Is it possible to conditionally compile a code block inside a function?

Question

I\'m wondering if something like this is possible

fn main() {
    #[cfg(foo)] {
        println!(\"using foo config\");
    }

}

The context is

Answer 1

You may interested in the crate cfg-if, or a simple macro will do:

macro_rules! conditional_compile {
    ($(#[$ATTR:meta])* { $CODE: tt }) => {
        {
            match 0 {
                $(#[$ATTR])*
                0 => $CODE,

                // suppress clippy warnning `single_match`.
                1 => (),
                _ => (),
            }
        }
    }
}

fn main() {
    conditional_compile{
        #[cfg(foo)]
        {{
            println!("using foo config");
            // Or something only exists in cfg foo, like a featured mod.
        }}
    }
}