#+title: Emacs configuration
#+author: Oreodave
#+description: My new Emacs configuration
#+property: header-args:emacs-lisp :tangle config.el :comment link
#+options: toc:nil

#+begin_center
My configuration for vanilla Emacs
#+end_center
#+latex: \clearpage
#+toc: headlines
#+latex: \clearpage

* Initial
** Who am I?
Set full name and mail address for use in a variety of applications,
including encryption.
#+begin_src emacs-lisp
(setq user-full-name "Aryadev Chavali"
      user-mail-address "aryadev@aryadevchavali.com")
#+end_src
** Saving files
Setup backup files at =user-emacs-directory/saves=, auto-revert mode
for everything and save my place in a file if possible
#+begin_src emacs-lisp
(setq backup-directory-alist `(("." . "~/.config/emacs/saves")))
(global-auto-revert-mode 1)
(setq global-auto-revert-non-file-buffers nil
      auto-revert-verbose nil)
#+end_src
** All yes or no questions to y or n
Sets yes or no questions to single letter responses.
#+begin_src emacs-lisp
(fset 'yes-or-no-p 'y-or-n-p)
#+end_src
** Hs Minor mode
Turn on hs minor mode for all prog-mode.
#+begin_src emacs-lisp
(add-hook 'prog-mode-hook #'hs-minor-mode)
#+end_src
** Themes
Load my custom "Grayscale" theme (look at [[file:Grayscale-theme.el][this file]]).
#+begin_src emacs-lisp
(load-theme 'Grayscale t)
#+end_src
** Turn off startup buffer and turn off bells
#+begin_src emacs-lisp
(setq inhibit-startup-screen t
      ring-bell-function 'ignore)
#+end_src
** Setup scratch buffer
Write into the scratch buffer some nice information about Emacs.
#+begin_src emacs-lisp
(setq initial-scratch-message
      (format ";; Emacs v%s\n;; Entered emacs in %s"
              emacs-version (emacs-init-time)))
#+end_src
* Emacs Mode-line
Firstly, declare a variable for the separator between each module
#+begin_src emacs-lisp
(defconst +modeline/separator " " "Separator between modules.")
#+end_src

Then declare a variable for the number of separators between each
module in the modeline.
#+begin_src emacs-lisp
(defconst +modeline/sep-count 4 "Number of +modline/separator instances separating modules.")
#+end_src

Then, declare a list of reserved characters for which the previously
declared seperator won't be applied when placed at the end of a module
string.
#+begin_src emacs-lisp
(defconst +modeline/reserved-chars (list "[" "(")
        "Characters that, when at the end of a module string, won't have the separator applied to them.")
#+end_src

Now declare a function that applies the separator with respect to the
reserved characters to any one string.
#+begin_src emacs-lisp
(defun +modeline/handle-string (STR)
  (condition-case nil
      (progn
        (string-blank-p STR)
        (cond ((cl-member (car (last (split-string STR "" t))) +modeline/reserved-chars :test #'string=) STR)
              (t (concat STR (cl-reduce #'concat (cl-loop for i from 1 to +modeline/sep-count collect +modeline/separator))))))
    (error STR)))
#+end_src

Finally, set the mode-line-format.
#+begin_src emacs-lisp
(setq-default
 mode-line-format
 (mapcar #'+modeline/handle-string
       (list "%l:%c"
             "%p["
             '(:eval (upcase
                      (substring
                       (format "%s" (if (bound-and-true-p evil-state) evil-state ""))
                       0 1)))
             "]"
             "%+%b("
             '(:eval (format "%s" major-mode))
             ")"
             "%I"
             vc-mode
             mode-line-end-spaces)))
#+end_src
* Custom Functions
These are custom functions I have defined
** New line function
Vim bindings don't have a nice way of adding new lines before or after
the current line while staying in normal mode.  You can use =o/O= to
enter insert mode at a new line, but this isn't the same as being able
to stay in normal mode while opening newlines and only adds extra
keypresses if your only purpose was to open up some lines.

