Rusty Variation

A library for deadlock-free session-typed communication in Rust.

```rust

[macro_use]

extern crate rusty_variation;

use std::boxed::Box; use std::error::Error; use rusty_variation::*;

type CalcSrv = Recv; enum CalcOp { Done(End), Neg(Recv>), Add(Recv>>)}

fn calcserver(s: CalcSrv) -> Result<(), Box> { offer!(s, { CalcOp::Done(End) => { Ok(()) }, CalcOp::Neg(s) => { let (x, s) = recv(s)?; let s = send(-x, s)?; calcserver(s) }, CalcOp::Add(s) => { let (x, s) = recv(s)?; let (y, s) = recv(s)?; let s = send(x.wrappingadd(y), s)?; calcserver(s) }, }) }

fn main() { assert!(|| -> Result<(), Box> {

    // Test the negation function.
    {
        let s: <CalcSrv as Session>::Dual = fork!(calc_server);
        let s = select!(CalcOp::Neg, s)?;
        let s = send(6, s)?;
        let (y, s) = recv(s)?;
        let End = select!(CalcOp::Done, s)?;
        assert_eq!(-6, y);
    }

    // Test the addition function.
    {
        let s: <CalcSrv as Session>::Dual = fork!(calc_server);
        let s = select!(CalcOp::Add, s)?;
        let s = send(4, s)?;
        let s = send(5, s)?;
        let (z, s) = recv(s)?;
        let End = select!(CalcOp::Done, s)?;
        assert_eq!(9, z);
    }

    Ok(())

}().is_ok());

} ```