main_exeuctor from smol-macros

[brandonros]

based on smol-rs/smol-macros#10 (comment)

[notgull]

I feel like this is an XY problem. What is the use case here? MainExecutor is an awkward interface for a public trait, which is why it's not public in smol-macros.

[brandonros]

It lets me do this:

fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
    Arc::<Executor>::with_main(|ex| smol::block_on(async_main(ex)))
}

while boils down to this:

impl MainExecutor for Arc<Executor<'_>> {
    #[inline]
    fn with_main<T, F: FnOnce(&Self) -> T>(f: F) -> T {
        let ex = Arc::new(Executor::new());
        with_thread_pool(&ex, || f(&ex))
    }
}

which is mildly less awkward / more clear (to me at least)

We can close it if you think it doesn't gain anything. It felt weird to me that async-executor ships without a default that can handle multiple tasks on different threads or whatever but only smol-macros did with it tucked away/private.