Macro immense::rule

macro_rules! rule {
    ($($transforms:expr => $subrule:expr),+ $(,)*) => { ... };
}

An ergonomics macro for defining rules out of transformed subrule invocations.

Where normally you would have to write

let rule = Rule::new().push(Tf::tx(2.0), cube())
                      .push(Tf::s(0.5), cube());

you can write

let rule = rule![Tf::tx(2.0) => cube(),
                 Tf::s(0.5) => cube()];