;; -*- Mode: Lisp; -*-
;; ---------------------------------------------------------------------------
;;     Title: My idea of global variables
;;   Created: 2020-05-25
;;    Author: Gilbert Baumann
;; ---------------------------------------------------------------------------
;;  (c) copyright 2020 by Gilbert Baumann

(defpackage :bauhh-global
  (:use :common-lisp)
  (:export
   #:defgobal))

(in-package :bauhh-global)

(defmacro defglobal (symbol &optional (init nil initp) documentation)
  `(progn
     (define-symbol-macro ,symbol (symbol-value ',symbol))
     ,@(and initp
            (list `(unless (boundp ',symbol)
                     (set ',symbol ,init))))
     ,@(and documentation
            (list `(setf (documentation ',symbol 'variable) ,documentation)))
     ',symbol))

(defglobal -bar- :global-value-of-bar)

(defun foo ()
  (let ((-bar- :foo-value-of-bar))
    (list -bar- (bar))))

(defun bar ()
  -bar-)

;;
;; (FOO) => (:FOO-VALUE-OF-BAR :GLOBAL-VALUE-OF-BAR)
;;