Emacs setup for use with LaTeX, Lisp, Org, and Python

• Copying
• Quick start
• Introduction
• Early Init File (info)
• Init File (info) header
• Install the selected packages (info)
• Emacs Tree-sitter
• Text faces or styles (info)
• Window management (info)
• Advising functions (info)
• Bookmarks (info)
• Registers (info)
• Dired: directory editor as file manager (info)
• Minibuffer completion styles (info)
• Processes (info)
• Help (info)
  • Shortdoc-display-group (info)
  • Info (info)
• Key bindings (info)
  • Disabling Commands (info)
  • Interaction-log
  • Keycast
• Using Emacs as a server (info)
  • Latexmk save-compile-display loop
  • Qutebrowser userscript
• Calendar, Diary, and Time (info)
• Tools to handle buffers and modes
• Completion
  • Vertico (info)
  • Embark (info)
  • Marginalia (info)
  • Consult (info)
  • Company (info)
• Search and replace (info)
  • Regexp Replace (info)
  • Incremental Search (info) and Other Search and Loop Commands (info)
  • Ugrep
  • XR - Emacs regexp parser and analyzer
• Version Control (info)
  • Ediff (info)
  • Git
    • Magit (info)
    • Github quick setup
    • Learn git
    • List all Git branches
• Reading
  • Reading DjVu files
  • Reading EPUB files
  • Reading PDF files
• Writing
  • Writing LaTeX files
  • Writing Markdown files
  • Writing Org (info) files and Org activation (info)
    • Setup Org
    • Org HTML style default
    • Buffer properties
    • Column View (info) and Property Syntax (info)
    • Org introspection
    • Citar: citing bibliography with Org Mode
    • Compare bibtex and biblatex
    • Engrave Faces
    • Making Org hyperlink types (info)
    • Extending org-mode to handle YouTube links
    • Translate capital keywords (old) to lower case (new)
    • Evaluate specific source blocks at load-time
    • Org-mode macro utilities
    • Testing Org
    • LaTex preamble editing using Noweb (info)
    • Deprecated LaTeX preamble editing methods
    • HTML export (info)
    • Advanced LaTeX export settings
    • Org Syntax
  • Grammar, spelling, and style tools
    • Abbrevs (info)
    • DICT.org local server fails on Darwin
    • Writegood mode
  • Which-function-mode (info)
• Saving Emacs sessions (info)
• Programming Tools
  • Eglot (info)
  • Format-all
  • Flymake (info)
• Programming Modes
  • Common Lisp programming
    • Sly
    • CS 325 AI Programming
    • Quicklisp
  • Lisp mode custom font locking for Common Lisp
    • Initialize Common Lisp custom font locking
    • Collect standard symbol function names
    • Collect standard symbol value names
    • Finalize Common Lisp custom font locking
  • Emacs Lisp Programming (info)
    • Debugging Emacs Lisp (info)
    • Writing Better Elisp Docstrings
  • Go Programming
  • Julia programming
    • ESS Makefile for Homebrew patch
  • Python programming
    • Python-mode
    • Org Babel Ackermann Python test
    • Package Installer for Python
    • Eglot for python-mode
    • Jedi
    • Code-cells
• Libraries
  • Library dash.el (info)
  • Library f.el
  • Library s.el
• Minor Modes (info)
  • Synchronal multiple-region editing
  • Unobtrusive whitespace trimming
  • Structural editing
  • Electric operators
  • Smart snippets
• Display (info)
  • Narrowing
  • Visualize color codes and names
  • Flash the line around point for visual feedback
• Applications
  • Hyperlinking and Web Navigation Features (info)
    • Browse URL (info)
    • Emacs Web Wowser
    • Mailcap
    • Open Street Map viewer for Emacs
    • Restclient
    • Webjump
  • Elfeed: Emacs web feed reader
  • Emacs Multimedia System (info)
• Init File (info) footer
• Local variables linking to Latexmk save-compile-display-loop

,#+latex_header: <<latex-header-1>>
,#+latex_header: <<latex-header-2>>
,#+latex_header: <<latex-header-3>>
,#+latex_header: <<latex-header-4>>
,#+latex_header: <<latex-header-5>>

Copying

This README contains my Emacs setup for use with LaTeX, Lisp, Org, and Python. Copyright © 2021-2023 Gerard Vermeulen.

All Org-mode source blocks with function definitions in this document are free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.

Permission is granted to copy, distribute and/or modify the other parts of this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. You should have received a copy of the GNU Free Documentation License with the source file of this document. If not, see <https://www.gnu.org/licenses/>.

Quick start

This setup requires at least Emacs-30. The installation procedure starts with:

1. Backup the user-emacs-directory which defaults often to ~/.emacs.d.
2. Run the listing prepare the user-emacs-directory without ssh access or the listing prepare the user-emacs-directory with ssh access commands.

After invoking Emacs interactively, Emacs will ask you to install a selected set of packages. Quit Emacs and invoke Emacs again.

cd ~
git clone https://forge.chapril.org/gav451/emacs.d.git .emacs.d
make --directory=.emacs.d init
emacs &

cd ~
git clone ssh://gitea@forge.chapril.org:222/gav451/emacs.d.git .emacs.d
make --directory=.emacs.d init
emacs &

Introduction

This Emacs setup aims to install automatically a minimal set of extension packages that allows to handle my reports and presentations. The file format of the reports is Org Mode plain text with Python source code blocks and the file format of the presentations is LaTeX.

This org file (more precisely the original org source file of this file) illustrates three methods in my work-flow:

1. How to tangle (or export) source blocks from org files. This file contains source blocks to produce the files early-init.el, init.el, latexmkrc, org-store-link, and example.py by tangling.
2. How to export org files to other formats such as HTML, LaTeX, and PDF.
3. How org hyperlinks (info) allow to link inside and outside Org Mode: hover over or click on the links to experiment.

The AUCTeX - Aalborg University Center TeX extension package provides a powerful Text-based User Interface (TUI) environment to edit the LaTeX presentations.

The Citar extension package provides quick filtering and selecting of bibliographic entries, and the option to run different commands on those selections. Citar exploits the extension packages Vertico, Embark, Marginalia, and Consult. The CiteProc extension package provides CSL: citation style language processing capabilities to Citar and Org Mode. A curated repository of CSL styles is the citation style language repository.

The PDF-Tools extension package renders PDF file with the possibility to annotate the file or to click on anchors in the PDF file that link back to the original LaTeX file of the document. An example of my work-flow are the steps to convert this org file to PDF and to see the result with PDF-Tools in Emacs: execute the commands pdf-tools-install, org-babel-tangle, org-latex-export-latex-to-latex, and compile. This sets up an infinite LaTeX compilation loop to update and redisplay the PDF file after execution of the org-latex-export-latex-to-latex command in this buffer.

Here follows a list of interesting Emacs configurations:

1. Kyle Meyer's configuration shows the working environment of an Emacs and Org developer.
2. Musa Al-hassy's configuration is an impressive example of producing the Emacs initialization files and other files by tangling an org file. His methodology is impressive, as his Elisp Cheat Sheet and org-special-block-extra package show. To me, this is a configuration to admire, but his methodology is way over my head.
3. Omar Antolin Camarena's configuration exploits built-in packages, Omar's own small packages, and large external packages. Omar is the author of orderless and embark. My use setopt to set Emacs options instead of the customize interface comes from his idea of using custom-set-variables although that idea is bad Emacs advice for new users.
4. Pierre Neirhardt's configuration implements lazy loading without help of external packages. I have stolen his approach of using lazy loading to silently ignore the setup stanzas of uninstalled extension packages.
5. Sacha Chua's configuration is a practical example of producing the Emacs initialization files by tangling an org file. It gives me the impression that she is a practical person trying to achieve her goals by the most efficient means.
6. Steve Purcell's configuration is well organized and a showcase of readable code. Its commit and issue histories are also helpful: see for instance the discussion The order of company candidates is incorrect in Emacs lisp mode.

Here follows a list of links on how to use Emacs and Elisp:

1. Mastering Emacs is a link to a blog with interesting posts that promotes a book on how to become a proficient Emacs user.
2. Use GNU Emacs: The Plain Text Computing Environment explains the fundamentals of the Emacs abstractions before showing how to exploit those abstractions interactively. It targets a similar audience as the Mastering Emacs book.
3. A guided tour of Emacs is a link to a video tour pointing how buffers (info), dired (info), documentation (info), elisp (info), elisp debugging (info), eshell (info), and keyboard macros (info) turn Emacs in an powerful coding and editing environment.
4. Emergency Emacs is a link to a video on fundamental editing features and principles with focus on ediff (info), undo (info), moving point (info), erasing (info), and dynamic abbreviations (info).
5. Endless Parentheses is a blog with mindblowing code snippets.
6. How to open a file in Emacs looks into elisp (info) and elisp debugging (info) and then compares Emacs, Vim, Neovim, and Visual Studio Code with respect to values and technology.
7. Learning Emacs and Elisp is a link to a video tutorial with a transcript on the best approach to learn Emacs and Elisp.

Early Init File (info)

Try to load no-littering as early as possible, since it helps to keep ~/.emacs.d clean.

;;; early-init.el --- user early-init file        -*- lexical-binding: t -*-
;;; Commentary:
;;; Code:
(setq load-prefer-newer t)

(require 'no-littering nil 'noerror)

(provide 'early-init)
;; Emacs looks for "Local variables:" after the last "?\n?\f".

;; Local Variables:
;; indent-tabs-mode: nil
;; End:
;;; early-init.el ends here

In order to get help in understanding the code block above in a buffer showing the original Org source file, type

(eval

after moving point (or cursor) to one of the items of the list:

1. src_emacs-lisp[:results none]{(describe-variable #'load-prefer-newer t)}
2. src_emacs-lisp[:results none]{(apropos-library "no-littering")}
3. src_emacs-lisp{(find-function #'hack-local-variables)}

to execute the code between the curly braces for access to help. This shows that Emacs is a self-documenting editor.

Init File (info) header

The user-init-file header requires cl-lib and sets Emacs options. It consists of three parts in listing lst:1st-setopt-call, lst:2nd-setopt-call, and lst:2nd-setopt-call in order to limit the length of the listings for exporting to LaTeX.

The init file (info) does load the custom-file according to the recommendation of saving customizations (info).

;;; init.el --- user init file                    -*- lexical-binding: t -*-
;;; Commentary:
;;; Code:

(require 'cl-lib)

(when (< emacs-major-version 30)
  (error "This `init.el' requires at least Emacs-30"))

(setopt
 after-save-hook #'executable-make-buffer-file-executable-if-script-p
 column-number-mode t
 cursor-type 'box
 custom-file (locate-user-emacs-file "custom.el")
 ;; Known problem: EasyPG fails to save files encrypted with GnuPG v2.4.1.
 ;; Darwin: brew install gnupg@2.2
 epg-pinentry-mode 'loopback
 global-hl-line-mode t
 global-hl-line-sticky-flag t
 history-delete-duplicates t
 history-length 500
 indent-tabs-mode nil
 inhibit-startup-buffer-menu t
 inhibit-startup-screen t
 initial-buffer-choice t
 initial-scratch-message ""
 isearch-lazy-count t
 kill-ring-max 300
 lazy-count-prefix-format nil
 lazy-count-suffix-format " (%s/%s)"
 lazy-highlight-initial-delay 1.0
 mode-line-compact t
 next-error-message-highlight t
 recentf-max-saved-items 100
 recentf-mode t
 scroll-bar-mode nil
 tab-always-indent 'complete
 tab-width 8
 tool-bar-mode nil
 tooltip-mode nil
 url-cookie-trusted-urls nil
 url-cookie-untrusted-urls '(".*")
 use-dialog-box nil
 use-short-answers t
 view-read-only t)

(setopt
 ;; See https://github.com/melpa/melpa#mirrors for official Melpa mirrors.
 ;; ("melpa" . "https://www.mirrorservice.org/sites/melpa.org/packages/")
 package-archives '(("gnu" . "https://elpa.gnu.org/packages/")
                    ("gnu-devel" . "https://elpa.gnu.org/devel/")
                    ("melpa" . "https://melpa.org/packages/")
                    ("melpa-stable" . "https://stable.melpa.org/packages/")
                    ("nongnu" . "https://elpa.nongnu.org/nongnu/"))
 package-install-upgrade-built-in nil
 ;; Pin packages to GNU ELPA or to MELPA STABLE for info and/or stability.
 package-pinned-packages  '((auctex . "gnu")
                            (citar . "melpa-stable")
                            (citar-embark . "melpa-stable")
                            (compat . "gnu")
                            (consult . "gnu")
                            (dash . "melpa-stable")
                            (debbugs . "gnu")
                            (denote . "gnu")
                            (embark . "gnu")
                            (embark-consult . "gnu")
                            (emms . "gnu")
                            (engrave-faces . "gnu-devel")
                            (f . "melpa-stable")
                            (forge . "melpa-stable")
                            (git-commit . "nongnu")
                            (keycast . "nongnu")
                            (magit . "nongnu")
                            (magit-section . "nongnu")
                            (marginalia . "gnu")
                            (osm . "gnu")
                            (parsebib . "melpa-stable")
                            (queue . "gnu")
                            (rainbow-mode . "gnu")
                            (s . "melpa-stable")
                            (xr . "gnu")
                            (vertico . "gnu")
                            (with-editor . "nongnu")
                            (yasnippet . "gnu"))
 package-selected-packages '(debbugs no-littering))

;; Tweak warnings:
(setopt warning-display-at-bottom nil
        ;; Suppress the missing lexical-binding cookie warnings.
        ;; warning-suppress-log-types '((lexical-binding))
        )

;; To use different Org git repositories (org or gro):
(push (expand-file-name "~/VCS/org-mode/lisp") load-path)
(push (expand-file-name "~/VCS/org-contrib/lisp") load-path)
;; (byte-recompile-directory "~/VCS/org-contrib/lisp" 0)
;; Postpone (require 'org) after shadowing Org and sh-script faces below.

(when (eq system-type 'darwin)
  (setopt ns-alternate-modifier nil
          ns-command-modifier 'meta
          ns-right-command-modifier 'super))
(when (eq window-system 'ns)
  (add-to-list 'initial-frame-alist '(height . 51))
  (add-to-list 'initial-frame-alist '(width . 180)))

(when (file-exists-p custom-file)
  (load custom-file))

Install the selected packages (info)

Emacs installs packages from archives on the internet. This setup uses five archives:

1. The GNU Emacs Lisp Package Archive.
2. The Development Emacs Lisp Package Archive.
3. The NonGNU Emacs Lisp Package Archive.
4. The Milkypostman's Emacs Lisp Package Archive (MELPA) with its official mirror in case is Melpa.org down? tells MELPA is down for everyone.
5. The Stable Milkypostman's Emacs Lisp Package Archive.

The code in listing lst:install-selected-packages assumes that the package system is in a virgin state if the package no-littering is not present:

1. It installs and loads no-littering after ensuring refreshing of the contents of available packages.
2. It calls src_emacs-lisp[:results silent]{(package-install-selected-packages)} to check the installation status of all packages in src_emacs-lisp[:results silent]{package-selected-packages} and to install the missing packages after the user has agreed to its prompt.
3. It defines a function to ensure the installation of packages in other source blocks.

In case of normal Emacs usage, src_emacs-lisp[:results silent]{(list-packages)} refreshes the contents of packages and allows to update packages to the latest version.

(defvar package-selected-packages)

(unless noninteractive
  (unless (require 'no-littering nil 'noerror)
    (unless (bound-and-true-p package-archive-contents)
      (package-refresh-contents))
    ;; Install and require `no-littering'.
    (package-install 'no-littering)
    (require 'no-littering)
    ;; (package-upgrade 'org) ; Use builtin or git!
    ;; Install the selected packages.
    (package-install-selected-packages)))

(defun ensure-package-selection (package)
  "Ensure selection of PACKAGE."
  (when (and (package-installed-p package)
             (bound-and-true-p package-selected-packages))
    (cl-pushnew package package-selected-packages)))

(defun ensure-package-installation (&rest packages)
  "Ensure installation of all packages in PACKAGES."
  (let ((ok t))
    (dolist (package packages)
      (unless (package-installed-p package)
        (package-install package))
      (unless (ensure-package-selection package)
        (setq ok nil)))
    ok))

Emacs Tree-sitter

Mickey Peterson's post How To Get Started with Tree-Sitter explains how to use tree-sitter in Emacs-29.1. Listing Setup treesit grammar sources configures where to find the different tree-sitter grammar sources for different languages. Listing Setup Go programming shows how to configure tab-width for go-ts-mod and go-mode-ts-mode.

(when (require 'treesit nil 'noerror)
  (setopt
   treesit-language-source-alist
   '((bash "https://github.com/tree-sitter/tree-sitter-bash" "master" "src")
     (c "https://github.com/tree-sitter/tree-sitter-c" "master" "src")
     (cmake "https://github.com/uyha/tree-sitter-cmake" "master" "src")
     (cpp "https://github.com/tree-sitter/tree-sitter-cpp" "master" "src")
     (css "https://github.com/tree-sitter/tree-sitter-css" "master" "src")
     (glsl "https://github.com/theHamsta/tree-sitter-glsl" "master" "src")
     ;; go-ts-mode requires libtree-sitter-go and libtree-sitter-gomode.
     (go "https://github.com/tree-sitter/tree-sitter-go" "master" "src")
     (gomod "https://github.com/camdencheek/tree-sitter-go-mod" "main" "src")
     (html "https://github.com/tree-sitter/tree-sitter-html" "master" "src")
     (java "https://github.com/tree-sitter/tree-sitter-java" "master" "src")
     (javascript "https://github.com/tree-sitter/tree-sitter-javascript"
                 "master" "src")
     (json "https://github.com/tree-sitter/tree-sitter-json" "master" "src")
     (julia "https://github.com/tree-sitter/tree-sitter-julia" "master" "src")
     (lua "https://github.com/MunifTanjim/tree-sitter-lua" "main" "src")
     (make "https://github.com/alemuller/tree-sitter-make" "main" "src")
     (perl "https://github.com/ganezdragon/tree-sitter-perl" "master" "src")
     (python "https://github.com/tree-sitter/tree-sitter-python" "master" "src")
     (ruby "https://github.com/tree-sitter/tree-sitter-ruby" "master" "src")
     (rust "https://github.com/tree-sitter/tree-sitter-rust" "master" "src")
     (scala "https://github.com/tree-sitter/tree-sitter-scala" "master" "src")
     (sql "https://github.com/m-novikov/tree-sitter-sql" "main" "src")
     (swift "https://github.com/tree-sitter/tree-sitter-swift" "master" "src")
     (toml "https://github.com/tree-sitter/tree-sitter-toml" "master" "src")
     (tsx "https://github.com/tree-sitter/tree-sitter-typescript"
          "master" "tsx/src")
     (typescript "https://github.com/tree-sitter/tree-sitter-typescript"
                 "master" "typescript/src")
     (yaml "https://github.com/ikatyang/tree-sitter-yaml" "master" "src"))))

Text faces or styles (info)

This setup does not use custom themes (info), but it does a minimal setup of fonts and faces. The note on mixed font heights in Emacs for how to setup fonts properly. It boils down to two rules:

1. The height of the default face must be an integer number to make the height a physical quantity.
2. The heights of all other faces must be real numbers to scale those heights with respect to the height of the face (those heights default to 1.0 for no scaling).

The code in listing lst:configure-face-attributes implements those rules. Listing lst:face-setting-functions shows that font scaling is easy in case of proper initialization of all face heights in a frame. To adjust the font size in windows, invoke src_emacs-lisp adjust the font size in the current buffer, type to invoke src_emacs-lisp[:results silent]{(text-scale-adjust +1)} before making further adjustments as displayed. Listing lst:face-setting-functions, lst:shadow-org-font-lock-faces, and lst:shadow-emacs-font-lock-faces show tweaks to improve visibility without theming:

1. Toggling between a dark and light background by means of src_emacs-lisp{(invert-default-face)}.
2. Shadowing the definition of faces before loading. The last item in the page on fontifying Org mode source code blocks describes this method.

Listing lst:use-buffer-face-mode-for-fixed-or-variable-pitch-face contains functions to set a fixed or variable pitch face in the current buffer and selects a fixed pitch face for magit-mode and progmode buffers. Type

(eval

to inspect faces at point.

(with-eval-after-load 'emacs
  ;; Set face attributes.
  (cond
   ((eq system-type 'darwin)
    (set-face-attribute 'default nil :family "Hack" :height 120)
    (set-face-attribute 'fixed-pitch nil :family "Hack")
    (set-face-attribute 'variable-pitch nil :family "FiraGo"))
   ((eq system-type 'gnu/linux)
    (set-face-attribute 'default nil :family "Hack" :height 110)
    (set-face-attribute 'fixed-pitch nil :family "Hack")
    (set-face-attribute 'variable-pitch nil :family "FiraGo"))
   (t
    (set-face-attribute 'default nil :family "Hack" :height 110)
    (set-face-attribute 'fixed-pitch nil :family "Hack")
    (set-face-attribute 'variable-pitch nil :family "DejaVu Sans"))))

(with-eval-after-load 'emacs
  ;; Neither `set-default-face-height' nor `text-scale-adjust' work well.
  (defun set-default-face-height ()
    "Set the default face height in all current and future frames.

Scale all other faces with a height that is a real number."
    (interactive)
    (let* ((prompt (format "face height (%s): "
                           (face-attribute 'default :height)))
           (choices (mapcar #'number-to-string
                            (number-sequence 50 200 10)))
           (height (string-to-number
                    (completing-read prompt choices nil 'require-match))))
      (message "Setting the height of the default face to %s" height)
      (set-face-attribute 'default nil :height height)))

  (defun invert-default-face ()
    "Invert the default face."
    (interactive)
    (invert-face 'default)))

(with-eval-after-load 'emacs
  ;; Shadow two definitions in org-faces.el:
  (defface org-block
    ;; https://emacs.stackexchange.com/a/9604 answers:
    ;; How to override a defined face for light and dark backgrounds?
    `((((background dark))
       :inherit (fixed-pitch)
       ,@(and (>= emacs-major-version 27) '(:extend t))
       :background "#444444")
      (t
       :inherit (fixed-pitch)
       ,@(and (>= emacs-major-version 27) '(:extend t))
       :background "#FFFFD0"))
    "My face used for text inside blocks.

It is always used for source blocks.  You can refine what face
should be used depending on the source block language by setting,
`org-src-block-faces', which takes precedence.

When `org-fontify-quote-and-verse-blocks' is not nil, text inside
verse and quote blocks are fontified using the `org-verse' and
`org-quote' faces, which inherit from `org-block'."
    :group 'org-faces)

  (defface org-table
    ;; https://emacs.stackexchange.com/a/9604 answers:
    ;; How to override a defined face for light and dark backgrounds?
    `((((background dark))
       :inherit (fixed-pitch)
       ,@(and (>= emacs-major-version 27) '(:extend t))
       :background "#444444")
      (t
       :inherit (fixed-pitch)
       ,@(and (>= emacs-major-version 27) '(:extend t))
       :background "#FFFFD0"))
    "My face for tables."
    :group 'org-faces))

(with-eval-after-load 'emacs
  ;; Shadow one definition in sh-script.el:
  (defface sh-heredoc
    '((((class color) (background dark))
       (:foreground "yellow"))
      (((class color) (background light))
       (:foreground "magenta"))
      (t
       (:weight bold)))
    "My face to show a here-document."
    :group 'sh-indentation))

(require 'org)

;; Use proportional font faces in current buffer
(defun set-buffer-variable-pitch-face ()
  "Set a variable width (proportional) font in current buffer."
  (interactive)
  (setq-local buffer-face-mode-face 'variable-pitch)
  (buffer-face-mode))

;; Use monospaced font faces in current buffer
(defun set-buffer-fixed-pitch-face ()
  "Set a fixed width (monospace) font in current buffer."
  (interactive)
  (setq-local buffer-face-mode-face 'fixed-pitch)
  (buffer-face-mode))

(add-hook 'magit-mode-hook #'set-buffer-fixed-pitch-face)
(add-hook 'prog-mode-hook #'set-buffer-fixed-pitch-face)

(when (fboundp 'visual-wrap-prefix-mode)
  (add-hook 'visual-line-mode-hook 'visual-wrap-prefix-mode))

Window management (info)

Mickey Peterson's post Demystifying Emacs's Window Manager invites to improve window placement. Listing lst:1st-window-management, lst:2nd-window-management and lst:3rd-window-management implement a selection of his recommendations. See:

1. The Zen of Buffer Display (info)
2. Configuring the Emacs display system

for technical information.

(with-eval-after-load 'emacs
  ;; https://www.masteringemacs.org/article/demystifying-emacs-window-manager
  (defun split-root-below (arg)
    "Split window below from the root or from the parent with ARG."
    (interactive "P")
    (split-window (if arg
                      (window-parent (selected-window))
                    (frame-root-window))
                  nil 'below nil))

  (defun split-root-right (arg)
    "Split window right from the root or from the parent with ARG."
    (interactive "P")
    (split-window (if arg
                      (window-parent (selected-window))
                    (frame-root-window))
                  nil 'right nil))

   (defun toggle-window-dedication ()
    "Toggles window dedication in the selected window."
    (interactive)
    (set-window-dedicated-p
     (selected-window) (not (window-dedicated-p (selected-window)))))

   (defun make-display-buffer-matcher-function (major-modes)
    "Return a lambda function to match a list of MAJOR-MODES."
    (lambda (buf-name _action)
      (with-current-buffer buf-name (apply #'derived-mode-p major-modes))))

   (keymap-global-set "M-o" #'other-window))

(with-eval-after-load 'emacs
  (winner-mode +1))

(with-eval-after-load 'emacs
  ;; https://www.masteringemacs.org/article/demystifying-emacs-window-manager
  ;; GAV: `display-buffer-alist' fails to set the *Warnings* buffer position.
  (setopt switch-to-buffer-obey-display-actions t)
  (add-to-list 'display-buffer-alist
               `(,(rx (or "*Apropos*" "*Dictionary*" "*Help*" "*info"))
                 (display-buffer-reuse-window display-buffer-pop-up-window)
                 (inhibit-same-window . nil)))
  (add-to-list 'display-buffer-alist
               `(,(rx (or "*Occur*" "*grep*" "*xref*"))
                 display-buffer-reuse-window
                 (inhibit-same-window . nil)))
  ;; Handling the *Warnings* buffer like the *compilation* buffer also fails.
  ;; BUG#70773: Eli tells `(setq delayed-warnings-hook nil)' is better.
  ;; https://lists.gnu.org/archive/html/bug-gnu-emacs/2024-05/msg00253.html
  ;; Works after setting `warnings-display-at-bottom' to `nil'.
  (add-to-list 'display-buffer-alist
               `(,(rx (or "*Warnings*" "*compilation*"))
                 display-buffer-no-window
                 (allow-no-window . t))))

Advising functions (info)

(with-eval-after-load 'emacs
  (defun advice-toggle (symbol where function &optional props)
    "Toggle between states after `advice-remove' and `advice-add'."
    (let ((how "%s `%s' advice `%s' %s `%s'"))
      (if (advice-member-p function symbol)
          (progn
            (message how "Removal of" where function "from" symbol)
            (advice-remove symbol function))
        (message how "Addition of" where function "to" symbol)
        (advice-add symbol where function props)))))

(with-eval-after-load 'emacs
  (defun toggle-eww-display-pdf-around ()
    "Toggle `eww-display-advice' advice."
    (interactive)
    (advice-toggle 'eww-display-pdf :around #'eww-display-pdf-as-binary))

  (defun toggle-ilog-timer-function-after ()
    "Toggle `ilog-timer-function' advice."
    (interactive)
    (advice-toggle 'ilog-timer-function :after #'ilog-ensure-ilog-buffer-window))

  (defun toggle-keycast-log-update-buffer-override ()
    "Toggle `keycast-log-update-buffer' advice."
    (interactive)
    (advice-toggle 'keycast-log-update-buffer
                   :override #'keycast-log-update-buffer-plain))

  (defun toggle-org-babel-python-format-session-value-override ()
    "Toggle `org-babel-python-format-session-value' advice."
    (interactive)
    (advice-toggle 'org-babel-python-format-session-value
                   :override #'org-babel-python-format-session-value-override)))

Bookmarks (info)

Listing bookmark setup preserves bookmark history in bookmark-default.el. Table tab:bookmark-commands-and-bindings lists all bookmark commands with working key bindings. Not all key bindings in src_emacs-lisp[:results silent]{(describe-variable 'bookmark-map)} are operational for different reasons.

