I would find this sort of thing infuriating. Every time you learn a syntax, it gets replaced by another? Your error messages depend on how far along you are? Wo

I would find this sort of thing infuriating. Every time you learn a syntax, it gets replaced by another? Your error messages depend on how far along you are? Worse: program correctness depends on how far along you are? Good luck going to a TA with that one... Also, it's shooting yourself in the foot w.r.t. those people who come into the program already knowing something. Driving away the advanced people isn't the best thing in the world. As an aside, that first example pretty much sums up why I don't like Haskell. Not the error message, but that it doesn't work in the first place. It's too bad, because I know I'm kind of shooting myself in the foot. But first impressions leave a mark.