#+title: Emacs Configuration

* Package Setup
Bootstrap package management. I use =elpaca= with =use-package= to allow asynchronous declarative package management.
#+begin_src emacs-lisp
  (defvar elpaca-installer-version 0.10)
  (defvar elpaca-directory (expand-file-name "elpaca/" user-emacs-directory))
  (defvar elpaca-builds-directory (expand-file-name "builds/" elpaca-directory))
  (defvar elpaca-repos-directory (expand-file-name "repos/" elpaca-directory))
  (defvar elpaca-order '(elpaca :repo "https://github.com/progfolio/elpaca.git"
                                :ref nil :depth 1 :inherit ignore
                                :files (:defaults "elpaca-test.el" (:exclude "extensions"))
                                :build (:not elpaca--activate-package)))
  (let* ((repo  (expand-file-name "elpaca/" elpaca-repos-directory))
         (build (expand-file-name "elpaca/" elpaca-builds-directory))
         (order (cdr elpaca-order))
         (default-directory repo))
    (add-to-list 'load-path (if (file-exists-p build) build repo))
    (unless (file-exists-p repo)
      (make-directory repo t)
      (when (<= emacs-major-version 28) (require 'subr-x))
      (condition-case-unless-debug err
          (if-let* ((buffer (pop-to-buffer-same-window "*elpaca-bootstrap*"))
                    ((zerop (apply #'call-process `("git" nil ,buffer t "clone"
                                                    ,@(when-let* ((depth (plist-get order :depth)))
                                                        (list (format "--depth=%d" depth) "--no-single-branch"))
                                                    ,(plist-get order :repo) ,repo))))
                    ((zerop (call-process "git" nil buffer t "checkout"
                                          (or (plist-get order :ref) "--"))))
                    (emacs (concat invocation-directory invocation-name))
                    ((zerop (call-process emacs nil buffer nil "-Q" "-L" "." "--batch"
                                          "--eval" "(byte-recompile-directory \".\" 0 'force)")))
                    ((require 'elpaca))
                    ((elpaca-generate-autoloads "elpaca" repo)))
              (progn (message "%s" (buffer-string)) (kill-buffer buffer))
            (error "%s" (with-current-buffer buffer (buffer-string))))
        ((error) (warn "%s"

                       err) (delete-directory repo 'recursive))))
    (unless (require 'elpaca-autoloads nil t)
      (require 'elpaca)
      (elpaca-generate-autoloads "elpaca" repo)
      (load "./elpaca-autoloads")))
  (add-hook 'after-init-hook #'elpaca-process-queues)
  (elpaca `(,@elpaca-order))

  (setq use-package-always-ensure t)

  (elpaca elpaca-use-package
    (elpaca-use-package-mode))
#+end_src

* Appearance

Use =diredfl= for a colourful =dired= and =ns-auto-titlebar= for a macOS native title-bar look.
#+begin_src emacs-lisp
  (use-package diredfl
    :init
    (diredfl-global-mode 1))
  (use-package ns-auto-titlebar
    :init
    (ns-auto-titlebar-mode))
#+end_src

Colourful delimiters with =rainbow-delimiters=.
#+begin_src emacs-lisp
  (use-package rainbow-delimiters
    :hook
    (prog-mode . rainbow-delimiters-mode))
#+end_src

Tell Emacs to show line numbers, column numbers, and the time by default.
#+begin_src emacs-lisp
  (global-display-line-numbers-mode 1)
  (column-number-mode 1)
  (display-time-mode)
#+end_src

Configure Emacs to default to spaces over tabs and use a width of 4 by default.
#+begin_src emacs-lisp
  (setq-default indent-tabs-mode nil)
  (setq tab-width 4
        c-basic-offset tab-width)
#+end_src

Install and configure =visual-fill-column= to make some file types display with a narrow window centred in the frame.
#+begin_src emacs-lisp
  (defun jj/run-visual-line-mode ()
    "run visual-line-mode"
    (visual-line-mode)
    (visual-fill-column-mode)
    (setq visual-fill-column-width 100
          visual-fill-column-center-text t))
  (use-package visual-fill-column
    :hook
    (org-mode . jj/run-visual-line-mode)
    (markdown-mode . jj/run-visual-line-mode)
    :config
    (setq visual-fill-column-width 100
          visual-fill-column-center-text t))
#+end_src

