lisp/ox-md.el

   1 ;;; ox-md.el --- Markdown Back-End for Org Export Engine
   2
   3 ;; Copyright (C) 2012-2014 Free Software Foundation, Inc.
   4
   5 ;; Author: Nicolas Goaziou <n.goaziou@gmail.com>
   6 ;; Keywords: org, wp, markdown
   7
   8 ;; This file is part of GNU Emacs.
   9
  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.
  14
  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.
  19
  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/>.
  22
  23 ;;; Commentary:
  24
  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.
  28
  29 ;;; Code:
  30
  31 (eval-when-compile (require 'cl))
  32 (require 'ox-html)
  33
  34
  35 \f
  36 ;;; User-Configurable Variables
  37
  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"))
  44
  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)))
  52
  53
  54 \f
  55 ;;; Define Back-End
  56
  57 (org-export-define-derived-backend 'md 'html
  58   :export-block '("MD" "MARKDOWN")
  59   :filters-alist '((:filter-parse-tree . org-md-separate-elements))
  60   :menu-entry
  61   '(?m "Export to Markdown"
  62        ((?M "To temporary buffer"
  63             (lambda (a s v b) (org-md-export-as-markdown a s v)))
  64         (?m "To file" (lambda (a s v b) (org-md-export-to-markdown a s v)))
  65         (?o "To file and open"
  66             (lambda (a s v b)
  67               (if a (org-md-export-to-markdown t s v)
  68                 (org-open-file (org-md-export-to-markdown nil s v)))))))
  69   :translate-alist '((bold . org-md-bold)
  70                      (code . org-md-verbatim)
  71                      (comment . (lambda (&rest args) ""))
  72                      (comment-block . (lambda (&rest args) ""))
  73                      (example-block . org-md-example-block)
  74                      (fixed-width . org-md-example-block)
  75                      (footnote-definition . ignore)
  76                      (footnote-reference . ignore)
  77                      (headline . org-md-headline)
  78                      (horizontal-rule . org-md-horizontal-rule)
  79                      (inline-src-block . org-md-verbatim)
  80                      (italic . org-md-italic)
  81                      (item . org-md-item)
  82                      (line-break . org-md-line-break)
  83                      (link . org-md-link)
  84                      (paragraph . org-md-paragraph)
  85                      (plain-list . org-md-plain-list)
  86                      (plain-text . org-md-plain-text)
  87                      (quote-block . org-md-quote-block)
  88                      (quote-section . org-md-example-block)
  89                      (section . org-md-section)
  90                      (src-block . org-md-example-block)
  91                      (template . org-md-template)
  92                      (verbatim . org-md-verbatim)))
  93
  94
  95 \f
  96 ;;; Filters
  97
  98 (defun org-md-separate-elements (tree backend info)
  99   "Make sure elements are separated by at least one blank line.
 100
 101 TREE is the parse tree being exported.  BACKEND is the export
 102 back-end used.  INFO is a plist used as a communication channel.
 103
 104 Assume BACKEND is `md'."
 105   (org-element-map tree org-element-all-elements
 106     (lambda (elem)
 107       (unless (eq (org-element-type elem) 'org-data)
 108         (org-element-put-property
 109          elem :post-blank
 110          (let ((post-blank (org-element-property :post-blank elem)))
 111            (if (not post-blank) 1 (max 1 post-blank)))))))
 112   ;; Return updated tree.
 113   tree)
 114
 115
 116 \f
 117 ;;; Transcode Functions
 118
 119 ;;;; Bold
 120
 121 (defun org-md-bold (bold contents info)
 122   "Transcode BOLD object into Markdown format.
 123 CONTENTS is the text within bold markup.  INFO is a plist used as
 124 a communication channel."
 125   (format "**%s**" contents))
 126
 127
 128 ;;;; Code and Verbatim
 129
 130 (defun org-md-verbatim (verbatim contents info)
 131   "Transcode VERBATIM object into Markdown format.
 132 CONTENTS is nil.  INFO is a plist used as a communication
 133 channel."
 134   (let ((value (org-element-property :value verbatim)))
 135     (format (cond ((not (string-match "`" value)) "`%s`")
 136                   ((or (string-match "\\``" value)
 137                        (string-match "`\\'" value))
 138                    "`` %s ``")
 139                   (t "``%s``"))
 140             value)))
 141
 142
 143 ;;;; Example Block and Src Block
 144
 145 (defun org-md-example-block (example-block contents info)
 146   "Transcode EXAMPLE-BLOCK element into Markdown format.
 147 CONTENTS is nil.  INFO is a plist used as a communication
 148 channel."