BUG: The virtual buffers of the consult-buffer command do not seem to work. Therefore, consult-buffer is no means to access the bookmark history (contrary to claims in consult (info)).

(with-eval-after-load 'bookmark
  (setopt bookmark-save-flag 1)
  (setf bookmark-exit-hook 'bookmark-unload-function))

command	key binding
bookmark-delete
bookmark-delete-all
bookmark-insert	(eval
bookmark-insert-location
bookmark-jump	(eval
bookmark-jump-other-frame
bookmark-jump-other-window
bookmark-load
bookmark-rename
bookmark-save
bookmark-set	(eval
bookmark-set-no-overwrite	(eval
bookmark-write
consult-bookmark	(eval
list-bookmarks

Registers (info)

Listing register separator usage example shows how to use a register

(eval

as register separator when appending regions to text registers. Listing setup register usage prepares my preferred register usage. Table tab:register-commands-and-bindings lists all register commands with working key bindings. The desktop library allows to preserve the register history between Emacs sessions.

When I set register ?+ to
(set-register ?+ "\n*REGISTER SEPARATOR*\n")
to test append-to-register on two regions like
Mark this line without new-line as region 1
Mark this line without new-line as region 2
The correct result of
"C-x r s T" with region 1 marked
"C-x r + T" with region 2 marked
"C-x r i T"
is:
Mark this line without new-line as region 1
*REGISTER SEPARATOR*
Mark this line without new-line as region 2

(with-eval-after-load 'register
  ;; Register `?+' serves as register separator when using `append-to-register':
  (set-register ?+ "\n")

  ;; https://emacs.stackexchange.com/a/52290
  (defun delete-all-registers ()
    "Delete all registers."
    (interactive)
    (setq register-alist nil)))

command	key binding
append-to-register
copy-rectangle-to-register	(eval
copy-to-register	(eval
frameset-to-register	(eval
increment-register	(eval
insert-register	(eval
jump-to-register	(eval
kmacro-to-register	(eval
number-to-register	(eval
point-to-register	(eval
prepend-to-register
set-register
window-configuration-to-register	(eval

Dired: directory editor as file manager (info)

Dired (info) and the ranger file manager offer similar capabilities for copying, deleting, opening, renaming, and viewing files and directories, but the integration of dired (info) in Emacs is obviously much better than the integration of ranger in Emacs.

For instance, this setup allows to insert an org-mode link to a file containing a specific image into an org-mode buffer by means of the facilities of dired (info) as follows:

1. Type

   (eval

   to open the directory containing the file with the specific image in a dired-mode buffer.
2. Start searching for the specific image by navigating to the name of any image file.
3. Type

   (eval

   to switch to view the file in an image-mode buffer.

4. In the image-mode buffer, continue searching for the specific image by typing:

   • (eval

     to view the next image in the dired-mode buffer,

   • (eval

     to view the previous image in the dired-mode buffer, and

   • (eval

     to quit the image-mode buffer and to go back to the dired-mode buffer.
5. After finding the specific image, use

   (eval

   in the image-mode buffer or the dired-mode buffer to store the org-link.
6. Switch to the org-mode buffer and use

   (eval

   to insert the org-link into the buffer.

Listing lst:set-dired-options makes the directory editor sort entries alphabetically after grouping the directories before grouping the files by extension.

(with-eval-after-load 'dired
  (setopt dired-dwim-target t
          ;; | switch | action                                 |
          ;; |--------+----------------------------------------|
          ;; | -a     | also list hidden entries               |
          ;; | -l     | use a long listing format              |
          ;; | -X     | sort alphabetically by entry extension |
          ;; | -G     | skip long listing format group names   |
          ;; | -1     | list one entry per line                |
          dired-listing-switches "-alGX1 --group-directories-first"
          dired-recursive-copies 'always
          dired-recursive-deletes 'always))

(with-eval-after-load 'wdired
  (setopt wdired-allow-to-change-permissions t))

Listing lst:extra-dired-key-bindings adds a new key binding to dired-mode-map to open files with the Emacs Web Wowser inside Emacs.

(with-eval-after-load 'dired
  (defun dired-eww-open-file ()
    "In Dired, open the regular file named on this line with eww"
    (interactive)
    (let ((file (dired-get-file-for-visit)))
      (if (file-regular-p file)
          (eww-open-file file)
        (error "Eww rejects `%s', since it is not a regular file" file))))

  (keymap-set dired-mode-map "E" #'dired-eww-open-file))

Minibuffer completion styles (info)

Listing set minibuffer options implements ideas of the post Understanding minibuffer completion.

(when (require 'minibuffer nil 'noerror)
  ;; https://www.masteringemacs.org/article/understanding-minibuffer-completion
  (setopt
   completion-category-overrides '((file (styles basic substring)))
   completion-ignore-case nil
   completion-styles '(basic flex partial-completion substring)))

Processes (info)

Listing lst:process-utilities defines a function to run a (command-line) program with arguments and to obtain a list with its numeric exit status as well as its output to stdout.

;; https://gitlab.com/howardabrams/spacemacs.d/blob/master/layers/ha-org/funcs.el#L418
(defun shell-command-with-exit-code (program &rest args)
  "Run PROGRAM with ARGS and return exit-code and output in a list."
  (with-temp-buffer
    (list (apply 'call-process program nil (current-buffer) nil args)
          (buffer-substring-no-properties (point-min) (point-max)))))

Help (info)

Listing lst:setup-help enriches the help buffer. Table tab:help-key-bindings lists a number of key bindings to start playing with the help facilities of Emacs. Try .

(with-eval-after-load 'help-fns
  (add-hook 'help-fns-describe-function-functions
            #'shortdoc-help-fns-examples-function)
  (setopt help-enable-symbol-autoload t))

command	key map	keys
Info-goto-emacs-command-node	help-map	(eval
describe-function	help-map	(eval
describe-key	help-map	(eval
describe-symbol	help-map	(eval
describe-variable	help-map	(eval
info	help-map	(eval

Shortdoc-display-group (info)

Listing lst:configure-shortdoc binds

(eval

to short-doc-display-group and defines a short documentation group for functions defined in this Org file.

(when (fboundp 'shortdoc-display-group)
  (keymap-set help-map "y" #'shortdoc-display-group)
  (with-eval-after-load 'shortdoc
    ;; Ensure defining the functions before documenting them.
    (define-short-documentation-group init
      "Advice"
      (advice-toggle :no-manual t)
      (toggle-eww-display-pdf-around :no-manual t)
      (toggle-ilog-timer-function-after :no-manual t)
      (toggle-keycast-log-update-buffer-override :no-manual t)
      (toggle-org-babel-python-format-session-value-override :no-manual t)
      "Face"
      (invert-default-face :no-manual t)
      (set-default-face-height :no-manual t)
      "Interaction"
      (enable-this-command :no-manual t)
      (narrow-or-widen-dwim :no-manual t)
      (org-narrow-to-table :no-manual t)
      "LaTeX"
      (biber-delete-cache :no-manual t)
      (update-lualatex-opentype-font-name-database :no-manual t)
      "Org"
      (by-backend :no-manual t)
      (by-backend-kbd-org-macro :no-manual t)
      ;; (org-active-current-time-stamp :nomanual t)
      (org-babel-execute:latex-extra-header :no-manual t)
      (org-babel-execute:latex-header :no-manual t)
      (org-electric-dollar :no-manual t)
      (org-eval-emacs-lisp-setup-blocks :no-manual t)
      (org-eval-python-setup-blocks :no-manual t)
      (org-eval-infixed-blocks :no-manual t)
      (org-latex-engraved-source-block-filter :no-manual t)
      ;; (org-inactive-current-time-stamp :nomanual t)
      ;; (org-insert-source-block :nomanual t)
      (org-syntax-convert-keyword-case-to-lower :no-manual t)
      (smart-latex-engrave-org-source-blocks :no-manual t)
      (zero-all-org-src-blocks-indentation :no-manual t))))

Info (info)

Listing lst:configure-info adds the required paths to the places where info looks for files.

(with-eval-after-load 'info
  ;; Make Emacs find ALL "*.info" files in `package-user-dir' on Gentoo Linux.
  (when (eq system-type 'gnu/linux)
    (dolist (path
             (nreverse
              (mapcar
               (lambda (name)
                 (expand-file-name (file-name-directory name)))
               (directory-files-recursively package-user-dir "\\.info\\'"))))
      (add-to-list 'Info-directory-list path nil #'file-equal-p)))
  ;; Make Emacs find the git Org info files.
  (add-to-list 'Info-directory-list
               (expand-file-name "~/VCS/org-mode/doc")))

Key bindings (info)

command	key map	keys
undo	global-map	(eval
backward-kill-word	global-map	(eval
backward-char	global-map	(eval
forward-char	global-map	(eval
backward-word	global-map	(eval
forward-word	global-map	(eval
backward-sentence	global-map	(eval
forward-sentence	global-map	(eval

Disabling Commands (info)

Execute src_emacs-lisp{(find-library "novice")} to see how Emacs prevents new users from shooting themselves in the feet. Listing lst:configure-disabled-command-function enables disabled commands on the fly.

(with-eval-after-load 'emacs
  (setq disabled-command-function
        (defun enable-this-command (&rest _args)
          "Called when executing a disabled command.
Enable it and re-execute it."
          (put this-command 'disabled nil)
          (message "You typed %s.  Emacs enabled %s."
                   (key-description (this-command-keys)) this-command)
          (sit-for 0)
          (call-interactively this-command))))

Interaction-log

(when (and (ensure-package-installation 'interaction-log)
           (require 'interaction-log nil 'noerror))

  ;; https://www.skybert.net/emacs/show-shortcuts-when-giving-presentations/
  (defun ilog-ensure-ilog-buffer-window ()
    "Ensure the visibility of the `ilog' buffer, when it exists."
    (when (and (get-buffer ilog-buffer-name)
               (not (get-buffer-window ilog-buffer-name)))
      (display-buffer (get-buffer ilog-buffer-name))))

  (keymap-set help-map "C-l" #'interaction-log-mode)
  (advice-add 'ilog-timer-function :after #'ilog-ensure-ilog-buffer-window))

Keycast

Listing lst:configure-keycast configures keycast.

;; Make `keycast-log-update-buffer' use a buffer similar to the
;; control buffer `ediff-setup-windows-plain' returns.
(when (ensure-package-installation 'keycast)
  (setopt keycast-log-newest-first t
          keycast-mode-line-window-predicate #'keycast-bottom-right-window-p)

  (defun keycast-log-update-buffer-plain ()
    (let ((buffer (get-buffer keycast-log-buffer-name)))
      (unless (buffer-live-p buffer)
        (setq buffer (get-buffer-create keycast-log-buffer-name))
        (with-current-buffer buffer
          (setq buffer-read-only t)))
      (unless (get-buffer-window buffer)
        (display-buffer buffer '(display-buffer-at-bottom
                                 (dedicated . t)
                                 (window-height . 10))))
      (when-let ((output (keycast--format keycast-log-format)))
        (with-current-buffer buffer
          (goto-char (if keycast-log-newest-first (point-min) (point-max)))
          (let ((inhibit-read-only t))
            (when (and (> keycast--command-repetitions 0)
                       (string-match-p "%[rR]" keycast-log-format))
              (unless keycast-log-newest-first
                (backward-char))
              (ignore-errors
                (delete-region (line-beginning-position)
                               (1+ (line-end-position)))))
            (insert output))
          (goto-char (if keycast-log-newest-first (point-min) (point-max)))))))

  (advice-add 'keycast-log-update-buffer
              :override #'keycast-log-update-buffer-plain))

Using Emacs as a server (info)

Emacs can act as a server that listens to a socket to share its state (for instance buffers and command history) with other programs by means of a shell command emacsclient. Section #sec:latexmk-save-compile-display-loop and #sec:qutebrowser-userscript show how to use emacsclient to:

1. Install an asynchronous (or background) loop of saving a LaTeX file, compiling it, and redisplaying the output in Emacs.
2. Make qutebrowser send html links with document titles to Emacs.

The code in listing lst:start-emacs-server starts the Emacs server.

(when window-system
  (unless (or noninteractive (daemonp))
    (add-hook 'after-init-hook #'server-start)))

Latexmk save-compile-display loop

The latexmk resource file in the next source code block shows how to use emacsclient to (re)display the PDF file in Emacs after each successful (re)compilation on condition that the local compile-command variable is correct. The local compile-command variable in the local variables section (only visible in org files, but not in html and pdf files) shows how to make use of the latexmkrc file.

# pdf creator
$pdf_mode = 4;  # 4 means lualatex
# pdf previewer and update pdf previewer
$pdf_previewer = "emacsclient -e '(find-file-other-window %S)'";
$pdf_update_method = 4;  # 4 runs $pdf_update_command to force the update
$pdf_update_command = "emacsclient -e '(with-current-buffer (find-buffer-visiting %S) (pdf-view-revert-buffer nil t))'";
# see for instance glossary.latexmkrc
add_cus_dep( 'acn', 'acr', 0, 'makeglossaries' );
add_cus_dep( 'glo', 'gls', 0, 'makeglossaries' );
# use ".=" to append to $clean_ext
$clean_ext .= " acr acn alg bbl dvi glo gls glg ist lol lst";
$clean_ext .= " nav run.xml snm synctex.gz";
sub makeglossaries {
    my ($name, $path) = fileparse( $$Psource );
    return system "makeglossaries -d '$path' '$name'";
}
# Emacs looks for "Local variables:" after the last "newline-formfeed".

# Local Variables:
# mode: perl
# End:

Qutebrowser userscript

The next block contains an userscript that sends a store-link org-protocol message with the url and the title from qutebrowser to emacsclient. The function urlencode translates the url and the title for the message. The Python urllib examples show how to use urlencode. The final execvp call deals with a qutebrowser userscript requirement: the emacsclient process must get the PID of the userscript that must kill itself after the take-over. Termination of the emacsclient process hands control back to qutebrowser.

On a POSIX system, you can run the userscript from qutebrowser or from a terminal to see whether it works. In case you try to run it from Emacs, Emacs may hang or die.

#!/usr/bin/env python
from urllib.parse import urlencode
from os import environ, execvp

url = environ.get("QUTE_URL", "https://orgmode.org")
title = environ.get("QUTE_TITLE", "Org Mode")
parameters = urlencode({"url": url, "title": title})
print(payload := f"org-protocol://store-link?{parameters}")
execvp("emacsclient", ("-n", payload))

Calendar, Diary, and Time (info)

(with-eval-after-load 'time
  (setopt world-clock-list
          '(("America/Los_Angeles" "Seattle")
            ("America/New_York" "New York")
            ("Europe/London" "London")
            ("Europe/Moscow" "Moscow")
            ("Europe/Paris" "Paris")
            ("Europe/Istanbul" "Istanbul")
            ("Africa/Cairo" "Cairo")
            ("Asia/Jerusalem" "Jerusalem")
            ("Asia/Singapore" "Singapore")
            ("Asia/Tokyo" "Tokyo"))
          world-clock-time-format "%a %d %b %R %z"))

Tools to handle buffers and modes

(defun set-all-buffers-with-modes (minor-mode value modes)
  "Set MINOR-MODE to VALUE for all buffers with a mode derived from MODES."
  (dolist (buffer (buffer-list))
    (with-current-buffer buffer
      (when (and (derived-mode-p modes) (buffer-file-name))
        (funcall minor-mode value)))))

(defun enable-ro-all-org-mode-buffers ()
  "Enable `buffer-read-only' of all `org-mode' buffers."
  (interactive)
  (set-all-buffers-with-modes #'read-only-mode +1 '(org-mode))
  (message "Enabled `buffer-read-only' of all `org-mode' buffers."))

(defun disable-ro-all-org-mode-buffers ()
  "Disable `buffer-read-only' of all `org-mode' buffers."
  (interactive)
  (set-all-buffers-with-modes #'read-only-mode -1 '(org-mode))
  (message "Disabled `buffer-read-only' of all `org-mode' buffers."))

(defun active-major-modes ()
  "Return a list of active major modes found by iterating over all buffers."
  (let (result)
    (dolist (buffer (buffer-list))
      (with-current-buffer buffer
        (let ((mode major-mode))
          (push mode result))))
    (cl-sort (cl-remove-duplicates result) #'string-lessp)))

Completion

Vertico (info) provides a performant and minimalistic vertical completion UI based on the default completion system and behaves therefore correctly under all circumstances. Using Vertico, Marginalia, Consult, and Embark links to a video demonstration. Vertico integrates well with fully supported complementary packages to enrich the completion UI:

1. Embark (info) for minibuffer actions with context menus,
2. Marginalia (info) for rich annotations in the minibuffer, and
3. Consult (info) for useful search and navigation commands,

where the order is that of enhancing citar's experience and the configuration steps below.

Finally, company: a modular complete-anything framework for Emacs provides completion in any buffer.

Vertico (info)

Listing lst:enable-vertico-mode configures and enables savehist-mode and enables vertico-mode. The documentation src_emacs-lisp{(describe-function 'savehist-mode)} why it is best to turn on savehist-mode in the Emacs init file. BUG: Adding eww-history, register-alist, regexp-search-string, or search-string to savehist-additional-variables fails to save the relevant histories.

(when (require 'savehist nil 'noerror)
  (setopt savehist-additional-variables '(kill-ring search-ring))
  (savehist-mode +1))
(when (and (ensure-package-installation 'vertico)
           (fboundp 'vertico-directory-delete-char)
           (fboundp 'vertico-directory-delete-word)
           (fboundp 'vertico-mode)
           (fboundp 'vertico-directory-enter))
  (vertico-mode +1)
  (with-eval-after-load 'vertico
    (defvar vertico-map)
    (keymap-set vertico-map "DEL" #'vertico-directory-delete-char)
    (keymap-set vertico-map "M-DEL" #'vertico-directory-delete-word)
    (keymap-set vertico-map "RET" #'vertico-directory-enter)))

command	remap	keys
vertico-directory-delete-char		(eval
vertico-directory-delete-word		(eval
vertico-directory-enter		(eval
vertico-exit	exit-minibuffer	(eval
vertico-exit-input		(eval
vertico-first	beginning-of-buffer	(eval
vertico-first	minibuffer-beginning-of-buffer	(eval
vertico-insert		(eval
vertico-last	end-of-buffer	(eval
vertico-next-group	forward-paragraph	(eval
vertico-next	next-line-or-history-element	(eval
vertico-next	next-line	(eval
vertico-previous-group	backward-paragraph	(eval
vertico-previous	previous-line-or-history-element	(eval
vertico-previous	previous-line	(eval
vertico-save	kill-ring-save	(eval
vertico-scroll-down	scroll-down-command	(eval
vertico-scroll-up	scroll-up-command	(eval

Embark (info)

Listing bind embark commands binds embark commands to the global key map:

1. embark-act prompts the user for an action and performs it. GAV: org-mode and embark do not play together nicely.

2. Except for highlighting of email and web URLs, embark-dwim englobes the functionality of src_emacs-lisp{(find-library "goto-addr")} that activates mail and web URLs to turn them into clickable buttons. Since embark-dwim acts on a superset of target types, it renders goto-addr superfluous. See:

   1. Goto Address mode (info).
   2. The default (embark-dwim) action on a target (info).
3. embark-bindings allows to explore all current command key bindings in the minibuffer.
4. The initialization of prefix-help-command enables minibuffer help after a prefix key (for instance ) as typing shows.

;; GAV: ~org-mode~ and ~embark~ do not play together nicely.
;; GAV: ~embark~ is a dependency of ~citar-embark~ and ~embark-consult~.
(when (ensure-package-installation 'embark-consult)
  (when (fboundp 'embark-act)
    (keymap-global-set "C-," #'embark-act))
  (when (fboundp 'embark-dwim)
    (keymap-global-set "C-:" #'embark-dwim))
  (when (fboundp 'embark-bindings)
    (keymap-global-set "C-h B" #'embark-bindings))
  (when (fboundp 'embark-prefix-help-command)
    (setq prefix-help-command #'embark-prefix-help-command)))

Marginalia (info)

Listing lst:enable-marginalia-mode enables marginalia-mode.

(when (and (ensure-package-installation 'marginalia)
           (fboundp 'marginalia-mode))
  (marginalia-mode +1))

Consult (info)

Consult (info) provides practical commands based on the Emacs minibuffer completion function completing-read. Listing bind consult commands binds consult commands to different key maps. Consult usage tips are:

1. Add a buffer position to the mark ring by means of

   (eval

   and jump to one of the marks in the ring by means of

   (eval

   lt-mark)}}} or

   (eval

   . See Emacs: Mark Ring.
2. is an alternative to .
3. Listing lst:find-file-preview uses the internal functions consult--file-preview and consult--read to visit files with previewing during selection. See: Consult Wiki.

command	key map	keys
consult-bookmark	ctl-x-r-keymap	(eval
consult-buffer-other-frame	ctl-x-5-keymap	(eval
consult-buffer-other-window	ctl-x-4-keymap	(eval
consult-buffer	ctl-x-keymap	(eval
consult-compile-error	goto-map	(eval
consult-complex-command	ctl-x-keymap	(eval
consult-find	search-map	(eval
consult-focus-lines	search-map	(eval
consult-git-grep	search-map	(eval
consult-global-mark	goto-map	(eval
consult-goto-line	goto-map	(eval
consult-goto-line	goto-map	(eval
consult-history	global-map	(eval
consult-imenu	goto-map	(eval
consult-keep-lines	search-map	(eval
consult-line	search-map	(eval
consult-mark	goto-map	(eval
consult-mode-command	global-map	(eval
consult-multi-occur	search-map	(eval
consult-org-heading	org-mode-map	(eval
consult-outline	goto-map	(eval
consult-register	ctl-x-r-keymap	(eval
consult-yank-pop	global-map	(eval
elfeed	global-map	(eval
embark-act	global-map	(eval
embark-bindings	global-map	(eval
embark-dwim	global-map	(eval
iedit-mode	global-map	(eval
minibuffer-complete-history	minibuffer-local-map	(eval
narrow-or-widen-dwim	ctl-x-keymap	(eval
org-agenda	global-map	(eval
org-capture	global-map	(eval
org-cite	org-mode-map	(eval
org-goto	org-goto	(eval
org-insert-link-global	global-map	(eval
org-narrow-to-table	ctl-x-keymap	(eval
org-store-link	global-map	(eval

(when (ensure-package-installation 'consult)
  ;; C-c bindings (current-global-map)
  (keymap-global-set "C-c h" #'consult-history)
  (keymap-global-set "C-c m" #'consult-mode-command)
  ;; C-x bindings (ctl-x-map)
  (keymap-set ctl-x-map "M-:"  #'consult-complex-command)
  (keymap-set ctl-x-map "b" #'consult-buffer)
  (keymap-set ctl-x-4-map "b" #'consult-buffer-other-window)
  (keymap-set ctl-x-5-map "b" #'consult-buffer-other-frame)
  (keymap-set ctl-x-r-map "x" #'consult-register)
  (keymap-set ctl-x-r-map "b" #'consult-bookmark)
  ;; M-g bindings (goto-map)
  (keymap-set goto-map "g" #'consult-goto-line)
  (keymap-set goto-map "M-g" #'consult-goto-line)
  (keymap-set goto-map "o" #'consult-outline)
  (keymap-set goto-map "m" #'consult-mark)
  (keymap-set goto-map "k" #'consult-global-mark)
  (keymap-set goto-map "i" #'consult-imenu)
  (keymap-set goto-map "e" #'consult-compile-error)
  (with-eval-after-load 'org
    (keymap-set org-mode-map "C-c C-h" #'consult-org-heading))
  ;; M-s bindings (search-map)
  (keymap-set search-map "g" #'consult-git-grep)
  (keymap-set search-map "f" #'consult-find)
  (keymap-set search-map "k" #'consult-keep-lines)
  (keymap-set search-map "l" #'consult-line)
  (keymap-set search-map "m" #'consult-multi-occur)
  (keymap-set search-map "u" #'consult-focus-lines)
  ;; Other bindings (current-global-map)
  (keymap-global-set "M-y" #'consult-yank-pop))

(defun consult-find-file-preview
    (prompt &optional dir _default mustmatch initial predicate)
  "Helper to implement previewing when calling `find-file'.
See `read-file-name' for the meaning of PROMPT, DIR, MUSTMATCH, INITIAL,
and PREDICATE."
  (interactive)
  (let ((default-directory (or dir default-directory))
        (minibuffer-completing-file-name t))
    (consult--read #'read-file-name-internal :state (consult--file-preview)
                   :prompt prompt :initial initial
                   :require-match mustmatch :predicate predicate)))

(defun toggle-find-file-preview ()
  "Toggle previewing when calling `find-file'."
  (interactive)
  (let ((done "Enabled"))
    (if (eq read-file-name-function #'read-file-name-default)
        (setq read-file-name-function #'consult-find-file-preview)
      (setq read-file-name-function #'read-file-name-default
            done "Disabled"))
    (message "%s `find-file' previewing" done)))

Company (info)

Company (info) is a modular completion framework and listing lst:setup-company configures company after ensuring the company installation.

