Yeah I know exactly what you mean in Haskell. Its just that in scala given the java inter-op there are a whole hunch of escape hatches that will always be there

Yeah I know exactly what you mean in Haskell. Its just that in scala given the java inter-op there are a whole hunch of escape hatches that will always be there. I remember in the coursera exercises when you submitted code that used mutable vars...it would flag your code and deduct points. So essentially even if someone provided a purefn annotation...to actually enforce that, the compiler would have to scan each function and disbar i/o, calls to rng, calls to global vars... tall order.