Macro join 

macro_rules! join {
    (@inner, $temp:expr, $value:expr) => { ... };
    (binary :: $( $value:expr ),+ ) => { ... };
    (string :: $( $value:expr ),+ ) => { ... };
}

Joining data of Binary and String types

Usage

use we_cdk::*;

#[action]
fn _constructor() {
    let bytes: Binary = join!(binary :: &[0, 1], &[2, 3]);
    let hello_world: String = join!(string :: "Hello", ", ", "world", "!");
}