(when (and (ensure-package-installation 'company)
           (fboundp 'company-mode))
  ;; https://github.com/purcell/emacs.d/issues/778
  (setopt company-transformers '(company-sort-by-occurrence))
  (dolist (symbol '(LaTeX-mode-hook
                    org-mode-hook
                    emacs-lisp-mode-hook
                    lisp-interaction-mode-hook
                    lisp-mode-hook
                    python-mode-hook
                    ielm-mode-hook
                    sly-mrepl-mode-hook))
    (add-hook symbol #'company-mode)))

Search and replace (info)

Regexp Replace (info)

Executing

(eval

prompts for a regular expression REGEXP and a substitution NEWSTRING to replace REGEXP with NEWSTRING. The tools in section Narrowing allow to limit the scope of {{{kbd(M-x replace-regexp)}}}. A list pointing to relevant documentation is:

1. Regexp Replace (info) explains how the substitution handles references to regular expression groups and lisp expressions.
2. Syntax of Regular Expressions (info) describes regular expression features for users.
3. Emacs Lisp Regular Expressions (info) describes regular expression features for programmers.
4. Emacs Wiki has an article on replacing regexp with lisp expressions.

Table tab:replace-regexp-tranform tabulates how to perform example tasks by means of

(eval

using (regular-expression transform) pairs.

task	regular expression	substitution
move dot two digits forward	0\.\([[:digit:]][[:digit:]]\)	0\1.
move dot two digits forward	0\.\([0-9][0-9]\)	0\1.
renumber grep/occur matches	\(.+:\)	\,(1+ \#)._

Incremental Search (info) and Other Search and Loop Commands (info)

;; https://www.masteringemacs.org/article/searching-buffers-occur-mode
(defun get-buffers-matching-mode (mode)
  "Return a list of buffers whose major-mode is equal to MODE."
  (let ((buffer-mode-matches '()))
    (dolist (buf (buffer-list))
      (with-current-buffer buf
        (when (eq mode major-mode)
          (push buf buffer-mode-matches))))
    buffer-mode-matches))

(defun multi-occur-in-this-mode ()
  "Show all lines matching REGEXP in buffers with this major mode."
  (interactive)
  (multi-occur
   (get-buffers-matching-mode major-mode)
   (car (occur-read-primary-args))))

;; https://blog.chmouel.com/posts/emacs-isearch/
(when (package-installed-p 'consult)
  (defun consult-line-from-isearch ()
    "Invoke `consult-line' from isearch."
    (interactive)
    (let ((query (if isearch-regexp
                     isearch-string
                   (regexp-quote isearch-string))))
      (isearch-update-ring isearch-string isearch-regexp)
      (let (search-nonincremental-instead)
        (ignore-errors (isearch-done t t)))
      (consult-line query)))

  (keymap-set isearch-mode-map "C-l" #'consult-line-from-isearch))

;; https://blog.chmouel.com/posts/emacs-isearch/
(defun occur-from-isearch ()
  "Invoke `occur' from isearch."
  (interactive)
  (let ((query (if isearch-regexp
                   isearch-string
                 (regexp-quote isearch-string))))
    (isearch-update-ring isearch-string isearch-regexp)
    (let (search-nonincremental-instead)
      (ignore-errors (isearch-done t t)))
    (occur query)))

(defun project-find-regexp-from-isearch ()
  "Invoke `project-find-regexp' from isearch."
  (interactive)
  (let ((query (if isearch-regexp
                   isearch-string
                 (regexp-quote isearch-string))))
    (isearch-update-ring isearch-string isearch-regexp)
    (let (search-nonincremental-instead)
      (ignore-errors (isearch-done t t)))
    (project-find-regexp query)))

(keymap-set isearch-mode-map "C-o" #'occur-from-isearch)
(keymap-set isearch-mode-map "C-f" #'project-find-regexp-from-isearch)

Ugrep

Ugrep is an ultra fast grep with interactive query UI and fuzzy search. The pages Using ugrep within Emacs and Ugrep in Emacs show how to make Emacs use it with lgrep and xref. Listing set grep and xref options shows my implementation of the suggestions on those pages. To do:

1. None of the commands listed in Searching with Grep under Emacs (info) works on my system with the exception of lgrep when using ugrep.
2. None of the grep, agrep, egrep, fgrep, and glimpse builtins listed in Eshell builtins (info) works.

(when (executable-find "ugrep")
  (with-eval-after-load 'grep
    (setopt grep-template (string-join '("ugrep"
                                         "--color=always"
                                         "--decompress"
                                         "--ignore-binary"
                                         "--ignore-case"
                                         "--include=\"<F>\""
                                         "--line-number"
                                         "--null"
                                         "--recursive"
                                         "--regexp=<R>")
                                       " ")
            grep-command "ugrep --color=always --null -nH -e "
            grep-use-null-device nil))
  (with-eval-after-load 'xref
    (setopt
     xref-search-program 'ugrep
     xref-search-program-alist
     `((grep . "xargs -0 grep <C> --null -snHE -e <R>")
       (ripgrep . ,(concat "xargs -0 rg <C> --null -nH"
                           " --no-heading --no-messages -g '!*/' -e <R>"))
       (ugrep . "xargs -0 ugrep <C> --null -ns -e <R>")))))

XR - Emacs regexp parser and analyzer

XR converts Emacs regular expressions to the structured rx form, thus being an inverse of rx. It can also find mistakes and questionable constructs inside regexp strings.

(when (ensure-package-installation 'xr) t)

Version Control (info)

Ediff (info)

Video links to complete the ediff (info) manual are:

1. Emergency Emacs.
2. Use smerge and ediff to resolve file conflicts.

Listing lst:setup-ediff configures ediff to display all its buffers in a single frame and to make all text visible prior to ediffing Org buffers.

(with-eval-after-load 'ediff-wind
  (when (fboundp 'ediff-setup-windows-plain)
    (setopt ediff-merge-split-window-function #'split-window-horizontally
            ediff-split-window-function #'split-window-horizontally
            ediff-window-setup-function #'ediff-setup-windows-plain)))
(with-eval-after-load 'org
  ;; https://github.com/oantolin/emacs-config#readme
  (add-hook 'org-mode-hook
            (defun ediff-with-org-show-all ()
              "Expand all headings prior to ediffing org buffers."
              (add-hook 'ediff-prepare-buffer-hook #'org-fold-show-all nil t))))

Git

Magit (info)

Magit (info) is an Emacs interface to the version control system Git and the snippet below ensures its installation. Magit usage tips are:

1. Most upvoted Magit questions on Stack Overflow.
2. Abort an active rebase by pressing

   (eval

   .

I still have to understand Magit pushing (info) and to figure out how to use src_emacs-lisp{(magit-push-current-to-pushremote)} or src_emacs-lisp{(magit-push-current-to-upstream)}.

(ensure-package-installation 'magit)

Github quick setup

echo "# oglot" >> README.md
git init
git add README.md
git commit -m "first commit"
git branch -M main
git remote add origin git@github.com:gav451/oglot.git
git push -u origin main

git remote add origin git@github.com:gav451/oglot.git
git branch -M main
git push -u origin main

Learn git

Useful Git links are:

• Abort a merge in Git
• Change the URI for a Git remote
• Check out a remote branch in Git
• Clone a Git repository to a specific folder
• Clone a specific Git repository branch
• Create a new Git branch from an existing branch
• Create a remote branch in Git
• Delete a commit from a branch in Git
• Delete a file from a Git repository
• Delete a Git branch locally and remotely
• Determine the origin of a cloned Git repository
• Undo the most recent local Git commits

List all Git branches

git -C ~/VCS/oglot branch -a

* main
  remotes/origin/main

Reading

Reading DjVu files

Document View (info) allows to read DjVu files on condition that it can use the command line DjVu decoder ddjvu from the DjVuLibre utilities as shown by the code of src_emacs-lispvu->tiff-converter-ddjvu)}. Use to enlarge or shrink what doc-view-mode displays and use to scroll down or up through when pages are larger than the doc-view-mode window.

Reading EPUB files

The package nov.el provides a major mode for reading EPUB files in Emacs. Listing lst:configure-nov configures nov.el.

(when (and (ensure-package-installation 'nov)
           (fboundp 'nov-mode))
  (add-to-list 'auto-mode-alist `(,(rx ".epub" eos) . nov-mode)))

Reading PDF files

The pdf-tools package exploits the poppler library to render and to let you annotate PDF files. It also exploits the SyncTeX library to link anchors in PDF files produced with LaTeX to the original LaTeX sources. In order to use pdf-tools, you have to type

(eval

after installation of pdf-tools from MELPA or after each update of poppler to build or rebuild the epdfinfo executable that serves the PDF files to Emacs. Table tab:pdf-view-mode-commands-and-bindings lists important local map key bindings in pdf-view-mode. Note: image-save saves the page under point to a png file.

(when (and (ensure-package-installation 'pdf-tools)
           (fboundp 'pdf-loader-install))
  ;; Use `pdf-loader-install' for faster startup than with `pdf-tools-install'.
  (pdf-loader-install)

  (with-eval-after-load 'pdf-view
    (setopt pdf-view-display-size 'fit-page
            pdf-view-use-scaling (eq system-type 'darwin))))

command	key binding
image-save	(eval
pdf-outline	(eval
pdf-view-fit-height-to-window	(eval
pdf-view-fit-width-to-window	(eval

Writing

Writing LaTeX files

Loading tex.el immediately instead of lazily ensures proper initialization of AUCTeX. In particular, the TeX-master safe local variable in the tex.el elisp library file has no autoload cookie. Without prior loading of tex.el, Emacs will complain that TeX-master is no safe local variable in case it reads a LaTeX file that sets TeX-master. The list below summarizes the main AUCTeX configuration objectives:

1. Listing lst:set-tex-options ensures installation of AUCTeX and initializes AUCTeX properly for LuaTeX or LuaLaTeX.
2. Listing lst:set-tex-options also enables indenting between square brackets which is a recent feature.
3. Listing lst:update-lualatex-opentype-font-name-database defines a function to update the OpenType Font name database for LuaLaTeX when the output of LuaLaTeX shows missing fonts.
4. Listing lst:set-bibtex-options configures the Emacs bibtex library to use the LaTeX BiBTeX dialect for backwards compatibility.
5. Listing lst:set-font-latex-options disables font scaling of section titles.
6. Listing lst:set-latex-options configures latex for a full featured LaTeX-section-command.

(when (ensure-package-installation 'auctex)
  ;; Use `require' to make `TeX-master' a safe local variable.
  (when (require 'tex nil 'noerror)
    (setopt
     TeX-auto-save t
     TeX-engine 'luatex
     TeX-indent-close-delimiters "]"
     TeX-indent-open-delimiters "["
     TeX-parse-self t
     ;; Disable `TeX-electric-math' to prevent collisions with `smartparens'.
     TeX-electric-math nil)))

(with-eval-after-load 'emacs
  (defun update-lualatex-opentype-font-name-database ()
    "Update the \"OpenType Font\" name database for \"LuaLaTeX\"."
    (interactive)
    (cl-destructuring-bind (exit-code output)
        (shell-command-with-exit-code
         "luaotfload-tool" "-vv" "--update" "--force")
      (if (= 0 exit-code)
          (message "%s" (string-trim output))
        (error "%s" (string-trim output))))))

(with-eval-after-load 'bibtex
  (setopt bibtex-dialect 'BibTeX))

(with-eval-after-load 'font-latex
  (setopt font-latex-fontify-sectioning 1.0))

(with-eval-after-load 'latex
  (setopt LaTeX-electric-left-right-brace t
          LaTeX-section-hook '(LaTeX-section-heading
                               LaTeX-section-title
                               LaTeX-section-toc
                               LaTeX-section-section
                               LaTeX-section-label)))

Writing Markdown files

(when (ensure-package-installation 'markdown-mode) t)

Writing Org (info) files and Org activation (info)

Listing lst:bind-org-commands activates Org (info) by means of global key bindings.

(with-eval-after-load 'emacs
  (global-set-key (kbd "C-c a") #'org-agenda)
  (global-set-key (kbd "C-c c") #'org-capture)
  (global-set-key (kbd "C-c l") #'org-store-link))

Links to Org-mode videos are:

1. Analyze Your Time with Org Mode Clocktables
2. Basic Task Management with Org: Checklists, TODOs, and Org-Agenda
3. Emacs Org-mode: a system for note-taking and project planning
4. Getting Started With Org Mode
5. Org Mode Time and Task Tools

Setup Org

I have split the initial Org-mode setup over fourteen listings. Here, follows a list detailing and motivating each listing:

1. Listing lst:set-org-options handles basic Org-mode options.
2. Listing lst:org-capture-templates initializes a simple capture template.
3. Listing lst:setup-org-babel sets ob-core, ob-latex, and ob-lisp options. See working with source code (info) for Org Babel information.
4. Listing lst:no-org-babel-eval prevents evaluation of blocks without an org-babel-execute:<LANG> function and adds fake org-babel-execute:<LANG> functions to silence

   (eval

   warnings.
5. Listing lst:set-org-link-options handles Org-mode options specific to hyperlinks (info).
6. Listing lst:looking-at-org-id enables recent org-id features.
7. Listing lst:setup-org-mode-map-1 and lst:setup-org-mode-map-2 extend the org-mode-map with useful key-bindings.
8. Listing lst:setup-org-src facilitates editing source code blocks, and it provides functions to change the indentation of all org-src-mode blocks.
9. Listing lst:setup-ob-python allows to pretty-print Python session source block values with black instead of pprint. This snippet may break in the future, because it sets org-babel-python--def-format-value which is a constant declared "private" by two dashes in its name!
10. Listing lst:set-org-export-options selects the non-intrusive expert user interface for export dispatching.
11. Listing lst:setup-org-for-lualatex-export and lst:set-ox-latex-options-for-lualatex-export configure Org-mode to generate output for the LuaLaTeX compiler.
12. Listing lst:setup-org-latex-classes defines org-latex-classes (info) for backward compatibility. For an explanation of the code in listing lst:setup-org-latex-classes, type

    (eval

    .

(with-eval-after-load 'org
  (setopt
   org-agenda-files '("gerard.org")
   org-agenda-include-diary t
   org-babel-load-languages `((calc . t)
                              (dot . ,(fboundp 'grapviz-dot-mode))
                              (emacs-lisp . t)
                              (eshell . t)
                              (fortran . t)
                              (gnuplot . ,(fboundp 'gnuplot-mode))
                              (julia . t)
                              (latex . t)
                              (lilypond . ,(fboundp 'lilypond-mode))
                              (lisp . t)
                              (lua . ,(fboundp 'lua-mode))
                              (org . t)
                              (perl . t)
                              ;; Beware of circular Python dependencies.
                              (python . t)
                              (ruby . ,(fboundp 'ruby-mode))
                              (shell . t))
   org-directory "~/org"
   org-export-backends '(ascii beamer html icalendar latex md odt texinfo)
   org-file-apps '((auto-mode . emacs)
                   (directory . emacs)
                   ("\\.mm\\'" . default)
                   ("\\.x?html?\\'" . default)
                   ("\\.pdf\\'" . emacs))
   org-modules '(ol-bibtex
                 ol-doi
                 ol-eww
                 ol-info
                 org-collector
                 org-id
                 org-protocol
                 org-tempo)
   org-use-property-inheritance t))

(with-eval-after-load 'org-capture
  (setopt org-capture-templates
          '(("f" "Flat capture database" entry (file "flat.org")
             "* %^{Prompt}t %?
%a"))))

(with-eval-after-load 'ob-core
  (setopt org-confirm-babel-evaluate nil))

(with-eval-after-load 'ob-latex
  (setopt org-babel-latex-preamble
          (lambda (_)
            "\\documentclass[preview]{standalone}\n")))

(with-eval-after-load 'ob-lisp
  ;; Default to `sly-eval' whenever feasible:
  (when (and (package-installed-p 'sly)
             (fboundp 'sly-eval))
    (setopt org-babel-lisp-eval-fn #'sly-eval)))

(defvar org-babel-default-header-args:conf '((:eval . "no")))
(defvar org-babel-default-header-args:diff '((:eval . "no")))
(defvar org-babel-default-header-args:text '((:eval . "no")))
(defvar org-babel-default-header-args:toml '((:eval . "no")))

;;; Kludges to silence `org-lint' warnings:
(defun org-babel-execute:conf (_body _params)
  "Silence `org-lint' warnings." nil)
(defun org-babel-execute:diff (_body _params)
  "Silence `org-lint' warnings." nil)
(defun org-babel-execute:text (_body _params)
  "Silence `org-lint' warnings." nil)
(defun org-babel-execute:toml (_body _params)
  "Silence `org-lint' warnings." nil)

(with-eval-after-load 'ol
  ;; Setting `org-link-descriptive' to `t' has caused worse `isearch'
  ;; behavior.  Set `org-link-descriptive' interactively by calling
  ;; `org-toggle-link-display'.
  (setopt org-link-descriptive t
          org-link-file-path-type 'adaptive
          org-link-search-must-match-exact-headline nil))

(with-eval-after-load 'org-id
  (setopt org-id-link-to-org-use-id t
          org-id-track-globally t)
  ;; https://stackoverflow.com/a/16247032 answers
  ;; "How to assign IDs to all entries in a buffer."
  (defun org-id-add-ids-to-headlines-in-buffer ()
    "Add slowly ID properties to all headlines without such an ID property.
Undo this by means of `org-delete-property-globally'."
    (interactive)
    (org-map-entries #'org-id-get-create)))

;; From: "Nicolas Richard" <theonewiththeevillook@yahoo.fr>
;; Date: Fri, 08 Mar 2013 16:23:02 +0100	[thread overview]
;; Message-ID: <87vc913oh5.fsf@yahoo.fr> (raw)
(defun org-electric-dollar ()
  "When called once, insert \\(\\) and leave point in between.
When called twice, replace the previously inserted \\(\\) by one $."
  (interactive)
  (if (and (looking-at "\\\\)") (looking-back "\\\\(" (- (point) 2)))
      (progn (delete-char 2)
             (delete-char -2)
             (insert "$"))
    (insert "\\(\\)")
    (backward-char 2)))

(defun org-active-current-time-stamp ()
  "Insert an active date-time stamp of the current time."
  (interactive)
  (if (fboundp 'org-insert-time-stamp)
      (org-insert-time-stamp (current-time) 'with-hm)
    (let ((stamp (format-time-string "<%Y-%m-%d %a %H:%M>" (current-time))))
      (insert stamp)
      stamp)))

(defun org-inactive-current-time-stamp ()
  "Insert an inactive date-time stamp of the current time."
  (interactive)
  (if (fboundp 'org-insert-time-stamp)
      (org-insert-time-stamp (current-time) 'with-hm 'inactive)
    (let ((stamp (format-time-string "[%Y-%m-%d %a %H:%M]" (current-time))))
      (insert stamp)
      stamp)))

(with-eval-after-load 'org
  (setopt org-return-follows-link t)
  (keymap-set org-mode-map "C-c <SPC>" #'org-inactive-current-time-stamp)
  (keymap-set org-mode-map "C-c C-<SPC>" #'org-active-current-time-stamp)
  (keymap-set org-mode-map "$" #'org-electric-dollar)
  (keymap-set org-mode-map "M-q" #'org-fill-paragraph))

;; Stolen from `org-insert-structure-template'.
;; Note: `org-tempo' does not require `tempo' at all.
(defcustom org-insert-source-block-defaults
  '("calc -n :results silent"
    "emacs-lisp -n :results silent"
    "julia -n :results silent"
    "latex -n"
    "lisp -n :results silent :package :cs325-user"
    "org -n"
    "python -i -n :results silent")
  "Default values for `org-insert-source-block'."
  :group 'org
  :type '(repeat string))

(defun org-insert-source-block ()
  "Insert a source block #+begin_src/SPEC/BODY/#+end_src.
Prompt for the source block SPEC.  With an active region, the
region becomes the block BODY.  Otherwise, insert an empty block."
  (interactive)
  (let* ((spec (completing-read
                "Block spec: " org-insert-source-block-defaults nil 'confirm))
         (region? (use-region-p))
         (region-start (and region? (region-beginning)))
         (region-end (and region? (copy-marker (region-end)))))
    (when region? (goto-char region-start))
    (let ((column (current-indentation)))
      (if (save-excursion (skip-chars-backward " \t") (bolp))
          (forward-line 0)
        (insert "\n"))
      (save-excursion
        (indent-to column)
        (insert (format "#+begin_src %s\n" spec))
        (when region?
          (org-escape-code-in-region (point) region-end)
          (goto-char region-end)
          (skip-chars-backward " \n\t\r")
          (end-of-line))
        (unless (bolp) (insert "\n"))
        (indent-to column)
        (insert "#+end_src")
        (if (looking-at "[ \t]*$") (replace-match "") (insert "\n"))
        (when (and (eobp) (not (bolp))) (insert "\n")))
      (end-of-line))))

(with-eval-after-load 'org
  (keymap-set org-mode-map "C-c C-;" #'org-insert-source-block))

(with-eval-after-load 'emacs
  (with-eval-after-load 'org-src
    ;; https://list.orgmode.org/c3cc4ff1fcfb3bc741df89a3f45be30e@posteo.net/
    (setopt org-src-preserve-indentation nil
            org-edit-src-content-indentation 0)

    (defun org-left-shift-block ()
      "Left-shift the block at point using `org-indent-block'."
      (interactive)
      (let ((org-adapt-indentation nil)
            (org-edit-src-content-indentation 0)
            (org-src-preserve-indentation nil))
        (org-indent-block))))

  (defun org-right-shift-block (&optional arg)
    "Right-shift the block at point 4 spaces.
With prefix argument ARG, prompt for the number of spaces."
    (interactive "P")
    (let ((spaces 4)
          (start (org-babel-where-is-src-block-head)))
      (if (not start) (message "Not at block")
        (when arg
          (setq spaces (read-number "Number of spaces: ")))
        ;; The `SUBEXP' of the block body is 5.
        (goto-char (match-end 5))
        (forward-line -1)
        (string-insert-rectangle
         (match-beginning 5) (point) (make-string spaces ?\s)))))

  (declare-function org-babel-map-src-blocks "ext:ob-core" (file &rest body))
  (declare-function org-do-remove-indentation "ext:org-macs" (n skip-fl))

  (defun zero-all-org-src-blocks-indentation ()
    "Remove the indentation of all `org-src-mode' blocks without `-i' switch."
    (interactive)
    (when (derived-mode-p 'org-mode)
      (save-excursion
        (org-babel-map-src-blocks
            nil
          (unless (or (string-match "-i " switches)
                      (string-match (rx (or bos bol) graph) body))
            (when-let ((new (with-temp-buffer
                              (insert body)
                              (org-do-remove-indentation)
                              (buffer-string))))
              (goto-char beg-body)
              (delete-region beg-body end-body)
              (insert new))))))))

(with-eval-after-load 'ob-python
  (setq org-babel-python--def-format-value "\
def __org_babel_python_format_value(result, result_file, result_params):
    with open(result_file, 'w') as f:
        if 'graphics' in result_params:
            result.savefig(result_file)
        elif 'pp' in result_params:
            import black
            f.write(black.format_str(repr(result), mode=black.Mode()))
        elif 'list' in result_params and isinstance(result, dict):
            f.write(str(['{} :: {}'.format(k, v) for k, v in result.items()]))
        else:
            if not set(result_params).intersection(\
['scalar', 'verbatim', 'raw']):
                def dict2table(res):
                    if isinstance(res, dict):
                        return [(k, dict2table(v)) for k, v in res.items()]
                    elif isinstance(res, list) or isinstance(res, tuple):
                        return [dict2table(x) for x in res]
                    else:
                        return res
                if 'table' in result_params:
                    result = dict2table(result)
                try:
                    import pandas
                except ImportError:
                    pass
                else:
                    if isinstance(result, pandas.DataFrame) and 'table' in result_params:
                        result = [[result.index.name or ''] + list(result.columns)] + \
[None] + [[i] + list(row) for i, row in result.iterrows()]
                    elif isinstance(result, pandas.Series) and 'table' in result_params:
                        result = list(result.items())
                try:
                    import numpy
                except ImportError:
                    pass
                else:
                    if isinstance(result, numpy.ndarray):
                        if 'table' in result_params:
                            result = result.tolist()
                        else:
                            result = repr(result)
            f.write(str(result))"))

(with-eval-after-load 'ox
  (setopt org-export-dispatch-use-expert-ui t))

(with-eval-after-load 'org
  ;; https://list.orgmode.org/87o84fd4oi.fsf@posteo.net/
  (add-to-list
   'org-preview-latex-process-alist
   '(luamagick
     :programs ("lualatex" "convert")
     :description "pdf > png"
     :message "you need to install lualatex and imagemagick."
     :image-input-type "pdf"
     :image-output-type "png"
     :image-size-adjust (1.0 . 1.0)
     :post-clean nil
     :latex-header nil
     :latex-compiler
     ("lualatex -interaction nonstopmode -output-directory %o %f")
     :image-converter
     ("convert -density %D -trim -antialias %f -quality 100 %O")))
  (setopt
   org-preview-latex-default-process 'luamagick
   org-latex-default-packages-alist '(("" "fontspec" t ("lualatex"))
                                      ("AUTO" "inputenc" t ("pdflatex"))
                                      ("T1" "fontenc" t ("pdflatex"))
                                      ("" "graphicx" t)
                                      ("" "longtable" nil)
                                      ("" "wrapfig" nil)
                                      ("" "rotating" nil)
                                      ("normalem" "ulem" t)
                                      ("" "amsmath" t)
                                      ("" "amssymb" t)
                                      ("" "capt-of" nil)
                                      ("" "hyperref" nil))))

(when (require 'ox-latex nil 'noerror) ;; To use the safe file local variables!
  (setopt
   org-latex-compiler "lualatex"
   org-latex-compiler-file-string
   "%% -*- LaTeX -*-\n%% Intended LaTeX compiler: %s\n"
   org-latex-hyperref-template "\\hypersetup{
  pdfauthor={%a},
  pdftitle={%t},
  pdfkeywords={%k},
  pdfsubject={%d},
  pdfcreator={%c},
  pdflang={%L},
  citecolor=blue,
  colorlinks=true,
  filecolor=blue,
  hyperfootnotes=false,
  linkcolor=blue,
  unicode=true,
  urlcolor=blue,
}\n"
   org-latex-minted-langs '((cc "c++")
                            (conf "text")
                            (cperl "perl")
                            (diff "diff")
                            (shell-script "bash")
                            (json "json")
                            (org "text")
                            (toml "toml"))
   org-latex-minted-options '(("bgcolor" "LightGoldenrodYellow"))
   org-latex-logfiles-extensions
   (cl-union '("lof" "lot") org-latex-logfiles-extensions :test #'equal)
   ;; https://tecosaur.github.io/emacs-config/#compiling
   org-latex-pdf-process (list (concat "latexmk -f -pdf -%latex"
                                       " -interaction=nonstopmode"
                                       " -shell-escape -outdir=%o %f"))
   org-latex-prefer-user-labels t)

  (put 'org-latex-toc-command 'safe-local-variable 'stringp))

