lisp/ob-tangle.el

   1 ;;; ob-tangle.el --- Extract Source Code From Org Files -*- lexical-binding: t; -*-
   2
   3 ;; Copyright (C) 2009-2018 Free Software Foundation, Inc.
   4
   5 ;; Author: Eric Schulte
   6 ;; Keywords: literate programming, reproducible research
   7 ;; Homepage: https://orgmode.org
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; Extract the code from source blocks out into raw source-code files.
  27
  28 ;;; Code:
  29
  30 (require 'cl-lib)
  31 (require 'org-src)
  32 (require 'org-macs)
  33
  34 (declare-function make-directory "files" (dir &optional parents))
  35 (declare-function org-at-heading-p "org" (&optional ignored))
  36 (declare-function org-babel-update-block-body "ob-core" (new-body))
  37 (declare-function org-back-to-heading "org" (&optional invisible-ok))
  38 (declare-function org-before-first-heading-p "org" ())
  39 (declare-function org-element-at-point "org-element" ())
  40 (declare-function org-element-type "org-element" (element))
  41 (declare-function org-fill-template "org" (template alist))
  42 (declare-function org-heading-components "org" ())
  43 (declare-function org-in-commented-heading-p "org" (&optional no-inheritance))
  44 (declare-function org-link-escape "org" (text &optional table merge))
  45 (declare-function org-open-link-from-string "org" (s &optional arg reference-buffer))
  46 (declare-function org-remove-indentation "org" (code &optional n))
  47 (declare-function org-store-link "org" (arg))
  48 (declare-function org-trim "org" (s &optional keep-lead))
  49 (declare-function outline-previous-heading "outline" ())
  50 (declare-function org-id-find "org-id" (id &optional markerp))
  51
  52 (defvar org-link-types-re)
  53
  54 (defcustom org-babel-tangle-lang-exts
  55   '(("emacs-lisp" . "el")
  56     ("elisp" . "el"))
  57   "Alist mapping languages to their file extensions.
  58 The key is the language name, the value is the string that should
  59 be inserted as the extension commonly used to identify files
  60 written in this language.  If no entry is found in this list,
  61 then the name of the language is used."
  62   :group 'org-babel-tangle
  63   :version "24.1"
  64   :type '(repeat
  65           (cons
  66            (string "Language name")
  67            (string "File Extension"))))
  68
  69 (defcustom org-babel-tangle-use-relative-file-links t
  70   "Use relative path names in links from tangled source back the Org file."
  71   :group 'org-babel-tangle
  72   :type 'boolean)
  73
  74 (defcustom org-babel-post-tangle-hook nil
  75   "Hook run in code files tangled by `org-babel-tangle'."
  76   :group 'org-babel
  77   :version "24.1"
  78   :type 'hook)
  79
  80 (defcustom org-babel-pre-tangle-hook '(save-buffer)
  81   "Hook run at the beginning of `org-babel-tangle'."
  82   :group 'org-babel
  83   :version "24.1"
  84   :type 'hook)
  85
  86 (defcustom org-babel-tangle-body-hook nil
  87   "Hook run over the contents of each code block body."
  88   :group 'org-babel
  89   :version "24.1"
  90   :type 'hook)
  91
  92 (defcustom org-babel-tangle-comment-format-beg "[[%link][%source-name]]"
  93   "Format of inserted comments in tangled code files.
  94 The following format strings can be used to insert special
  95 information into the output using `org-fill-template'.
  96 %start-line --- the line number at the start of the code block
  97 %file --------- the file from which the code block was tangled
  98 %link --------- Org style link to the code block
  99 %source-name -- name of the code block
 100
 101 Upon insertion the formatted comment will be commented out, and
 102 followed by a newline.  To inhibit this post-insertion processing
 103 set the `org-babel-tangle-uncomment-comments' variable to a
 104 non-nil value.
 105
 106 Whether or not comments are inserted during tangling is
 107 controlled by the :comments header argument."
 108   :group 'org-babel
 109   :version "24.1"
 110   :type 'string)
 111
 112 (defcustom org-babel-tangle-comment-format-end "%source-name ends here"
 113   "Format of inserted comments in tangled code files.
 114 The following format strings can be used to insert special
 115 information into the output using `org-fill-template'.
 116 %start-line --- the line number at the start of the code block
 117 %file --------- the file from which the code block was tangled
 118 %link --------- Org style link to the code block
 119 %source-name -- name of the code block
 120
 121 Upon insertion the formatted comment will be commented out, and
 122 followed by a newline.  To inhibit this post-insertion processing
 123 set the `org-babel-tangle-uncomment-comments' variable to a
 124 non-nil value.
