Re: [BABEL] tangling with leaving non-source code lines as empty lines?

["Eric Schulte" <schulte.eric@gmail.com>]

Hi Rainer,

With the tangling comments generated by the latest Org-mode, the
following function should be able to jump from any code in a tangled
code file back to the relevant block in the original Org-mode file.

--8<---------------cut here---------------start------------->8---
(defun org-babel-tangle-jump-to-org ()
  "Jump from a tangled code file to the related Org-mode file."
  (interactive)
  (let ((mid (point))
	target-buffer target-char
	start end link path block-name)
    (save-window-excursion
      (save-excursion
	(unless (and (re-search-backward org-bracket-link-analytic-regexp nil t)
		     (setq start (point))
		     (setq link (match-string 0))
		     (setq path (match-string 3))
		     (setq block-name (match-string 5))
		     (re-search-forward (concat " " (regexp-quote block-name)
						" ends here[\n\r]") nil t)
		     (setq end (point))
		     (< start mid) (< mid end))
	  (error "not in tangled code")))
      (when (string-match "::" path)
	(setq path (substring path 0 (match-beginning 0))))
      (find-file path) (setq target-buffer (current-buffer))
      (goto-char start) (org-open-link-from-string link)
      (if (string-match "[^ \t\n\r]:\\([[:digit:]]+\\)" block-name)
	  (org-babel-next-src-block
	   (string-to-int (match-string 1 block-name)))
	(org-babel-goto-named-src-block block-name))
      (setq target-char (point)))
    (pop-to-buffer target-buffer)
    (goto-char target-char)))
--8<---------------cut here---------------end--------------->8---

This is too large of a block of untested code to push into Org-mode now,
however please give it a try, and let me know if you think this could be
generally useful.  Hopefully after the feature-freeze we can fold
something like this into Babel to ease navigation between Org files and
their tangled offspring.

Cheers -- Eric

"Eric Schulte" <schulte.eric@gmail.com> writes:

> Hi Rainer,
>
> If I'm understand you correctly you want the absolute position (by LOC)
> of the lines of R code to be the same in both the original org file and
> the tangled file or R code.  I don't think this is possible.  It is
> possible to tangle code blocks in any order (not just the order in which
> they appear in the original org file), so there are many valid tangling
> scenarios in which this feature could not work.
>
> Rather, I think that it may make sense to have a function for jumping
> back and forth between tangled code blocks and the related Org file.  In
> that case the R errors could be followed to the tangled R code file,
> from which you could easily jump to the relevant line in the relevant
> code block in the Org file.  If you are tangling with comments, then it
> should be possible to have a function called from a line in a tangled
> code file which when called
>
> 1) finds it's enclosing comments
> 2) remembers it's offset from the comments (which would then be it's
>    offset in the code block in the Org file)
> 3) read the comment to learn which code block in which Org file it's
>    tangled from
> 4) jump to the relevant line, in the relevant block, in the relevant
>    file
>
> Similarly when called form within a code block in an Org file the
> function could
>
> 1) read it's header argument to find the relevant tangled code file
> 2) jump to that file
> 3) use the comments in that file to move to the appropriate section of
>    code and related line
>
> I'll think about such a function, and if it makes sense to implement it
> apart from a more general "activate org-mode links in comments" minor
> mode.  Any ideas or suggestions would be welcome!
>
> Thanks -- Eric
>
> Rainer M Krug <r.m.krug@gmail.com> writes:
>
>> Hi Eric,
>>
>> would it be possible, when tangling, to leave lines without source code in
>> the resulting code file as empty lines? The reasoning would be that error
>> messages (at least in R) give the line in which the error occurred. If the
>> line numbers in which the code sits would be preserved (by leaving empty
>> lines where no code is in the .org file), debugging would be much easier.
>>
>> By the way: I am using the after tangle hook and it works absolutely
>> perfectly.
>>
>> Thanks and cheers,
>>
>> Rainer