(with-eval-after-load 'ox-latex
  (mapc (function (lambda (element)
                    (add-to-list 'org-latex-classes element)))
        (nreverse
         (quote (("elsarticle-1+2+3"	; Elsevier journals
                  "\\documentclass{elsarticle}
[NO-DEFAULT-PACKAGES]
[PACKAGES]
[EXTRA]"
                  ("\\section{%s}" . "\\section*{%s}")
                  ("\\subsection{%s}" . "\\subsection*{%s}")
                  ("\\subsubsection{%s}" . "\\subsubsection*{%s}")
                  ("\\paragraph{%s}" . "\\paragraph*{%s}")
                  ("\\subparagraph{%s}" . "\\subparagraph*{%s}"))
                 ("article-1+2+3"
                  "\\documentclass{article}
[NO-DEFAULT-PACKAGES]
[PACKAGES]
[EXTRA]"
                  ("\\section{%s}" . "\\section*{%s}")
                  ("\\subsection{%s}" . "\\subsection*{%s}")
                  ("\\subsubsection{%s}" . "\\subsubsection*{%s}")
                  ("\\paragraph{%s}" . "\\paragraph*{%s}")
                  ("\\subparagraph{%s}" . "\\subparagraph*{%s}"))
                 ("report-1+2+3"
                  "\\documentclass[11pt]{report}
[NO-DEFAULT-PACKAGES]
[PACKAGES]
[EXTRA]"
                  ("\\part{%s}" . "\\part*{%s}")
                  ("\\chapter{%s}" . "\\chapter*{%s}")
                  ("\\section{%s}" . "\\section*{%s}")
                  ("\\subsection{%s}" . "\\subsection*{%s}")
                  ("\\subsubsection{%s}" . "\\subsubsection*{%s}"))
                 ("book-1+2+3"
                  "\\documentclass[11pt]{book}
[NO-DEFAULT-PACKAGES]
[PACKAGES]
[EXTRA]"
                  ("\\part{%s}" . "\\part*{%s}")
                  ("\\chapter{%s}" . "\\chapter*{%s}")
                  ("\\section{%s}" . "\\section*{%s}")
                  ("\\subsection{%s}" . "\\subsection*{%s}")
                  ("\\subsubsection{%s}" . "\\subsubsection*{%s}")))))))

Org HTML style default

Set org-html-style-default option to clean up the selection of languages and to add HTML+CSS+JS for mhtml-mode:

(setopt org-html-style-default "<style>
  #content { max-width: 60em; margin: auto; }
  .title  { text-align: center;
             margin-bottom: .2em; }
  .subtitle { text-align: center;
              font-size: medium;
              font-weight: bold;
              margin-top:0; }
  .todo   { font-family: monospace; color: red; }
  .done   { font-family: monospace; color: green; }
  .priority { font-family: monospace; color: orange; }
  .tag    { background-color: #eee; font-family: monospace;
            padding: 2px; font-size: 80%; font-weight: normal; }
  .timestamp { color: #bebebe; }
  .timestamp-kwd { color: #5f9ea0; }
  .org-right  { margin-left: auto; margin-right: 0px;  text-align: right; }
  .org-left   { margin-left: 0px;  margin-right: auto; text-align: left; }
  .org-center { margin-left: auto; margin-right: auto; text-align: center; }
  .underline { text-decoration: underline; }
  #postamble p, #preamble p { font-size: 90%; margin: .2em; }
  p.verse { margin-left: 3%; }
  pre {
    border: 1px solid #e6e6e6;
    border-radius: 3px;
    background-color: #f2f2f2;
    padding: 8pt;
    font-family: monospace;
    overflow: auto;
    margin: 1.2em;
  }
  pre.src {
    position: relative;
    overflow: auto;
  }
  pre.src:before {
    display: none;
    position: absolute;
    top: -8px;
    right: 12px;
    padding: 3px;
    color: #555;
    background-color: #f2f2f299;
  }
  pre.src:hover:before { display: inline; margin-top: 14px;}
  /* Language selection start. */
  pre.src-asm:before { content: 'Assembler'; }
  pre.src-asymptote:before { content: 'Asymptote'; }
  pre.src-awk:before { content: 'Awk'; }
  pre.src-C:before { content: 'C'; }
  /* pre.src-C++ doesn't work in CSS */
  pre.src-calc:before { content: 'Emacs Calc'; }
  pre.src-clojure:before { content: 'Clojure'; }
  pre.src-conf:before { content: 'Configuration File'; }
  pre.src-cpp:before  { content: 'C++'; }
  pre.src-css:before { content: 'CSS'; }
  pre.src-D:before { content: 'D'; }
  pre.src-delphi:before { content: 'Delphi'; }
  pre.src-ditaa:before { content: 'ditaa'; }
  pre.src-dot:before { content: 'Graphviz'; }
  pre.src-emacs-lisp:before { content: 'Emacs Lisp'; }
  pre.src-fortran:before { content: 'Fortran'; }
  pre.src-gnuplot:before { content: 'gnuplot'; }
  pre.src-haskell:before { content: 'Haskell'; }
  pre.src-html:before { content: 'HTML'; }
  pre.src-idl:before { content: 'IDL'; }
  pre.src-J:before { content: 'J'; }
  pre.src-java:before { content: 'Java'; }
  pre.src-js:before { content: 'Javascript'; }
  pre.src-latex:before { content: 'LaTeX'; }
  pre.src-ledger:before { content: 'Ledger'; }
  pre.src-lisp:before { content: 'Lisp'; }
  pre.src-lilypond:before { content: 'Lilypond'; }
  pre.src-lua:before { content: 'Lua'; }
  pre.src-makefile:before { content: 'Makefile'; }
  pre.src-matlab:before { content: 'MATLAB'; }
  pre.src-maxima:before { content: 'Maxima'; }
  pre.src-mercury:before { content: 'Mercury'; }
  pre.src-metapost:before { content: 'MetaPost'; }
  pre.src-mhtml:before { content: 'HTML+CSS+JS'; }
  pre.src-modula-2:before { content: 'Modula-2'; }
  pre.src-nxml:before { content: 'XML'; }
  pre.src-ocaml:before { content: 'Objective Caml'; }
  pre.src-octave:before { content: 'Octave'; }
  pre.src-org:before { content: 'Org mode'; }
  pre.src-pascal:before { content: 'Pascal'; }
  pre.src-perl:before { content: 'Perl'; }
  pre.src-plain-tex:before { content: 'Plain TeX'; }
  pre.src-plantuml:before { content: 'Plantuml'; }
  pre.src-processing:before { content: 'Processing.js'; }
  pre.src-prolog:before { content: 'Prolog'; }
  pre.src-ps:before { content: 'PostScript'; }
  pre.src-python:before { content: 'Python'; }
  pre.src-R:before { content: 'R'; }
  pre.src-ruby:before { content: 'Ruby'; }
  pre.src-sass:before { content: 'Sass'; }
  pre.src-scala:before { content: 'Scala'; }
  pre.src-scheme:before { content: 'Scheme'; }
  pre.src-screen:before { content: 'Gnu Screen'; }
  pre.src-sed:before { content: 'Sed'; }
  pre.src-sh:before { content: 'shell'; }
  pre.src-simula:before { content: 'Simula'; }
  pre.src-sql:before { content: 'SQL'; }
  pre.src-sqlite:before { content: 'SQLite'; }
  pre.src-tcl:before { content: 'tcl'; }
  pre.src-tex:before { content: 'TeX'; }
  pre.src-verilog:before { content: 'Verilog'; }
  pre.src-vhdl:before { content: 'VHDL'; }
  pre.src-xml:before { content: 'XML'; }
  /* ob-shell and sub-shells. */
  pre.src-shell:before { content: 'Shell Script'; }
  pre.src-bash:before  { content: 'bash'; }
  pre.src-csh:before  { content: 'csh'; }
  pre.src-ash:before  { content: 'ash'; }
  pre.src-dash:before  { content: 'dash'; }
  pre.src-ksh:before  { content: 'ksh'; }
  pre.src-mksh:before  { content: 'mksh'; }
  pre.src-posh:before  { content: 'posh'; }
  pre.src-zsh:before  { content: 'zsh'; }
  /* Language selection end. */

  table { border-collapse:collapse; }
  caption.t-above { caption-side: top; }
  caption.t-bottom { caption-side: bottom; }
  td, th { vertical-align:top;  }
  th.org-right  { text-align: center;  }
  th.org-left   { text-align: center;   }
  th.org-center { text-align: center; }
  td.org-right  { text-align: right;  }
  td.org-left   { text-align: left;   }
  td.org-center { text-align: center; }
  dt { font-weight: bold; }
  .footpara { display: inline; }
  .footdef  { margin-bottom: 1em; }
  .figure { padding: 1em; }
  .figure p { text-align: center; }
  .equation-container {
    display: table;
    text-align: center;
    width: 100%;
  }
  .equation {
    vertical-align: middle;
  }
  .equation-label {
    display: table-cell;
    text-align: right;
    vertical-align: middle;
  }
  .inlinetask {
    padding: 10px;
    border: 2px solid gray;
    margin: 10px;
    background: #ffffcc;
  }
  #org-div-home-and-up
   { text-align: right; font-size: 70%; white-space: nowrap; }
  textarea { overflow-x: auto; }
  .linenr { font-size: smaller }
  .code-highlighted { background-color: #ffff00; }
  .org-info-js_info-navigation { border-style: none; }
  #org-info-js_console-label
    { font-size: 10px; font-weight: bold; white-space: nowrap; }
  .org-info-js_search-highlight
    { background-color: #ffff00; color: #000000; font-weight: bold; }
  .org-svg { }
</style>"
)

Buffer properties

(with-eval-after-load 'org
  (defun org-get-buffer-properties ()
    "Get all properties in buffer."
    (org-element-map (org-element-parse-buffer) 'keyword
      (lambda (el)
        (and ;; Use (upcase "property"), else it fails.
         (string= (org-element-property :key el) "PROPERTY")
         (let* ((strings (split-string (org-element-property :value el)))
                (value (string-join (cdr strings) " "))
                (name (car strings)))
           (cons name value)))))))

Column View (info) and Property Syntax (info)

Listing column view demonstration tangles to column-view-demonstration.org which complements the Org view tutorial and the Org view screencast. Listing property syntax demonstration tangles to property-syntax-demonstration.org which complements property syntax (info).

,#+TITLE: Column View Demonstration
,* Column view use
1. Type "M-x org-columns" in the "Columns view top" tree to turn on column view.
2. Press "tab" to (un-)fold the "Example 1", "Example 2", and "Example 3" rows.
3. Move point to the "OK?" cell of the "Example 1" row and type "e" to edit it.
   - This changes the "Columns view top" row "OK?" field value.
4. Move point to the "DURATION" cell and type "e"" to edit it.
   - This changes the "Columns view top" row "DURATION" field value.
5. Type "q" on one of the column view rows to turn off column view.
,* Column view top
SCHEDULED: <2023-06-30 Fri>
:PROPERTIES:
:COLUMNS:  %17ITEM %OK(OK?){X} %OWNER %STATUS %DURATION{:} %TODO %16SCHEDULED
:OWNER_ALL: Ada Bob Carl
:STATUS_ALL: "Shopping" "Cooking" "Eating"
:OK_ALL: "[ ]" "[X]"
:END:
,** DONE Example 1
:PROPERTIES:
:OWNER:    Ada
:STATUS:   Shopping
:DURATION: 1:00
:OK:       [X]
:END:
,** DONE Example 2
:PROPERTIES:
:OWNER:    Bob
:STATUS:   Cooking
:DURATION: 1:00
:OK:       [X]
:END:
,** TODO Example 3
:PROPERTIES:
:OWNER:    Carl
:STATUS:   Eating
:DURATION: 0:00
:OK:       [ ]
:END:

,#+TITLE: Property Syntax Demonstration
,* Column view use
1. Type "M-x org-columns" in the "CD collection" tree to turn on column view.
   - The column view appends the value of ":GENRES+:" to that of ":GENRES:".
2. Type "q" on one of the column view rows to turn off column view.
,* Dynamic block use
1. Type "M-x org-insert-columns-dblock" to capture a column view table.
   - Type headline title of the tree to capture
   - The block appends the value of ":GENRES+:" to that of ":GENRES:".
,* CD collection
:PROPERTIES:
:NDISK_ALL: 1 2 3 4
:PUBLISHER_ALL: "Deutsche Grammophon" Philips EMI
:COLUMNS:  %TITLE %ARTIST %GENRES %NDISK(N) %PUBLISHER
:ID:       CD collection
:END:
,** Classic
:PROPERTIES:
:GENRES:   Classic
:END:
,*** Goldberg Variations
:PROPERTIES:
:TITLE:    Goldberg Variations
:COMPOSER: J.S. Bach
:ARTIST:   G. Gould
:GENRES+:  Baroque
:NDISK: 1
:PUBLISHER: Deutsche Grammophon
:END:
,#+NAME: CD collection
,#+BEGIN: columnview :hlines 1 :id "CD collection"
| TITLE               | ARTIST   | GENRES          | N | PUBLISHER           |
|---------------------+----------+-----------------+---+---------------------|
|                     |          |                 |   |                     |
|                     |          | Classic         |   |                     |
| Goldberg Variations | G. Gould | Classic Baroque | 1 | Deutsche Grammophon |
,#+END:

Org introspection

1. Listing lst:valid-org-babel-load-languages-entries extracts an association list of library names and org-babel-execute:LANGUAGE function names.
2. Listing lst:org-babel-active-languages produces a list containing language names that have org-babel-execute:LANGUAGE functions.
3. Listing lst:get-in-buffer-settings and lst:get-in-buffer-settings-result show how to access In-buffer Settings (info).

;; "Search failed:" with paren mismatching problems start here,
;; but the problems are not due to this source block.
(defun all-org-babel-execute-fns ()
  "Find `ob-LANGUAGE' files in Org defining `org-babel-execute:LANGUAGE'.

Return a list of items where the filename is the `car' of each item and the
`cdr' of each item lists the `org-babel-execute:LANGUAGE' functions."
  (let* ((dir (file-name-parent-directory (locate-library "org")))
         (names (directory-files dir t (rx "ob-" (+ print) ".el" eos))))
    (cl-loop for name in names
             for found = (has-org-babel-execute-fn name)
             when found collect found)))

(defun has-org-babel-execute-fn (name)
  (let* ((buffer (find-file-noselect name))
         (base (file-name-base (buffer-file-name buffer)))
         (regexp (rx "defun" (+ blank) "org-babel-execute:" (group (+ graphic))))
         (matches))
    (save-match-data
      (save-excursion
        (with-current-buffer buffer
          (save-restriction
            (widen)
            (goto-char 1)
            (while (re-search-forward regexp nil t 1)
              (push (match-string-no-properties 1) matches))))))
    (when matches
      `(,base ,@matches))))

(all-org-babel-execute-fns)

#+caption[Org Babel libraries with org-babel-execute:language functions]:

(("ob-C" "C" "D" "C++" "cpp") ("ob-R" "R") ("ob-awk" "awk")
 ("ob-calc" "calc") ("ob-clojure" "clojurescript" "clojure")
 ("ob-css" "css") ("ob-ditaa" "ditaa") ("ob-dot" "dot")
 ("ob-emacs-lisp" "emacs-lisp") ("ob-eshell" "eshell")
 ("ob-forth" "forth") ("ob-fortran" "fortran")
 ("ob-gnuplot" "gnuplot") ("ob-groovy" "groovy")
 ("ob-haskell" "haskell") ("ob-java" "java") ("ob-js" "js")
 ("ob-julia" "julia") ("ob-latex" "latex") ("ob-lilypond" "lilypond")
 ("ob-lisp" "lisp") ("ob-lua" "lua") ("ob-makefile" "makefile")
 ("ob-maxima" "maxima") ("ob-ocaml" "ocaml")
 ("ob-octave" "octave" "matlab") ("ob-org" "org") ("ob-perl" "perl")
 ("ob-plantuml" "plantuml") ("ob-processing" "processing")
 ("ob-python" "python") ("ob-ruby" "ruby") ("ob-sass" "sass")
 ("ob-scheme" "scheme") ("ob-screen" "screen") ("ob-sed" "sed")
 ("ob-shell" "shell") ("ob-sql" "sql") ("ob-sqlite" "sqlite"))

Org Babel libraries with org-babel-execute:language functions.

(defun org-babel-active-languages ()
  (let (result)
    (mapatoms
     (lambda (x)
       (when (and
              (string-prefix-p "org-babel-execute:" (symbol-name x))
              ;; Get rid of all sub-modes in `ob-shell':
              (not (eq 'org-babel-shell-initialize (get x 'definition-name)))
              ;; Get rid of aliases:
              (not (eq 'symbol (type-of (symbol-function x)))))
         (when (symbol-file x)
           (push (string-remove-prefix "org-babel-execute:" (symbol-name x))
                 result)))))
    result))

(mapcar #'list (cl-sort (org-babel-active-languages) #'string-lessp))

(("calc") ("conf") ("emacs-lisp") ("eshell") ("fortran") ("julia")
 ("latex") ("latex-extra-header") ("latex-header") ("lisp") ("org")
 ("perl") ("python") ("ruby") ("shell") ("text") ("toml"))

Active Org Babel languages.

(org-collect-keywords '("title" "author" "latex_class"))

(("TITLE" "Emacs setup for use with LaTeX, Lisp, Org, and Python")
 ("AUTHOR" "Gerard Vermeulen") ("LATEX_CLASS" "article"))

Citar: citing bibliography with Org Mode

Citar is a completing-read front-end to browse and act on BibTeX, BibLaTeX, as well as CSL JSON bibliographic data with LaTeX, markdown, and org-cite editing support. In combination with vertico, embark, marginalia, and consult, Citar provides quick filtering and selecting of bibliographic entries from the minibuffer as well as the option to run different commands on those selections. The article Citations in org-mode: Org-cite and Citar tries to walk you from understanding the general context (bibliography producer, text processor, text to product converter) to an Emacs setup. Listing lst:set-oc+citar-options shows the oc and citar setup with binding of

(eval

to src_emacs-lisp{(call-interactively 'org-cite-insert)} in org-mode-map.

(when (ensure-package-installation 'citar 'citar-embark)
  (with-eval-after-load 'embark
    (when (fboundp 'citar-embark-mode)
      (citar-embark-mode +1)))

  (with-eval-after-load 'oc
    (setopt org-cite-export-processors '((latex biblatex)
                                         (t csl))
            org-cite-global-bibliography '("~/VCS/research/refs.bib"))
    (if (not (require 'citar nil 'noerror))
        (user-error "Fails to require `citar' and to setup `citar' and `oc'")
      ;; Synchronize the two involved bibliographies.
      (setopt citar-bibliography org-cite-global-bibliography
              citar-library-file-extensions '("djvu" "pdf")
              ;; Here are the `.djvu' and `.pdf' files.
              citar-library-paths '("~/VCS/research/papers/"))
      (setopt org-cite-activate-processor 'citar
              org-cite-follow-processor 'citar
              org-cite-insert-processor 'citar)
      (with-eval-after-load 'org
        (keymap-set org-mode-map "C-c b" #'org-cite-insert)))))

Ref. [cite:@Schulte.MCSE.2011.41] shows that Org-mode is a simple, plain-text markup language for hierarchical documents allowing intermingling of data, code, and prose. It serves as an example link to show how to use Citar within this setup, provided that citar-bibliography and citar-library-paths point to valid directories and files. In an Org-mode buffer this setup allows to:

1. Insert one or more Org-mode cite links:

   1. Type .

   2. Choose one or multiple citations from the bibliography:

      1. by navigating to an item and selecting it with

         (eval

      2. by repeatingly navigating to an item and preselecting it with .

2. View an electronic copy of an Org-mode cite link:

   1. Move point to the Org-mode cite link.
   2. Type .
   3. Navigate to the corresponding library file.
   4. Select it.

3. Open the DOI of an Org-mode cite link:

   1. Move point to the Org-mode cite link.
   2. Type .
   3. Navigate to the corresponding link.
   4. Select it.

4. The following citar functions may be useful too:

   1. src_emacs-lisp{(call-interactively 'citar-insert-citation)}.
   2. src_emacs-lisp[:results silent]{(call-interactively 'citar-open)}.

TODO Compare bibtex and biblatex

1. Using bibtex: a short guide
2. The biblatex package
3. Rebiber: A tool for normalizing bibtex with official info
4. A biblatex implementation of the AIP and APS bibliography style

(with-eval-after-load 'emacs
  ;; https://tex.stackexchange.com/a/579356 answers
  ;; "How to solve Biber exiting with error code 2 but no error messages?"
  (defun biber-delete-cache ()
    "Delete the `Biber' cache to get rid of `Biber' exit code 2."
    (interactive)
    (cl-destructuring-bind (exit-code output)
        (shell-command-with-exit-code "rm" "-rf" "$(biber --cache)")
      (if (= 0 exit-code)
          (message "%s" (string-trim output))
        (error "%s" (string-trim output))))))

Engrave Faces

This package has a front-end that processes fontified buffers and pipes its output into one of three back-ends for export to LaTeX, HTML and text with ANSI escape codes. It is an alternative to minted in case of LaTeX export or to htmlized in case of HTML export.

The listings below work around one issue with spacing in the pdf output resulting from use of the engraved source block back-end during LaTeX export. They increase the quality of the export results of this README.org and the user-friendliness of this facility to a level acceptable for my workflow:

1. The default Org export configuration for engraving listings produces pdf output with a non-equidistant interline spacing in floating listings (those with captions) and equidistant interline spacing in non-floating tcolorbox environments (those without captions). I have traced the non-equidistant interline spacing back to the breakable option of Code environments inside listing environments. However, tcolorbox requires breakable for listings that do not fit on a page. The filter org-latex-engraved-source-block-filter in listing lst:org-latex-engraved-source-block-filter and the org-latex-engraved-preamble customization in listing lst:smart-latex-engrave-org-source-blocks allow to engrave org-mode source blocks to "floating unbreakable with caption" or "non-floating breakable without caption" LaTeX environments. This is a partial work-around, but part of my workflow.
2. Listing lst:ox-engraved-emacs-lisp-setup shows how to use this configuration.

(ensure-package-installation 'engrave-faces)

(defun org-latex-engraved-source-block-filter (data _backend _info)
  "Replace \"Code\" with \"Breakable\" in non-floating DATA environments.

Set `org-latex-engraved-preamble' to define a Breakable (non-floating)
environment and an unbreakable Code (floating) environment."
  (unless (string-match "^\\\\DeclareTColorBox\\[\\]{Breakable}"
                        org-latex-engraved-preamble)
    (user-error
     "`org-latex-engraved-preamble' defines no `Breakable' environment"))
  (when (eq org-latex-src-block-backend 'engraved)
    ;; Transform only blocks matching at position 0.  Therefore, do
    ;; not transform blocks that are listing environments.
    (when (string-match "\\`\\\\begin{Code}\n" data)
      (setq data (replace-match "\\begin{Breakable}\n" t 'literal data))
      (if (string-match "^\\\\end{Code}\n" data)
          (setq data (replace-match "\\end{Breakable}\n" t 'literal data))
        (error "Match `^\\\\end{Code}' failure")))))

(defun smart-latex-engrave-org-source-blocks ()
  "Enable smart LaTeX engraving of `org-src-mode' blocks.

Sets backend and preamble locally to support floating unbreakable LaTeX
environments and non-floating breakable LaTeX environments by means of
`org-latex-engraved-source-block-filter'."
  (interactive)
  (when (require 'ox-latex nil 'noerror)
    (setq-local org-latex-src-block-backend 'engraved
                org-latex-engraved-preamble "\\usepackage{fvextra}
[FVEXTRA-SETUP]

% Make code and line numbers normalsize. Make line numbers grey.
\\renewcommand\\theFancyVerbLine{
  \\normalsize\\color{black!40!white}\\arabic{FancyVerbLine}}
% Do not rely on an eventual call to `engrave-faces-latex-gen-preamble'.
\\usepackage{xcolor}
\\providecolor{EfD}{HTML}{f7f7f7}
\\providecolor{EFD}{HTML}{28292e}
% To use \\DeclareTColorBox from the tcolorbox package:
\\usepackage[breakable,xparse]{tcolorbox}
% Define a Breakable environment to fontify code outside floats.
\\DeclareTColorBox[]{Breakable}{o}{
  colback=EfD, colframe=EFD, colupper=EFD,
  fontupper=\\normalsize\\setlength{\\fboxsep}{0pt},
  IfNoValueTF={#1}{
    boxsep=1pt, arc=1pt, outer arc=1pt, boxrule=0.5pt,
  }{
    boxsep=1pt, arc=0pt, outer arc=0pt, boxrule=0pt, leftrule=1pt
  },
  left=2pt, right=2pt, top=1pt, bottom=1pt, breakable
}
% Define an unbreakable Code environment to fontify code inside floats.
\\DeclareTColorBox[]{Code}{o}{
  colback=EfD, colframe=EFD, colupper=EFD,
  fontupper=\\normalsize\\setlength{\\fboxsep}{0pt},
  IfNoValueTF={#1}{
    boxsep=1pt, arc=1pt, outer arc=1pt, boxrule=0.5pt
  }{
    boxsep=1pt, arc=0pt, outer arc=0pt, boxrule=0pt, leftrule=1pt
  },
  left=2pt, right=2pt, top=1pt, bottom=1pt
}

[LISTINGS-SETUP]")))

(with-eval-after-load 'ox-latex
  (make-local-variable 'org-export-filter-src-block-functions)
  (add-to-list 'org-export-filter-src-block-functions
               'org-latex-engraved-source-block-filter)
  (when (fboundp 'smart-latex-engrave-org-source-blocks)
    (smart-latex-engrave-org-source-blocks)))

Making Org hyperlink types (info)

The listings below implement or reimplement three groups of org-link types:

1. Listing lst:org-ref-like-org-link-types defines org-link types for backwards compatibility with org-ref.
2. Listing lst:define-org-pdfview-link-type uses ideas from the definition of docview-org-link and doi-org-link types to define an pdfview-org-link type for use with pdf-tools.
3. Listing lst:patch-org-info-link-type patches the function org-info-export and listing lst:emacs-lisp-setup-buffer-local-ol-info sets the constants org-info-emacs-documents and org-info-other-documents as buffer local variables in order to export the info-org-link types in this document to html and LaTeX correctly.