 125
 126 Whether or not comments are inserted during tangling is
 127 controlled by the :comments header argument."
 128   :group 'org-babel
 129   :version "24.1"
 130   :type 'string)
 131
 132 (defcustom org-babel-tangle-uncomment-comments nil
 133   "Inhibits automatic commenting and addition of trailing newline
 134 of tangle comments.  Use `org-babel-tangle-comment-format-beg'
 135 and `org-babel-tangle-comment-format-end' to customize the format
 136 of tangled comments."
 137   :group 'org-babel
 138   :type 'boolean)
 139
 140 (defcustom org-babel-process-comment-text 'org-remove-indentation
 141   "Function called to process raw Org text collected to be
 142 inserted as comments in tangled source-code files.  The function
 143 should take a single string argument and return a string
 144 result.  The default value is `org-remove-indentation'."
 145   :group 'org-babel
 146   :version "24.1"
 147   :type 'function)
 148
 149 (defun org-babel-find-file-noselect-refresh (file)
 150   "Find file ensuring that the latest changes on disk are
 151 represented in the file."
 152   (find-file-noselect file 'nowarn)
 153   (with-current-buffer (get-file-buffer file)
 154     (revert-buffer t t t)))
 155
 156 (defmacro org-babel-with-temp-filebuffer (file &rest body)
 157   "Open FILE into a temporary buffer execute BODY there like
 158 `progn', then kill the FILE buffer returning the result of
 159 evaluating BODY."
 160   (declare (indent 1))
 161   (let ((temp-path (make-symbol "temp-path"))
 162         (temp-result (make-symbol "temp-result"))
 163         (temp-file (make-symbol "temp-file"))
 164         (visited-p (make-symbol "visited-p")))
 165     `(let* ((,temp-path ,file)
 166             (,visited-p (get-file-buffer ,temp-path))
 167             ,temp-result ,temp-file)
 168        (org-babel-find-file-noselect-refresh ,temp-path)
 169        (setf ,temp-file (get-file-buffer ,temp-path))
 170        (with-current-buffer ,temp-file
 171          (setf ,temp-result (progn ,@body)))
 172        (unless ,visited-p (kill-buffer ,temp-file))
 173        ,temp-result)))
 174 (def-edebug-spec org-babel-with-temp-filebuffer (form body))
 175
 176 ;;;###autoload
 177 (defun org-babel-tangle-file (file &optional target-file lang)
 178   "Extract the bodies of source code blocks in FILE.
 179 Source code blocks are extracted with `org-babel-tangle'.
 180 Optional argument TARGET-FILE can be used to specify a default
 181 export file for all source blocks.  Optional argument LANG can be
 182 used to limit the exported source code blocks by language.
 183 Return a list whose CAR is the tangled file name."
 184   (interactive "fFile to tangle: \nP")
 185   (let ((visited-p (get-file-buffer (expand-file-name file)))
 186         to-be-removed)
 187     (prog1
 188         (save-window-excursion
 189           (find-file file)
 190           (setq to-be-removed (current-buffer))
 191           (mapcar #'expand-file-name (org-babel-tangle nil target-file lang)))
 192       (unless visited-p
 193         (kill-buffer to-be-removed)))))
 194
 195 (defun org-babel-tangle-publish (_ filename pub-dir)
 196   "Tangle FILENAME and place the results in PUB-DIR."
 197   (unless (file-exists-p pub-dir)
 198     (make-directory pub-dir t))
 199   (setq pub-dir (file-name-as-directory pub-dir))
 200   (mapc (lambda (el) (copy-file el pub-dir t)) (org-babel-tangle-file filename)))
 201
 202 ;;;###autoload
 203 (defun org-babel-tangle (&optional arg target-file lang)
 204   "Write code blocks to source-specific files.
 205 Extract the bodies of all source code blocks from the current
 206 file into their own source-specific files.
 207 With one universal prefix argument, only tangle the block at point.
 208 When two universal prefix arguments, only tangle blocks for the
 209 tangle file of the block at point.
 210 Optional argument TARGET-FILE can be used to specify a default
 211 export file for all source blocks.  Optional argument LANG can be
 212 used to limit the exported source code blocks by language."
