Ok, I was thinking the idea behind this sounded a lot like the M.O. of Aspect-Oriented Programming, and it wasn't until I followed your github link that I saw that it was an "AOP library for JavaScript".
Not to take anything away from Raganwald, but there are other AOP JS projects (meld[1] would be an example).
This shows the beauty of Coffeescript syntax for functional programming. For a deep understanding read Raganwald's new book http://ristrettolo.gy.