Pretty much every mainstream language has adopted concepts from FP. C++ has closures. Even Java is getting pattern matching. Everyone has map/fold. ... Most ne

Pretty much every mainstream language has adopted concepts from FP. C++ has closures. Even Java is getting pattern matching. Everyone has map/fold. ... Most new languages I can think of have a concept of immutability and sum types. (Kotlin, Swift, Rust) Many languages are in fact converging on what seems like a local optimum, with a blend of functional and non-functional idioms. The line has become a lot blurrier, which makes the question hard to answer.