* Behaviour

Make Emacs use the correct =PATH= variable as macOS fails to load the =PATH= variable from my login shell.
#+begin_src emacs-lisp
  (let ((path-from-shell (replace-regexp-in-string
                          "[ \t\n]*$" "" (shell-command-to-string
                                          "$SHELL --login -c 'echo $PATH'"))))
    (setenv "PATH" path-from-shell)
    (setq exec-path (split-string path-from-shell path-separator)))
#+end_src

I hate macOS scroll inertia. Scrolling in one window, switching to Emacs, and hitting control occasionally changes the text size and can even cause Emacs (and my window manager for some reason) to hang forcing me to force quit Emacs.
#+begin_src emacs-lisp
  (global-unset-key (kbd "<C-wheel-up>"))
  (global-unset-key (kbd "<C-wheel-down>"))
#+end_src

Disable the bell sound on invalid commands.
#+begin_src emacs-lisp
  (setq ring-bell-function 'ignore)
#+end_src

Make Emacs confirm that I want to close it on kill.
#+begin_src emacs-lisp
  (setq confirm-kill-emacs 'yes-or-no-p)
#+end_src

Make Emacs delete trailing whitspace on save. This does not happen in =markdown-mode= which sometimes needs trailing whitespace.
#+begin_src emacs-lisp
  (add-hook 'before-save-hook
            (lambda ()
              (unless (eql (with-current-buffer (current-buffer) major-mode)
                           'markdown-mode)
                (delete-trailing-whitespace))))
#+end_src

Make Emacs create directories if they don't exist if the user selects that answer.
#+begin_src emacs-lisp
  (add-to-list 'find-file-not-found-functions
               (lambda ()
                 (let ((parent-directory (file-name-directory buffer-file-name)))
                   (when (and (not (file-exists-p parent-directory))
                              (y-or-n-p (format "Directory `%s' does not exist! Create it?" parent-directory)))
                     (make-directory parent-directory t)))))
#+end_src

Disable the creation of backup files which pollute the file system.
#+begin_src emacs-lisp
  (setq make-backup-files nil)
#+end_src

Make PDFs save where in the document it was last.
#+begin_src emacs-lisp
  (use-package saveplace-pdf-view
    :config
    (save-place-mode 1))
#+end_src

Configure superior Emacs window management with =windmove=.
#+begin_src emacs-lisp
  (keymap-global-set "C-c w h" 'windmove-left)
  (keymap-global-set "C-c w j" 'windmove-down)
  (keymap-global-set "C-c w k" 'windmove-up)
  (keymap-global-set "C-c w l" 'windmove-right)

  (keymap-global-set "C-c C-w h" 'windmove-swap-states-left)
  (keymap-global-set "C-c C-w j" 'windmove-swap-states-down)
  (keymap-global-set "C-c C-w k" 'windmove-swap-states-up)
  (keymap-global-set "C-c C-w l" 'windmove-swap-states-right)
#+end_src

Don't show tooltips on hover; they are annoying with my window manager.
#+begin_src emacs-lisp
  (tooltip-mode -1)
#+end_src

Automatically increase the size of the focused window.
#+begin_src emacs-lisp
  (use-package zoom
   :init
   (zoom-mode)
   :config
   (setq zoom-size '(0.618 . 0.618)))
#+end_src

* Tools
Install =esup= as a profiling tool.
#+begin_src emacs-lisp
  (use-package esup
    :config
    (setq esup-depth 0))
#+end_src

Use =consult= for better search and navigation.
#+begin_src emacs-lisp
  (use-package consult
    :bind
    (
         ("C-c M-x" . consult-mode-command)
         ("C-c h" . consult-history)
         ("C-c k" . consult-kmacro)
         ("C-c m" . consult-man)
         ("C-c i" . consult-info)
         ([remap Info-search] . consult-info)

         ("C-x M-:" . consult-complex-command)
         ("C-x b" . consult-buffer)
         ("C-x 4 b" . consult-buffer-other-window)
         ("C-x 5 b" . consult-buffer-other-frame)
         ("C-x t b" . consult-buffer-other-tab)
         ("C-x r b" . consult-bookmark)
         ("C-x p b" . consult-project-buffer)

         ("M-#" . consult-register-load)
         ("M-'" . consult-register-store)
         ("C-M-#" . consult-register)

         ("M-y" . consult-yank-pop)

