Reducing boilerplate with proc macros

[tyranron]

In our codebase we've built some proc macro machinery, which allows us to reduce boilerplate using this library. An example could've looked something like this:

use std::convert::Infallible;

use async_trait::async_trait;
use cucumber::gherkin::Step;
use cucumber_codegen::given;

#[derive(cucumber_codegen::World)]
pub struct World {
    pub foo: i32,
}

#[async_trait(?Send)]
impl cucumber::World for World {
    type Error = Infallible;

    async fn new() -> Result<Self, Self::Error> {
        Ok(Self { foo: 0 })
    }
}

#[given(regex = r"(\S+) is (\d+)")]
async fn test_regex_async(
    w: &mut World,
    step: String,
    #[given(step)] s: &Step,
    num: usize,
) {
    tokio::time::delay_for(std::time::Duration::new(1, 0)).await;

    assert_eq!(step, "foo");
    assert_eq!(num, 0);
    assert_eq!(s.value, "foo is 0");

    w.foo += 1;
}

#[tokio::main]
async fn main() {
    use cucumber_codegen::WorldInit as _;

    let runner = World::init(&["./features"]);
    runner.run().await;
}

Under-the-hood it uses code generation via proc macros, some additional glue type definitions, and inventory for automatic step assertions registration.

We want to make public that machinery.

Are you interested with adding all of that to this crate? Or should we go with a diffent one?

[bbqsrc]

I'd be pretty happy to integrate that, sure. 😄

[bbqsrc]

Hey @tyranron, need any assistance with the integration work?

[tyranron]

@bbqsrc nope, thanks. I'm just quite a bit limited in time dedicated to this. Will try to land it this/next week.