You might like http://felix-lang.org http://felix-lang.org in particular if you have a taste for the ML family of languages. It fits your description to a T. No

You might like http://felix-lang.org http://felix-lang.org in particular if you have a taste for the ML family of languages. It fits your description to a T. No, really, dead serious and I don't have any dog in this fight. Has had coroutines and fibres from the start. Certainly not a new language. Its relationship to C++ is much like F#'s relationship to C# or Scala's to Java OTOH if you are really after C++ but done right then that would be D http://dlang.org http://dlang.org If you wish something like this for C then I would likely point to Nim.