         ("M-g e" . consult-compile-error)
         ("M-g f" . consult-flymake)
         ("M-g g" . consult-goto-line)
         ("M-g M-g" . consult-goto-line)
         ("M-g o" . consult-outline)
         ("M-g m" . consult-mark)
         ("M-g k" . consult-global-mark)
         ("M-g i" . consult-imenu)
         ("M-g I" . consult-imenu-multi)

         ("M-s d" . consult-find)
         ("M-s c" . consult-locate)
         ("M-s g" . consult-grep)
         ("M-s G" . consult-git-grep)
         ("M-s r" . consult-ripgrep)
         ("M-s l" . consult-line)
         ("M-s L" . consult-line-multi)
         ("M-s k" . consult-keep-lines)
         ("M-s u" . consult-focus-lines)

         ("M-s e" . consult-isearch-history)
         :map isearch-mode-map
         ("M-e" . consult-isearch-history)
         ("M-s e" . consult-isearch-history)
         ("M-s l" . consult-line)
         ("M-s L" . consult-line-multi)

         :map minibuffer-local-map
         ("M-s" . consult-history)
         ("M-r" . consult-history))

    :hook
    (completion-list-mode . consult-preview-at-point-mode)

    :init
    (advice-add #'register-preview :override #'consult-register-window)
    (setq register-preview-delay 0.5)
    (setq xref-show-xrefs-function #'consult-xref
          xref-show-definitions-function #'consult-xref)

    :config
    (consult-customize
     consult-theme :preview-key '(:debounce 0.2 any)
     consult-ripgrep consult-git-grep consult-grep consult-man
     consult-bookmark consult-recent-file consult-xref
     consult--source-bookmark consult--source-file-register
     consult--source-recent-file consult--source-project-recent-file
     :preview-key '(:debounce 0.4 any))
    (setq consult-narrow-key "<"))
#+end_src

Disable =ls= for =dired=.
#+begin_src emacs-lisp
  (setq dired-use-ls-dired nil)
#+end_src

Allow multiple cursors.
#+begin_src emacs-lisp
  (use-package multiple-cursors
    :bind
    ("C->" . mc/mark-next-like-this)
    ("C-<" . mc/unmark-next-like-this))
#+end_src

Configure =dumb-jump= for better lookup.
#+begin_src emacs-lisp
  (use-package dumb-jump
    :init
    (add-hook 'xref-backend-functions #'dumb-jump-xref-activate))
#+end_src

Configure and install =magit= as a =git= front end.
#+begin_src emacs-lisp
  (use-package transient)
  (use-package magit)
#+end_src

Install a better PDF viewer than =DocView=.
#+begin_src emacs-lisp
  (use-package pdf-tools
    :hook
    (doc-view-mode . (lambda () (pdf-tools-install))) ;; install on first pdf opened instead of startup
    (pdf-view-mode . (lambda () (display-line-numbers-mode -1)))
    :init
    (add-hook 'TeX-after-compilation-finished-functions #'TeX-revert-document-buffer)
    :config
    (setq TeX-view-program-selection '((output-pdf "PDF Tools"))
          TeX-view-program-list '(("PDF Tools" TeX-pdf-tools-sync-view))
          TeX-source-correlate-start-server t))
#+end_src

Install and configure =eat= as a terminal emulator in Emacs with =eshell= as a shell.
#+begin_src emacs-lisp
  (use-package eat
    :init
    (setopt eat-kill-buffer-on-exit t)
    (eat-eshell-mode)

    ;; Overwrite a default function that makes the prompt editable for some reason
    (defun eshell-emit-prompt ()
     "Emit a prompt if eshell is being used interactively."
     (when (boundp 'ansi-color-context-region)
       (setq ansi-color-context-region nil))
     (run-hooks 'eshell-before-prompt-hook)
     (if (not eshell-prompt-function)
         (set-marker eshell-last-output-end (point))
       (let ((prompt (funcall eshell-prompt-function)))
         (add-text-properties
          0 (length prompt)
          (if eshell-highlight-prompt
              '( read-only t
                 field prompt
                 font-lock-face eshell-prompt
                 front-sticky (read-only field font-lock-face)
                 rear-nonsticky (read-only field font-lock-face))
            '( read-only t
               field prompt
               front-sticky (read-only field font-lock-face)
               rear-nonsticky (read-only field font-lock-face)))
          prompt)
         (eshell-interactive-filter nil prompt)))
     (run-hooks 'eshell-after-prompt-hook))