 213   (interactive "P")
 214   (run-hooks 'org-babel-pre-tangle-hook)
 215   ;; Possibly Restrict the buffer to the current code block
 216   (save-restriction
 217     (save-excursion
 218       (when (equal arg '(4))
 219         (let ((head (org-babel-where-is-src-block-head)))
 220           (if head
 221               (goto-char head)
 222             (user-error "Point is not in a source code block"))))
 223       (let ((block-counter 0)
 224             (org-babel-default-header-args
 225              (if target-file
 226                  (org-babel-merge-params org-babel-default-header-args
 227                                          (list (cons :tangle target-file)))
 228                org-babel-default-header-args))
 229             (tangle-file
 230              (when (equal arg '(16))
 231                (or (cdr (assq :tangle (nth 2 (org-babel-get-src-block-info 'light))))
 232                    (user-error "Point is not in a source code block"))))
 233             path-collector)
 234         (mapc ;; map over all languages
 235          (lambda (by-lang)
 236            (let* ((lang (car by-lang))
 237                   (specs (cdr by-lang))
 238                   (ext (or (cdr (assoc lang org-babel-tangle-lang-exts)) lang))
 239                   (lang-f (intern
 240                            (concat
 241                             (or (and (cdr (assoc lang org-src-lang-modes))
 242                                      (symbol-name
 243                                       (cdr (assoc lang org-src-lang-modes))))
 244                                 lang)
 245                             "-mode")))
 246                   she-banged)
 247              (mapc
 248               (lambda (spec)
 249                 (let ((get-spec (lambda (name) (cdr (assoc name (nth 4 spec))))))
 250                   (let* ((tangle (funcall get-spec :tangle))
 251                          (she-bang (let ((sheb (funcall get-spec :shebang)))
 252                                      (when (> (length sheb) 0) sheb)))
 253                          (tangle-mode (funcall get-spec :tangle-mode))
 254                          (base-name (cond
 255                                      ((string= "yes" tangle)
 256                                       (file-name-sans-extension
 257                                        (nth 1 spec)))
 258                                      ((string= "no" tangle) nil)
 259                                      ((> (length tangle) 0) tangle)))
 260                          (file-name (when base-name
 261                                       ;; decide if we want to add ext to base-name
 262                                       (if (and ext (string= "yes" tangle))
 263                                           (concat base-name "." ext) base-name))))
 264                     (when file-name
 265                       ;; Possibly create the parent directories for file.
 266                       (let ((m (funcall get-spec :mkdirp))
 267                             (fnd (file-name-directory file-name)))
 268                         (and m fnd (not (string= m "no"))
 269                              (make-directory fnd 'parents)))
 270                       ;; delete any old versions of file
 271                       (and (file-exists-p file-name)
 272                            (not (member file-name (mapcar #'car path-collector)))
 273                            (delete-file file-name))
 274                       ;; drop source-block to file
 275                       (with-temp-buffer
 276                         (when (fboundp lang-f) (ignore-errors (funcall lang-f)))
 277                         (when (and she-bang (not (member file-name she-banged)))
 278                           (insert (concat she-bang "\n"))
 279                           (setq she-banged (cons file-name she-banged)))
 280                         (org-babel-spec-to-string spec)
 281                         ;; We avoid append-to-file as it does not work with tramp.
 282                         (let ((content (buffer-string)))
 283                           (with-temp-buffer
 284                             (when (file-exists-p file-name)
 285                               (insert-file-contents file-name))
 286                             (goto-char (point-max))
 287                             ;; Handle :padlines unless first line in file
 288                             (unless (or (string= "no" (cdr (assq :padline (nth 4 spec))))
 289                                         (= (point) (point-min)))
 290                               (insert "\n"))
 291                             (insert content)
 292                             (write-region nil nil file-name))))
 293                       ;; if files contain she-bangs, then make the executable
 294                       (when she-bang
 295                         (unless tangle-mode (setq tangle-mode #o755)))
 296                       ;; update counter
 297                       (setq block-counter (+ 1 block-counter))
 298                       (unless (assoc file-name path-collector)
 299                         (push (cons file-name tangle-mode) path-collector))))))
 300               specs)))
 301          (if (equal arg '(4))
 302              (org-babel-tangle-single-block 1 t)
 303            (org-babel-tangle-collect-blocks lang tangle-file)))
 304         (message "Tangled %d code block%s from %s" block-counter
 305                  (if (= block-counter 1) "" "s")
 306                  (file-name-nondirectory
 307                   (buffer-file-name
 308                    (or (buffer-base-buffer) (current-buffer)))))
 309         ;; run `org-babel-post-tangle-hook' in all tangled files
 310         (when org-babel-post-tangle-hook
 311           (mapc
 312            (lambda (file)
 313              (org-babel-with-temp-filebuffer file
 314                (run-hooks 'org-babel-post-tangle-hook)))
 315            (mapcar #'car path-collector)))
 316         ;; set permissions on tangled files
 317         (mapc (lambda (pair)
 318                 (when (cdr pair) (set-file-modes (car pair) (cdr pair))))
 319               path-collector)
 320         (mapcar #'car path-collector)))))
 321
 322 (defun org-babel-tangle-clean ()
 323   "Remove comments inserted by `org-babel-tangle'.