(with-eval-after-load 'ol
  (org-link-set-parameters "ac*" :export #'org-ref-ac*-export)
  (org-link-set-parameters "cite" :export #'org-ref-cite-export)
  (org-link-set-parameters "eqref" :export #'org-ref-eqref-export)
  (org-link-set-parameters "hyperlink" :export #'org-ref-hyperlink-export)
  (org-link-set-parameters "label" :export #'org-ref-label-export)
  (org-link-set-parameters "ref" :export #'org-ref-ref-export)

  (defun org-ref-ac*-export (path _desc backend _info)
    (pcase backend
      (`latex (format "\\gls*{%s}" path))
      (_ path)))

  (defun org-ref-cite-export (path _desc backend _info)
    (pcase backend
      (`latex (format "\\cite{%s}" path))
      (_ path)))

  (defun org-ref-eqref-export (path _desc backend _info)
    (pcase backend
      (`latex (format "\\eqref{%s}" path))
      (_ path)))

  (defun org-ref-hyperlink-export (path desc backend _info)
    (pcase backend
      (`latex (format "\\hyperlink{%s}{%s}" path desc))
      (_ path)))

  (defun org-ref-label-export (path _desc backend _info)
    (pcase backend
      (`latex (format "\\label{%s}" path))
      (_ path)))

  (defun org-ref-ref-export (path _desc backend _info)
    (pcase backend
      (`latex (format "\\ref{%s}" path))
      (_ path))))

(declare-function pdf-view-current-page "pdf-macs" (&optional window))
(declare-function pdf-view-goto-page "pdf-view" (page &optional window))

(defun org-pdfview-export (link description backend _)
  "Export LINK as a \"pdfview\" type link using DESCRIPTION and export BACKEND.
The paths of the links export as file relative paths in order to
facilate moving single directories or whole directory trees."
  (let ((path (if (string-match "\\(.+\\)::.+" link)
                  (match-string 1 link)
                link))
        (desc (or description link)))
    (when (stringp path)
      (setq path (file-relative-name path))
      (pcase backend
        (`html (format "<a href=\"%s\">%s</a>" path desc))
        (`latex (format "\\href{%s}{%s}" path desc))
        (`ascii (format "%s (%s)" desc path))
        (_ path)))))

(defun org-pdfview-open (link _)
  "Open LINK as a \"pdfview\" type link."
  (string-match "\\(.*?\\)\\(?:::\\([0-9]+\\)\\)?$" link)
  (let ((path (match-string 1 link))
        (page (and (match-beginning 2)
                   (string-to-number (match-string 2 link)))))
    ;; Let Org mode open the file to respect org-link-frame-setup.
    (org-open-file path 1)
    (when page (pdf-view-goto-page page))))

(defun org-pdfview-store-link ()
  "Store a \"pdfview\" type link."
  (when (eq major-mode 'pdf-view-mode)
    (let* ((path buffer-file-name)
           (page (pdf-view-current-page))
           (link (concat "pdfview:" path "::" (number-to-string page))))
      (org-link-store-props
       :type "pdfview"
       :link link
       :description path))))

(with-eval-after-load 'ol
  (org-link-set-parameters "pdfview"
                           :follow #'org-pdfview-open
                           :export #'org-pdfview-export
                           :store #'org-pdfview-store-link))

(declare-function org-info-map-html-url "ol-info" (filename))
(declare-function org-info--expand-node-name "ol-info" (node))

(with-eval-after-load 'ol-info
  (defun org-info-export (path desc format)
    "Export an info link.
See `org-link-parameters' for details about PATH, DESC and FORMAT."
    (let* ((parts (split-string path "#\\|::"))
           (manual (car parts))
           (node (or (nth 1 parts) "Top")))
      (pcase format
        (`html
         (format "<a href=\"%s#%s\">%s</a>"
                 (org-info-map-html-url manual)
                 (org-info--expand-node-name node)
                 (or desc path)))
        (`latex
         (format "\\href{%s\\#%s}{%s}"
                 (org-info-map-html-url manual)
                 (org-info--expand-node-name node)
                 (or desc path)))
        (`texinfo
         (let ((title (or desc "")))
           (format "@ref{%s,%s,,%s,}" node title manual)))
        (_ nil)))))

(with-eval-after-load 'ol-info
  (make-variable-buffer-local 'org-info-emacs-documents)
  (setq org-info-emacs-documents (delete "org" org-info-emacs-documents))
  (make-variable-buffer-local 'org-info-other-documents)
  (setq org-info-other-documents
        (cl-union
         '(("consult" . "https://github.com/minad/consult")
           ("embark" . "https://github.com/oantolin/embark")
           ("magit" . "https://magit.vc/manual/magit.html")
           ("marginalia" . "https://github.com/minad/marginalia")
           ("org" . "https://orgmode.org/org.html")
           ("orderless" . "https://github.com/oantolin/orderless")
           ("sly" . "https://joaotavora.github.io/sly/")
           ("vertico" . "https://github.com/minad/vertico"))
         org-info-other-documents :test #'equal)))

Extending org-mode to handle YouTube links

Listing define org-yt-link type implements code to open the link to the following YouTube video Extending org-mode to handle YouTube links and the following Emacs setup.

Opening Extending org-mode to handle YouTube links may fail due to a bug in the interface between mpv and yt-dlp. Listing set EMMS options indicates how to work around this bug at the cost of making the user interface less clean. However, the link Absolute Beginner's Guide to Emacs works always.

The following posts provide programming information:

1. YouTube API reference.
2. YouTube Player API reference for iframe embeds.

;; https://bitspook.in/blog/extending-org-mode-to-handle-youtube-paths/
(declare-function emms-add-url "emms-source-file" (url))
(declare-function emms-playlist-last "emms" ())
(declare-function emms-playlist-mode-play-current-track "emms-playlist-mode" ())
(declare-function with-current-emms-playlist "emms" (&rest body))

(defun org-yt-emms-open (path)
  "Open an \"YouTube\" PATH link with `emms' using \"mpv\"."
  (let ((url (format "https://www.youtube.com/watch?v=%s" path)))
    (require 'emms nil 'noerror)
    (emms-add-url url)
    (with-current-emms-playlist
      (save-excursion
        (emms-playlist-last)
        (emms-playlist-mode-play-current-track)))))

(defun org-yt-url-browse-open (path)
  "Open an \"YouTube\" PATH link with `url-browse'."
  (let ((url (format "https://www.youtube.com/watch?v=%s" path)))
    (browse-url url)))

(defun org-yt-export (path desc backend _)
  "Export an \"YouTube\" PATH link according to DESC and BACKEND."
  (pcase backend
    (`ascii
     (format "[%s] <https://www.youtube.com/watch?v=%s>" desc path))
    (`html
     (format "<iframe
  frameborder=\"0\" width=\"600\" height=\"450\"
  src=\"https://www.youtube.com/embed/%s\"
  title=\"%s\"
  allowfullscreen></iframe>" path desc))
    (`latex
     (format "\\href{https://www.youtube.com/watch?v=%s}{%s}" path desc))
    (_ path)))

(with-eval-after-load 'ol
  (org-link-set-parameters
   "yt" :follow #'org-yt-emms-open :export #'org-yt-export))

Translate capital keywords (old) to lower case (new)

(with-eval-after-load 'emacs
  ;; https://tecosaur.github.io/emacs-config/#translate-capital-keywords
  (defun org-syntax-convert-keyword-case-to-lower ()
    "Convert all #+KEYWORDS to #+keywords."
    (interactive)
    (when (derived-mode-p 'org-mode)
      (save-excursion
        (goto-char (point-min))
        (let ((count 0)
              (case-fold-search nil))
          (while (re-search-forward "^[ \t]*#\\+[A-Z_]+" nil t)
            (unless (s-matches-p "RESULTS" (match-string 0))
              (replace-match (downcase (match-string 0)) t)
              (setq count (1+ count))))
          (message "Replaced %d keywords" count))))))

Evaluate specific source blocks at load-time

How to do load time source block evaluation

(with-eval-after-load 'emacs
  (defun org-eval-named-blocks-with-infix (infix)
    "Evaluate all source blocks having INFIX in their name."
    (when (eq major-mode 'org-mode)
      (let ((blocks
             (org-element-map
                 (org-element-parse-buffer 'greater-element nil) 'src-block
               (lambda (block)
                 (when-let ((name (org-element-property :name block)))
                   (when (string-match-p infix name) block))))))
        (dolist (block blocks)
          (goto-char (org-element-property :begin block))
          (org-babel-execute-src-block)))))

  (defun org-eval-emacs-lisp-setup-blocks ()
    "Evaluate all source blocks having \"emacs-lisp-setup\" in their name."
    (interactive)
    (org-eval-named-blocks-with-infix "emacs-lisp-setup"))

  (defun org-eval-python-setup-blocks ()
    "Evaluate all source blocks having \"python-setup\" in their name."
    (interactive)
    (org-eval-named-blocks-with-infix "python-setup"))

  ;; Emacs looks for "Local variables:" after the last "newline-formfeed".
  (add-to-list 'safe-local-eval-forms '(org-eval-emacs-lisp-setup-blocks))
  (add-to-list 'safe-local-eval-forms '(org-eval-python-setup-blocks)))

Org-mode macro utilities

Listing lst:by-backend-kbd-org-macro defines the Emacs Lisp utilities to define the Org mode kbd macro in listing lst:source-file-export-keyword-settings.

(with-eval-after-load 'emacs
  (when (ensure-package-installation 'htmlize)
    (autoload 'htmlize-protect-string "htmlize" nil t))

  ;; https://orgmode.org/worg/org-contrib/babel/languages/ob-doc-LaTeX.html
  (defmacro by-backend (&rest body)
    "Help for org-export backend dependent execution."
    `(cl-case ',(bound-and-true-p org-export-current-backend) ,@body))

  (defun by-backend-kbd-org-macro (keys)
    "Help for an org-export backend dependent \"#+macro: kbd\"."
    (by-backend
     (ascii (format "`kbd(%s)'" keys))
     (html (format "@@html:<kbd>%s</kbd>@@" (htmlize-protect-string keys)))
     (latex (format "@@latex:\\colorbox{PowderBlue}{\\texttt{%s}}@@" keys)))))

Testing Org

Listing lst:batch-org-testing shows the recommended way: use make test in a clean Org git repository. Listing lst:setup-org-mode-test-1 and lst:setup-org-mode-test-2 provide facilities for Testing Org interactively.

make test > out.txt 2>&1

(with-eval-after-load 'emacs
  (defvar org-testing-dir nil)
  (defvar org-testing-lisp-files nil)

  (defun setup-org-mode-test ()
    "Initialize an `org-mode' test."
    (interactive)
    (unless (and org-testing-dir org-testing-lisp-files)
      (find-library "org.el")
      (quit-window)
      (setq org-testing-dir
            (file-name-concat
             (file-name-directory
              (directory-file-name
               (file-name-directory
                (buffer-file-name (get-buffer "org.el")))))
             (file-name-as-directory "testing")))
      (setq org-testing-lisp-files
            (seq-filter
             (lambda (f)
               (string-suffix-p ".el" f))
             (directory-files
              (file-name-concat org-testing-dir
                                (file-name-as-directory "lisp"))))))
    (unless (fboundp 'org-test-with-temp-text)
      (find-file (file-name-concat org-testing-dir "org-test.el"))
      (eval-buffer)
      (quit-window))
    (let* ((test
            (completing-read "Org-mode test: "
                             org-testing-lisp-files nil 'require-match)))
      (find-file (file-name-concat
                  org-testing-dir (file-name-as-directory "lisp") test))
      (eval-buffer)
      (message "Evaluated '%s'"
               (file-name-nondirectory (buffer-file-name (get-buffer test))))
      (quit-window))))

(with-eval-after-load 'emacs
  ;; Stolen from `org-test-run-all-tests'.
  (defun org-test-run-some-tests ()
    "Run some defined tests.
Load all test files first."
    (interactive)
    (org-test-touch-all-examples)
    (org-test-update-id-locations)
    (org-test-load)
    (let (;; Catch errors in diary sexps better.
          (calendar-debug-sexp t))
      ;; test-org-element/normalize-contents fails (can't fix).
      ;; test-ob-exp/noweb-on-export fails due to spacing (can't fix).
      ;; test-ob-exp/noweb-on-export-with-exports-results due to spacing (idem).
      ;; ob-python hangs sometimes, but seldom.
      ;; ob-tangle/continued-code-blocks-w-noweb-ref fails.
      (ert (rx (or "org/" "org-fold" "org-element" "org-macro" "org-src"
                   "property-inheritance"
                   "ob/" "ob-emacs-lisp" "ob-eshell"
                   "ob-python" "ob-tangle")))
      (org-test-kill-all-examples)))

  (defun org-test-run-ob-tests ()
    "Run all \"ob\" tests.
Load all test files first."
    (interactive)
    (org-test-load)
    (let (;; Catch errors in diary sexps better.
          (calendar-debug-sexp t))
      (ert "ob/")))

  (defun org-test-run-a-test-file ()
    "Run all tests in an Org test file (trailing `/' matters).
Examples: `ob/' or `ob-python'."
    (interactive)
    (let ((text (read-string "Org test file (without leading test-): "
                             nil nil "ob-python")))
      (org-test-load)
      (let (;; Catch errors in diary sexps better.
            (calendar-debug-sexp t))
        (ert text)))))

LaTex preamble editing using Noweb (info)

Note: How to include LaTeX packages in a LaTeX export block.

Listing lst:source-file-export-keyword-settings shows the preamble lines of this /gav451/emacs.d/src/commit/2a23e9b796886a02b7d679107ebbd3ce364921a3/README.org file. It lists the export keyword settings, the definition of the Org mode kbd macro and the source block that generates part of the LaTeX preamble. Listing lst:latex-header-1, lst:latex-header-2, lst:latex-header-3, lst:latex-header-4, and lst:latex-header-5 show the LaTeX source blocks that contain the LaTeX preamble. All LaTeX listings in this section can be and are handled by noweb (info).

<<latex-header-1>>

<<latex-header-2>>

<<latex-header-3>>

<<latex-header-4>>

<<latex-header-5>>

Deprecated LaTeX preamble editing methods

NOTE: This Org (info) file uses the recommended method of noweb trickery in Section #sec:file-inclusion-and-noweb.

There are at least two deprecated (old and historic) ways to edit the Org #+latex_header: and #+latex_extra_header: keywords easily for export to LaTeX, see LaTeX header and sectioning (info).

The old way – exploiting an idea of Omar Antolin Camarena – is to code new <LANGUAGE>-modes allowing to edit in LaTeX mode and to export to LaTeX code with correct LaTeX preamble export setting prefixes. Here, are links to three posts exposing his idea:

1. Export LaTeX macros to LaTeX and HTML/MathJax preambles (reddit),
2. Export JavaScript source blocks to script tags in HTML (reddit),
3. Export JavaScript source blocks to script tags in HTML (SX).

Listing lst:org-babel-latex-header-blocks implements this way by means of two new <LANGUAGE>-modes: latex-header and latex-extra-header.

The old way is to define two Org Babel languages (latex-extra-header and latex-header) as done in Listing lst:org-babel-latex-header-blocks. The historic way is to use a special export attribute as in the function org-latex-header-blocks-filter in ox-extra.el. Apparently, nobody is using this broken function (broken, since it relies on support only in org-mode before 2014-11-11). Listing lst:org-latex-header-blocks-filter proposes a fix for org-latex-header-blocks-filter. This setup keeps the deprecated ways for backwards compatibility. A practical difference is that new way source blocks (contrary to old way export blocks) do not work in #+SETUPFILE: <FILE>, but only in #+INCLUDE: <FILE> files.

(with-eval-after-load 'emacs
  (defun prefix-all-lines (prefix body)
    (with-temp-buffer
      (insert body)
      (string-insert-rectangle (point-min) (point-max) prefix)
      (buffer-string)))

  (defun org-babel-execute:latex-extra-header (body _params)
    "Execute a block of LaTeX extra header lines with org-babel.
Calling `org-babel-execute-src-block' calls this function and
prefixes all lines with \"#+latex_extra_header: \"."
    (prefix-all-lines "#+latex_extra_header: " body))

  (defun org-babel-execute:latex-header (body _params)
    "Execute a block of LaTeX header lines with org-babel.
Calling `org-babel-execute-src-block' calls this function and
prefixes all lines with \"#+latex_header: \"."
    (prefix-all-lines "#+latex_header: " body))

  (defvar org-babel-default-header-args:latex-extra-header
    '((:exports . "results") (:results . "raw")))

  (defvar org-babel-default-header-args:latex-header
    '((:exports . "results") (:results . "raw")))

  (with-eval-after-load 'org-src
    (setopt org-src-window-setup 'current-window)

    (add-to-list 'org-src-lang-modes '("latex-header" . latex))
    (add-to-list 'org-src-lang-modes '("latex-extra-header" . latex))))

(with-eval-after-load 'ox
  (defun org-latex-header-blocks-filter (backend)
    "Convert marked LaTeX export blocks to \"#+latex_header: \" lines.
The marker is a line \"#+header: :header yes\" preceding the block.

For instance, the LaTeX export block

,#+header: :header yes
,#+begin_export latex
% This line converts to a LaTeX header line.
,#+end_export

converts to

\"#+latex_header: % This line converts to a LaTeX header line.\"."
    (when (org-export-derived-backend-p backend 'latex)
      (let ((blocks
             (org-element-map
                 (org-element-parse-buffer 'greater-element nil) 'export-block
               (lambda (block)
                 (let ((type (org-element-property :type block))
                       (header (org-export-read-attribute :header block :header)))
                   (when (and (string= type "LATEX") (string= header "yes"))
                     block))))))
        (mapc (lambda (block)
                ;; Set point to where to insert LaTeX header lines
                ;; after deleting the block.
                (goto-char (org-element-property :post-affiliated block))
                (let ((lines
                       (split-string (org-element-property :value block) "\n")))
                  (delete-region (org-element-property :begin block)
                                 (org-element-property :end block))
                  (dolist (line lines)
                    (insert (concat "#+latex_header: "
                                    (replace-regexp-in-string "\\` *" "" line)
                                    "\n")))))
              ;; Reverse to go upwards to avoid wrecking the list of
              ;; block positions in the file that would occur in case
              ;; of going downwards.
              (reverse blocks)))))

  ;; Push the filter on the hook.
  (cl-pushnew #'org-latex-header-blocks-filter
              org-export-before-parsing-functions))

HTML export (info)

The code label and link feature in Literal Examples (info) does not integrate with LaTeX export.

(with-eval-after-load 'ox-html
  ;; (Info-find-node "Org" "Literal Examples")
  (setopt org-html-head-include-scripts t)
  ;; Force `org-index-capture' loading after lazy `ox-html' loading.
  (require 'org-index-capture nil 'noerror))

Advanced LaTeX export settings

Listing lst:ox-latex-emacs-lisp-setup initializes the buffer local variables org-latex-classes, org-latex-title-command, org-latex-toc-command, and org-latex-subtitle-format. Read the documentation strings to understand how those variables control exporting from Org-mode to LaTeX.

(when (require 'ox-latex nil 'noerror)
  ;; https://emacs.stackexchange.com/questions/47347/
  ;; customizing-org-latex-title-command-to-edit-title-page
  ;; https://tex.stackexchange.com/questions/506102/
  ;; adding-header-and-footer-to-custom-titlepage
  (make-local-variable 'org-latex-classes)
  (cl-pushnew '("article-local"
                "\\documentclass[11pt]{article}
[NO-DEFAULT-PACKAGES]
[PACKAGES]
[EXTRA]"
                ("\\section{%s}" . "\\section*{%s}")
                ("\\subsection{%s}" . "\\subsection*{%s}")
                ("\\subsubsection{%s}" . "\\subsubsection*{%s}")
                ("\\paragraph{%s}" . "\\paragraph*{%s}")
                ("\\subparagraph{%s}" . "\\subparagraph*{%s}"))
              org-latex-classes :key #'car :test #'equal)

  (setq-local org-latex-title-command "\\begin{titlepage}
  %% https://emacs.stackexchange.com/questions/47347/
  %% customizing-org-latex-title-command-to-edit-title-page
  %% https://tex.stackexchange.com/questions/506102/
  %% adding-header-and-footer-to-custom-titlepage
  \\thispagestyle{titlepage}
  \\begin{center}
    %% Title
    \\begin{Huge}
      {\\bf %t} \\\\
      \\vspace{1em}
    \\end{Huge}
    %% Author
    \\begin{Large}
      {\\bf %a} \\\\
      \\vspace{1em}
    \\end{Large}
  \\end{center}
\\end{titlepage}")
  (setq-local org-latex-toc-command "
\\tableofcontents\\label{toc}
\\listoflistings
\\listoftables
\\newpage
")
  (setq-local org-latex-subtitle-format ""))

Org Syntax

Two tools to grok how Org mode parsing works are the Org Syntax specification and the Org mode parser tutorial. The Org element parsing API boils down to three functions:

1. The function org-element-parse-buffer implements a fully recursive buffer parser that returns an abstract syntax tree.
2. The functions org-element-at-point and org-element-context return information on the document structure around point either at the element level or at the object level in case of org-element-context.

Listing lst:grok-org-element-tree improves the Org mode parser tutorial by defining interactive wrappers that pretty print the results of those non-interactive org-element functions to an Emacs-lisp buffer.

(with-eval-after-load 'org-element
  (when (require 'pp nil 'noerror)
    (defconst grok-org-output
      "*Grok Org Element Output*"
      "Grok Org output buffer name.")

    (defun grok-org-element-at-point ()
      "Call `org-element-at-point' interactively and pretty-print."
      (interactive)
      (pp-display-expression
       (org-element-at-point) grok-org-output))

    (defun grok-org-element-context ()
      "Call `org-element-context' interactively and pretty-print."
      (interactive)
      (pp-display-expression
       (org-element-context) grok-org-output))

    (defun grok-org-element-parse-buffer ()
      "Call `org-element-parse-buffer' interactively and pretty-print."
      (interactive)
      (let ((what (completing-read
                   "granularity: "
                   '(headline element greater-element object)
                   nil 'require-match)))
        (pp-display-expression
         (org-element-parse-buffer what) grok-org-output)))

    (defun grok-org-element-parse-whole-buffer ()
      "Like `grok-org-element-parse-buffer' from point 1 and sans granularity."
      (interactive)
      (org-with-point-at 1
        (pp-display-expression (org-element-parse-buffer) grok-org-output)))

    (defun grok-org-heading-components ()
      "Call `org-heading-components' interactively and pretty-print."
      (interactive)
      (pp-display-expression
       (org-heading-components) grok-org-output))

    (defun grok-org-element-lineage ()
      "Call `org-element-lineage' interactively and pretty-print."
      (interactive)
      (org-load-modules-maybe)
      (pp-display-expression
       (org-element-lineage (org-element-context) nil t) grok-org-output))))

Grammar, spelling, and style tools

Abbrevs (info)

Mickey Peterson has posted Correcting Typos and Misspellings with Abbrev showing how to use Keyboard Macros (info) to exploit Wikipedia's list of common misspellings for machines. Listing lst:misspellings-abbrev defines his keyboard macro under the name misspellings-abrev. I have used those directions to define src_emacs-lisp[:results silent]{(describe-variable 'global-abbrev-table)} and to store it in src_emacs-lisp[:results silent]{(describe-variable 'abbrev-file-name)} to manage its changes with git. I can change the abbreviation definitions in this file by means of:

1. Execute src_emacs-lisp[:results silent]{(edit-abbrevs)} to alter abbreviation definitions by editing an *Abbrevs* buffer.
2. Add, edit, or remove definitions of the form "source" 1 "target" under the global or a mode-specific table.
3. Execute src_emacs-lisp{(abbrev-edit-save-buffer)} to save all user abbreviation definitions in the current buffer.

(with-eval-after-load 'emacs
  (defun browse-common-misspellings ()
    "Open the Wikipedia page of common misspellings for machines in EWW."
    (interactive)
    (eww (concat "https://en.wikipedia.org/wiki/Wikipedia"
                 ":Lists_of_common_misspellings/For_machines")))

  (fset 'misspellings-abbrev
        (kmacro-lambda-form
         [?\C-s ?- ?> return backspace backspace ?\C-k ?\C-x ?a ?i ?g ?\C-y return]
         0 "%d"))

  (setq-default abbrev-mode t))

TODO DICT.org local server fails on Darwin

Evaluating src_emacs-lisp{(dictionary)} connects to a local or remote dictd server. The following links explain how to configure and use dictd:

1. Looking up words with DICT
2. RFC 2229: A Dictionary Server Protocol
3. Wordsmithing in Emacs

I am using the following Debian Bullseye dictionaries on Darwin and Gentoo:

1. dict-devil_1.0-13.1_all.deb
2. dict-foldoc_20201018-1_all.deb
3. dict-gcide_0.48.5+nmu1_all.deb
4. dict-jargon_4.4.7-3.1_all.deb
5. dict-vera_1.24-1_all.deb
6. dict-wn_3.0-36_all.deb

# https://jpmens.net/2020/03/08/looking-up-words-with-dict/
server 127.0.0.1 {
   port 2628
}
# Local Variables:
# mode: conf-unix
# End:

cat > ~/.dictd.conf <<EOF
# https://www.masteringemacs.org/article/wordsmithing-in-emacs
database devil {
   data "${HOME}/.local/share/dictd/devil.dict.dz"
   index "${HOME}/.local/share/dictd/devil.index"
}
database foldoc {
   data "${HOME}/.local/share/dictd/foldoc.dict.dz"
   index "${HOME}/.local/share/dictd/foldoc.index"
}
database gcide {
   data "${HOME}/.local/share/dictd/gcide.dict.dz"
   index "${HOME}/.local/share/dictd/gcide.index"
}
database jargon {
   data "${HOME}/.local/share/dictd/jargon.dict.dz"
   index "${HOME}/.local/share/dictd/jargon.index"
}
database vera {
   data "${HOME}/.local/share/dictd/vera.dict.dz"
   index "${HOME}/.local/share/dictd/vera.index"
}
database wn {
   data "${HOME}/.local/share/dictd/wn.dict.dz"
   index "${HOME}/.local/share/dictd/wn.index"
}
EOF

# https://jpmens.net/2020/03/08/looking-up-words-with-dict/
/usr/local/sbin/dictd \
    --config .dictd.conf \
    --verbose \
    --logfile .dictd.log \
    -d nodetach

Writegood mode

Writegood mode is a minor mode to aid in finding common writing problems. The post Matt Might's "My Ph.D. advisor rewrote himself in bash" scripts inspired this mode. Listing lst:configure-writegood-mode configures writegood mode and enables writegood-mode for text-mode buffers. Therefore, the best way use it for this buffer is by typing

(eval

to export the it to a text-mode buffer where the writegood-mode faces are more visible.

(when (and (ensure-package-installation 'writegood-mode)
           (fboundp 'writegood-mode))

  (add-hook 'after-init-hook
            (defun on-after-change-mode-hook-enable-writegood-mode ()
              (add-hook 'after-change-major-mode-hook
                        (defun enable-writegood-mode ()
                          (when (derived-mode-p '(org-mode text-mode))
                            (writegood-mode +1)))))
            'depth)

  (global-set-key (kbd "C-c g") #'writegood-mode))

Which-function-mode (info)

Listing lst:setup-which-function-mode sets which-function-mode options. The post Emacs: which-function-mode claims that which-function-mode works in org-mode. This is true in case all document headlines are simple, but is not true in case document headlines contain links. The code in listing lst:define-for-which-func-functions has stolen ideas from the following links:

• Show current org-mode headline in frame header.
• Show current org-mode headline in modeline.