 149   (replace-regexp-in-string
 150    "^" "    "
 151    (org-remove-indentation
 152     (org-element-property :value example-block))))
 153
 154
 155 ;;;; Headline
 156
 157 (defun org-md-headline (headline contents info)
 158   "Transcode HEADLINE element into Markdown format.
 159 CONTENTS is the headline contents.  INFO is a plist used as
 160 a communication channel."
 161   (unless (org-element-property :footnote-section-p headline)
 162     (let* ((level (org-export-get-relative-level headline info))
 163            (title (org-export-data (org-element-property :title headline) info))
 164            (todo (and (plist-get info :with-todo-keywords)
 165                       (let ((todo (org-element-property :todo-keyword
 166                                                         headline)))
 167                         (and todo (concat (org-export-data todo info) " ")))))
 168            (tags (and (plist-get info :with-tags)
 169                       (let ((tag-list (org-export-get-tags headline info)))
 170                         (and tag-list
 171                              (format "     :%s:"
 172                                      (mapconcat 'identity tag-list ":"))))))
 173            (priority
 174             (and (plist-get info :with-priority)
 175                  (let ((char (org-element-property :priority headline)))
 176                    (and char (format "[#%c] " char)))))
 177            ;; Headline text without tags.
 178            (heading (concat todo priority title)))
 179       (cond
 180        ;; Cannot create a headline.  Fall-back to a list.
 181        ((or (org-export-low-level-p headline info)
 182             (not (memq org-md-headline-style '(atx setext)))
 183             (and (eq org-md-headline-style 'atx) (> level 6))
 184             (and (eq org-md-headline-style 'setext) (> level 2)))
 185         (let ((bullet
 186                (if (not (org-export-numbered-headline-p headline info)) "-"
 187                  (concat (number-to-string
 188                           (car (last (org-export-get-headline-number
 189                                       headline info))))
 190                          "."))))
 191           (concat bullet (make-string (- 4 (length bullet)) ? ) heading tags
 192                   "\n\n"
 193                   (and contents
 194                        (replace-regexp-in-string "^" "    " contents)))))
 195        ;; Use "Setext" style.
 196        ((eq org-md-headline-style 'setext)
 197         (concat heading tags "\n"
 198                 (make-string (length heading) (if (= level 1) ?= ?-))
 199                 "\n\n"
 200                 contents))
 201        ;; Use "atx" style.
 202        (t (concat (make-string level ?#) " " heading tags "\n\n" contents))))))
 203
 204
 205 ;;;; Horizontal Rule
 206
 207 (defun org-md-horizontal-rule (horizontal-rule contents info)
 208   "Transcode HORIZONTAL-RULE element into Markdown format.
 209 CONTENTS is the horizontal rule contents.  INFO is a plist used
 210 as a communication channel."
 211   "---")
 212
 213
 214 ;;;; Italic
 215
 216 (defun org-md-italic (italic contents info)
 217   "Transcode ITALIC object into Markdown format.
 218 CONTENTS is the text within italic markup.  INFO is a plist used
 219 as a communication channel."
 220   (format "*%s*" contents))
 221
 222
 223 ;;;; Item
 224
 225 (defun org-md-item (item contents info)
 226   "Transcode ITEM element into Markdown format.
 227 CONTENTS is the item contents.  INFO is a plist used as
 228 a communication channel."
 229   (let* ((type (org-element-property :type (org-export-get-parent item)))
 230          (struct (org-element-property :structure item))
 231          (bullet (if (not (eq type 'ordered)) "-"
 232                    (concat (number-to-string
 233                             (car (last (org-list-get-item-number
 234                                         (org-element-property :begin item)
 235                                         struct
 236                                         (org-list-prevs-alist struct)
 237                                         (org-list-parents-alist struct)))))
 238                            "."))))
 239     (concat bullet
 240             (make-string (- 4 (length bullet)) ? )
 241             (case (org-element-property :checkbox item)
 242               (on "[X] ")
 243               (trans "[-] ")
 244               (off "[ ] "))
 245             (let ((tag (org-element-property :tag item)))
 246               (and tag (format "**%s:** "(org-export-data tag info))))
 247             (and contents
 248                  (org-trim (replace-regexp-in-string "^" "    " contents))))))
 249
 250
 251 ;;;; Line Break
 252
 253 (defun org-md-line-break (line-break contents info)
 254   "Transcode LINE-BREAK object into Markdown format.
 255 CONTENTS is nil.  INFO is a plist used as a communication
 256 channel."
 257   "  \n")
 258
 259
 260 ;;;; Link
 261
 262 (defun org-md-link (link contents info)
 263   "Transcode LINE-BREAK object into Markdown format.