 324 Call this function inside of a source-code file generated by
 325 `org-babel-tangle' to remove all comments inserted automatically
 326 by `org-babel-tangle'.  Warning, this comment removes any lines
 327 containing constructs which resemble Org file links or noweb
 328 references."
 329   (interactive)
 330   (goto-char (point-min))
 331   (while (or (re-search-forward "\\[\\[file:.*\\]\\[.*\\]\\]" nil t)
 332              (re-search-forward (org-babel-noweb-wrap) nil t))
 333     (delete-region (save-excursion (beginning-of-line 1) (point))
 334                    (save-excursion (end-of-line 1) (forward-char 1) (point)))))
 335
 336 (defvar org-stored-links)
 337 (defvar org-bracket-link-regexp)
 338 (defun org-babel-spec-to-string (spec)
 339   "Insert SPEC into the current file.
 340
 341 Insert the source-code specified by SPEC into the current source
 342 code file.  This function uses `comment-region' which assumes
 343 that the appropriate major-mode is set.  SPEC has the form:
 344
 345   (start-line file link source-name params body comment)"
 346   (pcase-let*
 347       ((`(,start ,file ,link ,source ,info ,body ,comment) spec)
 348        (comments (cdr (assq :comments info)))
 349        (link? (or (string= comments "both") (string= comments "link")
 350                   (string= comments "yes") (string= comments "noweb")))
 351        (link-data `(("start-line" . ,(number-to-string start))
 352                     ("file" . ,file)
 353                     ("link" . ,link)
 354                     ("source-name" . ,source)))
 355        (insert-comment (lambda (text)
 356                          (when (and comments
 357                                     (not (string= comments "no"))
 358                                     (org-string-nw-p text))
 359                            (if org-babel-tangle-uncomment-comments
 360                                ;; Plain comments: no processing.
 361                                (insert text)
 362                              ;; Ensure comments are made to be
 363                              ;; comments, and add a trailing newline.
 364                              ;; Also ignore invisible characters when
 365                              ;; commenting.
 366                              (comment-region
 367                               (point)
 368                               (progn (insert (org-no-properties text))
 369                                      (point)))
 370                              (end-of-line)
 371                              (insert "\n"))))))
 372     (when comment (funcall insert-comment comment))
 373     (when link?
 374       (funcall insert-comment
 375                (org-fill-template
 376                 org-babel-tangle-comment-format-beg link-data)))
 377     (insert body "\n")
 378     (when link?
 379       (funcall insert-comment
 380                (org-fill-template
 381                 org-babel-tangle-comment-format-end link-data)))))
 382
 383 (defun org-babel-tangle-collect-blocks (&optional language tangle-file)
 384   "Collect source blocks in the current Org file.
 385 Return an association list of source-code block specifications of
 386 the form used by `org-babel-spec-to-string' grouped by language.
 387 Optional argument LANGUAGE can be used to limit the collected
 388 source code blocks by language.  Optional argument TANGLE-FILE
 389 can be used to limit the collected code blocks by target file."
 390   (let ((counter 0) last-heading-pos blocks)
 391     (org-babel-map-src-blocks (buffer-file-name)
 392       (let ((current-heading-pos
 393              (org-with-wide-buffer
 394               (org-with-limited-levels (outline-previous-heading)))))
 395         (if (eq last-heading-pos current-heading-pos) (cl-incf counter)
 396           (setq counter 1)
 397           (setq last-heading-pos current-heading-pos)))
 398       (unless (org-in-commented-heading-p)
 399         (let* ((info (org-babel-get-src-block-info 'light))
 400                (src-lang (nth 0 info))
 401                (src-tfile (cdr (assq :tangle (nth 2 info)))))
 402           (unless (or (string= src-tfile "no")
 403                       (and tangle-file (not (equal tangle-file src-tfile)))
 404                       (and language (not (string= language src-lang))))
 405             ;; Add the spec for this block to blocks under its
 406             ;; language.
