ox-md: Fix internal links
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1 ;;; ox-md.el --- Markdown Back-End for Org Export Engine -*- lexical-binding: t; -*-
3 ;; Copyright (C) 2012-2017 Free Software Foundation, Inc.
5 ;; Author: Nicolas Goaziou <n.goaziou@gmail.com>
6 ;; Keywords: org, wp, markdown
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software: you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation, either version 3 of the License, or
13 ;; (at your option) any later version.
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
23 ;;; Commentary:
25 ;; This library implements a Markdown back-end (vanilla flavor) for
26 ;; Org exporter, based on `html' back-end. See Org manual for more
27 ;; information.
29 ;;; Code:
31 (require 'cl-lib)
32 (require 'ox-html)
33 (require 'ox-publish)
36 ;;; User-Configurable Variables
38 (defgroup org-export-md nil
39 "Options specific to Markdown export back-end."
40 :tag "Org Markdown"
41 :group 'org-export
42 :version "24.4"
43 :package-version '(Org . "8.0"))
45 (defcustom org-md-headline-style 'atx
46 "Style used to format headlines.
47 This variable can be set to either `atx' or `setext'."
48 :group 'org-export-md
49 :type '(choice
50 (const :tag "Use \"atx\" style" atx)
51 (const :tag "Use \"Setext\" style" setext)))
54 ;;;; Footnotes
56 (defcustom org-md-footnotes-section "%s%s"
57 "Format string for the footnotes section.
58 The first %s placeholder will be replaced with the localized Footnotes section
59 heading, the second with the contents of the Footnotes section."
60 :group 'org-export-md
61 :type 'string
62 :version "26.1"
63 :package-version '(Org . "9.0"))
65 (defcustom org-md-footnote-format "<sup>%s</sup>"
66 "Format string for the footnote reference.
67 The %s will be replaced by the footnote reference itself."
68 :group 'org-export-md
69 :type 'string
70 :version "26.1"
71 :package-version '(Org . "9.0"))
74 ;;; Define Back-End
76 (org-export-define-derived-backend 'md 'html
77 :filters-alist '((:filter-parse-tree . org-md-separate-elements))
78 :menu-entry
79 '(?m "Export to Markdown"
80 ((?M "To temporary buffer"
81 (lambda (a s v b) (org-md-export-as-markdown a s v)))
82 (?m "To file" (lambda (a s v b) (org-md-export-to-markdown a s v)))
83 (?o "To file and open"
84 (lambda (a s v b)
85 (if a (org-md-export-to-markdown t s v)
86 (org-open-file (org-md-export-to-markdown nil s v)))))))
87 :translate-alist '((bold . org-md-bold)
88 (code . org-md-verbatim)
89 (example-block . org-md-example-block)
90 (export-block . org-md-export-block)
91 (fixed-width . org-md-example-block)
92 (headline . org-md-headline)
93 (horizontal-rule . org-md-horizontal-rule)
94 (inline-src-block . org-md-verbatim)
95 (inner-template . org-md-inner-template)
96 (italic . org-md-italic)
97 (item . org-md-item)
98 (keyword . org-md-keyword)
99 (line-break . org-md-line-break)
100 (link . org-md-link)
101 (node-property . org-md-node-property)
102 (paragraph . org-md-paragraph)
103 (plain-list . org-md-plain-list)
104 (plain-text . org-md-plain-text)
105 (property-drawer . org-md-property-drawer)
106 (quote-block . org-md-quote-block)
107 (section . org-md-section)
108 (src-block . org-md-example-block)
109 (template . org-md-template)
110 (verbatim . org-md-verbatim))
111 :options-alist
112 '((:md-footnote-format nil nil org-md-footnote-format)
113 (:md-footnotes-section nil nil org-md-footnotes-section)
114 (:md-headline-style nil nil org-md-headline-style)))
117 ;;; Filters
119 (defun org-md-separate-elements (tree _backend info)
120 "Fix blank lines between elements.
