emacs-date-at-point/date-at-point.el

;;; date-at-point.el --- Add `date' to `thing-at-point' function

;; Copyright © 2014-2015 Alex Kost

;; Author: Alex Kost <alezost@gmail.com>
;; Created: 31 Dec 2014
;; Version: 0.1
;; URL: https://github.com/alezost/date-at-point.el
;; Keywords: convenience

;; 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 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This file provides an additional `date' thing for `thing-at-point'
;; function.

;; Using:
;;
;; 1. Add (require 'date-at-point) to your elisp code.
;; 2. Use (thing-at-point 'date).

;; A default regexp (`date-at-point-regexp') is trying to match any
;; possible date style, e.g.: "2014-12-31", "31.12.2014", "12/31/14",
;; etc.  If you find problems with the current regexp, please contact
;; the maintainer.

;;; Code:

(require 'thingatpt)

(defvar date-at-point-regexp
  (let ((separator  (rx (any "-./")))
        (2-digits   (rx (repeat 2 digit)))
        (2-4-digits (rx (repeat 2 4 digit))))
    (concat 2-4-digits separator 2-digits separator 2-4-digits))
  "Regular expression matching a date.")

(defun date-at-point-bounds ()
  "Return the bounds of the date at point."
  (save-excursion
    (when (thing-at-point-looking-at date-at-point-regexp)
      (cons (match-beginning 0) (match-end 0)))))

(put 'date 'bounds-of-thing-at-point 'date-at-point-bounds)

;;;###autoload
(defun date-at-point ()
  "Return the date at point, or nil if none is found."
  (thing-at-point 'date))

(provide 'date-at-point)

;;; date-at-point.el ends here