;;; -*- lexical-binding: t -*-
;;
;; this file:
;;   https://dataswamp.org/~incal/emacs-init/vars-opts.el

(require 'cl-lib)

(defun check-binders (binds)
  (cl-loop
    for (n _) in binds
    with no-opt
    do (unless (special-variable-p n)
         (push (symbol-name n) no-opt) )
    finally (when no-opt
              (error "No option%s: %s"
                     (if (< 1 (length no-opt))
                         "s"
                       "")
                     (mapconcat #'identity (reverse no-opt) ", ") ))))

(defmacro opts (binds &rest body)
  (declare
    (indent 1)
    (debug let) )
  (check-binders binds)
  `(let ,binds ,@body) )

;; (opts ((fill-column 1)
;;        (a 0) )
;;   u) ; No option: a
;;
;; (defvar dynavar 2000)
;;
;; (opts ((dynavar 3000)
;;        (fill-column 1)
;;        (a 0)
;;        (y 2) )
;;   y) ; No options: a, y
;;
;; (opts ((dynavar 3000)
;;        (fill-column 10) )
;;   (delete-char 2)
;;   (fill-paragraph) ) ; eval me

(provide 'vars-opts)