Warning: this is an htmlized version!
The original is here, and
the conversion rules are here. 
;; This file:
;;   http://angg.twu.net/.emacs.u8.html
;;   http://angg.twu.net/.emacs.u8
;;           (find-angg ".emacs.u8")
;; Author: Eduardo Ochs <eduardoochs@gmail.com>
;;
;; Loaded by:
;;   (find-angg ".emacs" ".emacs.u8")


;; (rx (intersection (in "A-Z") (not "B")))

(setq badchar-re (rx (in "À-𝓩")))

(defun badchar ()
  (interactive)
  (re-search-forward badchar-re))

;; (find-elnode "Rx Constructs")
;; (find-elnode "Rx Constructs" "(intersection")
;; (find-einsert '((0 255)))
;; (rx (in "\000-\011\013-\016\020-\037"))
;; (rx (intersection (in "\177-\377") (not (in "«»ÀÁÂÃÄÅÇÈÉÊËÌÍÎÏÑÒÓÔÕÖÙÚÛÜàáâãäåçèéêëìíîïñòóôõöùúûü"))))

' (setq badchar-re
    (rx (intersection
	 (in "\000-\011\013-\016\020-\037\177-\377")
	 (not (in "«»ÀÁÂÃÄÅÇÈÉÊËÌÍÎÏÑÒÓÔÕÖÙÚÛÜàáâãäåçèéêëìíîïñòóôõöùúûü")))))

(rx (or (any "\000-\011\013-\016\020-\037\177-\377")
        (not (in "«»ÀÁÂÃÄÅÇÈÉÊËÌÍÎÏÑÒÓÔÕÖÙÚÛÜàáâãäåçèéêëìíîïñòóôõöùúûü"))))

;;
;; Local Variables:
;; mode:                 emacs-lisp
;; coding:               utf-8-unix
;; End: