Immutable data

What kind of idiot needs to have his data kept constant to keep himself from breaking something? If you can't keep your shit in order without stupid artificial constraints, then you don't know shit about programming.

>>5
Haskell is not for programming with, it is for circlejerking over. I doesn't even really need any sort of data. In fact, there have been numerous studies done that proved that there has not once in the entire history of Haskell, where it was used for anything practical.