Macro session_types::offer

macro_rules! offer {
    (
        $id:ident, $branch:ident => $code:expr, $($t:tt)+
    ) => { ... };
    (
        $id:ident, $branch:ident => $code:expr
    ) => { ... };
}

This macro is convenient for server-like protocols of the form:

Offer<A, Offer<B, Offer<C, ... >>>

Examples

Assume we have a protocol Offer<Recv<u64, Eps>, Offer<Recv<String, Eps>,Eps>>> we can use the offer! macro as follows:

extern crate session_types;
use session_types::*;
use std::thread::spawn;

fn srv(c: Chan<(), Offer<Recv<u64, Eps>, Offer<Recv<String, Eps>, Eps>>>) {
    offer! { c,
        Number => {
            let (c, n) = c.recv();
            assert_eq!(42, n);
            c.close();
        },
        String => {
            c.recv().0.close();
        },
        Quit => {
            c.close();
        }
    }
}

fn cli(c: Chan<(), Choose<Send<u64, Eps>, Choose<Send<String, Eps>, Eps>>>) {
    c.sel1().send(42).close();
}

fn main() {
    let (s, c) = session_channel();
    spawn(move|| cli(c));
    srv(s);
}

The identifiers on the left-hand side of the arrows have no semantic meaning, they only provide a meaningful name for the reader.