"other functional style syntaxes like pattern matching are being introduced in many of them" The Interpreter and its dual the Visitor GOF pattern have made wha

"other functional style syntaxes like pattern matching are being introduced in many of them" The Interpreter and its dual the Visitor GOF pattern have made what amounts to pattern matching possible in OO languages for a few decades now [1]. The whole point of these patterns is to write recursive functions following recursive data types, which is one of the main use cases for pattern matching (ok, more generally these are used to break data structures apart). In particular, if you look at an example of the Visitor pattern, you will see that it has exactly the same structure as a recursive function that separates cases in a FP language [2] Here is a detailed explanation of how to do it [3]; it is the "little language" technique (which I suspect is the reason why it is called the Interpreter). [1] https://eli.thegreenplace.net/2016/the-expression-problem-and-its-solutions/ https://eli.thegreenplace.net/2016/the-expression-problem-an... [2] http://blog.higher-order.com/blog/2009/08/21/structural-pattern-matching-in-java/ http://blog.higher-order.com/blog/2009/08/21/structural-patt... [3] https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-005-elements-of-software-construction-fall-2008/lecture-notes/MIT6_005f08_lec15.pdf https://ocw.mit.edu/courses/electrical-engineering-and-compu...