As this is Emacs I can extend it as I wish, so I decided to define a
new line function that won't remove me from normal state.

The logic is pretty simple:
- Use the predefined vim functions for opening new lines above and
  below with insert mode
  - Given the argument =BACKWARD= to assess whether to open lines
    above or below
- Return to previous location
- Enter normal state

  #+begin_src emacs-lisp
  (with-eval-after-load "evil"
    (defun dx:newline (&optional BACKWARD)
      (interactive)
      (let ((old (point)))
        (cond ((and BACKWARD (= BACKWARD 1)) (evil-open-below 1))
              (t (evil-open-above 1)))
        (goto-char (+ old 1))
        (evil-normal-state))))
  #+end_src
** Toggle buffer
For some buffer with name =buf-name= with a creation function
=buf-create=, toggle it via this function.
#+begin_src emacs-lisp
(defun +dx/toggle-buffer (buf-name buf-create)
  (interactive)
  (let* ((buffer (or (get-buffer buf-name) (funcall buf-create)))
         (displayed (get-buffer-window buffer))) ; Get window when displayed, nil otherwise
    (cond (displayed ; already displayed thus delete
           (select-window displayed)
           (delete-window))
          (t ; not displayed thus show and select
           (display-buffer buffer)
           (select-window (get-buffer-window buffer))))))
#+end_src
* General
Setup general, a good package for defining keys.  In this case, I
generate a new definer for the "LEADER" keys.  Leader is bound to SPC
and it's functionally equivalent the doom/spacemacs leader.
#+begin_src emacs-lisp
(use-package general
  :config
  (general-def 'normal global-map "SPC" nil)
  (general-def 'normal global-map
    "M-V" #'dx:newline
    "M-v" #'(lambda () (interactive) (dx:newline 1))
    "M--" #'whitespace-cleanup
    "C--" #'text-scale-decrease
    "C-=" #'text-scale-increase)

  (general-create-definer leader
    :states 'normal
    :keymaps 'override
    :prefix "SPC")

  (leader
    "!"   #'async-shell-command
    ";"   #'eval-expression
    "SPC" #'execute-extended-command
    "q"   #'kill-emacs
    "u"   #'universal-argument
    "cF"  #'(lambda () (interactive) (find-file "~/Code/"))
    "cc"  #'compile
    "si"  #'imenu
    "h"   #'help-command)

  (leader
    :infix "b"
    "d" #'kill-this-buffer
    "i" #'ibuffer
    "b" #'switch-to-buffer
    "j" #'next-buffer
    "k" #'previous-buffer)

  (leader
    :infix "f"
    "f" #'find-file
    "s" #'save-buffer
    "p" #'(lambda () (interactive) (find-file (concat user-emacs-directory "config.org")))))
#+end_src
* Evil
** Evil default
Setup the evil package, with some basic keybinds.  Also declare a
leader-map at "SPC".
#+begin_src emacs-lisp
(use-package evil
  :hook (after-init-hook . evil-mode)
  :init
  (setq evil-want-keybinding nil
        evil-split-window-below t
        evil-vsplit-window-right t)
  :config
  (evil-define-key 'normal global-map
    "TAB" #'evil-jump-item)
  (evil-define-key 'visual 'emacs-lisp-mode-map "gr" #'eval-region)
  (leader
    :infix "w"
    "h" #'evil-window-left
    "j" #'evil-window-down
    "k" #'evil-window-up
    "l" #'evil-window-right))
#+end_src
** Evil surround
#+begin_src emacs-lisp
(use-package evil-surround
  :after evil
  :config
  (global-evil-surround-mode))
#+end_src
** Evil commentary
#+begin_src emacs-lisp
(use-package evil-commentary
  :after evil
  :config
  (evil-commentary-mode))
#+end_src
** Evil mc
Setup for multicursors in Evil mode. Don't let evil-mc setup it's own
keymap because it uses 'gr' as its prefix, which I don't like.

