The Cloud Haskell project and language is likely the only one to get this right, thanks to strictly enforced purity. It's much simpler to understand, absence gl

The Cloud Haskell project and language is likely the only one to get this right, thanks to strictly enforced purity. It's much simpler to understand, absence global mutable state, whether it's safe and possible to serialize a closure and run it somewhere else. (fork(2) being a closure by another name.) In almost all other languages there's just no way to know if a closure is holding on to a file descriptor. Critics may say the Haskell closures could contain `unsafePerformIO`, but as the saying goes: now you have two problems.