this-month-in-org/2022-05-31-folding.org

# Created 2022-06-02 Thu 00:55
#+title: May 2022
#+date: 2022-05-31
#+author: TEC
#+subtitle: Folding more improvement into Org
Finding time as of late has been more difficult than I anticipated, and on top
of that, just as I was thinking of writing last month's post, I got distracted
by an exciting patchset that has been in the works for over a year finally
getting sorted out and landing. So, I hope that some of the fun developments in
this post will make up the absense of the last one 🙂.

Since it's been longer than I thought since the last standard post, we've got a
fair few commits to catch up on --- about 200. Most of these are miscellaneous
minor improvements and bugfixes, but a few notable changes have arrived too.

* Folding

The fabulous new folding engine (=org-fold-core=) should noticeably improve Org's
performance with large files. It contains a number of key optimisations to
improve speed, namely:
- Deferring fontification of folded regions
- Using text properties (\(\mathcal{O}(n \log n)\)) instead of overlays (\(\mathcal{O}(n^2)\)) for folded regions
- A collection of aggressive optimisations available under ~org-fold-core--optimise-for-huge-buffers~
- Convert text properties to overlays for =isearch= (which currently only supports overlays)

How noticeable is the overall performance impact? Well, I poked Ihor and he was
kind enough to whip up some benchmarks.

#+caption: The scaling of ~org-shifttab~ showing file contents, as file size increases, with and without org-fold.
[[file:figures/org-fold-perf-shifttab-contents.svg]]

#+caption: The scaling of ~org-shifttab~ showing the entire file, as file size increases, with and without org-fold.
[[file:figures/org-fold-perf-shifttab-showall.svg]]

Well this looks very promising[fn::Note the difference in scale, org-fold makes
the most difference in the graph where the times are an order of magnitude
more.]! Let's see how much of an improvement this is overall.

#+caption: Time to run =org-shifttab= twice, cycling through all three display modes (in seconds).
| File size (Mb) | Headings (thousands) | Bugfix (no org-fold) | Main (with org-fold) | Improvement |
|----------------+----------------------+----------------------+----------------------+-------------|
|             18 |                   36 |               115.31 |                 0.89 |         99% |
|            8.8 |                   24 |                19.03 |                 0.48 |         97% |
|            4.4 |                    5 |                 3.79 |                 0.13 |         97% |
|            2.2 |                    2 |                 1.29 |                 0.08 |         94% |
|            1.1 |                    1 |                 0.50 |                0.045 |         91% |
#+TBLFM: $5=100*(1 - $4/$3) ; %.0f%%

To be clear, even the smallest file in this data --- a 1.1 Mb Org file with around
a thousand headings, is fairly large. So, it's unlikely you'll notice much of a
difference with small--medium files, but if you a few large+ files this should
be a /fantastic/ improvement. Once again, thanks Ihor!

#+begin_warning
The change to text properties instead of overlays breaks a number of third party
packages like =evil-search= and =consult='s ~consult-line~.
If you are involved in any packages affected by this, you'll either want to
consider supporting invisible text, or look at ~isearch-filter-predicate~ and
~isearch-mode-end-hook~, which =org-fold= now uses.
If you're an end-user, perhaps politely make an issue on the repo for a project
/if no issue currently exists/, and either:
- Stay off Org's bleeding edge till the package ecosystem has adapted to this change
- Help the packages you use adapt to this change
- Set ~org-fold-core-style~ to ~overlays~ to restore the old behaviour
#+end_warning

* /Engraved/ source code blocks in LaTeX

All too often exporting code to LaTeX has been a disappointment, with lovely
syntax highlighting from Emacs major modes replaced with a markedly inferior
attempt by pygments (setting ~org-latex-listings~ to ~minted~) in a colour scheme I
don't really like.

A bit over a year ago, a project called [[https://github.com/tecosaur/engrave-faces][engrave-faces]] started with the aim of
making Emacs' font-lock more exportable, like a generalised =htmlize.el=. This has
recently been used to provide a new option for inline and block source code
exports in LaTeX.

#+caption: A screenshot of an Org code block, exported to a PDF,
#+caption: using =engrave-faces= and the =doom-one-light= theme.
[[file:figures/engraved-faces-sample.png]]

To use this, simply install the package and set ~org-latex-src-block-backend~ (a
rename of ~org-latex-listings~ to better reflect its usage) to ~engraved~.