122 TREE is the parse tree being exported. BACKEND is the export
123 back-end used. INFO is a plist used as a communication channel.
125 Enforce a blank line between elements. There are two exceptions
126 to this rule:
128 1. Preserve blank lines between sibling items in a plain list,
130 2. In an item, remove any blank line before the very first
131 paragraph and the next sub-list when the latter ends the
132 current item.
134 Assume BACKEND is `md'."
135 (org-element-map tree (remq 'item org-element-all-elements)
136 (lambda (e)
137 (org-element-put-property
138 e :post-blank
139 (if (and (eq (org-element-type e) 'paragraph)
140 (eq (org-element-type (org-element-property :parent e)) 'item)
141 (org-export-first-sibling-p e info)
142 (let ((next (org-export-get-next-element e info)))
143 (and (eq (org-element-type next) 'plain-list)
144 (not (org-export-get-next-element next info)))))
146 1))))
147 ;; Return updated tree.
148 tree)
152 ;;; Transcode Functions
154 ;;;; Bold
156 (defun org-md-bold (_bold contents _info)
157 "Transcode BOLD object into Markdown format.
158 CONTENTS is the text within bold markup. INFO is a plist used as
159 a communication channel."
160 (format "**%s**" contents))
163 ;;;; Code and Verbatim
165 (defun org-md-verbatim (verbatim _contents _info)
166 "Transcode VERBATIM object into Markdown format.
167 CONTENTS is nil. INFO is a plist used as a communication
168 channel."
169 (let ((value (org-element-property :value verbatim)))
170 (format (cond ((not (string-match "`" value)) "`%s`")
171 ((or (string-prefix-p "`" value)
172 (string-suffix-p "`" value))
173 "`` %s ``")
174 (t "``%s``"))
175 value)))
178 ;;;; Example Block, Src Block and export Block
180 (defun org-md-example-block (example-block _contents info)
181 "Transcode EXAMPLE-BLOCK element into Markdown format.
182 CONTENTS is nil. INFO is a plist used as a communication
183 channel."
184 (replace-regexp-in-string
185 "^" " "
186 (org-remove-indentation
187 (org-export-format-code-default example-block info))))
189 (defun org-md-export-block (export-block contents info)
190 "Transcode a EXPORT-BLOCK element from Org to Markdown.
191 CONTENTS is nil. INFO is a plist holding contextual information."
192 (if (member (org-element-property :type export-block) '("MARKDOWN" "MD"))
193 (org-remove-indentation (org-element-property :value export-block))
194 ;; Also include HTML export blocks.
195 (org-export-with-backend 'html export-block contents info)))
198 ;;;; Headline
200 (defun org-md-headline (headline contents info)
201 "Transcode HEADLINE element into Markdown format.
202 CONTENTS is the headline contents. INFO is a plist used as
203 a communication channel."
204 (unless (org-element-property :footnote-section-p headline)
205 (let* ((level (org-export-get-relative-level headline info))
206 (title (org-export-data (org-element-property :title headline) info))
207 (todo (and (plist-get info :with-todo-keywords)
208 (let ((todo (org-element-property :todo-keyword
209 headline)))
210 (and todo (concat (org-export-data todo info) " ")))))
211 (tags (and (plist-get info :with-tags)
212 (let ((tag-list (org-export-get-tags headline info)))
213 (and tag-list
214 (format " :%s:"
215 (mapconcat 'identity tag-list ":"))))))
216 (priority
217 (and (plist-get info :with-priority)
218 (let ((char (org-element-property :priority headline)))
219 (and char (format "[#%c] " char)))))
220 ;; Headline text without tags.
221 (heading (concat todo priority title))
222 (style (plist-get info :md-headline-style)))
223 (cond
224 ;; Cannot create a headline. Fall-back to a list.
