vitorenesduarte / pluscal-rs

Let's write some PlusCal in Rust!

pluscal-rs

Let's write some PlusCal in Rust!

The What

use pluscal::prelude::*;

fn main() {
    let mut module = Module::new("transfer");
    module.extends("Naturals");
    module.extends("TLC");

    let alice = module.natural("alice").value(10);
    let bob = module.natural("bob").value(10);
    let money = module.natural("money").in_range(1, 20);

    let transfer = module.label("Transfer");
    transfer
        .if_(alice.ge(&money))
        .then(|ctx| {
            let a = ctx.label("A");
            a.exec(alice.set(alice.minus(&money)));

            let b = ctx.label("B");
            b.exec(bob.set(bob.plus(&money)));
        })
        .end_if();
    let c = module.label("C");
    c.assert(alice.geq(&ZERO));

    println!("{}", module);
}

The above Rust code outputs (example from the Learn TLA+ website):

---- MODULE transfer ----
EXTENDS Naturals, TLC

(* --algorithm transfer

variables
    alice = 10,
    bob = 10,
    money \in 1..20;

begin
Transfer:
    if alice >= money then
        A:
            alice := alice - money;
        B:
            bob := bob + money;
    end if;
C:
    assert alice >= 0


end algorithm *)
====

The Why

I'm afraid I don't have a good answer. I can at least blame this PLTalk with Jean Yang, Hongyi Hu and Hillel Wayne on Practical Formal Methods.

License

Licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.