JSX would be an (early) example of this class of language. XML is equivalent to s-expressions. So React.js (drunkly) is just a reactive language embedded in a normal language with seamless ability to hop between them. I elaborate about this equivalence here https://www.reddit.com/r/Clojure/comments/mavg81/the_distinc... . The brilliance is they did this so smoothly that nobody noticed, and with dynamic types, and without the typed people even noticing!