 ;;; libxml-doc.el - look up libxml-symbols and start browser on documentation

;; Author: Felix Natter <fnatter@gmx.net>
;; Created: Jun 21 2000
;; Keywords: libxml documentation

;; 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 2
;; 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, write to the Free Software
;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ;;; Commentary / README

;; these functions allow you to browse the libxml documentation
;; (using lynx within emacs by default; 
;; ----- Installing
;; 1. add the following to ~/.emacs (adapt path and remove comments !)
;; (load ~/elisp/libxml-doc.el)
;; you can also load this conditionally in a c-mode-hook (preferred)
;;
;;(add-hook 'c-mode-hook (lambda()
;; 						   (load-file "~/elisp/libxml-doc.el")))
;;
;; or you can use this if you are using libxml2
;;(add-hook 'c-mode-hook (lambda()
;;						 (save-excursion
;;						   (if (search-forward "#include <libxml/" nil t nil)
;;							   (load-file "~/elisp/libxml-doc.el"))
;;						   )))
;;
;; 2. adapt libxmldoc-root:
;; i.e. (setq libxmldoc-root "~/libxml2-2.0.0/doc/html/")
;; 3. change the filter-regex: by default, cpp-defines, callbacks and
;; html-functions are excluded (C-h v libxmldoc-filter-regexp)
;; 4. consider customizing libxmldoc-browse-url (lynx by default);
;; cannot use Emacs/W3 4.0pre46 because it has problems with the html
;; ----- Using
;; call M-x libxmldoc-lookup-symbol: this will prompt with completion
;; and then open the browser showing the documentation. If the word
;; around the point matches a symbol, that is used instead (no completion).

 ;;; ChangeLog:
;; Wed Jun 21 01:07:12 2000: initial release
;; Wed Jun 21 01:45:29 2000: added libxmldoc-lookup-symbol-at-point
;; Wed Jun 21 23:37:58 2000: libxmldoc-lookup-symbol now uses
;; (thing-at-point 'word) if it matches a symbol
;; Thu Jun 22 02:37:46 2000: filtering is only done for completion
;; Thu Jun 22 21:03:41 2000: libxmldoc-browse-url can be customized

;;; TODO:
;; use command-execute for libxml-browse-url

 ;;; Code:

(defvar libxmldoc-root "~/libxml/www.xmlsoft.org"
  "The root-directory of the libxml2-documentation (~ will be expanded).")
(defvar libxmldoc-filter-regexp "^html\\|^\\*\\|^[A-Z_]+\\|^$"
  "Symbols that match this regular expression will be excluded when doing
completion.
 For example:
   callbacks:     \"^\\\\*\" 
   cpp-defines:   \"[A-Z_]+\"
   xml-functions  \"^xml\"
   html-functions \"^html\"
   sax-functions  \".*SAX\"
 By default, callbacks, cpp-defines and html* are excluded. If you redefine
 this, you should include \"^$\" as alternative, which removes empty
 tokens. i.e. removing \"^html\\\\|\" from the above regexp causes html* to
 be shown.")
(defvar libxmldoc-browse-url 'browse-url-lynx-emacs
  "Browser used for browsing documentation. Emacs/W3 4.0pre46 cannot handle
the html, so lynx-emacs is used by default.")
(defvar libxmldoc-symbol-history nil
  "History for looking up libxml-symbols.")

 ;;;; public functions

(defun libxmldoc-lookup-symbol(&optional symbol)
  "Look up xml-symbol." (interactive)
  (let ((symbols)
		(real-symbol symbol)
		(url))
	(if symbol
		(setq symbols (libxmldoc-get-list-of-symbols t))
	  (setq symbols (libxmldoc-get-list-of-symbols nil)))
	(if (null real-symbol)
		(if (assoc (thing-at-point 'word) symbols)
			(setq real-symbol (thing-at-point 'word))
		  (setq real-symbol (completing-read "Libxml: " symbols nil t ""
											 'libxmldoc-symbol-history "" t))))
	(if (null (assoc real-symbol symbols))
		(error (concat "libxmldoc: '" real-symbol "' not found !")))
	(setq url (cdr (assoc real-symbol symbols)))
;;	(minibuffer-message uri)
	(apply libxmldoc-browse-url (list url))))

;;(defun libxmldoc-lookup-symbol-at-point()
;;  "Look up libxml-symbol at point." (interactive)
;;  (libxmldoc-lookup-symbol (thing-at-point 'word)))

;;;; internal

(defun libxmldoc-get-list-of-symbols(&optional nofilter)
  "Get the list of html-links in the libxml-documentation."
  (let ((files (directory-files libxmldoc-root t
								"^gnome-xml-.*\\.html$" t))
		(symbols ())
		(case-fold-search t)
		(symbol)
		(uri))
;;	(minibuffer-message "collecting libxml-symbols...")
	(while (car files)
	  (find-file (car files))
	  (while (re-search-forward
			  "<a[^>]*href[ \t\n]*=[ \t\n]*\"\\([^=>]*\\)\"[^>]*>" nil t nil)
		(setq uri (concat "file://" (expand-file-name libxmldoc-root) "/"
						  (match-string 1)))
		(if (not (re-search-forward "\\([^<]*\\)<" nil t nil))
			(error "regexp error while finding libxml-symbols.."))
		(setq symbol (match-string 1))
		(setq case-fold-search nil)
		(if (or nofilter
				(null (string-match libxmldoc-filter-regexp symbol)))
			(add-to-list 'symbols (cons symbol uri)))
		(setq case-fold-search t)
		)
	  (kill-buffer (current-buffer))
	  (setq files (cdr files)))
	symbols))

;;; libxml-doc.el ends here