[O] Tidy automatically HTML files

[Sebastien Vauban]

Hello,

I'm trying to add Tidy to the HTML export process, so that files are
more easy to read and, possibly, to diff.

The code I wrote seems correct to me in theory:

--8<---------------cut here---------------start------------->8---
  ;; check that `tidy' is in PATH, and that configuration file exists
  (when (and (executable-find "tidy") (file-exists-p "~/.tidyrc"))

    (defun sva--export-html-final-filter (contents backend info)
      (if (not (eq backend 'html)) contents
        (with-output-to-string
          (insert contents)
          (shell-command-on-region (point-min) (point-max)
                                   "tidy -config ~/.tidyrc"
                                   t t "*Tidy errors*" t))))
    (add-to-list 'org-export-filter-final-output-functions
                 'sva--export-html-final-filter))
--8<---------------cut here---------------end--------------->8---

In practice, it isn't, as the results of `shell-command-on-region' is
the empty string.

Though, when executed interactively on an HTML buffer, it does work as
expected.

I don't get what's wrong... Maybe one of you can have an idea?

Best regards,
  Seb

-- 
Sebastien Vauban