;;; -*- lexical-binding: t -*-
;;;
;;; this file:
;;;   https://dataswamp.org/~incal/emacs-init/scope.el
;;;
;;; g  = global
;;; sd = special/dynamic
;;; ls = lexical/static
;;; v  = variable

(defvar gsd-v 1)            ; 1
(special-variable-p 'gsd-v) ; t

(defvar gls-v)
(setq gls-v 2)              ; 2
(special-variable-p 'gls-v) ; nil

(defun fun-lol ()
  (list gsd-v gls-v v) )

(setq lexical-binding nil)

(let ((gsd-v 100)
      (gls-v 200)
      (v     300) )
  (list (list gsd-v gls-v v)
        (fun-lol) )) ; ((100 200 300) (100 200 300))

(setq lexical-binding t)

(let ((gsd-v 100)
      (gls-v 200)
      (v     300) )
  (list (list gsd-v gls-v v)
        (fun-lol) )) ; DNC, lexical/static `let' binding v undefined in fun-lol

(defun fun-lol-2 ()
  (list gsd-v gls-v) )

(let ((gsd-v 100)
      (gls-v 200)
      (v     300) )
  (list (list gsd-v gls-v v)
        (fun-lol-2) )) ; ((100 200 300) (100 200))