    (defun jj/shorten-path-str (path)
     (let* ((components (split-string (replace-regexp-in-string (getenv "HOME") "~" path) "/"))
            (head-items (butlast components 2))
            (shortened-head (mapcar (lambda (element)
                                      (if (= (length element) 0)
                                          ""
                                        (substring element 0 1)))
                                    head-items))
            (tail-items (last components 2))
            (new-components (append shortened-head tail-items)))
       (propertize (string-join new-components "/") 'font-lock-face '(:foreground "dark green"))))

    (defun jj/curr-dir-git-branch (path)
     (when (and (not (file-remote-p path))
                (eshell-search-path "git")
                (locate-dominating-file path ".git"))
       (let* ((git-branch (s-trim (shell-command-to-string "git rev-parse --abbrev-ref HEAD")))
              (git-status (s-trim (shell-command-to-string "git status")))
              (outofsync (if (string-match-p "use \"git push\" to publish your local commits" git-status)
                             " "
                           ""))
              (staged (if (string-match-p "Changes to be committed:" git-status)
                          " "
                        ""))
              (unstaged (if (string-match-p "Changes not staged for commit:" git-status)
                            " "
                          ""))
              (untracked (if (string-match-p "Untracked files:"git-status)
                             " "
                           "")))
         (concat (propertize (concat " " git-branch) 'font-lock-face '(:foreground "blue"))
                 (propertize outofsync 'font-lock-face '(:foreground "dark green"))
                 (propertize staged 'font-lock-face '(:foreground "orange"))
                 (propertize unstaged 'font-lock-face '(:foreground "magenta"))
                 (propertize untracked 'font-lock-face '(:foreground "dark red"))))))

    (defun jj/eshell-quit-or-delete-char (arg)
      "Close the terminal if I hit C-d on an empty line"
      (interactive "p")
      (if (and (eolp) (looking-back eshell-prompt-regexp))
          (eshell-life-is-too-much)
        (delete-forward-char arg)))

    (defun eshell/manage-configs (arg)
      "run the argument through make at the root of my dotfiles repository"
      (let ((dir (eshell/pwd)))
       (eshell/cd "~/.dotfiles")
       (compile (concat "make " arg))
       (eshell/cd dir)))

    (defun eshell/yt-2-rss (url)
      "convert a youtube channel link into an rss link"
      (if (not (libxml-available-p))
        (message "libxml is not available")
        (browse-url-emacs url t)
        (let* ((dom (libxml-parse-html-region))
               (rss (dom-elements dom 'title "RSS"))
               (href (dom-attr rss 'href)))
          (kill-buffer)
          href)))

    (setq eshell-highlight-prompt nil)
    (setq eshell-prompt-function (lambda ()
                                   (concat (jj/shorten-path-str (eshell/pwd))
                                           (jj/curr-dir-git-branch (eshell/pwd))
                                           (unless (eshell-exit-success-p)
                                             (format " [%d]" eshell-last-command-status))
                                           (if (= (file-user-uid) 0) " # " " $ "))))

    :config
    (setq eshell-visual-commands '())

    :hook
    (eat-mode . (lambda () (display-line-numbers-mode -1)))
    (eshell-mode . (lambda ()
                     (display-line-numbers-mode -1)
                     (eshell/alias "ll" "ls -alF $@*")
                     (eshell/alias "la" "ls -a $@*")
                     (eshell/alias "l" "ls -F $@*")
                     (eshell/alias "ff" "find-file $@*")
                     (eshell/alias "clr" "clear-scrollback")))
    :bind
    ("C-c v" . eshell)
    (:map eshell-mode-map ("C-d" . jj/eshell-quit-or-delete-char)))
#+end_src

Use =corfu= and =vertico= for completions. =orderless= is used to allow searching in any portion of a string and =marginalia= gives descriptions of items in the list.
#+begin_src emacs-lisp
  (use-package corfu
    :custom
    (corfu-cycle t)
    (corfu-auto t)
    :init
    (global-corfu-mode))
  (use-package vertico
    :custom
    (vertico-cycle t)
    (vertico-mode 1))
  (use-package orderless
    :custom
    (completion-styles '(orderless basic))
    (completion-category-overrides '((file (styles basic partial-completion)))))
  (use-package marginalia
    :bind
    (:map minibuffer-local-map
          ("M-A" . marginalia-cycle))
    :init
    (marginalia-mode 1))
#+end_src

