A generic solution for handling structures, built into the language's themselves, not just some hidden lib that mostly nobody knows. I mean most modern language

A generic solution for handling structures, built into the language's themselves, not just some hidden lib that mostly nobody knows. I mean most modern languages come with some XML-parsers, and often they also come with some more or less useful XML-generator. Add them as a first class-citizen, pimp them up and allow them to barf out all kind of tree-like structure which are similar enough and shove it in peoples faces to animate them to use it. I mean it basically worked with JSON too.