225 ((or (org-export-low-level-p headline info)
226 (not (memq style '(atx setext)))
227 (and (eq style 'atx) (> level 6))
228 (and (eq style 'setext) (> level 2)))
229 (let ((bullet
230 (if (not (org-export-numbered-headline-p headline info)) "-"
231 (concat (number-to-string
232 (car (last (org-export-get-headline-number
233 headline info))))
234 "."))))
235 (concat bullet (make-string (- 4 (length bullet)) ?\s) heading tags "\n\n"
236 (and contents (replace-regexp-in-string "^" " " contents)))))
238 (let ((anchor
239 (and (org-md--headline-referred-p headline info)
240 (format "<a id=\"%s\"></a>"
241 (or (org-element-property :CUSTOM_ID headline)
242 (org-export-get-reference headline info))))))
243 (concat (org-md--headline-title style level title anchor tags)
244 contents)))))))
247 (defun org-md--headline-referred-p (headline info)
248 "Non-nil when HEADLINE is being referred to.
249 INFO is a plist used as a communication channel. Links and table
250 of contents can refer to headlines."
251 (or (plist-get info :with-toc)
252 (org-element-map (plist-get info :parse-tree) 'link
253 (lambda (link)
254 (eq headline
255 (pcase (org-element-property :type link)
256 ((or "custom-id" "id") (org-export-resolve-id-link link info))
257 ("fuzzy" (org-export-resolve-fuzzy-link link info))
258 (_ nil))))
259 info t)))
261 (defun org-md--headline-title (style level title &optional anchor tags)
262 "Generate a headline title in the preferred Markdown headline style.
263 STYLE is the preferred style (`atx' or `setext'). LEVEL is the
264 header level. TITLE is the headline title. ANCHOR is the HTML
265 anchor tag for the section as a string. TAGS are the tags set on
266 the section."
267 (let ((anchor-lines (and anchor (concat anchor "\n\n"))))
268 ;; Use "Setext" style
269 (if (and (eq style 'setext) (< level 3))
270 (let* ((underline-char (if (= level 1) ?= ?-))
271 (underline (concat (make-string (length title) underline-char)
272 "\n")))
273 (concat "\n" anchor-lines title tags "\n" underline "\n"))
274 ;; Use "Atx" style
275 (let ((level-mark (make-string level ?#)))
276 (concat "\n" anchor-lines level-mark " " title tags "\n\n")))))
278 ;;;; Horizontal Rule
280 (defun org-md-horizontal-rule (_horizontal-rule _contents _info)
281 "Transcode HORIZONTAL-RULE element into Markdown format.
282 CONTENTS is the horizontal rule contents. INFO is a plist used
283 as a communication channel."
284 "---")
287 ;;;; Italic
289 (defun org-md-italic (_italic contents _info)
290 "Transcode ITALIC object into Markdown format.
291 CONTENTS is the text within italic markup. INFO is a plist used
292 as a communication channel."
293 (format "*%s*" contents))
296 ;;;; Item
298 (defun org-md-item (item contents info)
299 "Transcode ITEM element into Markdown format.
300 CONTENTS is the item contents. INFO is a plist used as
301 a communication channel."
302 (let* ((type (org-element-property :type (org-export-get-parent item)))
303 (struct (org-element-property :structure item))
304 (bullet (if (not (eq type 'ordered)) "-"
305 (concat (number-to-string
306 (car (last (org-list-get-item-number
307 (org-element-property :begin item)
308 struct
309 (org-list-prevs-alist struct)
310 (org-list-parents-alist struct)))))
311 "."))))
312 (concat bullet
313 (make-string (- 4 (length bullet)) ? )
314 (pcase (org-element-property :checkbox item)
315 (`on "[X] ")
316 (`trans "[-] ")
317 (`off "[ ] "))
318 (let ((tag (org-element-property :tag item)))
319 (and tag (format "**%s:** "(org-export-data tag info))))
320 (and contents
321 (org-trim (replace-regexp-in-string "^" " " contents))))))
325 ;;;; Keyword
327 (defun org-md-keyword (keyword contents info)
328 "Transcode a KEYWORD element into Markdown format.