Set up =flycheck= and =flyspell= for syntax and spell checking respectively.
#+begin_src emacs-lisp
  (use-package flycheck
    :config
    (add-hook 'after-init-hook #'global-flycheck-mode))

  (require 'flyspell)
  (add-hook 'text-mode-hook #'flyspell-mode)
  (use-package flyspell-correct
    :after flyspell
    :bind
    (:map flyspell-mode-map ("C-;" . flyspell-correct-wrapper)))
#+end_src

Install =yasnippet= for managing snippets and =yasnippet-snippets= for a collection of useful snippets.
#+begin_src emacs-lisp
  (use-package yasnippet
    :init
    (yas-global-mode 1)
    :bind
    ("C-c s" . yas-insert-snippet))
  (use-package yasnippet-snippets)
#+end_src

Install =apheleia= and =clang-format= to automatically format code on save.
#+begin_src emacs-lisp
    (use-package apheleia
      :init (apheleia-global-mode 1))
    (use-package clang-format)
#+end_src

Configure and install =elfeed= to serve as an =rss= feed reader.
#+begin_src emacs-lisp
  (use-package elfeed
    :bind
    ("C-c e f" . elfeed)
    ("C-c e u" . elfeed-update))
  (use-package elfeed-goodies
    :after
    elfeed
    :config
    (elfeed-goodies/setup))
  (use-package elfeed-org
    :config
    (elfeed-org)
    (setq rmh-elfeed-org-files (list "~/.config/emacs/feed.org")))
#+end_src

Smooth scrolling with =ultra-scroll=.
#+begin_src emacs-lisp
  (use-package ultra-scroll
   :ensure (ultra-scroll :host github :repo "jdtsmith/ultra-scroll")
   :init
   (setq scroll-conservatively 101
     scroll-margin 0)
   :config
   (ultra-scroll-mode 1))
#+end_src

Install my pomodoro timer package.
#+begin_src emacs-lisp
  (use-package pomodoro-mode
    :ensure (pomodoro-mode :host github :repo "jjanzenn/pomodoro-mode"))
#+end_src

Configure =emms= as a music player.
#+begin_src emacs-lisp
  (use-package emms
    :init
    (emms-all)
    (setq emms-player-list '(emms-player-mpv)
          emms-info-functions '(emms-info-native)
          emms-browser-covers #'emms-browser-cache-thumbnail-async
          emms-browser-thumbnail-small-size 64
          emms-browser-thumbnail-medium-size 128
          emms-browser-thumbnail-large-size 256)
    (emms-librefm-scrobbler-enable))
#+end_src

* Languages

Configure =org-mode=. I use =~/org= as my =org= directory and hide emphasis markers because it's much easier to read that way. I enable =org-crypt= to allow reading and writing encrypted =org= files. I also replace bullets in bulleted lists with nicer looking icons. I configure faces to default to variable-width font, but switching to monospace where it is necessary. Finally, I use =visual-fill-column= to make =org= files display with a relatively narrow window centred in the frame.
#+begin_src emacs-lisp
  (use-package org
    :hook
    (org-mode . (lambda ()
                  (variable-pitch-mode)
                  (display-line-numbers-mode -1)))
    :bind
    (
     ("C-c l" . org-store-link)
     ("C-c a" . org-agenda)
     ("C-c c" . org-capture))

    :config
    (org-crypt-use-before-save-magic)

