fibo-gen1.js

function fibo2() {
  var a, b; // local vars
  return wrap(function (c) {
    while (1) {
      switch (c.next) {
        case 0:
          a=0, b=1;
        case 1: // while begin
          if (!true) { // while cond
            c.next = 3;
            break;
          }
          // while body ben

          // yield a
          c.next = 2;
          return a;
        case 2:
          b = a + b;
          a = b - a;
          // while body end
          
          c.next = 1;
          break;
        case 3:
          // while end
        case "end":
          return c.stop();
      }
    }
  });
}