Macro extendr_api::sym

macro_rules! sym {
    ($($tokens: tt)*) => { ... };
}

The sym! macro install symbols. You should cache your symbols in variables as generating them is costly.

use extendr_api::prelude::*;
test! {

let wombat = sym!(wombat);
assert_eq!(wombat, r!(Symbol("wombat")));
}