(with-eval-after-load 'which-func
  (setopt which-func-modes
          '(emacs-lisp-mode org-mode pdf-view-mode)))

;; It looks like `python-mode' does nothing when it is an element of
;; `which-func-modes'.

;; (setopt which-func-modes t)

;; (setopt which-func-display 'header) ;; AFAIU, fails on my system.

;; https://emacs.stackexchange.com/questions/30894/
(declare-function pdf-info-outline "pdf-info" (&optional file-or-buffer))
(declare-function org-element-type-p "org-element-ast" (node types))
(defvar which-func-functions nil)

(defun which-func-org-function ()
  "Return level and title of the current headline.
Return the document title when point is above the first headline."
  (interactive) ;; Keep this function interactive for fixing.
  (when (eq major-mode 'org-mode)
    (let (text)
      ;; Handle point eventually above the first headline.
      (unless (org-at-heading-p)
        (save-excursion
          (org-previous-visible-heading 1)
          (let ((eap (org-element-at-point)))
            (when (org-element-type-p eap 'keyword)
              (setq text (format "0|%s" (org-element-property :value eap)))))))
      ;; Handle point anywhere else.
      (unless text
        (let* ((chain (org-get-outline-path t))
               (count (length chain)))
          (setq text (format "%s|%s" count (nth (1- count) chain)))))
      text)))
(add-to-list 'which-func-functions 'which-func-org-function)

(defun which-func-pdf-view-function ()
  "Return the title of the current headline.
Return \"Front Matter\" when current page is above the first headline."
  (interactive) ;; Keep this function interactive for fixing.
  (when (eq major-mode 'pdf-view-mode)
    (let* ((current-page (pdf-view-current-page))
           (outline (pdf-info-outline (current-buffer)))
           (hl-count (length outline))
           (hl-index 0)
           (hl-page 0)
           (old-title "Front Matter")
           (new-title old-title))
      ;; Return the first headline on a page which is better than nothing.
      ;; I can't do better, since `pdf-view-mode' has no notion of point.
      (while (and (< hl-index hl-count) (< hl-page current-page))
        (setq old-title new-title)
        (setq hl-page (alist-get 'page (nth hl-index outline)))
        (setq new-title (alist-get 'title (nth hl-index outline)))
        (cl-incf hl-index))
      (if (< current-page hl-page) old-title new-title))))
(add-to-list 'which-func-functions 'which-func-pdf-view-function)

Saving Emacs sessions (info)

Listing setup desktop makes Emacs save its state between closing its session to opening the next session.

(with-eval-after-load 'emacs
  ;; Load and configure `Org' before enabling `desktop-save-mode'.
  (desktop-save-mode t)

  (setopt desktop-buffers-not-to-save
          (rx bos (or "*Apropos" "compilation*"))
          desktop-modes-not-to-save
          '(emacs-lisp-mode image-mode tags-table-mode)))

BUG: I fail to code a function to set the desktop-buffers-not-to-save-function option.

Programming Tools

Eglot (info)

Emacs polyGLOT (Eglot) is an Emacs language-server-protocol client that stays out of your way. Eglot (info) is a builtin since Emacs-29.1. The following listings contribute to a programming language mode independent Eglot configuration:

1. Listing minimal Eglot setup adds key bindings to eglot-mode-keymap.
2. Listing lst:setup-eglot-jl adds Julia support to Eglot (info).
3. Listing lst:cli-eglot-jl-setup shows how to setup eglot-jl from the command line.
4. Listing lst:setup-oglot uses oglot to enable using Eglot in org-src-mode Julia and Python buffers.
5. Listing lst:eglot-maybe-ensure starts Eglot in case of proper programming modes and proper directory local variables (meaning in presence of a proper file .dir-locals.el in the root directory of any project using proper programming modes).
6. Listing lst:whiten-black defines Emacs Lisp functions to undo (whiten) some output of Black after src_emacs-lisp[:results silent]{(org-babel-tangle)}.

(with-eval-after-load 'eglot
  (keymap-set eglot-mode-map "C-c n" 'flymake-goto-next-error)
  (keymap-set eglot-mode-map "C-c p" 'flymake-goto-prev-error)
  (keymap-set eglot-mode-map "C-c r" 'eglot-rename))

;; How to invoke `imenu-add-menubar-index' automatically?
;; Neither advising `eglot' nor hooking major modes seems to work.
(when (ensure-package-installation 'eglot-jl)
  (eglot-jl-init))

# Run this from `package-user-dir':
julia --project=eglot-jl-20240318.1159/ eglot-jl-20240318.1159/eglot-jl.jl
# The SymbolServer is ready caching dependencies when it displays:
# [ Info: Received new data from Julia Symbol Server.

(when (and (package-installed-p 'oglot)
           (require 'oglot nil 'noerror))
  (setopt oglot-maybe-ensure-modes '(julia-mode python-mode)))

(defun eglot-maybe-ensure ()
  "Call `eglot-ensure' under favorable conditions."
  (when (and (apply #'derived-mode-p '(python-mode))
             (assoc 'eglot-workspace-configuration dir-local-variables-alist))
    (eglot-ensure)))

;; The two hooks `after-change-major-mode-hook' and
;; `hack-local-variables-hook' are OK, but language mode hooks like
;; `python-mode-hook' are not.
(add-hook 'after-change-major-mode-hook #'eglot-maybe-ensure)

(with-eval-after-load 'emacs
  (defun black-python-sequence ()
    "Try to find a Blackened Python sequence to whiten."
    (interactive)
    (if (derived-mode-p 'python-mode)
        (re-search-forward "[[(][ \t]*$" nil t)
      (org-narrow-to-block)
      (re-search-forward "[[(][ \t]*$" nil t)
      (widen)))

  (defun whiten--python-sequence ()
    "Whiten a Blackened Python sequence without narrowing.
Call `widen' after an `user-error'."
    (if (not (and (looking-at-p "[ \t]*$")))
        (user-error "Call `widen': not seeing `new-line'")
      (skip-chars-backward " \t\\[\\(")
      (if (not (looking-at-p "[ \t]*[[(][ \t]*$"))
          (user-error "Call `widen': not seeing `[' or `(' before `new-line'")
        (fixup-whitespace)
        (skip-chars-forward " \\[\\(")
        (kill-line)
        (fixup-whitespace)
        (move-end-of-line 1)
        (while (and (eq ?\, (char-before)))
          (kill-line)
          (fixup-whitespace)
          (move-end-of-line 1))
        (save-excursion
          (when (memq (char-before) '(?\) ?\]))
            (goto-char (1- (point)))
            (delete-char -1))))))

  (defun whiten-python-sequence ()
    "Whiten a Blackened Python sequence.  Call `widen' after an `user-error'."
    (interactive)
    (if (derived-mode-p 'python-mode)
        (whiten--python-sequences)
      (org-narrow-to-block)
      (whiten--python-sequence)
      (widen))))

,#+title:  Sessions for ~eval-buffer~ in ~org-src~ buffers
,#+property: :tangle none

,* Real sessions in ~org-src-mode~ buffers

,#+header: :wrap "src text"
,#+begin_src python :results output :session
print("Hello *Python*!")
,#+end_src

,#+RESULTS:
,#+begin_src text
Hello *Python*!
,#+end_src

,#+header: :wrap "src text"
,#+begin_src python :results output :session Python
print("Hello *Python*!")
,#+end_src

,#+RESULTS:
,#+begin_src text
Hello *Python*!
,#+end_src

,#+header: :wrap "src text"
,#+begin_src python :results output :session snake
print("Hello *snake*!")
,#+end_src

,#+RESULTS:
,#+begin_src text
Hello *snake*!
,#+end_src

Real sessions for eval-buffer in org-src buffers.

,* Fake sessions in ~org-src-mode~ buffers

,#+header: :wrap "src text"
,#+begin_src python :results output :session none
print("Hello *none*!")
,#+end_src

,#+RESULTS:
,#+begin_src text
Hello *none*!
,#+end_src

,#+header: :wrap "src text"
,#+begin_src python :results output :session :default
print("Hello *Python* with `:default' unseen!")
,#+end_src

,#+RESULTS:
,#+begin_src text
Hello *Python* with `:default' unseen!
,#+end_src

,#+header: :wrap "src text"
,#+begin_src python :results output :session ":default"
print("Hello *Python* with `*:default*' seen!")
,#+end_src

,#+RESULTS:
,#+begin_src text
Hello *Python* with `*:default*' seen!
,#+end_src

Fake sessions for eval-buffer in org-src buffers.

Format-all

Listing lst:configure-format-all:

1. Configures format-all which is a package that provides an universal interface to code formatters of more than 60 computer languages.
2. Adds format-all-org-babel-post-tangle to org-babel-post-tangle-hook to format tangled Python code.

;; https://github.com/lassik/emacs-format-all-the-code#readme
;; https://ianyepan.github.io/posts/format-all/
;; https://jamesaimonetti.com/posts/formatting-tangled-output-in-org-mode/
(when (ensure-package-installation 'format-all)
  ;; `format-all' defines `format-all-buffer' as an autoloaded command.
  (with-eval-after-load 'ob-tangle
    (add-hook
     'org-babel-post-tangle-hook
     (defun format-all-org-babel-post-tangle ()
       (when (derived-mode-p 'python-mode)
         (setq-local format-all-formatters '(("Python" black)))
         (format-all-buffer)
         (save-buffer)
         (message "Saved reformatted tangled buffer `%s'"
                  (buffer-file-name)))))))

Flymake (info)

Flymake is an universal on-the-fly syntax checker for Emacs. It is a requirement of eglot, but you can use it without eglot for instance in python-mode buffers that do not visit a file. Listing lst:configure-flymake aliases list-errors (new) to flymake-show-buffer-diagnostics (old).

(with-eval-after-load 'flymake
  (defalias 'list-errors #'flymake-show-buffer-diagnostics
    "Show a list of Flymake diagnostics for current buffer.")

  (keymap-set flymake-mode-map "M-n" 'flymake-goto-next-error)
  (keymap-set flymake-mode-map "M-p" 'flymake-goto-prev-error))

Programming Modes

Common Lisp programming

Links to Common Lisp books and posts are:

1. Common Lisp
2. Kvardek Du - Luis Oliveira
3. Lisp Resources
4. On Lisp - Paul Graham
5. Traité de Programmation en Common Lisp

Sly

Listing lst:configure-sly configures the Sly (info) Common Lisp IDE for Emacs for use with Steel Bank Common Lisp (sbcl):

1. It configures sly-default-lisp and sly-lisp-implementations as in the sly documentation string instead of in the multiple lisps (info) manual.
2. It does not ensure the automatic connection to the lisp server (info) when opening a Common Lisp file because it does not play well with ob-lisp.
3. It configures searching documentation in the Common Lisp HyperSpec according to the basic customization (info) manual.

Listing lst:slink-sel allows to set or get the Sly string elision length. Finally, listing lst:configure-sly uses a technique to load Slynk faster (info) by means of a custom core file in src_emacs-lisp[:results silent]{(describe-variable 'no-littering-var-directory)}. Listing lst:sbcl-core-for-sly tangles to a script to dump such a SBCL core.

(when (ensure-package-installation 'sly 'sly-macrostep 'sly-named-readtables)
  (with-eval-after-load 'sly
    ;; Set `sly-default-lisp' instead of `inferior-lisp-program',
    ;; because `sly' uses `inferior-lisp-program' only as a backwards
    ;; compatibility fallback option.
    ;; The warning "Value ‘sbcl’ does not match type function" is due to
    ;; the buggy `defcustom' type of `sbcl-default-lisp' in `sly.el'.
    (setopt sly-db-initial-restart-limit 10
            sly-default-lisp 'sbcl
            sly-lisp-implementations
            `((ccl (,(executable-find "ccl64")))
              (sbcl (,(executable-find "sbcl")
                     "--core"
                     ,(no-littering-expand-var-file-name "sbcl.core-for-sly")))))

    ;; (add-hook 'sly-mode-hook
    ;;           (defun on-sly-mode-hook ()
    ;;             (unless (sly-connected-p)
    ;;               (save-excursion (sly)))))

    (cond
     ((eq system-type 'darwin)
      (setq common-lisp-hyperspec-root
            "file:///usr/local/share/doc/hyperspec/HyperSpec/")
      (setq common-lisp-hyperspec-symbol-table
            (concat common-lisp-hyperspec-root "Data/Map_Sym.txt")))
     ((eq system-type 'gnu/linux)
      (setq common-lisp-hyperspec-root
            "file:///usr/share/doc/hyperspec-7.0/HyperSpec/"))
     (t (message "Default Common Lisp HyperSpec access")))

    (keymap-set sly-prefix-map "M-h" #'sly-documentation-lookup)))

#+caption[Get/set Sly slynk:*string-elision-length* functionality]:

(with-eval-after-load 'sly
  (defconst slynk-command-get-sel
    "(cdr (assoc 'slynk:*string-elision-length* slynk:*slynk-pprint-bindings*))"
    "Slynk \"string elision length\" getter command.")

  (defun slynk-command-set-sel (length)
    "Slynk LENGTH \"string elision length\" setter command.
LENGTH values must be positive integers to enable or `nil' to disable elision."
    (format "(setf %s %s)" slynk-command-get-sel length))

  (defun slynk-get-sel ()
    "Get the Slynk \"string-elision-length\"."
    (cadr (sly-eval `(slynk:eval-and-grab-output ,slynk-command-get-sel))))

  ;; Most useful for Org source blocks.
  (defun slynk-set-sel (length)
    "Set the Slynk \"string-elision-length\" LENGTH.
LENGTH values must be positive integers to enable or `nil' to disable elision."
    (cadr
     (sly-eval `(slynk:eval-and-grab-output ,(slynk-command-set-sel length)))))

  ;; Most useful for interactive use.
  (defun slynk-eval-sel-command (string)
    "Evaluate the Slynk \"string-elision-length\" command STRING."
    (unless (sly-connected-p)
      (user-error "Slynk connection is not open: \"M-x sly\"?"))
    (message "Slynk string elision length is %S"
             (read (cadr (sly-eval `(slynk:eval-and-grab-output ,string))))))

  (defun slynk-get-string-elision-length ()
    "Get the Slynk \"string-elision-length\"."
    (interactive)
    (slynk-eval-sel-command slynk-command-get-sel))

  (defun slynk-set-string-elision-length (&optional length)
    "Set the Slynk \"string-elision-length\" LENGTH.
Valid LENGTH values are positive integers to set or `nil' to reset."
    (interactive "X\ Slink string elision length: ")
    (unless (or (null length) (and (integerp length) (> length 0)))
      (user-error
       "Slynk `length' must be `nil' or a positive integer (got `%S')" length))
    (slynk-eval-sel-command (slynk-command-set-sel length))))

#!/bin/sh

sbcl <<EOF
(mapc 'require '(sb-bsd-sockets sb-posix sb-introspect sb-cltl2 asdf))
(save-lisp-and-die "sbcl.core-for-sly")
EOF

# Local Variables:
# mode: shell-script
# sh-indentation: 2
# sh-basic-offset: 2
# End:

CS 325 AI Programming

The CS 325 AI Programming course allows to learn Common Lisp by self-study and the page CS 325: Setting up Lisp gives instructions how to:

1. Download and install common lisp.
2. Install Quicklisp.
3. Install the CS325 library.

Quicklisp

Quicklisp is a library manager for Common Lisp. Listing lst:download+verify-quicklisp downloads the Quicklisp installation file and verifies its signature to prevent tampering. Listing lst:bootstrap-quicklisp tangles to a shell script allowing to bootstrap Quicklisp with SBCL. Listing lst:quicklisp-sbclrc-file tangles to the a SBCL resource file with Quicklisp support. Listing lst:clone-local-projects shows how to make local projects out of unpackaged projects and listing lst:register-load-local-projects shows how to register local projects in order to load those unpackaged projects in the same way as packaged projects.

curl -sS -O https://beta.quicklisp.org/quicklisp.lisp
curl -sS -O https://beta.quicklisp.org/quicklisp.lisp.asc
curl -sS -O https://beta.quicklisp.org/release-key.txt
gpg --import release-key.txt
gpg --verify quicklisp.lisp.asc quicklisp.lisp

#!/bin/sh

sbcl --load ~/quicklisp.lisp <<EOF
(quicklisp-quickstart:install)
(quit)
EOF

# Local Variables:
# mode: shell-script
# sh-indentation: 2
# sh-basic-offset: 2
# End:

git clone https://gitlab.com/criesbeck/cs325.git
git clone git@github.com:ageldama/cl-state-machine.git

;; SBCL on Darwin fails to run cl-cffi-gtk:
;; https://lisp-journey.gitlab.io/blog/gui-programming-in-common-lisp-part-3-of-5-gtk3/
;; https://www.crategus.com/books/cl-cffi-gtk/
;; https://www.crategus.com/books/cl-gtk/gtk-tutorial.html
(defun probe--local-project-directory (name)
  (some #'identity (mapcar (lambda (x)
                             (let ((*default-pathname-defaults* x))
                               (probe-file name)))
                           ql:*local-project-directories*)))

(when (probe--local-project-directory "cs325")
  (ql:register-local-projects)
  (ql:quickload "cs325")
  (ql:quickload "meta")
  (ql:quickload '("named-readtables" "try")) ;; testing requires "try".
  #-:clozure
  (ql:quickload "nodgui") ;; requires https://www.tcl.tk/software/tklib/
  (ql:quickload '("rutils" "rutilsx"))
  (ql:quickload "ucons"))

(when (probe--local-project-directory "cl-state-machine")
  (ql:quickload '("cl-state-machine" "cl-state-machine-examples"
                  "cl-state-machine-graphing" "cl-state-machine-test")))

;;; Hey Emacs, this is my -*- lisp -*- .sbclrc file.

;;; The following lines added by ql:add-to-init-file:
#-quicklisp
(let ((quicklisp-init (merge-pathnames "quicklisp/setup.lisp"
                                       (user-homedir-pathname))))
  (when (probe-file quicklisp-init)
    (load quicklisp-init)))

;;; Load cs325.lisp to create the cs325 package.

;; (eval-when (:compile-toplevel :load-toplevel :execute)
;;   (ql:quickload "cs325")
;;   (setq *package* (find-package :cs325-user)))

Lisp mode custom font locking for Common Lisp

This section implements the code described in the Emacs Common Lisp Font Locking post.

Initialize Common Lisp custom font locking

;;; Common Lisp custom font lock configuration.
;;; https://www.n16f.net/blog/custom-font-lock-configuration-in-emacs/

(defface cl-character-face
  '((default :inherit font-lock-constant-face))
  "The face used to highlight Common Lisp character literals.")

(defface cl-standard-function-face
  '((default :inherit font-lock-keyword-face))
  "The face used to highlight standard Common Lisp function symbols.")

(defface cl-standard-value-face
  '((default :inherit font-lock-variable-name-face))
  "The face used to highlight standard Common Lisp value symbols.")

(defun standard-symbol-names (predicate)
  (let ((symbols nil))
    (do-external-symbols (symbol :common-lisp)
      (when (funcall predicate symbol)
        (push (string-downcase (symbol-name symbol)) symbols)))
    (sort symbols #'string<)))

#+caption[Set Sly ~slynk:*string-elision-length*~]:

(when (and (fboundp 'sly-connected-p) (sly-connected-p))
  (and (fboundp 'slynk-set-sel) (slynk-set-sel (ash 1 14))))

#+caption[Set Sly slynk:*string-elision-length* result]:

16384 (15 bits, #x4000)

Collect standard symbol function names

(format nil "(defvar~%  cl-function-names~%  '~S)~%"
        (standard-symbol-names #'fboundp))

(defvar
  cl-function-names
  '("*" "+" "-" "/" "/=" "1+" "1-" "<" "<=" "=" ">" ">=" "abort" "abs" "acons"
    "acos" "acosh" "add-method" "adjoin" "adjust-array" "adjustable-array-p"
    "allocate-instance" "alpha-char-p" "alphanumericp" "and" "append" "apply"
    "apropos" "apropos-list" "aref" "arithmetic-error-operands"
    "arithmetic-error-operation" "array-dimension" "array-dimensions"
    "array-displacement" "array-element-type" "array-has-fill-pointer-p"
    "array-in-bounds-p" "array-rank" "array-row-major-index" "array-total-size"
    "arrayp" "ash" "asin" "asinh" "assert" "assoc" "assoc-if" "assoc-if-not"
    "atan" "atanh" "atom" "bit" "bit-and" "bit-andc1" "bit-andc2" "bit-eqv"
    "bit-ior" "bit-nand" "bit-nor" "bit-not" "bit-orc1" "bit-orc2"
    "bit-vector-p" "bit-xor" "block" "boole" "both-case-p" "boundp" "break"
    "broadcast-stream-streams" "butlast" "byte" "byte-position" "byte-size"
    "caaaar" "caaadr" "caaar" "caadar" "caaddr" "caadr" "caar" "cadaar"
    "cadadr" "cadar" "caddar" "cadddr" "caddr" "cadr" "call-method" "car"
    "case" "catch" "ccase" "cdaaar" "cdaadr" "cdaar" "cdadar" "cdaddr" "cdadr"
    "cdar" "cddaar" "cddadr" "cddar" "cdddar" "cddddr" "cdddr" "cddr" "cdr"
    "ceiling" "cell-error-name" "cerror" "change-class" "char" "char-code"
    "char-downcase" "char-equal" "char-greaterp" "char-int" "char-lessp"
    "char-name" "char-not-equal" "char-not-greaterp" "char-not-lessp"
    "char-upcase" "char/=" "char<" "char<=" "char=" "char>" "char>="
    "character" "characterp" "check-type" "cis" "class-name" "class-of"
    "clear-input" "clear-output" "close" "clrhash" "code-char" "coerce"
    "compile" "compile-file" "compile-file-pathname" "compiled-function-p"
    "compiler-macro-function" "complement" "complex" "complexp"
    "compute-applicable-methods" "compute-restarts" "concatenate"
    "concatenated-stream-streams" "cond" "conjugate" "cons" "consp"
    "constantly" "constantp" "continue" "copy-alist" "copy-list"
    "copy-pprint-dispatch" "copy-readtable" "copy-seq" "copy-structure"
    "copy-symbol" "copy-tree" "cos" "cosh" "count" "count-if" "count-if-not"
    "ctypecase" "decf" "declaim" "decode-float" "decode-universal-time"
    "defclass" "defconstant" "defgeneric" "define-compiler-macro"
    "define-condition" "define-method-combination" "define-modify-macro"
    "define-setf-expander" "define-symbol-macro" "defmacro" "defmethod"
    "defpackage" "defparameter" "defsetf" "defstruct" "deftype" "defun"
    "defvar" "delete" "delete-duplicates" "delete-file" "delete-if"
    "delete-if-not" "delete-package" "denominator" "deposit-field" "describe"
    "describe-object" "destructuring-bind" "digit-char" "digit-char-p"
    "directory" "directory-namestring" "disassemble" "do" "do*"
    "do-all-symbols" "do-external-symbols" "do-symbols" "documentation"
    "dolist" "dotimes" "dpb" "dribble" "ecase" "echo-stream-input-stream"
    "echo-stream-output-stream" "ed" "eighth" "elt" "encode-universal-time"
    "endp" "enough-namestring" "ensure-directories-exist"
    "ensure-generic-function" "eq" "eql" "equal" "equalp" "error" "etypecase"
    "eval" "eval-when" "evenp" "every" "exp" "export" "expt" "fboundp"
    "fceiling" "fdefinition" "ffloor" "fifth" "file-author"
    "file-error-pathname" "file-length" "file-namestring" "file-position"
    "file-string-length" "file-write-date" "fill" "fill-pointer" "find"
    "find-all-symbols" "find-class" "find-if" "find-if-not" "find-method"
    "find-package" "find-restart" "find-symbol" "finish-output" "first" "flet"
    "float" "float-digits" "float-precision" "float-radix" "float-sign"
    "floatp" "floor" "fmakunbound" "force-output" "format" "formatter" "fourth"
    "fresh-line" "fround" "ftruncate" "funcall" "function" "function-keywords"
    "function-lambda-expression" "functionp" "gcd" "gensym" "gentemp" "get"
    "get-decoded-time" "get-dispatch-macro-character" "get-internal-real-time"
    "get-internal-run-time" "get-macro-character" "get-output-stream-string"
    "get-properties" "get-setf-expansion" "get-universal-time" "getf" "gethash"
    "go" "graphic-char-p" "handler-bind" "handler-case" "hash-table-count"
    "hash-table-p" "hash-table-rehash-size" "hash-table-rehash-threshold"
    "hash-table-size" "hash-table-test" "host-namestring" "identity" "if"
    "ignore-errors" "imagpart" "import" "in-package" "incf"
    "initialize-instance" "input-stream-p" "inspect" "integer-decode-float"
    "integer-length" "integerp" "interactive-stream-p" "intern" "intersection"
    "invalid-method-error" "invoke-debugger" "invoke-restart"
    "invoke-restart-interactively" "isqrt" "keywordp" "labels" "lambda" "last"
    "lcm" "ldb" "ldb-test" "ldiff" "length" "let" "let*"
    "lisp-implementation-type" "lisp-implementation-version" "list" "list*"
    "list-all-packages" "list-length" "listen" "listp" "load"
    "load-logical-pathname-translations" "load-time-value" "locally" "log"
    "logand" "logandc1" "logandc2" "logbitp" "logcount" "logeqv"
    "logical-pathname" "logical-pathname-translations" "logior" "lognand"
    "lognor" "lognot" "logorc1" "logorc2" "logtest" "logxor" "long-site-name"
    "loop" "loop-finish" "lower-case-p" "machine-instance" "machine-type"
    "machine-version" "macro-function" "macroexpand" "macroexpand-1" "macrolet"
    "make-array" "make-broadcast-stream" "make-concatenated-stream"
    "make-condition" "make-dispatch-macro-character" "make-echo-stream"
    "make-hash-table" "make-instance" "make-instances-obsolete" "make-list"
    "make-load-form" "make-load-form-saving-slots" "make-package"
    "make-pathname" "make-random-state" "make-sequence" "make-string"
    "make-string-input-stream" "make-string-output-stream" "make-symbol"
    "make-synonym-stream" "make-two-way-stream" "makunbound" "map" "map-into"
    "mapc" "mapcan" "mapcar" "mapcon" "maphash" "mapl" "maplist" "mask-field"
    "max" "member" "member-if" "member-if-not" "merge" "merge-pathnames"
    "method-combination-error" "method-qualifiers" "min" "minusp" "mismatch"
    "mod" "muffle-warning" "multiple-value-bind" "multiple-value-call"
    "multiple-value-list" "multiple-value-prog1" "multiple-value-setq"
    "name-char" "namestring" "nbutlast" "nconc" "nintersection" "ninth"
    "no-applicable-method" "no-next-method" "not" "notany" "notevery" "nreconc"
    "nreverse" "nset-difference" "nset-exclusive-or" "nstring-capitalize"
    "nstring-downcase" "nstring-upcase" "nsublis" "nsubst" "nsubst-if"
    "nsubst-if-not" "nsubstitute" "nsubstitute-if" "nsubstitute-if-not" "nth"
    "nth-value" "nthcdr" "null" "numberp" "numerator" "nunion" "oddp" "open"
    "open-stream-p" "or" "output-stream-p" "package-error-package"
    "package-name" "package-nicknames" "package-shadowing-symbols"
    "package-use-list" "package-used-by-list" "packagep" "pairlis"
    "parse-integer" "parse-namestring" "pathname" "pathname-device"
    "pathname-directory" "pathname-host" "pathname-match-p" "pathname-name"
    "pathname-type" "pathname-version" "pathnamep" "peek-char" "phase" "plusp"
    "pop" "position" "position-if" "position-if-not" "pprint" "pprint-dispatch"
    "pprint-exit-if-list-exhausted" "pprint-fill" "pprint-indent"
    "pprint-linear" "pprint-logical-block" "pprint-newline" "pprint-pop"
    "pprint-tab" "pprint-tabular" "prin1" "prin1-to-string" "princ"
    "princ-to-string" "print" "print-not-readable-object" "print-object"
    "print-unreadable-object" "probe-file" "proclaim" "prog" "prog*" "prog1"
    "prog2" "progn" "progv" "provide" "psetf" "psetq" "push" "pushnew" "quote"
    "random" "random-state-p" "rassoc" "rassoc-if" "rassoc-if-not" "rational"
    "rationalize" "rationalp" "read" "read-byte" "read-char"
    "read-char-no-hang" "read-delimited-list" "read-from-string" "read-line"
    "read-preserving-whitespace" "read-sequence" "readtable-case" "readtablep"
    "realp" "realpart" "reduce" "reinitialize-instance" "rem" "remf" "remhash"
    "remove" "remove-duplicates" "remove-if" "remove-if-not" "remove-method"
    "remprop" "rename-file" "rename-package" "replace" "require" "rest"
    "restart-bind" "restart-case" "restart-name" "return" "return-from"
    "revappend" "reverse" "room" "rotatef" "round" "row-major-aref" "rplaca"
    "rplacd" "sbit" "scale-float" "schar" "search" "second" "set"
    "set-difference" "set-dispatch-macro-character" "set-exclusive-or"
    "set-macro-character" "set-pprint-dispatch" "set-syntax-from-char" "setf"
    "setq" "seventh" "shadow" "shadowing-import" "shared-initialize" "shiftf"
    "short-site-name" "signal" "signum" "simple-bit-vector-p"
    "simple-condition-format-arguments" "simple-condition-format-control"
    "simple-string-p" "simple-vector-p" "sin" "sinh" "sixth" "sleep"
    "slot-boundp" "slot-exists-p" "slot-makunbound" "slot-missing"
    "slot-unbound" "slot-value" "software-type" "software-version" "some"
    "sort" "special-operator-p" "sqrt" "stable-sort" "standard-char-p" "step"
    "store-value" "stream-element-type" "stream-error-stream"
    "stream-external-format" "streamp" "string" "string-capitalize"
    "string-downcase" "string-equal" "string-greaterp" "string-left-trim"
    "string-lessp" "string-not-equal" "string-not-greaterp" "string-not-lessp"
    "string-right-trim" "string-trim" "string-upcase" "string/=" "string<"
    "string<=" "string=" "string>" "string>=" "stringp" "sublis" "subseq"
    "subsetp" "subst" "subst-if" "subst-if-not" "substitute" "substitute-if"
    "substitute-if-not" "subtypep" "svref" "sxhash" "symbol-function"
    "symbol-macrolet" "symbol-name" "symbol-package" "symbol-plist"
    "symbol-value" "symbolp" "synonym-stream-symbol" "tagbody" "tailp" "tan"
    "tanh" "tenth" "terpri" "the" "third" "throw" "time" "trace"
    "translate-logical-pathname" "translate-pathname" "tree-equal" "truename"
    "truncate" "two-way-stream-input-stream" "two-way-stream-output-stream"
    "type-error-datum" "type-error-expected-type" "type-of" "typecase" "typep"
    "unbound-slot-instance" "unexport" "unintern" "union" "unless"
    "unread-char" "untrace" "unuse-package" "unwind-protect"
    "update-instance-for-different-class" "update-instance-for-redefined-class"
    "upgraded-array-element-type" "upgraded-complex-part-type" "upper-case-p"
    "use-package" "use-value" "user-homedir-pathname" "values" "values-list"
    "vector" "vector-pop" "vector-push" "vector-push-extend" "vectorp" "warn"
    "when" "wild-pathname-p" "with-accessors" "with-compilation-unit"
    "with-condition-restarts" "with-hash-table-iterator"
    "with-input-from-string" "with-open-file" "with-open-stream"
    "with-output-to-string" "with-package-iterator" "with-simple-restart"
    "with-slots" "with-standard-io-syntax" "write" "write-byte" "write-char"
    "write-line" "write-sequence" "write-string" "write-to-string" "y-or-n-p"
    "yes-or-no-p" "zerop"))