 264 CONTENTS is the link's description.  INFO is a plist used as
 265 a communication channel."
 266   (let ((--link-org-files-as-html-maybe
 267          (function
 268           (lambda (raw-path info)
 269             ;; Treat links to `file.org' as links to `file.html', if
 270             ;; needed.  See `org-html-link-org-files-as-html'.
 271             (cond
 272              ((and org-html-link-org-files-as-html
 273                    (string= ".org"
 274                             (downcase (file-name-extension raw-path "."))))
 275               (concat (file-name-sans-extension raw-path) "."
 276                       (plist-get info :html-extension)))
 277              (t raw-path)))))
 278         (type (org-element-property :type link)))
 279     (cond ((member type '("custom-id" "id"))
 280            (let ((destination (org-export-resolve-id-link link info)))
 281              (if (stringp destination)  ; External file.
 282                  (let ((path (funcall --link-org-files-as-html-maybe
 283                                       destination info)))
 284                    (if (not contents) (format "<%s>" path)
 285                      (format "[%s](%s)" contents path)))
 286                (concat
 287                 (and contents (concat contents " "))
 288                 (format "(%s)"
 289                         (format (org-export-translate "See section %s" :html info)
 290                                 (mapconcat 'number-to-string
 291                                            (org-export-get-headline-number
 292                                             destination info)
 293                                            ".")))))))
 294           ((org-export-inline-image-p link org-html-inline-image-rules)
 295            (let ((path (let ((raw-path (org-element-property :path link)))
 296                          (if (not (file-name-absolute-p raw-path)) raw-path
 297                            (expand-file-name raw-path)))))
 298              (format "![%s](%s)"
 299                      (let ((caption (org-export-get-caption
 300                                      (org-export-get-parent-element link))))
 301                        (when caption (org-export-data caption info)))
 302                      path)))
 303           ((string= type "coderef")
 304            (let ((ref (org-element-property :path link)))
 305              (format (org-export-get-coderef-format ref contents)
 306                      (org-export-resolve-coderef ref info))))
 307           ((equal type "radio")
 308            (let ((destination (org-export-resolve-radio-link link info)))
 309              (org-export-data (org-element-contents destination) info)))
 310           ((equal type "fuzzy")
 311            (let ((destination (org-export-resolve-fuzzy-link link info)))
 312              (if (org-string-nw-p contents) contents
 313                (when destination
 314                  (let ((number (org-export-get-ordinal destination info)))
 315                    (when number
 316                      (if (atom number) (number-to-string number)
 317                        (mapconcat 'number-to-string number "."))))))))
 318           (t (let* ((raw-path (org-element-property :path link))
 319                     (path (cond
 320                            ((member type '("http" "https" "ftp"))
 321                             (concat type ":" raw-path))
 322                            ((equal type "file")
 323                             ;; Treat links to ".org" files as ".html",
 324                             ;; if needed.
 325                             (setq raw-path
 326                                   (funcall --link-org-files-as-html-maybe
 327                                            raw-path info))
 328                             ;; If file path is absolute, prepend it
 329                             ;; with protocol component - "file://".
 330                             (if (not (file-name-absolute-p raw-path)) raw-path
 331                               (concat "file://" (expand-file-name raw-path))))
 332                            (t raw-path))))
 333                (if (not contents) (format "<%s>" path)
 334                  (format "[%s](%s)" contents path)))))))
 335
 336
 337 ;;;; Paragraph
 338
 339 (defun org-md-paragraph (paragraph contents info)
 340   "Transcode PARAGRAPH element into Markdown format.
 341 CONTENTS is the paragraph contents.  INFO is a plist used as
 342 a communication channel."
 343   (let ((first-object (car (org-element-contents paragraph))))
 344     ;; If paragraph starts with a #, protect it.
 345     (if (and (stringp first-object) (string-match "\\`#" first-object))
 346         (replace-regexp-in-string "\\`#" "\\#" contents nil t)
 347       contents)))
 348
 349
 350 ;;;; Plain List
 351
 352 (defun org-md-plain-list (plain-list contents info)
 353   "Transcode PLAIN-LIST element into Markdown format.
 354 CONTENTS is the plain-list contents.  INFO is a plist used as
 355 a communication channel."
 356   contents)
 357
 358
 359 ;;;; Plain Text
 360
 361 (defun org-md-plain-text (text info)
 362   "Transcode a TEXT string into Markdown format.
 363 TEXT is the string to transcode.  INFO is a plist holding
 364 contextual information."