 407             (let ((by-lang (assoc src-lang blocks))
 408                   (block (org-babel-tangle-single-block counter)))
 409               (if by-lang (setcdr by-lang (cons block (cdr by-lang)))
 410                 (push (cons src-lang (list block)) blocks)))))))
 411     ;; Ensure blocks are in the correct order.
 412     (mapcar (lambda (b) (cons (car b) (nreverse (cdr b)))) blocks)))
 413
 414 (defun org-babel-tangle-single-block (block-counter &optional only-this-block)
 415   "Collect the tangled source for current block.
 416 Return the list of block attributes needed by
 417 `org-babel-tangle-collect-blocks'.  When ONLY-THIS-BLOCK is
 418 non-nil, return the full association list to be used by
 419 `org-babel-tangle' directly."
 420   (let* ((info (org-babel-get-src-block-info))
 421          (start-line
 422           (save-restriction (widen)
 423                             (+ 1 (line-number-at-pos (point)))))
 424          (file (buffer-file-name (buffer-base-buffer)))
 425          (src-lang (nth 0 info))
 426          (params (nth 2 info))
 427          (extra (nth 3 info))
 428          (cref-fmt (or (and (string-match "-l \"\\(.+\\)\"" extra)
 429                             (match-string 1 extra))
 430                        org-coderef-label-format))
 431          (link (let ((l (org-no-properties (org-store-link nil))))
 432                  (and (string-match org-bracket-link-regexp l)
 433                       (match-string 1 l))))
 434          (source-name
 435           (or (nth 4 info)
 436               (format "%s:%d"
 437                       (or (ignore-errors (nth 4 (org-heading-components)))
 438                           "No heading")
 439                       block-counter)))
 440          (expand-cmd (intern (concat "org-babel-expand-body:" src-lang)))
 441          (assignments-cmd
 442           (intern (concat "org-babel-variable-assignments:" src-lang)))
 443          (body
 444           ;; Run the tangle-body-hook.
 445           (let ((body (if (org-babel-noweb-p params :tangle)
 446                           (org-babel-expand-noweb-references info)
 447                         (nth 1 info))))
 448             (with-temp-buffer
 449               (insert
 450                ;; Expand body in language specific manner.
 451                (cond ((assq :no-expand params) body)
 452                      ((fboundp expand-cmd) (funcall expand-cmd body params))
 453                      (t
 454                       (org-babel-expand-body:generic
 455                        body params (and (fboundp assignments-cmd)
 456                                         (funcall assignments-cmd params))))))
 457               (when (string-match "-r" extra)
 458                 (goto-char (point-min))
 459                 (while (re-search-forward
 460                         (replace-regexp-in-string "%s" ".+" cref-fmt) nil t)
 461                   (replace-match "")))
 462               (run-hooks 'org-babel-tangle-body-hook)
 463               (buffer-string))))
 464          (comment
 465           (when (or (string= "both" (cdr (assq :comments params)))
 466                     (string= "org" (cdr (assq :comments params))))
 467             ;; From the previous heading or code-block end
 468             (funcall
 469              org-babel-process-comment-text
 470              (buffer-substring
 471               (max (condition-case nil
 472                        (save-excursion
 473                          (org-back-to-heading t) ; Sets match data
 474                          (match-end 0))
 475                      (error (point-min)))
 476                    (save-excursion
 477                      (if (re-search-backward
 478                           org-babel-src-block-regexp nil t)
 479                          (match-end 0)
 480                        (point-min))))
 481               (point)))))
 482          (result
 483           (list start-line
 484                 (if org-babel-tangle-use-relative-file-links
 485                     (file-relative-name file)
 486                   file)
 487                 (if (and org-babel-tangle-use-relative-file-links
 488                          (string-match org-link-types-re link)
 489                          (string= (match-string 0 link) "file"))
 490                     (concat "file:"
 491                             (file-relative-name (match-string 1 link)
 492                                                 (file-name-directory
 493                                                  (cdr (assq :tangle params)))))
 494                   link)
 495                 source-name
 496                 params
 497                 (if org-src-preserve-indentation
 498                     (org-trim body t)
 499                   (org-trim (org-remove-indentation body)))
 500                 comment)))
 501     (if only-this-block
 502         (list (cons src-lang (list result)))
 503       result)))
 504
 505 (defun org-babel-tangle-comment-links (&optional info)
 506   "Return a list of begin and end link comments for the code block at point."
