FYI: a possible AltJS like skin in ES6 era. #JavaScript

This is just a FYI about a proposal: Real ES6 JS with Coffeescript syntax.

I like coffeescript and livescript in ES5 world. But I also know the great power of ES6 now.
So, I'm interested in a possible AltJS in ES6 era.
I find mark-hahn's cool jsw trial.

Mark-hahn says:
"Unlike Coffeescript, JSW does not provide a new language with differing semantics. It is a thin skin over Javascript that only changes the syntax. ... JSW is a great way for Coffeescript users to migrate to real Javascript with ES6."

So,
JSW will turn jsw code such as

example.jsw

-> func1 arg1, arg2                 
  var hash1 = key1: val1            
              key2: val2            
              key3:                 
  block                             
    let x = y                       
    func2 x                         
    if q and z                      
      func1 "This is text spread    
             over two lines."

into Javascript code like that:

example.js

function func1 (arg1, arg2) {
  var hash1 = {
    key1: val1,
    key2: val2,
    key3: key3
  }
  {
    let x = y;
    func2(x);
    if (q && z) {
      func1("This is text spread " +
            "over two lines.");
    }
  }
}

A possible future ;)