G.js

G.js

// **************
// framework code

function sync(gen) {
  var iterable, resume;

  resume = function(err, retVal) {
    if (err) iterable.raise(err);
    iterable.next(retVal); // resume!  
  };

  iterable = gen(resume);
  iterable.next();
}

function _get(url, callback) {
  var x = new XMLHttpRequest();

  x.onreadystatechange = function() {
    if (x.readyState == 4) {
      callback(null, x.responseText);
    }
  };

  x.open("GET", url);
  x.send();
}

// ****************
// application code

sync(function* (resume) {
  log('foo');
  var resp = yield _get("blix.txt", resume); // suspend!
  log(resp);
});

log('bar'); // not part of our generator function’s body