 365   (when (plist-get info :with-smart-quotes)
 366     (setq text (org-export-activate-smart-quotes text :html info)))
 367   ;; Protect ambiguous #.  This will protect # at the beginning of
 368   ;; a line, but not at the beginning of a paragraph.  See
 369   ;; `org-md-paragraph'.
 370   (setq text (replace-regexp-in-string "\n#" "\n\\\\#" text))
 371   ;; Protect ambiguous !
 372   (setq text (replace-regexp-in-string "\\(!\\)\\[" "\\\\!" text nil nil 1))
 373   ;; Protect `, *, _ and \
 374   (setq text (replace-regexp-in-string "[`*_\\]" "\\\\\\&" text))
 375   ;; Handle special strings, if required.
 376   (when (plist-get info :with-special-strings)
 377     (setq text (org-html-convert-special-strings text)))
 378   ;; Handle break preservation, if required.
 379   (when (plist-get info :preserve-breaks)
 380     (setq text (replace-regexp-in-string "[ \t]*\n" "  \n" text)))
 381   ;; Return value.
 382   text)
 383
 384
 385 ;;;; Quote Block
 386
 387 (defun org-md-quote-block (quote-block contents info)
 388   "Transcode QUOTE-BLOCK element into Markdown format.
 389 CONTENTS is the quote-block contents.  INFO is a plist used as
 390 a communication channel."
 391   (replace-regexp-in-string
 392    "^" "> "
 393    (replace-regexp-in-string "\n\\'" "" contents)))
 394
 395
 396 ;;;; Section
 397
 398 (defun org-md-section (section contents info)
 399   "Transcode SECTION element into Markdown format.
 400 CONTENTS is the section contents.  INFO is a plist used as
 401 a communication channel."
 402   contents)
 403
 404
 405 ;;;; Template
 406
 407 (defun org-md-template (contents info)
 408   "Return complete document string after Markdown conversion.
 409 CONTENTS is the transcoded contents string.  INFO is a plist used
 410 as a communication channel."
 411   contents)
 412
 413
 414 \f
 415 ;;; Interactive function
 416
 417 ;;;###autoload
 418 (defun org-md-export-as-markdown (&optional async subtreep visible-only)
 419   "Export current buffer to a Markdown buffer.
 420
 421 If narrowing is active in the current buffer, only export its
 422 narrowed part.
 423
 424 If a region is active, export that region.
 425
 426 A non-nil optional argument ASYNC means the process should happen
 427 asynchronously.  The resulting buffer should be accessible
 428 through the `org-export-stack' interface.
 429
 430 When optional argument SUBTREEP is non-nil, export the sub-tree
 431 at point, extracting information from the headline properties
 432 first.
 433
 434 When optional argument VISIBLE-ONLY is non-nil, don't export
 435 contents of hidden elements.
 436
 437 Export is done in a buffer named \"*Org MD Export*\", which will
 438 be displayed when `org-export-show-temporary-export-buffer' is
 439 non-nil."
 440   (interactive)
 441   (org-export-to-buffer 'md "*Org MD Export*"
 442     async subtreep visible-only nil nil (lambda () (text-mode))))
 443
 444 ;;;###autoload
 445 (defun org-md-convert-region-to-md ()
 446   "Assume the current region has org-mode syntax, and convert it to Markdown.
 447 This can be used in any buffer.  For example, you can write an
 448 itemized list in org-mode syntax in a Markdown buffer and use
 449 this command to convert it."
 450   (interactive)
 451   (org-export-replace-region-by 'md))
 452
 453
 454 ;;;###autoload
 455 (defun org-md-export-to-markdown (&optional async subtreep visible-only)
 456   "Export current buffer to a Markdown file.
 457
 458 If narrowing is active in the current buffer, only export its
 459 narrowed part.
 460
 461 If a region is active, export that region.
 462
 463 A non-nil optional argument ASYNC means the process should happen
 464 asynchronously.  The resulting file should be accessible through
 465 the `org-export-stack' interface.
 466
 467 When optional argument SUBTREEP is non-nil, export the sub-tree
 468 at point, extracting information from the headline properties
 469 first.
 470
 471 When optional argument VISIBLE-ONLY is non-nil, don't export
 472 contents of hidden elements.
 473
 474 Return output file's name."
 475   (interactive)
 476   (let ((outfile (org-export-output-file-name ".md" subtreep)))
 477     (org-export-to-file 'md outfile async subtreep visible-only)))
 478
 479
 480 (provide 'ox-md)
 481
 482 ;; Local variables:
 483 ;; generated-autoload-file: "org-loaddefs.el"
 484 ;; End:
 485
 486 ;;; ox-md.el ends here