 507   (let ((link-data
 508          `(("start-line" . ,(number-to-string
 509                              (org-babel-where-is-src-block-head)))
 510            ("file" . ,(buffer-file-name))
 511            ("link" . ,(org-link-escape
 512                        (progn
 513                          (call-interactively #'org-store-link)
 514                          (org-no-properties (car (pop org-stored-links))))))
 515            ("source-name" .
 516             ,(nth 4 (or info (org-babel-get-src-block-info 'light)))))))
 517     (list (org-fill-template org-babel-tangle-comment-format-beg link-data)
 518           (org-fill-template org-babel-tangle-comment-format-end link-data))))
 519
 520 ;; de-tangling functions
 521 (defvar org-bracket-link-analytic-regexp)
 522 (defun org-babel-detangle (&optional source-code-file)
 523   "Propagate changes in source file back original to Org file.
 524 This requires that code blocks were tangled with link comments
 525 which enable the original code blocks to be found."
 526   (interactive)
 527   (save-excursion
 528     (when source-code-file (find-file source-code-file))
 529     (goto-char (point-min))
 530     (let ((counter 0) new-body end)
 531       (while (re-search-forward org-bracket-link-analytic-regexp nil t)
 532         (when (re-search-forward
 533                (concat " " (regexp-quote (match-string 5)) " ends here"))
 534           (setq end (match-end 0))
 535           (forward-line -1)
 536           (save-excursion
 537             (when (setq new-body (org-babel-tangle-jump-to-org))
 538               (org-babel-update-block-body new-body)))
 539           (setq counter (+ 1 counter)))
 540         (goto-char end))
 541       (prog1 counter (message "Detangled %d code blocks" counter)))))
 542
 543 (defun org-babel-tangle-jump-to-org ()
 544   "Jump from a tangled code file to the related Org mode file."
 545   (interactive)
 546   (let ((mid (point))
 547         start body-start end
 548         target-buffer target-char link path block-name body)
 549     (save-window-excursion
 550       (save-excursion
 551         (while (and (re-search-backward org-bracket-link-analytic-regexp nil t)
 552                     (not ; ever wider searches until matching block comments
 553                      (and (setq start (line-beginning-position))
 554                           (setq body-start (line-beginning-position 2))
 555                           (setq link (match-string 0))
 556                           (setq path (match-string 3))
 557                           (setq block-name (match-string 5))
 558                           (save-excursion
 559                             (save-match-data
 560                               (re-search-forward
 561                                (concat " " (regexp-quote block-name)
 562                                        " ends here") nil t)
 563                               (setq end (line-beginning-position))))))))
 564         (unless (and start (< start mid) (< mid end))
 565           (error "Not in tangled code"))
 566         (setq body (buffer-substring body-start end)))
 567       (when (string-match "::" path)
 568         (setq path (substring path 0 (match-beginning 0))))
 569       (find-file (or (car (org-id-find path)) path))
 570       (setq target-buffer (current-buffer))
 571       ;; Go to the beginning of the relative block in Org file.
 572       (org-open-link-from-string link)
 573       (if (string-match "[^ \t\n\r]:\\([[:digit:]]+\\)" block-name)
 574           (let ((n (string-to-number (match-string 1 block-name))))
 575             (if (org-before-first-heading-p) (goto-char (point-min))
 576               (org-back-to-heading t))
 577             ;; Do not skip the first block if it begins at point min.
 578             (cond ((or (org-at-heading-p)
 579                        (not (eq (org-element-type (org-element-at-point))
 580                                 'src-block)))
 581                    (org-babel-next-src-block n))
 582                   ((= n 1))
 583                   (t (org-babel-next-src-block (1- n)))))
 584         (org-babel-goto-named-src-block block-name))
 585       (goto-char (org-babel-where-is-src-block-head))
 586       ;; Preserve location of point within the source code in tangled
 587       ;; code file.
 588       (forward-line 1)
 589       (forward-char (- mid body-start))
 590       (setq target-char (point)))
 591     (org-src-switch-to-buffer target-buffer t)
 592     (goto-char target-char)
 593     body))
 594
 595 (provide 'ob-tangle)
 596
 597 ;; Local variables:
 598 ;; generated-autoload-file: "org-loaddefs.el"
 599 ;; End:
 600
 601 ;;; ob-tangle.el ends here