Instead, bind some useful functions to my personal =dx:evil-mc-map=
which is bound to 'gz'.  Furthermore, define a function
=dx:evil-mc-cursor-here= which pauses cursors upon placing a cursor at
the current position.
#+begin_src emacs-lisp
(use-package evil-mc
  :after evil
  :bind (("M-p" . evil-mc-skip-and-goto-prev-cursor)
         :map dx:evil-mc-map
         ("q"   . evil-mc-undo-all-cursors)
         ("d"   . evil-mc-make-and-goto-next-match)
         ("j"   . evil-mc-make-cursor-move-next-line)
         ("k"   . evil-mc-make-cursor-move-prev-line)
         ("j"   . evil-mc-make-cursor-move-next-line)
         ("m"   . evil-mc-make-all-cursors)
         ("z"   . dx:evil-mc-cursor-here)
         ("r"   . evil-mc-resume-cursors)
         ("s"   . evil-mc-pause-cursors))
  :init
  (setq evil-mc-key-map nil)
  (define-prefix-command 'dx:evil-mc-map)
  (bind-key "gz" dx:evil-mc-map evil-normal-state-map)
  :config
  (global-evil-mc-mode +1)
  (defun dx:evil-mc-cursor-here ()
    (interactive)
    (evil-mc-make-cursor-here)
    (evil-mc-pause-cursors)))
#+end_src

** Evil collection
Setup evil collection, but don't turn on the mode. Instead, I'll turn
on setups for specific modes I think benefit from it.
#+begin_src emacs-lisp
(use-package evil-collection
  :after evil)
#+end_src
* Ivy
Ivy is a completion framework for Emacs, and my preferred (sometimes
second favourite) one. It has a great set of features with little to
no pain with setting up.
** Ivy
Setup for ivy, in preparation for counsel. Turn on ivy-mode just
after init.

Setup vim-like bindings for the minibuffer ("C-(j|k)" for down|up the
selection list). Also setup evil-collection for ivy.
#+begin_src emacs-lisp
(use-package ivy
  :after evil-collection
  :general
  (general-def
    :keymaps 'ivy-minibuffer-map
    "M-j"     #'ivy-next-line-or-history
    "M-k"     #'ivy-previous-line-or-history
    "C-c C-e" #'ivy-occur)
  (general-def
    :keymaps 'ivy-switch-buffer-map
    "M-j"     #'ivy-next-line-or-history
    "M-k"     #'ivy-previous-line-or-history)
  :config
  (require 'counsel nil t)
  (setq ivy-height 10
        ivy-wrap t
        ivy-fixed-height-minibuffer t
        ivy-use-virtual-buffers nil
        ivy-virtual-abbreviate 'full
        ivy-on-del-error-function #'ignore
        ivy-use-selectable-prompt t)
  (evil-collection-ivy-setup)
  (ivy-mode))
#+end_src
** Counsel
Setup for counsel. Load after ivy and helpful.

Bind:
- Swiper to "C-s"
- Switch buffer to "C-x b"
- Counsel ripgrep to "M-s r" (search namespace)

Along with that, set the help function and variable functions to their
helpful counterparts.
#+begin_src emacs-lisp
(use-package counsel
  :defer t
  :general
  (leader
    "ss" #'counsel-grep-or-swiper)
  :init
  (general-def
    [remap describe-function]        #'counsel-describe-function
    [remap describe-variable]        #'counsel-describe-variable
    [remap describe-bindings]        #'counsel-descbinds
    [remap describe-face]            #'counsel-faces
    [remap execute-extended-command] #'counsel-M-x
    [remap find-file]                #'counsel-find-file
    [remap imenu]                    #'counsel-imenu
    [remap load-theme]               #'counsel-load-theme)
  :init
  (setq counsel-describe-function-function #'helpful-callable
        counsel-describe-variable-function #'helpful-variable)
  :config
  (setq ivy-initial-inputs-alist nil)
  (counsel-mode +1))
#+end_src
** Counsel etags
Counsel etags allows me to search generated tag files for tags. I
already have a function defined to generate the tags, so it's just
searching them which I find to be a bit of a hassle, and where this
package comes in.
#+begin_src emacs-lisp
(use-package counsel-etags
 :after counsel
 :general
 (leader "st" #'counsel-etags-find-tag))
#+end_src
* Prompt buffer switch
Essentially add advice to the window split functions so that they run
ivy-switch-buffer once they're finished.
#+begin_src emacs-lisp
(with-eval-after-load "ivy"
  (with-eval-after-load "evil"
    (advice-add #'evil-window-vsplit :after #'ivy-switch-buffer)
    (advice-add #'evil-window-split  :after #'ivy-switch-buffer)))
#+end_src
* Xwidget
Xwidget is a package (that must be compiled at source) which allows
for the insertion of arbitrary xwidgets into Emacs through
buffers. One of its premier uses is in navigating the web which it
provides through the function =xwidget-webkit-browse-url=. This
renders a fully functional web browser within Emacs.

