Macro using 

macro_rules! using {
    { $($p:pat = $v:expr),* ; $b:block } => { ... };
}

using

Usage

let v = (1, 2);
let v2 = (3, 4);
using!((a, b) = v, (c, d) = v2; {
  println!("{} {} {} {}", a, b, c, d)
})

equivalent to

let v = (1, 2);
let v2 = (3, 4);
{
  let (a, b) = v;
  let (c, d) = v2;
  {
    println!("{} {} {} {}", a, b, c, d)
  }
}