Realistically, what features can be provided by the language but not by libraries? If there are many cases, would that not indicate that the language's expressi

Realistically, what features can be provided by the language but not by libraries? If there are many cases, would that not indicate that the language's expressiveness is lacking? IMO, the goal of languages isn't to provide many features, but to provide constraints, so that programmers can stick to a set of rules that their peers can understand and agree upon. The most powerful language is the machine code for whatever CPU you're using, because there are no constraints, you have all of the power of the processor.