"Charles C. Berry" <ccbe...@ucsd.edu> writes:
[...]
> It sounds like you are re-inventing version control and wanting it to be
> implemented in org-babel-tangle.
>
> `org-babel-tangle' can do a lot of work to assemble the files that result
> from tangling. Modifying `org-babel-tangle' to do what you ask would be
> far from trivial and make a complicated function even more tortuous.
Yes, I agree it is not an easy task.
> IMHO, it is better to solve your problem as follows: Set up a separate
> directory into which files are tangled. Use version control on that
> directory. Inspect changes after each tangle using the version control
> system's diff tools, commit good changes, and revert unwanted ones. Then
> run a script that uses the VC's data to identify changed files and copy
> those files to the location on your system where they will be used.
I found 'C-x s' ('save-some-buffers') can be used as the "version
control", so I made a wrapper command for 'org-babel-tangle' using it.
The wrapper command is not perfect (I guess it doesn't support
remote-file and doesn't always respect tangle-mode, for example), but I
am OK with it and it already does what I want.
#+BEGIN_SRC emacs-lisp :results silent :lexical yes
(defun chunyang-org-babel-tangle (&optional arg target-file lang)
"Like `org-babel-tangle' but don't override without permission."
(declare (interactive-only org-babel-tangle))
(interactive "P")
(require 'ob-tangle)
(require 'seq)
(require 'cl-lib)
(save-some-buffers)
(let* ((tmpdir (let ((dir "/tmp/org-babel-tangle/"))
(or (file-exists-p dir) (make-directory dir))
dir))
(mkbak (lambda (filename)
(expand-file-name
(replace-regexp-in-string "/" "!" (expand-file-name
filename))
tmpdir)))
(diffp (lambda (file-a file-b)
(/= 0 (call-process diff-command nil nil nil
(expand-file-name file-a) file-b))))
(swap (lambda (file-a file-b)
(let ((tmp (make-temp-name tmpdir)))
(copy-file file-a tmp t t t t)
(copy-file file-b file-a t t t t)
(copy-file tmp file-b t t t t))))
deleted-files
tangled-files
(advice (define-advice delete-file (:around (old-fun filename
&rest args) dont-delete)
(push filename deleted-files)
(copy-file filename (funcall mkbak filename) t t t t)
(apply old-fun filename args))))
(unwind-protect
(progn
(setq tangled-files (org-babel-tangle arg target-file lang)
deleted-files (nreverse deleted-files))
(cl-loop for f in (seq-intersection deleted-files tangled-files)
for bak = (funcall mkbak f)
do
(funcall swap f bak)
(if (funcall diffp f bak)
(with-current-buffer (find-file-noselect f)
(message "Diff %s..." f)
(delete-region (point-min) (point-max))
(insert-file-contents bak))
(message "Skip %s..." f))
finally (save-some-buffers)))
(advice-remove 'delete-file advice))))
#+END_SRC
[...]
