./examples/data.rs):
```rust
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:
```rust
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
```rust
let mut io = ShellIO::new_io(sock);
```
where `sock` is the socket, then the shell can be started with
```rust
shell.run_loop(&mut io);
```
This is applied in example [socket.rs](./examples/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.
```rust
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](./examples/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](./examples/) directory