In a strict CS sense, languages are defined by what they accept, and how they parse what they accept. Given that this will only accept and correctly parse a su

In a strict CS sense, languages are defined by what they accept, and how they parse what they accept. Given that this will only accept and correctly parse a subset of the Ruby language, in a strict CS sense, it accepts a different language to Ruby. In time, this difference may shrink (as Natalie becomes more complete), become larger (as Ruby gets more fully featured) or diverge so that Natalie isn't a subset (e.g. if Natalie decides for some reason to parse some Ruby construct differently to Ruby).