jank

typename.rs

pub trait TypeName {
    const NAME: &'static str;
}

macro_rules! typename {
    ($($typ:ty,)*) => {
        $(impl TypeName for $typ {
            const NAME: &'static str = stringify!($typ);
        })*
    }
}

typename! {
    String,
    str,
    &str,
    i32,
    Box<String>,
    fn(),
}

fn type_name_of_val<T: TypeName + ?Sized>(_: &T) -> &'static str {
    T::NAME
}

fn main() {
    let a = Box::new(String::from("hello"));
    let b = 10;
    let c = "potato";
    println!("a: {}", type_name_of_val(&a));
    println!("b: {}", type_name_of_val(&b));
    println!("c: {}", type_name_of_val(&c));
    println!("{}", type_name_of_val(""));
}