    (setq org-directory "~/org"
          org-agenda-files (list org-directory)
          org-agenda-file-regexp "\\`[^.].*\\.org\\\(\\.gpg\\\)?\\'"
          org-todo-keywords '((sequence "TODO(t)" "PLANNING(p)" "IN-PROGRESS(i@/!)" "VERIFYING(v!)" "BLOCKED(b@)"  "|" "DONE(d!)" "WONT-DO(w@/!)"))
          org-todo-keyword-faces '(
                                   ("TODO" . (:foreground "GoldenRod" :weight bold))
                                   ("PLANNING" . (:foreground "DeepPink" :weight bold))
                                   ("IN-PROGRESS" . (:foreground "DarkCyan" :weight bold))
                                   ("VERIFYING" . (:foreground "DarkOrange" :weight bold))
                                   ("BLOCKED" . (:foreground "Red" :weight bold))
                                   ("DONE" . (:foreground "LimeGreen" :weight bold))
                                   ("OBE" . (:foreground "LimeGreen" :weight bold))
                                   ("WONT-DO" . (:foreground "LimeGreen" :weight bold)))
          org-log-done 'time
          org-hide-emphasis-markers t
          org-format-latex-options (plist-put org-format-latex-options :scale 2.0)
          org-return-follows-link t
          org-tags-exclude-from-inheritance '("crypt")
          org-crypt-key nil
          auto-save-default nil)
    (setq org-capture-templates
        '(
          ("n" "Note"
           entry (file+headline "~/org/notes.org.gpg" "Random Notes")
           "** %?"
           :empty-lines 0)
          ("g" "General To-Do"
           entry (file+headline "~/org/todos.org.gpg" "General Tasks")
           "* TODO [#B] %?\n:Created: %T\n "
           :empty-lines 0)
          ("d" "To-Do with Deadline"
           entry (file+headline "~/org/todos.org.gpg" "Time Dependent Tasks")
           "* TODO [#B] %?\n:Created: %T\n:Deadline: %^t\n"
           :empty-lines 0)))
    (font-lock-add-keywords 'org-mode
                            '(("^ *\\([-]\\) "
                               (0 (prog1 () (compose-region (match-beginning 1) (match-end 1) "•"))))))
    :custom-face
    (org-block ((t :font ,jj/mono-font)))
    (org-code ((t :font ,jj/mono-font (:inherit (shadow)))))
    (org-document-info-keyword ((t :font ,jj/mono-font (:inherit (shadow)))))
    (org-meta-line ((t :font ,jj/mono-font (:inherit (font-lock-comment-face)))))
    (org-verbatim ((t :font ,jj/mono-font (:inherit (shadow)))))
    (org-table ((t :font ,jj/mono-font (:inherit (shadow)))))
    (org-document-title ((t (:inherit title :height 2.0 :underline nil))))
    (org-level-1 ((t (:inherit outline-1 :weight bold :height 1.75))))
    (org-level-2 ((t (:inherit outline-2 :weight bold :height 1.5))))
    (org-level-3 ((t (:inherit outline-3 :weight bold :height 1.25))))
    (org-level-4 ((t (:inherit outline-4 :weight bold :height 1.1))))
    (org-level-5 ((t (:inherit outline-5 :height 1.1))))
    (org-level-6 ((t (:inherit outline-6)))))
#+end_src

Highlight comment tags like =TODO= and whatnot.
#+begin_src emacs-lisp
  (use-package comment-tags
    :init
    (setq comment-tags-keyword-faces
          `(("TODO" . ,(list :weight 'bold :foreground "#28ABE3"))
            ("FIXME" . ,(list :weight 'bold :foreground "#DB3340"))
            ("BUG" . ,(list :weight 'bold :foreground "#DB3340"))
            ("HACK" . ,(list :weight 'bold :foreground "#E8B71A"))
            ("KLUDGE" . ,(list :weight 'bold :foreground "#E8B71A"))
            ("XXX" . ,(list :weight 'bold :foreground "#F7EAC8"))
            ("INFO" . ,(list :weight 'bold :foreground "#F7EAC8"))
            ("DONE" . ,(list :weight 'bold :foreground "#1FDA9A"))))
    (setq comment-tags-comment-start-only t
          comment-tags-require-colon t
          comment-tags-case-sensitive t
          comment-tags-show-faces t
          comment-tags-lighter t)
    :hook
    (prog-mode . comment-tags-mode))
#+end_src

Install =cmake-mode=.
#+begin_src emacs-lisp
  (use-package cmake-mode)
#+end_src

Install =go-mode= and tools for =go= source code. Namely, =go-eldoc= gets documentation for =go= variables, functions, and arguments, =go-gen-tests= automatically generates tests for =go= code, and =go-guru= helps with refactoring =go= code.
#+begin_src emacs-lisp
  (use-package go-mode)
  (use-package go-eldoc
    :hook
    (go-mode . go-eldoc-setup))
  (use-package go-gen-test)
  (use-package go-guru
    :hook
    (go-mode . go-guru-hl-identifier-mode))
#+end_src

Install tools for LaTeX. Namely, =auctex= for better integration with Emacs and =cdlatex= for environment and macro insertion.
#+begin_src emacs-lisp
  (use-package auctex
    :hook
    (LaTeX-mode . (lambda () (put 'LaTeX-mode 'eglot-language-id "latex"))))
  (use-package cdlatex
    :hook
    (LaTeX-mode . turn-on-cdlatex))
#+end_src

