;;; markchars.el --- Mark chars fitting certain characteristics
;;
;; Author: Lennart Borgman (lennart O borgman A gmail O com)
;; Created: 2010-03-22 Mon
;; Version:
;; Last-Updated:
;; URL:
;; Keywords:
;; Compatibility:
;;
;; Features that might be required by this library:
;;
;;   None
;;
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;;
;;; Commentary:
;;
;; Mark special chars, by default nonascii chars. See `markchars-mode'.
;;
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;;
;;; Change log:
;;
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;;
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation; either version 3, or
;; (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth
;; Floor, Boston, MA 02110-1301, USA.
;;
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;;
;;; Code:

;; (re-search-forward "[[:nonascii:]]")
;; äåö

;;;###autoload
(defgroup markchars nil
  "Customization group for `markchars-mode'."
  :group 'convenience)

(defface markchars-light
  '((t (:underline "light blue")))
  "Light face for `markchars-mode' char marking."
  :group 'markchars)

(defface markchars-heavy
  '((t (:underline "magenta")))
  "Heavy face for `markchars-mode' char marking."
  :group 'markchars)

(defcustom markchars-face 'markchars-heavy
  "Pointer to face used for marking chars."
  :type 'face
  :group 'markchars)

(defcustom markchars-pattern "[[:nonascii:]]"
  "Regexp for characters to mark.
This is supposed to match single characters, but you can of
course \(mis)use it anyway you want.

By default it matches nonascii-chars."
  :type 'regexp
  :group 'markchars)

(defvar markchars-keywords nil
  "Keywords for font lock.")

(defun markchars-set-keywords ()
  "Set `markchars-keywords' from options."
  (set (make-local-variable 'markchars-keywords)
       (list
        (list markchars-pattern
              (list 0 '(put-text-property (match-beginning 0) (match-end 0)
                                         'face markchars-face))))))

;;;###autoload
(define-minor-mode markchars-mode
  "Mark special characters.
Which characters to mark are defined by `markchars-pattern'.

The default is to mark nonascii chars with a magenta underline."
  :group 'markchars
  (if markchars-mode
      (progn
        (markchars-set-keywords)
        (font-lock-add-keywords nil markchars-keywords))
    (font-lock-remove-keywords nil markchars-keywords))
  (font-lock-fontify-buffer))

;;;###autoload
(define-globalized-minor-mode markchars-global-mode markchars-mode
  (lambda () (markchars-mode 1))
  :group 'markchars)

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;;; markchars.el ends here