Two observations. First, great how do we debug it? How can we see our signals between each step? How about beyond simple print/logging?

And two, I like his contrast between async vs synchronous flows, and recognizing synchronous style programming has many benefits that CPS doesn't. However, I think even this style still hasn't solved the bigger problem with asynchronous style programming. The ability to reuse it easily. In synchronous style programming I can reuse code and add to that block by calling the method, then after that method is done add my code.

   ... my code before ...
   var result = someMethod()
   ... my code after ...

It's just that simple with synchronous style. With async style the author has to provide you a hook to hook onto the end or beginning of this flow (adding a callback param, returning a promise, etc). I think even with using signals you have the same issue. Without explicit hooks you can't hook more code onto it like you can with good old fashion synchronous programming. Not to mention error control flow is turned upside down too.

I'm intrigued by the ideas of signals over callbacks, but I don't know if they fix enough problems with callbacks yet.