While this is sufficient to get started, this new backend also allows for some
new options. The theme used for /engraving/ a source block can be set globally
with the new variable ~org-latex-engraved-theme~, or per-file with the
=#+latex_engraved_theme= keyword. It takes either the name of a theme, or the
symbol =t= as a stand-in for the current theme.

The theme can also be set on a per-block level using the LaTeX attribute
=:engraved-theme=.

#+caption: Seven code blocks exported to LaTeX, each with a different engrave-faces theme.
[[file:figures/engraved-faces-multitheme.png]]

Here's what using these new capabilities looks like in practice.

#+begin_src org
,#+title: Engraving source blocks
,#+latex_engraved_theme: modus-operandi

,#+begin_src emacs-lisp
(message "look ma, some %s" 'code)
,#+end_src

,#+attr_latex: :engraved-theme modus-viviandi
,#+begin_src shell
echo "This is shell code"
,#+end_src
#+end_src

This may well be the best syntax-highlighting solution available for PDFs/LaTeX
currently available, but I am a tad biased 😛.

* TexInfo export improvements

Jonas Bernoulli has been using a custom TexInfo backend for Magit's
documentation for a while now, and over the past few months he's worked the
features he was missing into Org's built-in TexInfo exporter.

Upstreaming like this always takes a fair bit of effort, so thank you Jonas for
going through with this!

* Toggle noweb prefix handling

Previously, whenever a noweb reference appeared on a non-empty line, a
multi-line replacement would duplicate the content before the noweb reference.

Clearly, this is not always desirable, and this behaviour can now be turned of
by setting the new header argument =:noweb-prefix no=.

#+begin_src org
,#+begin_src emacs-lisp :noweb yes :noweb-prefix no
(setq example-data "<<example>>")
,#+end_src

Will now expand to

,#+begin_src emacs-lisp
(setq example-data "some
multi-line
content")
,#+end_src

Instead of

,#+begin_src emacs-lisp
(setq example-data "some
(setq example-data "multiline
(setq example-data "content")
,#+end_src
#+end_src

* Package highlight: org-modern
I think we've all [[https://github.com/integral-dw/org-superstar-mode][seen]] [[https://github.com/sabof/org-bullets][plenty]] of =org-mode= [[https://github.com/Fuco1/org-pretty-table][prettification]] [[https://github.com/harrybournis/org-fancy-priorities][packages]] [[https://gitlab.com/marcowahl/org-pretty-tags][before]], so
what makes Minad's [[https://github.com/minad/org-modern][org-modern]] special? It's actually doing something similar to
Ihor's org-fold improvements, switching out slower overlay-based approaches for
text properties. I can confirm that switching out =org-superstar-mode= for
=org-modern= has made a substantial improvement in my experience, halving the
first-load time of my =config.org= to around 20 seconds. If you're a fan of Org
prettification and haven't taken a look at this package, I highly recommend
giving it a shot.

#+caption: A demonstration of org-modern taken from the project README.
[[file:figures/org-modern-readme-demo.gif]]

* Other improvements
- Clean up some magic numbers in =org-attach= _Marco Wahl_
- Allow /any/ command form in ~org-attach-commands~ (including keyboard macros)
 _Marco Wahl_
- Allow =dest= in ~org-list-send-item~ to be a buffer position _Sacha Chua_
- Improve CSL-JSON date handling in =oc-basic= _David Lukes_
- Add =TOML= and =desktop= language aliases _TEC_
- Speed up cached bibliography retrieval in =oc-basic= _Ihor Radchenko_
- Allow setting PlantUML jar arguments _Ihor Radchenko_
- Allow for customisation of property separators with ~org-property-separators~
 _Tyler Grinn_
- New =ox-latex= maintainer, Daniel Fleischer
- More unit tests _Kyle Keyer, Nick Dokos_
- Documentation improvements _Kyle Meyer, Juan Manuel Macias, Bastien, Karl
  Fogel, Cody Harris_

* Bugfixes
- An Emacs <28 bug in =org-persist= _Ihor Radchenko_
- Author extraction in =oc-basic= _Nicolas Goaziou_
- Fix behaviour of ~org-copy-visible~ with adjacent tex and
 ~buffer-invisibility-spec~ _Kyle Meyer_
- Parsing of inline footnotes with parentheses _Nicolas Goaziou_
- Honor ~default-directory~ in =ob-gnuplot= _Ihor Radchenko_
- Heading fontification bug _Anders Johansson_
- Template expansion where one key is a substring of another _Andrew Arensburger_