Collect standard symbol value names

(format nil "(defvar~%  cl-value-names~%  '~S)~%"
        (standard-symbol-names #'boundp))

(defvar
  cl-value-names
  '("*" "**" "***" "*break-on-signals*" "*compile-file-pathname*"
    "*compile-file-truename*" "*compile-print*" "*compile-verbose*"
    "*debug-io*" "*debugger-hook*" "*default-pathname-defaults*"
    "*error-output*" "*features*" "*gensym-counter*" "*load-pathname*"
    "*load-print*" "*load-truename*" "*load-verbose*" "*macroexpand-hook*"
    "*modules*" "*package*" "*print-array*" "*print-base*" "*print-case*"
    "*print-circle*" "*print-escape*" "*print-gensym*" "*print-length*"
    "*print-level*" "*print-lines*" "*print-miser-width*"
    "*print-pprint-dispatch*" "*print-pretty*" "*print-radix*"
    "*print-readably*" "*print-right-margin*" "*query-io*" "*random-state*"
    "*read-base*" "*read-default-float-format*" "*read-eval*" "*read-suppress*"
    "*readtable*" "*standard-input*" "*standard-output*" "*terminal-io*"
    "*trace-output*" "+" "++" "+++" "-" "/" "//" "///" "array-dimension-limit"
    "array-rank-limit" "array-total-size-limit" "boole-1" "boole-2" "boole-and"
    "boole-andc1" "boole-andc2" "boole-c1" "boole-c2" "boole-clr" "boole-eqv"
    "boole-ior" "boole-nand" "boole-nor" "boole-orc1" "boole-orc2" "boole-set"
    "boole-xor" "call-arguments-limit" "char-code-limit" "double-float-epsilon"
    "double-float-negative-epsilon" "internal-time-units-per-second"
    "lambda-list-keywords" "lambda-parameters-limit"
    "least-negative-double-float" "least-negative-long-float"
    "least-negative-normalized-double-float"
    "least-negative-normalized-long-float"
    "least-negative-normalized-short-float"
    "least-negative-normalized-single-float" "least-negative-short-float"
    "least-negative-single-float" "least-positive-double-float"
    "least-positive-long-float" "least-positive-normalized-double-float"
    "least-positive-normalized-long-float"
    "least-positive-normalized-short-float"
    "least-positive-normalized-single-float" "least-positive-short-float"
    "least-positive-single-float" "long-float-epsilon"
    "long-float-negative-epsilon" "most-negative-double-float"
    "most-negative-fixnum" "most-negative-long-float"
    "most-negative-short-float" "most-negative-single-float"
    "most-positive-double-float" "most-positive-fixnum"
    "most-positive-long-float" "most-positive-short-float"
    "most-positive-single-float" "multiple-values-limit" "nil" "pi"
    "short-float-epsilon" "short-float-negative-epsilon" "single-float-epsilon"
    "single-float-negative-epsilon" "t"))

Finalize Common Lisp custom font locking

(defvar cl-font-lock-keywords
  (let* ((character-re (concat "#\\\\" lisp-mode-symbol-regexp "\\_>"))
         (function-re (concat "(" (regexp-opt cl-function-names t) "\\_>"))
         (value-re (regexp-opt cl-value-names 'symbols)))
    `((,character-re . 'cl-character-face)
      (,function-re
       (1 'cl-standard-function-face))
      (,value-re . 'cl-standard-value-face))))

(defvar cl-font-lock-defaults
  '((cl-font-lock-keywords)
    nil                                 ; enable syntaxic highlighting
    t                                   ; case insensitive highlighting
    nil                                 ; use the lisp-mode syntax table
    (font-lock-mark-block-function . mark-defun)
    (font-lock-extra-managed-props help-echo)
    (font-lock-syntactic-face-function
     . lisp-font-lock-syntactic-face-function)))

(defun cl-init-lisp-font-lock ()
  "Hook to initialize Common Lisp font locking."
  (setq font-lock-defaults cl-font-lock-defaults))

(add-hook 'lisp-mode-hook 'cl-init-lisp-font-lock)

Emacs Lisp Programming (info)

Here is a list of links describing how to program and debug Emacs Lisp (info) code:

1. Evaluating Elisp in Emacs
2. Debugging Elisp Part 1: Earn your independence
3. Debugging Elisp Part 2: Advanced topics
4. Xah talk show: Elisp coding: xah-add-space-after-comma
5. Xah talk show: Elisp coding: narrow-to-region, sort-lines, hilight-unicode

Ref. [cite:@Monnier.ACM-PL.4.1] exposes the evolution of Emacs Lisp and explains important Emacs Lisp idioms.

Listing setup ielm configures the Interactive Emacs Lisp Mode for better interoperability with Smartparens: get help on the key bindings by means of src_emacs-lisp[:results silent]{(describe-function 'ielm)}.

(with-eval-after-load 'ielm
  (setopt ielm-dynamic-return nil))

Debugging Emacs Lisp (info)

Listing edebug example from the source level debugger (edebug) wiki entry is a minimal example of how to use edebug:

1. Type

   (eval

   to open its org-src-mode buffer.
2. Type

   (eval

   with point in foo.
3. Type

   (eval

   with point in bar.
4. Evaluate (foo).
5. Type

   (eval

   with point in bar.
6. Evaluate (foo).
7. Type the space bar to step through bar.

Note: I fail to instrument functions as in Edebug (info).

(defun foo ()
  (interactive)
  (bar))

(defun bar ()
  (let ((a 5)
	(b 7))
    (message "%d" (+ a b))))

Writing Better Elisp Docstrings

;; Stolen from Charles Choi:
;; http://yummymelon.com/devnull/writing-better-elisp-docstrings.html
;; GAV: Org changes the semantics of calling `beginning-of-defun'.
(defun describe-function-at-point ()
  "Call `describe-function' on the Elisp function at point.
Switch temporarily from `org-mode' to `text-mode', since `org-mode'
changes the semantics of calling `beginning-of-defun'."
  (interactive)
  (let ((mode major-mode))
    (when (eq major-mode 'org-mode)
      (text-mode))
    (save-excursion
      (beginning-of-defun)
      (forward-char)
      (forward-sexp 2)
      (let ((end-point (point)))
        (backward-sexp)
        (let* ((fn-name (buffer-substring (point) end-point))
               (interned (intern-soft fn-name)))
          (if interned
              (describe-function interned)
            (message "Can't find function at point")))))
    (when (eq mode 'org-mode)
      (org-mode))))

(with-eval-after-load 'org-mode
  (keymap-set org-mode-map "C-c d" #'describe-function-at-point))
(with-eval-after-load 'emacs-lisp-mode
  (keymap-set emacs-lisp-mode-map "C-c d" #'describe-function-at-point))

Go Programming

Links for further investigation are:

1. Go by example is a showcase of short examples with explanations.

(when (featurep 'treesit)
  ;; Set `tab-width' in `after-change-major-mode-hook' function too.
  (setopt go-ts-mode-indent-offset 2)
  (add-hook 'after-change-major-mode-hook
            (defun on-go-ts-mode-hook ()
              (when (derived-mode-p 'go-ts-mode 'go-mod-ts-mode)
                (setq-local tab-width 2))))
  (add-to-list 'auto-mode-alist `(,(rx ".go" eos) . go-ts-mode)))

Julia programming

Points for further investigation are:

1. Application of the Julia Pkg documentation requires

   (eval

   or a terminal because the inferior Julia interpreter provides no genuine terminal. Type or click BREAK on the SIGNALS menu to leave package mode. Type

   (eval

   in package mode to see a list of added packages. Julia does not recognize dependencies anymore. Therefore, I have used package mode to add StaticLint and SymbolServer to make a patched version of eglot-jl work.
2. ESS support for the Julia language is a somewhat outdated description of how to obtain Julia support for Emacs Speaks Statistics and Emacs.
3. Hands-On: Design Patterns and Best Practices with Julia is a Julia book with good reviews.
4. Julia by example is a showcase of 1- or 2-liners.
5. PkgTemplates and PkgTemplates User Guide explain how to write a Julia package. How to develop a Julia package is friendlier but not up to date.
6. Practical Julia is Julia book with good reviews.
7. The list of installed packages in listing lst:list-julia-packages-result facilitate Julia Code Blocks in Babel because the list contains CSV and DataFrames.
8. How to update automatically to the current stable release of Julia.

A list of interesting online course material is:

1. A Deep Introduction to Julia for Data Science and Scientific Computing.
2. Julia for Optimization and Learning.
3. Julia for Optimization and Learning Scripts.
4. Quantitative Economics with Julia (use backspace to leave package mode).

Here are links to Julia programming background videos:

1. Creating a Julia Pkg with PkgTemplates.jl
2. Revise.jl, Docstrings, Tests, and structuring a Julia package

Listing lst:setup-julia setups Julia support but requires manual tweaking of Makefile to replace sed with gsed and of ess-autoloads.el.

(push (expand-file-name "~/VCS/ESS/lisp") load-path)
(when (require 'ess-julia nil 'noerror)
  (setopt inferior-julia-program (executable-find "julia")))

cat "$HOME/.julia/environments/v1.10/Project.toml"

[deps]
BenchmarkTools = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
CSV = "336ed68f-0bac-5ca0-87d4-7b16caf5d00b"
Calculus = "49dc2e85-a5d0-5ad3-a950-438e2897f1b9"
DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
IJulia = "7073ff75-c697-5162-941a-fcdaad2a7d2a"
LanguageServer = "2b0e0bc5-e4fd-59b4-8912-456d1b03d8d7"
Luxor = "ae8d54c2-7ccd-5906-9d76-62fc9837b5bc"
Measurements = "eff96d63-e80a-5855-80a2-b1b0885c5ab7"
Pkg = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
PkgTemplates = "14b8a8f1-9102-5b29-a752-f990bacb7fe1"
Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
StaticLint = "b3cc710f-9c33-5bdb-a03d-a94903873e97"
SymbolServer = "cf896787-08d5-524d-9de7-132aaa0cb996"

cat "$HOME/VCS/ESS/0001-Patch-Makefile-for-Home-Brew.patch"

ESS Makefile for Homebrew patch

From 71729a02a190c1f1bfca02dd6db6d5f736437d5a Mon Sep 17 00:00:00 2001
From: Gerard Vermeulen <gerard.vermeulen@posteo.net>
Date: Mon, 26 Feb 2024 19:48:19 +0100
Subject: [PATCH] Patch Makefile for Home Brew

---
 Makefile | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/Makefile b/Makefile
index 182094a3..3409cf66 100644
--- a/Makefile
+++ b/Makefile
@@ -4,14 +4,14 @@
 include ./Makeconf

 ESSVERSION := $(shell cat VERSION)
-PKGVERSION := $(shell sed -n 's/;; Version: *\(.*\) */\1/p' lisp/ess.el)
+PKGVERSION := $(shell gsed -n 's/;; Version: *\(.*\) */\1/p' lisp/ess.el)
 ESSDIR := ess-$(ESSVERSION)
 ifneq ($(ESSVERSION), $(PKGVERSION))
-  $(shell sed -i 's/Version: .*/Version: $(ESSVERSION)/' VERSION)
-  ${shell sed -i 's/;; Version: .*/;; Version: $(ESSVERSION)/' lisp/ess.el}
+  $(shell gsed -i 's/Version: .*/Version: $(ESSVERSION)/' VERSION)
+  ${shell gsed -i 's/;; Version: .*/;; Version: $(ESSVERSION)/' lisp/ess.el}
 endif

-ESSR-VERSION := $(shell sed -n "s/;; ESSR-Version: *\(.*\) */\1/p" lisp/ess.el)
+ESSR-VERSION := $(shell gsed -n "s/;; ESSR-Version: *\(.*\) */\1/p" lisp/ess.el)

 .PHONY: all
 all: lisp doc etc autoloads
@@ -19,10 +19,10 @@ all: lisp doc etc autoloads
 .PHONY: version
 version: VERSION
 	@echo "********************* VERSIONS **************************"
-	@echo $(shell $(EMACS) --version | sed -n 1p)
+	@echo $(shell $(EMACS) --version | gsed -n 1p)
 	@echo ESS $(ESSVERSION)
 	@echo ESSR $(ESSR-VERSION)
-	@sed -i "s/\"VERSION\"/\"$(ESSVERSION)\"/" lisp/ess-custom.el
+	@gsed -i "s/\"VERSION\"/\"$(ESSVERSION)\"/" lisp/ess-custom.el
 	@echo "*********************************************************"

 .PHONY: lisp
@@ -59,7 +59,7 @@ autoloads:
 essr: VERSION
 	@echo "**********************************************************"
 	@echo "** Making ESSRv$(ESSR-VERSION) **"
-	@sed -i "s/^ *VERSION <- .*/    VERSION <- \"$(ESSR-VERSION)\"/" etc/ESSR/R/.load.R
+	@gsed -i "s/^ *VERSION <- .*/    VERSION <- \"$(ESSR-VERSION)\"/" etc/ESSR/R/.load.R
 	cd etc/ESSR/; ./BUILDESSR; cd -
 	@git add etc/ESSR.rds lisp/ess.el etc/ESSR/R/.load.R
 	git commit -m"ESSR Version $(ESSR-VERSION)"
@@ -160,7 +160,7 @@ cleanup-rel:
 	@rm -f tarballs dist tag homepage upload rel

 %.spec: %.spec.in VERSION
-	sed 's/@@VERSION@@/$(ESSVERSION)/g' $< > $@
+	gsed 's/@@VERSION@@/$(ESSVERSION)/g' $< > $@

 ## --- RELEASE section ---

--
2.42.0

Python programming

The Python Programming in Emacs wiki page lists options to enhance Emacs's built-in python-mode. Here, the focus is on two Emacs packages and four Python packages:

1. Eglot - Emacs polyGLOT: a builtin LSP client since Emacs-29.1 and its author (who is a prolific Common Lisp and Emacs Lisp programmer) has also contributed to other parts of Emacs.
2. Jedi is a static analysis tool for Python that is typically used in plugins for editors or integrated development environments. Jedi has a focus on autocompletion and object definition lookup functionality.
3. Nowadays, Ruff is the fastest Python linter and a replacement for Flake8 with a variety of its plugins. Charlie Marsh explains why he started Ruff in the post Python tooling could be much faster.
4. Python LSP Server is in my opinion the most complete Language Server Protocol implementation for Python and it handles Ruff thanks to the python-lsp-ruff plugin.
5. Code-cells allows to edit IPython or Jupyter notebooks in Emacs with help from either Jupytext or Pandoc.

Here are links covering how to integrate Emacs, Python and a Python LSP server, before plunging into the configuration steps:

1. Building Your Own Emacs IDE with LSP
2. Doom Emacs and Language Servers
3. Eglot based Emacs Python IDE
4. Getting started with lsp-mode for Python
5. Python & Emacs, Take 3
6. Python with Emacs: py(v)env and lsp-mode

Here are links to Python programming background videos:

1. Dataclasses: The Code Generator to End All Code Generators - Raymond Hettinger
2. Modern Dictionaries - Raymond Hettinger
3. Python's Class Development Kit - Raymond Hettinger
4. The Big Leap of Python-3.13 - Lukasz Langa
5. The Mental Game of Python - Raymond Hettinger
6. Thinking about Concurrency - Raymond Hettinger
7. Thinking outside the GIL with AsyncIO and MultiProcessing - John Reese
8. What can't WebAssembly do? - Katie Bell

Python-mode

Listing setup Python mode selects a common Python interpreter in a virtual environment for use in python-mode and ob-python. The pythonic, pyvenv, and pyvenv packages allow to handle Python virtual environments within Emacs. The pyenv package provides support to work with pyenv (eventually with pyenv-virtualenv) to select between different python versions (eventually each with different environments). In the end, all those packages do is to set python-shell-virtualenv-root (in case of pyenv and pythonic) or tweak the environment variables and restart the relevant Python child processes (in case of pyvenv). Therefore, I replace those packages with listing access pyenv and select a Python interpreter in a virtual environment to set python-shell-virtualenv-root from within Emacs.

Install isort and pyflakes to enable adding, removing, sorting, and fixing import statements in Python-mode, see the end of the commentary src_emacs-lisp[:results silent]{(find-library "python")} section.

Listing kickoff pyproject.toml proposal facilitates dropping a pyproject.toml file into Python projects which anyhow should switch to using a pyproject.toml file as explained in the post This Way Up: A Bottom-Up Look At Python Packaging. The packaging Python projects tutorial and the Python sample project walk you through the process of writing a pyproject.toml file. Ruff docstring setup explains how to setup documentation string checking in the pyproject.toml file.

Listing kickoff setup.cfg proposal implements the using black with other tools rules which make flake8 or pycodestyle agree with black's uncompromising style.

Finally, listing flake8-nocolor and ruff-nocolor pipe the stdout output of the flake8 and ruff executables through cat to remove escape sequences.

(with-eval-after-load 'ob-python
  (setopt org-babel-python-command (concat (or (executable-find "python3")
                                               (executable-find "python"))
                                           " -E")))

(with-eval-after-load 'python
  (setopt python-indent-guess-indent-offset nil
          python-shell-completion-native-disabled-interpreters '("ipython3"
                                                                 "pypy")
          python-shell-interpreter (or (executable-find "python3")
                                       (executable-find "python"))
          python-shell-interpreter-args "-E -i"
          python-check-command (executable-find "ruff-nocolor")
          python-flymake-command (list (executable-find "ruff-nocolor")
                                       "--stdin-filename" "stdin" "-")))

(when (executable-find "pyenv")
  (defun pyenv-full-path (version)
    "Return the full path for VERSION."
    (unless (string= version "system")
      (concat (pyenv-root) (file-name-as-directory "versions") version)))

  (defun pyenv-root ()
    "Return \"pyenv root\" as a directory."
    (cl-destructuring-bind (exit-code output)
        (shell-command-with-exit-code "pyenv" "root")
      (if (= 0 exit-code)
          (file-name-as-directory (string-trim output))
        (error "%s" (string-trim output)))))

  (defun pyenv-version-name ()
    "Return \"pyenv version-name\"."
    (cl-destructuring-bind (exit-code output)
        (shell-command-with-exit-code "pyenv" "version-name")
      (if (= 0 exit-code)
          (string-trim output)
        (error "%s" (string-trim output)))))

  (defun pyenv-versions ()
    "Return \"pyenv versions --bare --skip-aliases\" as a list.
Complete the result with \"system\"."
    (cl-destructuring-bind (exit-code output)
        (shell-command-with-exit-code
         "pyenv" "versions" "--bare" "--skip-aliases")
      (if (= 0 exit-code)
          (cons "system" (split-string output))
        (error "%s" (string-trim output)))))

  (defun pyenv-virtualenvs ()
    "Return \"pyenv virtualenvs --bare --skip-aliases\" as a list."
    (cl-destructuring-bind (exit-code output)
        (shell-command-with-exit-code
         "pyenv" "virtualenvs" "--bare" "--skip-aliases")
      (if (= 0 exit-code)
          (split-string output)
        (error "%s" (string-trim output))))))

(with-eval-after-load 'python
  (when (cl-every #'fboundp '(pyenv-full-path
                              pyenv-version-name
                              pyenv-versions
                              pyenv-virtualenvs))
    (setq python-shell-virtualenv-root
          (pyenv-full-path (or (pyenv-version-name)
                               (car (pyenv-virtualenvs))
                               (car (pyenv-versions)))))
    (message "Now `python-shell-virtualenv-root' equals %S"
             python-shell-virtualenv-root)

    (defun set-python-shell-virtualenv-root-to-pyenv-version ()
      "Set `python-shell-virtual-env-root' to a pyenv version."
      (interactive)
      (let* ((version-name (pyenv-version-name))
             (prompt (format "pyenv version (%s): " version-name))
             (choices (pyenv-versions))
             (version (completing-read prompt choices nil 'require-match)))
        (unless (string= version-name version)
          (setq python-shell-virtualenv-root (pyenv-full-path version))
          (setenv "PYENV_VERSION" version))
        (message "Now `python-shell-virtualenv-root' equals %S"
                 python-shell-virtualenv-root)))

    (defun set-python-shell-virtualenv-root-to-pyenv-virtualenv ()
      "Set `python-shell-virtual-env-root' to a pyenv virtualenv."
      (interactive)
      (let* ((version-name (pyenv-version-name))
             (prompt (format "pyenv virtualenv (%s): " version-name))
             (choices (pyenv-virtualenvs))
             (version (completing-read prompt choices nil 'require-match)))
        (unless (string= version-name version)
          (setq python-shell-virtualenv-root (pyenv-full-path version))
          (setenv "PYENV_VERSION" version))
        (message "Now `python-shell-virtualenv-root' equals %S"
                 python-shell-virtualenv-root)))))

# See:
# https://docs.astral.sh/ruff/configuration/
# https://pycqa.github.io/isort/docs/configuration/black_compatibility.html
# https://setuptools.pypa.io/en/latest/userguide/pyproject_config.html

[tool.black]
line-length = 88

[tool.isort]
profile = "black"

[tool.ruff]
line-length = 88
select = [
  "ARG", # flake8-unused-arguments
  "B",   # flake8-bugbear
  "C",   # mccabe
  "C4",  # flake8-comprehensions
  "E",   # pycodestyle
  "D",   # pydocstyle
  "F",   # pyflakes
  "UP",  # pyupgrade
  "W",   # pycodestyle
]
ignore = [
  "B905", # `zip()` without an explicit `strict=` parameter
  "D202", # no blank lines allowed after function docstring
]

[tool.ruff.mccabe]
max-complexity = 15

[tool.ruff.pydocstyle]
convention = "numpy"

# Local Variables:
# mode: conf-toml-mode
# End:

[flake8]
docstring-convention = numpy
extend-select = B,F,W
extend-ignore = W503
max-complexity = 15
max-line-length = 88

[pycodestyle]
ignore = W503
max-line-length = 88

# Local Variables:
# mode: conf-toml
# End:

#!/bin/sh

flake8 "$@" | cat

# Local Variables:
# mode: shell-script
# sh-indentation: 2
# sh-basic-offset: 2
# End:

#!/bin/sh

ruff "$@" | cat

# Local Variables:
# mode: shell-script
# sh-indentation: 2
# sh-basic-offset: 2
# End:

Org Babel Ackermann Python test

# https://rosettacode.org/wiki/Ackermann_function#Python
# https://www.youtube.com/watch?v=i7sm9dzFtEI

def ack(M, N):
    if M == 0:
        return N + 1
    elif N == 0:
        return ack(M - 1, 1)
    else:
        return ack(M - 1, ack(M, N - 1))

ack(3, 3)

61

Package Installer for Python

Listing lst:shell-pip-list-outdated and lst:shell-pip-index-versions are two examples of invoking pip in org-mode shell source blocks with the respective results in listing lst:shell-pip-list-outdated-results and lst:shell-pip-index-versions-results.

pip list --outdated

# WARNING: "pip index" is currently an experimental command.
pip index versions circular-buffer --no-color

circular-buffer (0.2.0)
Available versions: 0.2.0, 0.1.1, 0.1.0

(defgroup pip nil
  "Client for accessing the \"Package Installer for Python\" and \"PyPI\"."
  :group 'applications)

(defcustom pip-frozen-packages nil
  "Frozen Python packages."
  :group 'pip
  :type '(repeat string))

;; Updating "docutils" may require a compatible "Sphinx" release.
;; (setopt pip-frozen-packages '("docutils"))

(defvar pip-outdated-packages nil
  "Outdated Python packages.")

