;; footnote-balloons.el --- Show footnotes in balloon-help frame   -*- Emacs-Lisp -*-

;; Copyright (C) 2012 Steve Youngs

;; Author:     Steve Youngs <steve@sxemacs.org>
;; Maintainer: Steve Youngs <steve@sxemacs.org>
;; Created:    <2012-01-27>
;; Time-stamp: <Tuesday Mar 25, 2014 10:38:13 steve>
;; Homepage:   http://www.xemacs.org
;; Keywords:   mail, news, text, footnote

;; This file is part of XEmacs.

;; Redistribution and use in source and binary forms, with or without
;; modification, are permitted provided that the following conditions
;; are met:
;;
;; 1. Redistributions of source code must retain the above copyright
;;    notice, this list of conditions and the following disclaimer.
;;
;; 2. Redistributions in binary form must reproduce the above copyright
;;    notice, this list of conditions and the following disclaimer in the
;;    documentation and/or other materials provided with the distribution.
;;
;; 3. Neither the name of the author nor the names of any contributors
;;    may be used to endorse or promote products derived from this
;;    software without specific prior written permission.
;;
;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
;; IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
;; DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
;; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
;; CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
;; SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
;; BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
;; WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
;; OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
;; IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

;;; Commentary:
;; 
;;    

;;; Todo:
;;
;;     

;;; Code:
(require 'footnote)
(require 'balloon-help) 


(defvar footnote-balloon-regexp "\\[[^\]\n]+\\]") 

(defun get-foot-string () 
  (let (b ext)
    (while (looking-at "[ \t]") 
      (forward-char)) 
    (setq b (point)) 
    ;; Find the end of the footnote. 
    (re-search-forward (concat "\\\n\\\n\\|\\'\\|" 
			       footnote-balloon-regexp) nil t) 
    (beginning-of-line) 
    (while (looking-at "^") 
      (backward-char)) 
    (setq ext (make-extent b (point))) 
    (set-extent-property ext 'footnote t) 
    (set-extent-face ext 'green)
    (extent-string ext)))

(defun footnote-balloons () 
  "Turn footnote refs into extents containing the fn string as balloon-help."
  (interactive) 
  (map-extents 
   #'(lambda (extent ignore) 
       (when (extent-property extent 'footnote) 
	 (delete-extent extent)))) 
  (save-excursion 
    (let (ref-beg ref-end ext footnum note) 
      (goto-char (point-min)) 
      ;; Looking for footnote refs in the text. 
      (while (re-search-forward footnote-balloon-regexp nil t) 
	(setq ref-beg (match-beginning 0)) 
	(setq ref-end (match-end 0)) 
	(setq footnum (buffer-substring ref-beg ref-end)) 
	(goto-char (point-max)) 
	;; Now find the footnote itself. 
	(when (search-backward footnum ref-end t) 
	  (search-forward footnum nil t) 
	  (setq note (get-foot-string))
	  (setq ext (make-extent ref-beg ref-end)) 
	  (set-extent-face ext 'red) 
	  (set-extent-property ext 'footnote t)
	  (set-extent-property ext 'highlight t)
	  (set-extent-property ext 'balloon-help note)) 
	(goto-char ref-end)))))

(provide 'footnote-balloons)
;;; footnote-balloons.el ends here