Those languages aren't FP though. They aren't even close. Kotlin advertises itself as 'multi-paradigm', like C++. One reply observes they don't have pure funct

Those languages aren't FP though. They aren't even close. Kotlin advertises itself as 'multi-paradigm', like C++. One reply observes they don't have pure functions which is rather fundamental to most modern definitions of an FP language. But they also use imperative flow control in which statement ordering matters, their APIs are object oriented, there's no lazyness, type inference is intentionally limited. I don't think they've really borrowed many ideas from academic FP. Most such ideas were in fact explicitly rejected.