(defun pip--list-outdated-sentinel (process _event)
  "Sentinel function for when the `pip-list-outdated' PROCESS succeeds."
  (when (and (eq (process-status process) 'exit)
             (zerop (process-exit-status process))
             (buffer-live-p (process-buffer process)))
    (with-current-buffer (process-buffer process)
      (goto-char (point-min))
      (setq pip-outdated-packages
            (json-parse-buffer :array-type 'list :object-type 'alist))
      (let ((alists pip-outdated-packages))
        (while alists
          (setcdr (assq 'name (car alists))
                  (string-replace "_" "-" (alist-get 'name (car alists))))
          (setq alists (cdr alists))))
      (kill-buffer)
      (describe-variable 'pip-outdated-packages)
      (message "Calling `%S' succeeded" #'pip-list-outdated))))

(defun pip-list-outdated ()
  "Save the outdated Python packages in `pip-outdated-packages'.

This invokes an asynchronous process and finishes with a message."
  (interactive)
  (let ((command '("pip" "list" "--outdated" "--format" "json")))
    (make-process
     :name "pip-list-outdated"
     :buffer (generate-new-buffer-name "*pip-list-outdated-output*")
     :command command
     :sentinel #'pip--list-outdated-sentinel)
    (message "Running `%s' asynchronously" (string-join command " "))))

(defun pip--upgrade-maybe-sentinel (process _event)
  "Sentinel function for when the `pip-upgrade-maybe' PROCESS succeeds."
  (when (and (eq (process-status process) 'exit)
             (buffer-live-p (process-buffer process)))
    (display-buffer (process-buffer process))))

(defun pip-upgrade-maybe ()
  "Install the latest version of outdated packages unless they are frozen.

This invokes an asynchronous process and finishes with displaying the process
buffer to check whether upgrading has made the dependencies incompatible."
  (interactive)
  (let (found)
    (dolist (alist pip-outdated-packages found)
      (let ((name (alist-get 'name alist))
            (latest_version (alist-get 'latest_version alist)))
        (unless (member name pip-frozen-packages)
          (push (format "%s==%s" name latest_version) found))))
    (if (consp found)
        (let ((command
               `("pip" "install" "--progress-bar" "off" ,@(nreverse found))))
          (make-process
           :name "pip-upgrade-maybe"
           :buffer (generate-new-buffer-name "*pip-upgrade-maybe*")
           :command command
           :sentinel #'pip--upgrade-maybe-sentinel)
          (message "Running `%s' asynchronously" (string-join command " ")))
      (message "`pip-upgrade-maybe' found no packages to install"))))

Eglot for python-mode

Listing lst:configure-eglot+pylsp-ruff configures eglot for Python using the python-lsp-server with the pylsp-ruff plugin for the easiest way to let python-lsp-server use Ruff. It is better to uninstall the Python packages autopep8, flake8, pydocstyle, pylint, and rope.

Listing lst:eglot-directory-variables-for-python shows a proper .dir-locals.el file in the root directory of any Python project to start eglot automatically according to the configuration in listing lst:eglot-maybe-ensure.

Type

(eval

to dump a JSON representation of src_emacs-lisp[:results silent]{(describe-variable 'eglot-workspace-configuration)} for debugging. The comment in listing minimal Eglot setup also shows how to decrease or to increase the verbosity of Python LSP server log output for debugging.

(with-eval-after-load 'eglot
  (setq-default
   eglot-workspace-configuration
   ;; Enable the `:pylsp_ruff' plugin and ensure to disable the
   ;; `:flake8', `:mccabe', and `:pycodestye' plugins.
   '(:pylsp (:plugins
             (:pylsp_ruff
              (:enabled t)
              :flake8           ;; It is better to uninstall flake8
              (:enabled :json-false)
              :mccabe           ;; It is better to uninstall mccabe
              (:enabled :json-false)
              :pycodestyle      ;; It is better to uninstall pycodestyle
              (:enabled :json-false)
              :jedi
              (:auto_import_modules ["numpy"])
              :jedi_completion
              (:cache_for ["astropy"]))))))

;; A .dir-locals.el file proposal in the root of any
;; Python project or Org-mode project tangling Python files
;; to launch eglot automatically.
((nil  ;; nil, since Emacs-29.1 filters out irrelevant variable names.
  . ((eglot-workspace-configuration
      ;; Enable the `:pylsp_ruff' plugin and ensure to disable the
      ;; `:flake8', `:mccabe', and `:pycodestye' plugins.
      . (:pylsp (:plugins
                 (:pylsp_ruff
                  (:enabled t)
                  :flake8           ;; It is better to uninstall flake8
                  (:enabled :json-false)
                  :mccabe           ;; It is better to uninstall mccabe
                  (:enabled :json-false)
                  :pycodestyle      ;; It is better to uninstall pycodestyle
                  (:enabled :json-false)
                  :jedi
                  (:auto_import_modules ["numpy"])
                  :jedi_completion
                  (:cache_for ["astropy"]))))))))

command	key map	keys
xref-find-definition	global-map	(eval
xref-pop	global-map	(eval
flymake-goto-next-error	eglot-mode-map	(eval
flymake-goto-prev-error	eglot-mode-map	(eval
eglot-rename	eglot-mode-map	(eval
eldoc-doc-buffer	eglot-mode-map	(eval

Jedi

Listing lst:example-py is a Python example to test whether jedi in combination with eglot works when coding for instance numpy universal functions.

import numpy
import astropy.units as apu

a = numpy.arange(0, 11)
a = numpy.linspace(0, 10, num=11)
a = numpy.arccos(a)
q = apu.Quantity(a, apu.meter)
print(q)

Code-cells

Code-cells allows to edit IPython or Jupyter notebooks in Emacs with help from either Jupytext or Pandoc to translate between the ipynb format and different plain text formats. Sofar, I have used code-cells to open ipynb notebooks with

(eval

in Emacs for viewing. Listing lst:configure-code-cells configures code-cells.

(when (ensure-package-installation 'code-cells)
  (with-eval-after-load 'code-cells
    (let ((map code-cells-mode-map))
      (keymap-set map "M-p" #'code-cells-backward-cell)
      (keymap-set map "M-n" #'code-cells-forward-cell)
      (keymap-set map "C-c C-c" #'code-cells-eval))))

Libraries

Library dash.el (info)

The library dash.el (info) positions itself as a modern alternative for the list processing API of cl. It is a requirement of important packages in this Emacs setup (for instance citeproc, magit, and smartparens). Listing lst:configure-dash enables fontification of dash macros and makes info-lookup-symbol take into account the dash macros.

(when (fboundp #'global-dash-fontify-mode)
  (global-dash-fontify-mode))

(when (fboundp #'dash-register-info-lookup)
  (with-eval-after-load 'info-look
    (dash-register-info-lookup)))

Library f.el

The library f.el positions itself as a modern API for working with files and directories in Emacs. It is a requirement of the citeproc package in this Emacs setup and requires no configuration.

Library s.el

The library s.el positions itself as the long lost Emacs string manipulation library. It is a requirement of the citeproc and citar packages in this Emacs setup and requires no configuration.

Minor Modes (info)

Synchronal multiple-region editing

(when (ensure-package-installation 'iedit)
  (require 'iedit nil 'noerror))

Unobtrusive whitespace trimming

(when (and (ensure-package-installation 'ws-butler)
           (fboundp 'ws-butler-mode))
  (setopt ws-butler-keep-whitespace-before-point nil)
  (add-hook 'prog-mode-hook #'ws-butler-mode)
  (add-hook 'text-mode-hook #'ws-butler-mode))

Structural editing

Structural editing keeps character pairs (for instance parentheses, curly and square brackets as well as single and double quotes) balanced to leave code (for instance Lisp and Python) and text (for instance LaTeX and Org) structure intact. I use smartparens which offers a normal mode (smartparens-mode) and a strict mode (smartparens-strict-mode). Although both modes insert character pairs, the normal mode allows to delete one of the paired characters easily while the strict mode does not. Therefore, the strict mode is more for code editing since it never breaks programming language rules and the normal mode is more for text editing where structure is a matter of convention instead of programming language rules.

For instance, the strict mode in Python allows to delete entire lists, tuples, or the arguments after the cursor (what Emacs calls point) in a function call without breaking the character pair balance. In order to repair a broken character pair balance, insert a single character by prefixing it with "C-q" bound to quoted-insert.

The smartparens documentation targets experienced Emacs users. The following links show how to put the documentation to practical use:

1. The smartparens cheatsheet demonstrates its usage visually.
2. Omar Antolin's gist "my-smartparens-config.el" is the first place to look for how to tweak smartparens. However, the gist may be partially obsolete, since it is not part of his current Emacs configuration.
3. How to enable smartparens in the minibuffer after eval-expression explains how the machinery after the first and after later usages of eval-expression differ and discusses options how to handle those differences.

Listing lst:configure-smartparens aims to configure smartparens for Go, LaTeX, Lisp dialects, Org, and Python. Execute src_emacs-lisp[:results silent]{(sp-cheat-sheet)} for short documentation taking into account the overridden key bindings in listing lst:configure-smartparens. Table tab:smartparens-commands-and-bindings lists commands with key bindings taken in order from src_emacs-lisp[:results silent]{(sp-cheat-sheet)} that takes the overrides of listing lst:configure-smartparens into account.

Despite the provocative post "What if structural editing was a mistake?", smartparens is one of my favorite packages. In particular, smartparens handles matching pairs in Org-mode files with export and source blocks for multiple formats and languages almost (exceptions are due to Search failed errors inside source blocks) correctly. Therefore, show-smartparens-mode highlights matching pairs immediately in front or after point in such files correctly, contrary to for instance rainbow-delimiters.

(when (and (ensure-package-installation 'smartparens)
           ;; Require `smartparens-config' instead of `smartparens' to
           ;; disable pairing of the quote character for lisp modes.
           (require 'smartparens-config nil 'noerror))
  (setopt sp-base-key-bindings 'sp
          sp-override-key-bindings '(("C-(" . sp-backward-slurp-sexp)
                                     ("C-)" . sp-forward-slurp-sexp)
                                     ("C-M-(" . sp-backward-barf-sexp)
                                     ("C-M-)" . sp-forward-barf-sexp)))

  (when (fboundp 'smartparens-mode)
    (dolist (symbol '(conf-toml-mode-hook prog-mode-hook text-mode-hook))
      (add-hook symbol #'smartparens-mode)))

  (when (fboundp 'smartparens-strict-mode)
    (dolist (symbol '(emacs-lisp-mode-hook
                      go-ts-mode-hook
                      ielm-mode-hook
                      inferior-python-mode-hook
                      lisp-data-mode-hook
                      lisp-mode-hook
                      python-mode-hook
                      sly-mrepl-mode-hook))
      (add-hook symbol #'smartparens-strict-mode)))

  (when (fboundp 'go-ts-mode)
    ;; Stolen from `smartparens-go':
    (sp-with-modes 'go-ts-mode
      (sp-local-pair "{" nil :post-handlers '(("||\n[i]" "RET")))
      (sp-local-pair "/*" "*/" :post-handlers '(("| " "SPC")
                                                ("* ||\n[i]" "RET"))))
    ;; Go has no sexp suffices.  This fixes slurping:
    ;; (|foo).bar -> (foo.bar)
    (add-to-list 'sp-sexp-suffix (list #'go-ts-mode 'regexp "")))

  ;; https://xenodium.com/emacs-smartparens-auto-indent/index.html
  (defun indent-between-pair (&rest _ignored)
    (newline)
    (indent-according-to-mode)
    (forward-line -1)
    (indent-according-to-mode))

  (dolist (left '("(" "[" "{"))
    (sp-local-pair 'prog-mode left
                   nil :post-handlers '((indent-between-pair "RET"))))

  (show-smartparens-global-mode +1))

command	keys	status
sp-forward-sexp	(eval
sp-backward-sexp	(eval
sp-next-sexp	(eval
sp-prev-sexp	(eval
sp-down-sexp	(eval	shadowed
sp-backward-down-sexp	(eval
sp-beginning-of-sexp	(eval
sp-end-of-sexp	(eval
sp-up-sexp	(eval
sp-backward-up-sexp	(eval
sp-kill-sexp	(eval
sp-copy-sexp	(eval
sp-forward-slurp-sexp	(eval	override
sp-backward-slurp-sexp		override
sp-forward-barf-sexp	(eval	override
sp-backward-barf-sexp		override
sp-forward-symbol	(eval
sp-backward-symbol	(eval
sp-unwrap-sexp	(eval	shadowed
sp-backward-unwrap-sexp	(eval
sp-splice-sexp	(eval
sp-splice-killing-backward	(eval
sp-splice-sexp-killing-forward	(eval	shadowed
sp-select-next-thing	(eval
sp-select-next-thing-exchange	(eval
sp-mark-sexp	(eval

Electric operators

Listing lst:configure-electric-operator configures electric-operator-mode to add spaces around operators for compatibility with for instance the Black code formatter for Python.

(when (and (ensure-package-installation 'electric-operator)
           (fboundp 'electric-operator-mode))
  (dolist (symbol '(c-mode-common-hook julia-mode-hook python-mode-hook))
    (add-hook symbol #'electric-operator-mode)))

Smart snippets

(when (ensure-package-installation 'yasnippet)
  ;; Set `yas-alias-to-yas/prefix-p' before loading `yasnippet'.
  (setopt yas-alias-to-yas/prefix-p nil)
  (when (fboundp 'yas-minor-mode)
    (dolist (symbol '(LaTeX-mode-hook
                      org-mode-hook
                      python-mode-hook
                      python-ts-mode-hook))
      (add-hook symbol #'yas-minor-mode))))

Display (info)

Narrowing

Narrowing means focusing in on some portion of the buffer and widening means focussing out on the whole buffer. This allows to concentrate temporarily on for instance a particular function or paragraph by removing clutter. The "Do What I Mean" narrow-or-widen-dwim function allows to toggle between narrowed and widened buffer states. Here, the function narrow-or-widen-dwim operates also on any Org table, Org source block, Org block, or Org subtree.

(with-eval-after-load 'emacs
  (declare-function org-at-table-p "org" (&optional table-type))

  (defun org-narrow-to-table ()
    "Narrow buffer to table at point."
    (interactive)
    (if (org-at-table-p)
        (narrow-to-region (org-table-begin) (org-table-end))
      (user-error "Not in a table")))

  (defun narrow-or-widen-dwim (p)
    "Widen a narrowed buffer, narrow \"Do What I Mean\" otherwise.
DWIM means: region, Org table, Org source block, Org block, Org
subtree, LaTeX environment, TeX group, or defun, whichever
applies first.  Narrowing to org-src-block actually calls
`org-edit-src-code'.

With prefix P, don't widen, just narrow even if buffer is already
narrowed."
    (declare (interactive-only t))
    (interactive "P")
    (cond ((and (buffer-narrowed-p) (not p))
           (widen))
          ((and (bound-and-true-p org-src-mode) (not p))
           (org-edit-src-exit))
          ((region-active-p)
           (narrow-to-region (region-beginning) (region-end)))
          ((derived-mode-p 'org-mode)
           (or (with-demoted-errors "DWIM: %S" (org-narrow-to-table) t)
               (with-demoted-errors "DWIM: %S" (org-edit-src-code) t)
               (with-demoted-errors "DWIM: %S" (org-narrow-to-block) t)
               (org-narrow-to-subtree)))
          ((derived-mode-p 'latex-mode)
           (LaTeX-narrow-to-environment))
          ((derived-mode-p 'tex-mode)
           (TeX-narrow-to-group))
          (t
           (narrow-to-defun))))

  (keymap-set ctl-x-map "n t" #'org-narrow-to-table)
  (keymap-set ctl-x-map "C-n" #'narrow-or-widen-dwim))

Visualize color codes and names

Listing lst:enable-rainbow-mode enables rainbow-mode to colorize color codes and names in buffers for debugging.

(when (and (ensure-package-installation 'rainbow-mode)
           (fboundp 'rainbow-mode))
  (setopt rainbow-x-colors-major-mode-list '(c++-mode
                                             c-mode
                                             emacs-lisp-mode
                                             inferior-emacs-lisp-mode
                                             lisp-interaction-mode
                                             org-mode
                                             python-mode))
  (rainbow-mode +1))

Flash the line around point for visual feedback

Listing lst:flash-line-around-point implements flashing of the line around point for visual feedback after a selection of commands that make it hard to track point movements visually.

;; Ensure loading `pulse' with the dynamic variables `pulse-delay' and
;; `pulse-iterations' before masking them lexically instead of after
;; to prevent the warning triggered by lazy loading.
(when (require 'pulse nil 'noerror)
  ;; https://karthinks.com/software/batteries-included-with-emacs/
  ;; https://github.com/karthink/.emacs.d/blob/master/init.el#L2077
  (defun flash-line-around-point (&rest _)
    "Flash the line around point."
    (let ((pulse-iterations 16)
          (pulse-delay 0.1))
      (pulse-momentary-highlight-one-line (point))))

  (dolist (command '(scroll-up-command
                     scroll-down-command
                     recenter-top-bottom
                     other-window))
    (advice-add command :after #'flash-line-around-point)))

Applications

Hyperlinking and Web Navigation Features (info)

Browse URL (info)

Listing lst:configure-browse-url configures browse-url.

(with-eval-after-load 'browse-url
  (defun browse-url-mpv (url &optional _)
    (start-process "mpv" nil "mpv" url))

  (defconst browse-url-mpv-regexp
    (rx bos "http" (opt "s") "://"
        (or (seq "youtu.be/")
            (seq "www.youtube.com/" (or "embed/" "watch?"))
            (seq (+? nonl) (or ".mp4" ".webm") eos)))
    "Match hyperlinks to open with mpv.")

  (setopt
   browse-url-generic-program (or (when (eq system-type 'darwin) "open")
                                  (executable-find "firefox"))
   browse-url-handlers `((,browse-url-mpv-regexp . browse-url-mpv)
                         ("." . eww-browse-url))))

Emacs Web Wowser

(with-eval-after-load 'eww
  (defun eww-display-pdf-as-binary (fn &rest args)
    (let ((buffer-file-coding-system 'binary))
      (apply fn args)))

  (defun eww-rename-buffer ()
    "Rename the buffer using title or url."
    (let* ((title (plist-get eww-data :title))
           (name (or (and (eq "" title) (plist-get eww-data :url)) title)))
      (rename-buffer (format "*%s # eww*" name) t)))

  (add-hook 'eww-after-render-hook #'eww-rename-buffer)
  (advice-add 'eww-display-pdf :around #'eww-display-pdf-as-binary))

Mailcap

Extension packages as EWW (info), Gnus (info), and Org (info) rely on a mailcap file to know what application should open a specific media file type. Listing lst:tangle-mailcap-file specifies emacsclient as the application to open PDF files.

# https://emacs.stackexchange.com/a/24502 answers the question:
# How to use pdf-tools (pdf-view-mode) in emacs?
application/pdf; emacsclient %s

Open Street Map viewer for Emacs

Open Street Map is a tile-based map viewer with a responsive movable and zoomable display and with a list of multiple preconfigured tile servers. Listing lst:ensure-osm-installation ensures the installation of osm and listing lst:using-osm-example is a minimal example of how to use osm. Inside osm-mode buffers, the key binding for the command src_emacs-lisp

(eval

)} is

(eval

allowing to bookmark such buffers. Outside osm-mode buffers, the key binding for the command src_emacs-lisp

(eval

ly 'consult-bookmark)} is

(eval

.

(ensure-package-installation 'osm)

(osm "Tower of London")

Restclient

Restclient is a tool to manually explore and test HTTP REST webservices. It runs queries from a plain-text query sheet and displays results as images, pretty-printed XML, and pretty-printed JSON.

(ensure-package-installation 'restclient)

# Get the JSON project list from PyPI using PEP-691 and PEP-700
GET https://pypi.org/simple
Accept: application/vnd.pypi.simple.latest+json

# Get the JSON project details of "circular-buffer" using PEP-691 and PEP-700
GET https://pypi.org/simple/circular-buffer
Accept: application/vnd.pypi.simple.latest+json

# Get the JSON project details of "holygrail" using PEP-691 and PEP-700
GET https://pypi.org/simple/holygrail
Accept: application/vnd.pypi.simple.latest+json

# Get the JSON project details of "pipdeptree" using PEP-691 and PEP-700
GET https://pypi.org/simple/pipdeptree
Accept: application/vnd.pypi.simple.latest+json

# Get the JSON project details of "numpy" using PEP-691 and PEP-700
GET https://pypi.org/simple/numpy
Accept: application/vnd.pypi.simple.latest+json

Webjump

Listing lst:set-webjump-options binds

(eval

to webjump and sets the webjump-sites option.

(when (fboundp 'webjump)
  (keymap-global-set "C-c j" 'webjump)
  (with-eval-after-load 'webjump
    (setopt
     webjump-sites
     '(("CS 325 AI Programming" . "courses.cs.northwestern.edu/325")
       ("Emacs News" . "sachachua.com/blog/category/emacs-news")
       ("Mastering Emacs" . "www.masteringemacs.org")
       ("Planet Emacs Life" . "planet.emacslife.com")
       ("Worg - Org Mode Community" . "orgmode.org/worg")
       ("Git: Emacs" . "git.savannah.gnu.org/cgit/emacs.git")
       ("Git: Emacs MultiMedia System" .
        "https://git.savannah.gnu.org/cgit/emms.git")
       ("Git: GNU AUCTeX" . "git.savannah.gnu.org/cgit/auctex.git")
       ("Git: GNU ELPA" . "git.savannah.gnu.org/cgit/emacs/elpa.git")
       ("Git: NonGNU ELPA" . "git.savannah.gnu.org/cgit/emacs/nongnu.git")
       ("Git: Org Mode" . "git.savannah.gnu.org/cgit/emacs/org-mode.git")
       ("List: Org Mode" . "list.orgmode.org")
       ("List: Emacs Developer Archives" .
        "lists.gnu.org/archive/html/emacs-devel/")
       ("List: Help GNU Emacs Archives" .
        "lists.gnu.org/archive/html/help-gnu-emacs/")
       ("Counterpunch" . "www.counterpunch.org")
       ("Dictionary FR" . [simple-query "www.cnrtl.fr"
                                        "www.cnrtl.fr/definition/" ""])
       ("Dictionary NL" . [simple-query "www.woorden.org"
                                        "www.woorden.org/woord/" ""])))))

Elfeed: Emacs web feed reader

Listing lst:set-elfeed-options sets elfeed options, binds the elfeed command, and makes a minimal attempt to enable emms.

(when (and (ensure-package-installation 'elfeed)
           (fboundp 'elfeed))
  (keymap-global-set "C-x w" #'elfeed)

  (with-eval-after-load 'elfeed
    (setopt
     elfeed-feeds
     '(("https://frame.work/fr/fr/blog.rss" framework)
       ("https://nullprogram.com/feed/" c-wellons)
       ("https://planet.emacslife.com/atom.xml" planet-emacs)
       ("https://protesilaos.com/codelog.xml" p-stavrou)
       ("https://sachachua.com/blog/category/emacs/feed" s-chua)
       ("https://updates.orgmode.org/feed/updates" org-updates)
       ("https://www.bof.nl/rss/" bof)
       ("https://www.laquadrature.net/fr/rss.xml" lqdn)
       ("https://www.lemonde.fr/blog/huet/feed/" sciences))))

  (with-eval-after-load 'elfeed-show
    (when (fboundp 'emms-all)
      (emms-all))))

Emacs Multimedia System (info)

The link my emms and elfeed setup is a nice introduction to configuring and using emms with elfeed. Listing lst:set-emms-options configures emms for mpv while eliminating use of mpd.

(when (ensure-package-installation 'emms)
  (with-eval-after-load 'emms
    (emms-all)
    ;; Since `emms-all' may add `emms-player-mpd' to `emms-player-list',
    ;; get rid off `emms-player-mpd' after calling `emms-all'.
    (setopt emms-player-list '(emms-player-mpv)))

  (with-eval-after-load 'emms-mode-line
    (setopt emms-mode-line-format ""))

  (with-eval-after-load 'emms-player-mpd
    (setopt emms-player-mpd-music-directory (expand-file-name "~/Music")
            emms-player-mpd-server-name "localhost"
            emms-player-mpd-server-port "6600"
            emms-player-mpd-verbose t))

  (with-eval-after-load 'emms-player-mpv
    (setopt emms-player-mpv-ipc-method 'ipc-server
            emms-player-mpv-update-metadata t)
    ;; Uncomment the next two lines in case of too many broken YouTube links:
    (add-to-list 'emms-player-mpv-parameters "--ytdl-format=best" 'append)
    (add-to-list 'emms-player-mpv-parameters "--config=no" 'append)
    ;; The two previous lines may make the setup less user friendly.
    (add-to-list 'emms-player-mpv-parameters "--fullscreen" 'append))

  (with-eval-after-load 'emms-playing-time
    (setopt emms-playing-time-display-format " %s "))

  (with-eval-after-load 'emms-playlist-mode
    (setopt emms-playlist-mode-center-when-go t))

  (with-eval-after-load 'emms-streams
    (setopt emms-streams-file
            (no-littering-expand-etc-file-name "emms/streams.emms"))))

Init File (info) footer

(provide 'init)

;; Emacs looks for "Local variables:" after the last "newline-formfeed".

;; Local Variables:
;; indent-tabs-mode: nil
;; End:
;;; init.el ends here

Local variables linking to Latexmk save-compile-display-loop

Only the Org source file shows the local variables footer.