Install tools for Emacs Lisp. Namely =parinfer-rust-mode= which handles parentheses nicely in Emacs Lisp.
#+begin_src emacs-lisp :tangle yes
  (use-package parinfer-rust-mode
    :hook
    (emacs-lisp-mode . parinfer-rust-mode)
    :init
    (setq parinfer-rust-auto-download t))
#+end_src

Install =lua-mode=.
#+begin_src emacs-lisp
  (use-package lua-mode)
#+end_src

Configure how Markdown is displayed (default to variable-width font and use monospace where necessary) and installs =markdown-mode=.
#+begin_src emacs-lisp
  (use-package markdown-mode
    :hook
    (markdown-mode . (lambda ()
                       (variable-pitch-mode)
                       (display-line-numbers-mode -1)
                       (eglot-ensure)))
    :config
    (setq markdown-hide-markup t)
    :custom-face
    (markdown-header-face ((t :font ,jj/var-font :weight bold)))
    (markdown-header-face-1 ((t (:inherit markdown-header-face :height 2.0))))
    (markdown-header-face-2 ((t (:inherit markdown-header-face :height 1.75))))
    (markdown-header-face-3 ((t (:inherit markdown-header-face :height 1.5))))
    (markdown-header-face-4 ((t (:inherit markdown-header-face :height 1.25))))
    (markdown-header-face-5 ((t (:inherit markdown-header-face :height 1.1))))
    (markdown-header-face-6 ((t (:inherit markdown-header-face :height 1.1))))
    (markdown-blockquote-face ((t :font ,jj/var-font)))
    (markdown-code-face ((t :font ,jj/mono-font)))
    (markdown-html-attr-name-face ((t :font ,jj/mono-font)))
    (markdown-html-attr-value-face ((t :font ,jj/mono-font)))
    (markdown-html-entity-face ((t :font ,jj/mono-font)))
    (markdown-html-tag-delimiter-face ((t :font ,jj/mono-font)))
    (markdown-html-tag-name-face ((t :font ,jj/mono-font)))
    (markdown-html-comment-face ((t :font ,jj/mono-font)))
    (markdown-header-delimiter-face ((t :font ,jj/mono-font)))
    (markdown-hr-face ((t :font ,jj/mono-font)))
    (markdown-inline-code-face ((t :font ,jj/mono-font)))
    (markdown-language-info-face ((t :font ,jj/mono-font)))
    (markdown-language-keyword-face ((t :font ,jj/mono-font)))
    (markdown-link-face ((t :font ,jj/mono-font)))
    (markdown-markup-face ((t :font ,jj/mono-font)))
    (markdown-math-face ((t :font ,jj/mono-font)))
    (markdown-metadata-key-face ((t :font ,jj/mono-font)))
    (markdown-metadata-value-face ((t :font ,jj/mono-font)))
    (markdown-missing-link-face ((t :font ,jj/mono-font)))
    (markdown-plain-url-face ((t :font ,jj/mono-font)))
    (markdown-reference-face ((t :font ,jj/mono-font)))
    (markdown-table-face ((t :font ,jj/mono-font)))
    (markdown-url-face ((t :font ,jj/mono-font))))
#+end_src

Install =nix-mode=.
#+begin_src emacs-lisp
    (use-package nix-mode
      :mode
      "\\.nix\\'")
#+end_src

Install =yaml-mode=.
#+begin_src emacs-lisp :tangle yes
  (use-package yaml-mode)
#+end_src

Install =zig-mode=.
#+begin_src emacs-lisp
  (use-package zig-mode)
#+end_src

Set up =eglot= to run on languages that have been configured.
#+begin_src emacs-lisp
  (global-set-key (kbd "C-c r") 'eglot-rename)
  (use-package tree-sitter)
  (use-package tree-sitter-langs)
  (dolist (lang-hook '(sh-mode-hook
                       c-mode-hook
                       c++-mode-hook
                       cc-mode-hook
                       cmake-mode-hook
                       html-mode-hook
                       css-mode-hook
                       js-json-mode-hook
                       js-mode-hook
                       python-mode-hook
                       go-mode-hook
                       lua-mode-hook
                       tex-mode-hook
                       LaTeX-mode-hook
                       yaml-mode-hook
                       nix-mode-hook
                       zig-mode-hook))
    (add-hook lang-hook (lambda ()
                          (eglot-ensure)
                          (tree-sitter-mode 1)
                          (tree-sitter-hl-mode 1))))
#+end_src
