Getting it into a mainstream OS is a huge undertaking - but doing it within the confines of a new programming language is straightforward. Haskell mostly does i

Getting it into a mainstream OS is a huge undertaking - but doing it within the confines of a new programming language is straightforward. Haskell mostly does it, at least with the Safe Haskell implementation. In an object oriented setting, it's simply a matter of not exposing the filesystem (etc.) as globals, but instead as an object that is passed around explicitly, starting from main(). There are a few upcoming languages that do this.