But functional programming and OOP are intrinsically the same, but expressed using different primitives. The thing that empowers first-class functions and clos

But functional programming and OOP are intrinsically the same, but expressed using different primitives. The thing that empowers first-class functions and closures (lexical binding) is the exact same method by which encapsulation works, even if the latter opts for heap vs stack. The fundamentals are the same. Here's a simple one in Emacs Lisp: (defmacro send (object method &rest args) "Sends a METHOD to an OBJECT with ARGS." `(funcall ,object ',method ,@args)) (defun make-animal (name) ;; 'hunger' is entirely private (encapsulated) (let ((hunger 5)) ;; here's our lambda using lexical binding (lambda (method &rest args) (cond ((eq method 'get-name) name) ((eq method 'feed) (setq hunger (max 0 (1- hunger))) "Yum!") (t (error "Animal does not understand: %s" method)))))) (let ((good-boy (make-animal "Rex"))) ;; "call" (via our macro) the "get-name" method; then feed. hunger does down 1. (send good-boy get-name) (send good-boy feed) ;; pretty-print the "object" good-boy (pp good-boy)) ;; this is the state of it after the two calls. #[(method &rest args) ((cond ((eq method 'get-name) name) ((eq method 'feed) (setq hunger (max 0 (1- hunger))) "Yum!") (t (error "Animal does not understand: %s" method)))) ((hunger . 4) (name . "Rex"))]