> Right, but FP has been around for quite some time, and given that none of the current implementations actually solve this issue right now I think it is a vali

> Right, but FP has been around for quite some time, and given that none of the current implementations actually solve this issue right now I think it is a valid critique of FP because it's simple what current FP implementations are limited to. No idea what you mean. Mutable state is not a problem in Haskell. You can have high performance libraries that provide mutable APIs that are safe to use. You can have code that looks more imperative if you want. If you really want to go nuts you can use linear types and solve such problems in a completely general way. > Maybe a "sufficiently advanced compiler" in the future will solve this, but it's not at all clear such a thing can be created in a way that's practical right now. There's no need for any advanced compiler. We have all of this today.