Rust code snippets

debug_print.rs

macro_rules! p {
    ($($e:expr),+) => ({
        $(
        println!("{} = {:?}", stringify!($e), $e);
        )+
    })
}

expr_alias.rs

macro_rules! alias {
    ($name:ident = $e:expr) => (
        macro_rules! $name {
            () => ($e)
        }
    )
}

fn main() {
    let a = 1;
    let mut b = 2;
    let c = 3;
    
    alias!(f = a + b + c);
    
    println!("{}", f!());
    b = 10;
    println!("{}", f!());
}

left_shifting_printer.rs

#[allow(non_camel_case_types)]
struct cout;

impl<T> std::ops::Shl<T> for cout {
    type Output = cout;

    fn shl(self, x: T) -> cout {
        print!("{}", x);
        cout
    }
}

fn main() {
    cout << "1 + 1 = " << 1 + 1 << '\n';
}