;;; ox-gfm.el --- Github Flavored Markdown Back-End for Org Export Engine
;; Copyright (C) 2014 Lars Tveito
;; Author: Lars Tveito
;; Keywords: org, wp, markdown, github
;; This file is not part of GNU Emacs.
;; GNU Emacs 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.
;; GNU Emacs 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 GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;; This library implements a Markdown back-end (github flavor) for Org
;; exporter, based on the `md' back-end.
;;; Code:
(require 'ox-md)
;;; User-Configurable Variables
(defgroup org-export-gfm nil
"Options specific to Markdown export back-end."
:tag "Org Github Flavored Markdown"
:group 'org-export
:version "24.4"
:package-version '(Org . "8.0"))
(defcustom org-gfm-lang '(("emacs-lisp" . "lisp") ("elisp" . "lisp"))
"Alist of languages that are not recognized by Github, to
languages that are. Emacs lisp is a good example of this, where
we can use lisp as a nice replacement."
:group 'org-export-gfm)
;;; Define Back-End
(org-export-define-derived-backend 'gfm 'md
:filters-alist '((:filter-parse-tree . org-md-separate-elements))
:menu-entry
'(?g "Export to Github Flavored Markdown"
((?G "To temporary buffer"
(lambda (a s v b) (org-gfm-export-as-markdown a s v)))
(?g "To file" (lambda (a s v b) (org-gfm-export-to-markdown a s v)))
(?o "To file and open"
(lambda (a s v b)
(if a (org-gfm-export-to-markdown t s v)
(org-open-file (org-gfm-export-to-markdown nil s v)))))))
:translate-alist '((inner-template . org-gfm-inner-template)
(strike-through . org-gfm-strike-through)
(src-block . org-gfm-src-block)))
;;; Transcode Functions
;;;; Src Block
(defun org-gfm-src-block (src-block contents info)
"Transcode SRC-BLOCK element into Github Flavored Markdown
format. CONTENTS is nil. INFO is a plist used as a communication
channel."
(let* ((lang (org-element-property :language src-block))
(lang (or (assoc-default lang org-gfm-lang) lang))
(code (org-export-format-code-default src-block info))
(prefix (concat "```" lang "\n"))
(suffix "```"))
(concat prefix code suffix)))
;;;; Strike-Through
(defun org-html-strike-through (strike-through contents info)
"Transcode STRIKE-THROUGH from Org to Markdown (GFM).
CONTENTS is the text with strike-through markup. INFO is a plist
holding contextual information."
(format "~~%s~~" contents))
;;;; Table of contents
(defun org-gfm-format-toc (headline)
"Return an appropriate table of contents entry for HEADLINE. INFO is a
plist used as a communication channel."
(let* ((title (org-export-data
(org-export-get-alt-title headline info) info))
(level (1- (org-element-property :level headline)))
(indent (concat (make-string (* level 2) ? )))
(ref-str (replace-regexp-in-string " " "-" (downcase title))))
(concat indent "- [" title "]" "(#" ref-str ")")))
;;;; Template
(defun org-gfm-inner-template (contents info)
"Return body of document after converting it to Markdown syntax.
CONTENTS is the transcoded contents string. INFO is a plist
holding export options."
(let* ((depth (plist-get info :with-toc))
(headlines (and depth (org-export-collect-headlines info depth)))
(toc-string (or (mapconcat 'org-gfm-format-toc headlines "\n") ""))
(toc-tail (if headlines "\n\n" "")))
(concat toc-string toc-tail contents)))
;;; Interactive function
;;;###autoload
(defun org-gfm-export-as-markdown (&optional async subtreep visible-only)
"Export current buffer to a Github Flavored Markdown buffer.
If narrowing is active in the current buffer, only export its
narrowed part.
If a region is active, export that region.
A non-nil optional argument ASYNC means the process should happen
asynchronously. The resulting buffer should be accessible
through the `org-export-stack' interface.
When optional argument SUBTREEP is non-nil, export the sub-tree
at point, extracting information from the headline properties
first.
When optional argument VISIBLE-ONLY is non-nil, don't export
contents of hidden elements.
Export is done in a buffer named \"*Org GFM Export*\", which will
be displayed when `org-export-show-temporary-export-buffer' is
non-nil."
(interactive)
(org-export-to-buffer 'gfm "*Org GFM Export*"
async subtreep visible-only nil nil (lambda () (text-mode))))
;;;###autoload
(defun org-gfm-convert-region-to-md ()
"Assume the current region has org-mode syntax, and convert it
to Github Flavored Markdown. This can be used in any buffer.
For example, you can write an itemized list in org-mode syntax in
a Markdown buffer and use this command to convert it."
(interactive)
(org-export-replace-region-by 'gfm))
;;;###autoload
(defun org-gfm-export-to-markdown (&optional async subtreep visible-only)
"Export current buffer to a Github Flavored Markdown file.
If narrowing is active in the current buffer, only export its
narrowed part.
If a region is active, export that region.
A non-nil optional argument ASYNC means the process should happen
asynchronously. The resulting file should be accessible through
the `org-export-stack' interface.
When optional argument SUBTREEP is non-nil, export the sub-tree
at point, extracting information from the headline properties
first.
When optional argument VISIBLE-ONLY is non-nil, don't export
contents of hidden elements.
Return output file's name."
(interactive)
(let ((outfile (org-export-output-file-name ".md" subtreep)))
(org-export-to-file 'gfm outfile async subtreep visible-only)))
(provide 'ox-gfm)
;; Local variables:
;; generated-autoload-file: "org-loaddefs.el"
;; End:
;;; ox-gfm.el ends here