329 CONTENTS is nil. INFO is a plist used as a communication
330 channel."
331 (if (member (org-element-property :key keyword) '("MARKDOWN" "MD"))
332 (org-element-property :value keyword)
333 (org-export-with-backend 'html keyword contents info)))
336 ;;;; Line Break
338 (defun org-md-line-break (_line-break _contents _info)
339 "Transcode LINE-BREAK object into Markdown format.
340 CONTENTS is nil. INFO is a plist used as a communication
341 channel."
342 " \n")
345 ;;;; Link
347 (defun org-md-link (link contents info)
348 "Transcode LINE-BREAK object into Markdown format.
349 CONTENTS is the link's description. INFO is a plist used as
350 a communication channel."
351 (let ((link-org-files-as-md
352 (lambda (raw-path)
353 ;; Treat links to `file.org' as links to `file.md'.
354 (if (string= ".org" (downcase (file-name-extension raw-path ".")))
355 (concat (file-name-sans-extension raw-path) ".md")
356 raw-path)))
357 (type (org-element-property :type link)))
358 (cond
359 ;; Link type is handled by a special function.
360 ((org-export-custom-protocol-maybe link contents 'md))
361 ((member type '("custom-id" "id" "fuzzy"))
362 (let ((destination (if (string= type "fuzzy")
363 (org-export-resolve-fuzzy-link link info)
364 (org-export-resolve-id-link link info))))
365 (pcase (org-element-type destination)
366 (`plain-text ; External file.
367 (let ((path (funcall link-org-files-as-md destination)))
368 (if (not contents) (format "<%s>" path)
369 (format "[%s](%s)" contents path))))
370 (`headline
371 (format
372 "[%s](#%s)"
373 ;; Description.
374 (cond ((org-string-nw-p contents))
375 ((org-export-numbered-headline-p destination info)
376 (mapconcat #'number-to-string
377 (org-export-get-headline-number destination info)
378 "."))
379 (t (org-export-data (org-element-property :title destination)
380 info)))
381 ;; Reference.
382 (or (org-element-property :CUSTOM_ID destination)
383 (org-export-get-reference destination info))))
385 (let ((description
386 (or (org-string-nw-p contents)
387 (let ((number (org-export-get-ordinal destination info)))
388 (cond
389 ((not number) nil)
390 ((atom number) (number-to-string number))
391 (t (mapconcat #'number-to-string number ".")))))))
392 (when description
393 (format "[%s](#%s)"
394 description
395 (org-export-get-reference destination info))))))))
396 ((org-export-inline-image-p link org-html-inline-image-rules)
397 (let ((path (let ((raw-path (org-element-property :path link)))
398 (if (not (file-name-absolute-p raw-path)) raw-path
399 (expand-file-name raw-path))))
400 (caption (org-export-data
401 (org-export-get-caption
402 (org-export-get-parent-element link)) info)))
403 (format "![img](%s)"
404 (if (not (org-string-nw-p caption)) path
405 (format "%s \"%s\"" path caption)))))
406 ((string= type "coderef")
407 (let ((ref (org-element-property :path link)))
408 (format (org-export-get-coderef-format ref contents)
409 (org-export-resolve-coderef ref info))))
410 ((equal type "radio") contents)
411 (t (let* ((raw-path (org-element-property :path link))
412 (path
413 (cond
414 ((member type '("http" "https" "ftp"))
415 (concat type ":" raw-path))
416 ((string= type "file")
417 (org-export-file-uri (funcall link-org-files-as-md raw-path)))
418 (t raw-path))))
419 (if (not contents) (format "<%s>" path)
420 (format "[%s](%s)" contents path)))))))
423 ;;;; Node Property
425 (defun org-md-node-property (node-property _contents _info)
426 "Transcode a NODE-PROPERTY element into Markdown syntax.
427 CONTENTS is nil. INFO is a plist holding contextual
428 information."
