hygienic destructuring var assignments with sweet.js

gistfile1.js

macro $do {
    case ($($x = $y) (,) ...) $body => {
        (function ($x (,) ...) $body)($y (,) ...)
    }
    case $name ($($x = $y) (,) ...) $body => {
        (function $name ($x (,) ...) $body)($y (,) ...)
    }
}

macro $var {
  case [$name (,) ...] = $expr => {
    var $name (,) ...
    $do (i = 0, array = $expr) {
      $($name = array[i++];) ...
    }
  }
 
  case {$name (,) ...} = $expr => { 
      var $name (,) ...
      $do (obj = $expr) {
           $($name = obj.$name;) ...
      }
  }
 
  case $name:ident = $expr => {
      var $name = $expr
  }
}

$var [x, y, z] = [0, 1, 2]
$var {a, b} = {a: 1, b: 45}

$var [x, y, z] = [0, 1, 2];
console.log(x, y, z); // 0 1 2

$var {x, y, z} = {x: 5, y: 6, z: 7};
console.log(x, y, z); // 5 6 7

$var w = 10;
console.log(w); // 10