This is fantastic work. It has a very approachable way of controlling side-effects. That's also one of Haskell's goals, but the learning curve is much steeper.

This is fantastic work. It has a very approachable way of controlling side-effects. That's also one of Haskell's goals, but the learning curve is much steeper. If I was going to teach Haskell to someone, I'd be very tempted to start them off by spending a few days noodling around with Koka. I love that you can even annotate a function to let it read from a variable, but not write to it, or vice versa.