429 (format "%s:%s"
430 (org-element-property :key node-property)
431 (let ((value (org-element-property :value node-property)))
432 (if value (concat " " value) ""))))
435 ;;;; Paragraph
437 (defun org-md-paragraph (paragraph contents _info)
438 "Transcode PARAGRAPH element into Markdown format.
439 CONTENTS is the paragraph contents. INFO is a plist used as
440 a communication channel."
441 (let ((first-object (car (org-element-contents paragraph))))
442 ;; If paragraph starts with a #, protect it.
443 (if (and (stringp first-object) (string-prefix-p "#" first-object))
444 (concat "\\" contents)
445 contents)))
448 ;;;; Plain List
450 (defun org-md-plain-list (_plain-list contents _info)
451 "Transcode PLAIN-LIST element into Markdown format.
452 CONTENTS is the plain-list contents. INFO is a plist used as
453 a communication channel."
454 contents)
457 ;;;; Plain Text
459 (defun org-md-plain-text (text info)
460 "Transcode a TEXT string into Markdown format.
461 TEXT is the string to transcode. INFO is a plist holding
462 contextual information."
463 (when (plist-get info :with-smart-quotes)
464 (setq text (org-export-activate-smart-quotes text :html info)))
465 ;; Protect ambiguous #. This will protect # at the beginning of
466 ;; a line, but not at the beginning of a paragraph. See
467 ;; `org-md-paragraph'.
468 (setq text (replace-regexp-in-string "\n#" "\n\\\\#" text))
469 ;; Protect ambiguous !
470 (setq text (replace-regexp-in-string "\\(!\\)\\[" "\\\\!" text nil nil 1))
471 ;; Protect `, *, _ and \
472 (setq text (replace-regexp-in-string "[`*_\\]" "\\\\\\&" text))
473 ;; Handle special strings, if required.
474 (when (plist-get info :with-special-strings)
475 (setq text (org-html-convert-special-strings text)))
476 ;; Handle break preservation, if required.
477 (when (plist-get info :preserve-breaks)
478 (setq text (replace-regexp-in-string "[ \t]*\n" " \n" text)))
479 ;; Return value.
480 text)
483 ;;;; Property Drawer
485 (defun org-md-property-drawer (_property-drawer contents _info)
486 "Transcode a PROPERTY-DRAWER element into Markdown format.
487 CONTENTS holds the contents of the drawer. INFO is a plist
488 holding contextual information."
489 (and (org-string-nw-p contents)
490 (replace-regexp-in-string "^" " " contents)))
493 ;;;; Quote Block
495 (defun org-md-quote-block (_quote-block contents _info)
496 "Transcode QUOTE-BLOCK element into Markdown format.
497 CONTENTS is the quote-block contents. INFO is a plist used as
498 a communication channel."
499 (replace-regexp-in-string
500 "^" "> "
501 (replace-regexp-in-string "\n\\'" "" contents)))
504 ;;;; Section
506 (defun org-md-section (_section contents _info)
507 "Transcode SECTION element into Markdown format.
508 CONTENTS is the section contents. INFO is a plist used as
509 a communication channel."
510 contents)
513 ;;;; Template
515 (defun org-md--footnote-formatted (footnote info)
516 "Formats a single footnote entry FOOTNOTE.
517 FOOTNOTE is a cons cell of the form (number . definition).
518 INFO is a plist with contextual information."
519 (let* ((fn-num (car footnote))
520 (fn-text (cdr footnote))
521 (fn-format (plist-get info :md-footnote-format))
522 (fn-anchor (format "fn.%d" fn-num))
523 (fn-href (format " href=\"#fnr.%d\"" fn-num))
524 (fn-link-to-ref (org-html--anchor fn-anchor fn-num fn-href info)))
525 (concat (format fn-format fn-link-to-ref) " " fn-text "\n")))
527 (defun org-md--footnote-section (info)
528 "Format the footnote section.
