[lomnakkus]

Agreed. Purescript[1] is definitely interesting as one the very few languages in the world with row types/polymorphism.

I'm not quite agreed on the effects bit being useful, but it's a good demo of what the type system can do. My main disagreement with the whole approach is that effects don't commute (in general) and so representing effects as such isn't quite valid.

[1] I'm still baffled as to why they named it thusly. I mean, I can guess at motivations, but it really deserves a much catchier name!