Re: org-mode: example blocks are no longer syntax highlighted in emacs

[Rudi C <rudiwillalwaysloveyou@gmail.com>]

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> Why is `:eval never` not as good ?  You don't have to write it on each
> code block; you may set it globally, per file, per headline, etc.

The main reason is that I also use source blocks for babel blocks that are
runnable. So I cannot use per headline etc. solutions. I can use snippets
to automatically insert `:eval never`, but it's not as good a UX.

I also already have lots of org-mode notes written using `example lang`
blocks. Rewriting all of these will be a PITA.

> My version of pandoc generates org source blocks from markdown code
> blocks (pandoc 3.1.11.1).

I upgraded my pandoc, and it now indeed does this if the markdown block has
a source lang defined.

---

NickD has identified the commit that introduced this breaking change:

```
commit 616e80a9f10c4bd085d7b5ac96fd6ea23e9c9191
Author: <elided>
Date:   Thu Apr 6 08:49:20 2023 -0500

    Handle block-type when checking `org-src-fontify-natively`

    * lisp/org.el (org-fontify-meta-lines-and-blocks-1): Only fontify
      natively for blocks of src type.

 lisp/org.el | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
```

Thanks to the above commit (
https://github.com/bzg/org-mode/commit/616e80a9f10c4bd085d7b5ac96fd6ea23e9c9191),
I wrote this patch which can be put in one's config to make this behavior
configurable.

Can you merge this upstream? emacs is all about user customizability, and
in general, breaking backward compatibility without giving a way out is bad.

```lisp
(defvar night/org-fontify-block-types '("src" "example")
  "List of block types to fontify in org-mode.")

(defun night/org-fontify-block-p (block-type)
  "Check if BLOCK-TYPE is one of the types to fontify."
  (member block-type night/org-fontify-block-types))

(defun night/org-fontify-meta-lines-and-blocks-1 (limit)
  "Fontify #+ lines and blocks."
  (let ((case-fold-search t))
    (when (re-search-forward
  (rx bol (group (zero-or-more (any " \t")) "#"
 (group (group (or (seq "+" (one-or-more (any "a-zA-Z")) (optional ":"))
   (any " \t")
   eol))
(optional (group "_" (group (one-or-more (any "a-zA-Z"))))))
 (zero-or-more (any " \t"))
 (group (group (zero-or-more (not (any " \t\n"))))
(zero-or-more (any " \t"))
(group (zero-or-more any)))))
  limit t)
      (let ((beg (match-beginning 0))
   (end-of-beginline (match-end 0))
   ;; Including \n at end of #+begin line will include \n
   ;; after the end of block content.
   (block-start (match-end 0))
   (block-end nil)
   (lang (match-string 7))     ; The language, if it is a source block.
   (bol-after-beginline (line-beginning-position 2))
   (dc1 (downcase (match-string 2)))
   (dc3 (downcase (match-string 3)))
   (whole-blockline org-fontify-whole-block-delimiter-line)
   beg-of-endline end-of-endline nl-before-endline quoting block-type)
(cond
((and (match-end 4) (equal dc3 "+begin"))
 ;; Truly a block
 (setq block-type (downcase (match-string 5))
;; Src, example, export, maybe more.
quoting (member block-type org-protecting-blocks))
 (when (re-search-forward
(rx-to-string `(group bol (or (seq (one-or-more "*") space)
      (seq (zero-or-more (any " \t"))
   "#+end"
   ,(match-string 4)
   word-end
   (zero-or-more any)))))
;; We look further than LIMIT on purpose.
nil t)
   ;; We do have a matching #+end line.
   (setq beg-of-endline (match-beginning 0)
 end-of-endline (match-end 0)
 nl-before-endline (1- (match-beginning 0)))
   (setq block-end (match-beginning 0)) ; Include the final newline.
   (when quoting
     (org-remove-flyspell-overlays-in bol-after-beginline nl-before-endline)
     (remove-text-properties beg end-of-endline
     '(display t invisible t intangible t)))
   (add-text-properties
    beg end-of-endline '(font-lock-fontified t font-lock-multiline t))
   (org-remove-flyspell-overlays-in beg bol-after-beginline)
   (org-remove-flyspell-overlays-in nl-before-endline end-of-endline)
            (cond
    ((and org-src-fontify-natively
                   (night/org-fontify-block-p block-type))
     (save-match-data
                (org-src-font-lock-fontify-block (or lang "") block-start
block-end))
     (add-text-properties bol-after-beginline block-end '(src-block t)))
    (quoting
     (add-text-properties
      bol-after-beginline beg-of-endline
      (list 'face
    (list :inherit
  (let ((face-name
 (intern (format "org-block-%s" lang))))
    (append (and (facep face-name) (list face-name))
    '(org-block)))))))
    ((not org-fontify-quote-and-verse-blocks))
    ((string= block-type "quote")
     (add-face-text-property
      bol-after-beginline beg-of-endline 'org-quote t))
    ((string= block-type "verse")
     (add-face-text-property
      bol-after-beginline beg-of-endline 'org-verse t)))
   ;; Fontify the #+begin and #+end lines of the blocks
   (add-text-properties
    beg (if whole-blockline bol-after-beginline end-of-beginline)
    '(face org-block-begin-line))
   (unless (eq (char-after beg-of-endline) ?*)
     (add-text-properties
      beg-of-endline
      (if whole-blockline
  (let ((beg-of-next-line (1+ end-of-endline)))
    (min (point-max) beg-of-next-line))
(min (point-max) end-of-endline))
      '(face org-block-end-line)))
   t))
((member dc1 '("+title:" "+subtitle:" "+author:" "+email:" "+date:"))
 (org-remove-flyspell-overlays-in
  (match-beginning 0)
  (if (equal "+title:" dc1) (match-end 2) (match-end 0)))
 (add-text-properties
  beg (match-end 3)
  (if (member (intern (substring dc1 1 -1)) org-hidden-keywords)
      '(font-lock-fontified t invisible t)
    '(font-lock-fontified t face org-document-info-keyword)))
 (add-text-properties
  (match-beginning 6) (min (point-max) (1+ (match-end 6)))
  (if (string-equal dc1 "+title:")
      '(font-lock-fontified t face org-document-title)
    '(font-lock-fontified t face org-document-info))))
((string-prefix-p "+caption" dc1)
 (org-remove-flyspell-overlays-in (match-end 2) (match-end 0))
 (remove-text-properties (match-beginning 0) (match-end 0)
 '(display t invisible t intangible t))
 ;; Handle short captions
 (save-excursion
   (forward-line 0)
   (looking-at (rx (group (zero-or-more (any " \t"))
  "#+caption"
  (optional "[" (zero-or-more any) "]")
  ":")
   (zero-or-more (any " \t")))))
 (add-text-properties (line-beginning-position) (match-end 1)
      '(font-lock-fontified t face org-meta-line))
 (add-text-properties (match-end 0) (line-end-position)
      '(font-lock-fontified t face org-block))
 t)
((member dc3 '(" " ""))
 ;; Just a comment, the plus was not there
 (org-remove-flyspell-overlays-in beg (match-end 0))
 (add-text-properties
  beg (match-end 0)
  '(font-lock-fontified t face font-lock-comment-face)))
(t ;; Just any other in-buffer setting, but not indented
 (org-remove-flyspell-overlays-in (match-beginning 0) (match-end 0))
 (remove-text-properties (match-beginning 0) (match-end 0)
 '(display t invisible t intangible t))
 (add-text-properties beg (match-end 0)
      '(font-lock-fontified t face org-meta-line))
 t))))))
(advice-add 'org-fontify-meta-lines-and-blocks-1 :override
#'night/org-fontify-meta-lines-and-blocks-1)
```

