#+title: Emacs Configuration

* Early 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

Force the use of a =custom.el= file instead of appending to =init.el=.
#+begin_src emacs-lisp
  (setq custom-file (concat user-emacs-directory "custom.el"))
  (when (file-exists-p custom-file)
    (load custom-file))
#+end_src

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

* Appearance

Set up fonts. I use Source Code Pro (Nerd Font) for =monospace= and Computer Modern for /variable width/.
#+begin_src emacs-lisp
  (defvar jj/mono-font)
  (defvar jj/var-font)
  (pcase system-type
    (`gnu/linux
     (setq jj/mono-font "SauceCodePro Nerd Font-11"
           jj/var-font "CMU Serif-14"))
    (`darwin
     (setq jj/mono-font "SauceCodePro Nerd Font-14:weight=thin"
           jj/var-font "CMU Serif-18")))
  (add-to-list 'default-frame-alist
               `(font . ,jj/mono-font))
  (custom-set-faces
   `(variable-pitch ((t :font ,jj/var-font)))
   `(fixed-pitch ((t :font ,jj/mono-font))))
 #+end_src

Use =diredfl= for a colourful =dired= and clean up the interface by removing scroll bars, tool bars, and menu bars. Allow Emacs to scale frames by pixel rather than character.
#+begin_src emacs-lisp
  (use-package diredfl
    :init
    (diredfl-global-mode 1))
  (use-package ns-auto-titlebar
    :init
    (ns-auto-titlebar-mode))
  (add-to-list 'default-frame-alist '(vertical-scroll-bars . nil)) ; saves about 0.02 seconds on startup over `(scroll-bar-mode -1)`
  (push '(tool-bar-lines . 0) default-frame-alist) ; saves about 0.1 seconds on startup over `(tool-bar-mode -1)`
  (menu-bar-mode -1)
  (setq frame-resize-pixelwise t)
#+end_src

Disable the default startup screen so Emacs starts in the =scratch= buffer and also defaults to an empty =scratch= buffer.
#+begin_src emacs-lisp
  (setq inhibit-startup-screen t
        initial-scratch-message nil)
#+end_src

Tell Emacs to use line numbers by default.
#+begin_src emacs-lisp
  (global-display-line-numbers-mode 1)
#+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

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

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

* Tools
Install =esup= as a profiling tool.
#+begin_src emacs-lisp
  (use-package esup
    :config
    (setq esup-depth 0))
#+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/mark-previous-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 =fzf= to be used as a fuzzy finder.
#+begin_src emacs-lisp
  (use-package fzf
    :bind
    ("C-c C-f" . fzf)
    :config
    (setq fzf/args "-x --color 16 --print-query --margin=1,0 --no-hscroll"
          fzf/executable "fzf"
          fzf/git-grep-args "-i --line-number %s"
          fzf/grep-command "grep -nrH"
          fzf/position-bottom nil
          fzf/window-height 15))
#+end_src

Install and configure =vterm= as a terminal emulator in Emacs.
#+begin_src emacs-lisp
  (use-package vterm
    :hook
    (vterm-mode . (lambda () (display-line-numbers-mode -1)))
    :bind
    ("C-c v" . vterm))
#+end_src

Install =company= for completions. It is configured to start with no delay immediately after the first key press. =vertico= is used as a front end 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 company
    :init
    (global-company-mode)
    :config
    (setq company-idle-delay 0.4
          company-minimum-prefix-length 1
          company-selection-wrap-around t))
  (use-package vertico
    :custom
    (vertico-cycle t)
    :init
    (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))
  (use-package flyspell-correct
    :hook
    (text-mode . flyspell-mode)
    :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. It stores the feed [[./feed.org.org][here]].
#+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

* 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)))
    :config
    (org-crypt-use-before-save-magic)
    (setq org-directory "~/org"
          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)
    (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

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)
  (global-set-key (kbd "C-c a") 'eglot-code-actions)
  (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