529 INFO is a plist used as a communication channel."
530 (let* ((fn-alist (org-export-collect-footnote-definitions info))
531 (fn-alist (cl-loop for (n _type raw) in fn-alist collect
532 (cons n (org-trim (org-export-data raw info)))))
533 (headline-style (plist-get info :md-headline-style))
534 (section-title (org-html--translate "Footnotes" info)))
535 (when fn-alist
536 (format (plist-get info :md-footnotes-section)
537 (org-md--headline-title headline-style 1 section-title)
538 (mapconcat (lambda (fn) (org-md--footnote-formatted fn info))
539 fn-alist
540 "\n")))))
542 (defun org-md-inner-template (contents info)
543 "Return body of document after converting it to Markdown syntax.
544 CONTENTS is the transcoded contents string. INFO is a plist
545 holding export options."
546 ;; Make sure CONTENTS is separated from table of contents and
547 ;; footnotes with at least a blank line.
548 (concat
549 ;; Table of contents.
550 (let ((depth (plist-get info :with-toc)))
551 (when depth (org-html-toc depth info)))
552 ;; Document contents.
553 contents
554 "\n"
555 ;; Footnotes section.
556 (org-md--footnote-section info)))
558 (defun org-md-template (contents _info)
559 "Return complete document string after Markdown conversion.
560 CONTENTS is the transcoded contents string. INFO is a plist used
561 as a communication channel."
562 contents)
566 ;;; Interactive function
568 ;;;###autoload
569 (defun org-md-export-as-markdown (&optional async subtreep visible-only)
570 "Export current buffer to a Markdown buffer.
572 If narrowing is active in the current buffer, only export its
573 narrowed part.
575 If a region is active, export that region.
577 A non-nil optional argument ASYNC means the process should happen
578 asynchronously. The resulting buffer should be accessible
579 through the `org-export-stack' interface.
581 When optional argument SUBTREEP is non-nil, export the sub-tree
582 at point, extracting information from the headline properties
583 first.
585 When optional argument VISIBLE-ONLY is non-nil, don't export
586 contents of hidden elements.
588 Export is done in a buffer named \"*Org MD Export*\", which will
589 be displayed when `org-export-show-temporary-export-buffer' is
590 non-nil."
591 (interactive)
592 (org-export-to-buffer 'md "*Org MD Export*"
593 async subtreep visible-only nil nil (lambda () (text-mode))))
595 ;;;###autoload
596 (defun org-md-convert-region-to-md ()
597 "Assume the current region has Org syntax, and convert it to Markdown.
598 This can be used in any buffer. For example, you can write an
599 itemized list in Org syntax in a Markdown buffer and use
600 this command to convert it."
601 (interactive)
602 (org-export-replace-region-by 'md))
605 ;;;###autoload
606 (defun org-md-export-to-markdown (&optional async subtreep visible-only)
607 "Export current buffer to a Markdown file.
609 If narrowing is active in the current buffer, only export its
610 narrowed part.
612 If a region is active, export that region.
614 A non-nil optional argument ASYNC means the process should happen
615 asynchronously. The resulting file should be accessible through
616 the `org-export-stack' interface.
618 When optional argument SUBTREEP is non-nil, export the sub-tree
619 at point, extracting information from the headline properties
620 first.
622 When optional argument VISIBLE-ONLY is non-nil, don't export
623 contents of hidden elements.
625 Return output file's name."
626 (interactive)
627 (let ((outfile (org-export-output-file-name ".md" subtreep)))
628 (org-export-to-file 'md outfile async subtreep visible-only)))
630 ;;;###autoload
631 (defun org-md-publish-to-md (plist filename pub-dir)
632 "Publish an org file to Markdown.
634 FILENAME is the filename of the Org file to be published. PLIST
635 is the property list for the given project. PUB-DIR is the
636 publishing directory.
638 Return output file name."
639 (org-publish-org-to 'md filename ".md" plist pub-dir))
641 (provide 'ox-md)
643 ;; Local variables:
644 ;; generated-autoload-file: "org-loaddefs.el"
645 ;; End:
647 ;;; ox-md.el ends here