On Thu, Feb 22, 2024 at 7:17 PM Bruno Barbier <brubar.cs@gmail.com> wrote:

>
> Hi Rudi,
>
> Rudi C <rudiwillalwaysloveyou@gmail.com> writes:
>
> > After upgrading to emacs 29.2 and org 9.7, my example blocks are no
> longer
> > syntax highlighted in emacs. They used to be syntax highlighted when I
> > specified the block's language. Any ideas?
> >
> > I use Doom, so it might have been a third-party feature.
> >
> > I know org-mode officially suggests that example blocks should not have
> > syntax highlighting, but I want it anyway. IMO `:eval never` is just not
> as
> > good,
>
> Why is `:eval never` not as good ?  You don't have to write it on each
> code block; you may set it globally, per file, per headline, etc.
>
> See https://orgmode.org/manual/Using-Header-Arguments.html.
>
>
> > not to mention tools like `pandoc` also produce example blocks from
> > markdown source blocks.
>
> My version of pandoc generates org source blocks from markdown code
> blocks (pandoc 3.1.11.1).
>
> I'm not sure you'll get a better answer than this SE answer:
>
>
> https://emacs.stackexchange.com/questions/76466/how-do-i-get-syntax-highlighting-in-example-blocks-when-exporting-org-mode-to-ht
>
> I.e. "begin_example" is just not designed for source blocks.  It
> may have worked by chance before.
>
> Hoping this helps,
>
> Bruno
>
>

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