Though I am not to keen on using Emacs to browse the web /via/ xwidget
(EWW does a good job on its own), I am very interested in its
capability to render full fledged HTML documents, as it may come of
use when doing web development. I can see the results of work very
quickly without switching windows or workspaces.
#+begin_src emacs-lisp
(use-package xwidget
  :straight nil
  :general
  (leader "au" #'xwidget-webkit-browse-url)
  (general-def
    :states 'normal
    :keymaps 'xwidget-webkit-mode-map
    "q"         #'quit-window
    "h"         #'xwidget-webkit-scroll-backward
    "j"         #'xwidget-webkit-scroll-up
    "k"         #'xwidget-webkit-scroll-down
    "l"         #'xwidget-webkit-scroll-forward
    (kbd "C-f") #'xwidget-webkit-scroll-up
    (kbd "C-b") #'xwidget-webkit-scroll-down
    "H"         #'xwidget-webkit-back
    "L"         #'xwidget-webkit-forward
    "gu"        #'xwidget-webkit-browse-url
    "gr"        #'xwidget-webkit-reload
    "gg"        #'xwidget-webkit-scroll-top
    "G"         #'xwidget-webkit-scroll-bottom))
#+end_src

* Avy
Setup avy with leader.
#+begin_src emacs-lisp
(use-package avy
  :after evil
  :general
  (leader
    :infix "s"
    "l" #'avy-goto-line
    "g" #'avy-goto-char-2))
#+end_src
* Projectile
Setup projectile, along with the tags command. Also bind "C-c C-p" to
the projectile command map for quick access.
#+begin_src emacs-lisp
(use-package projectile
  :after evil
  :hook (prog-mode-hook . projectile-mode)
  :general
  (leader "p" #'projectile-command-map)
  :init
  (setq projectile-tags-command "ctags -Re -f \"%s\" %s \"%s\"")
  :config
  (projectile-global-mode))
#+end_src
** Counsel projectile
Counsel projectile provides the ivy interface to projectile commands, which is really useful.
#+begin_src emacs-lisp
(use-package counsel-projectile
  :after (projectile counsel)
  :config
  (counsel-projectile-mode +1))
#+end_src
* Mail
Mail is a funny thing; most people use it just for business or
advertising and it's come out of use in terms of personal
communication in the west for the most part (largely due to "social"
media applications). However, this isn't true for the open source and
free software movement who heavily use mail for communication.

Integrating mail into Emacs helps as I can send source code and
integrate it into my workflow just a bit better.
** Notmuch
#+begin_src emacs-lisp
(setq +mail/signature "---------------\nAryadev Chavali")
(use-package notmuch
  :commands notmuch
  :general
  (leader "am" #'notmuch)
  :custom
  ((notmuch-show-logo nil)
   (message-signature +mail/signature)
   (mail-signature +mail/signature))
  :init
  (defun +mail/sync-mail ()
    "Sync mail via mbsync."
    (interactive)
    (start-process-shell-command "" nil "mbsync -a"))
  :config
  (evil-define-key 'normal notmuch-hello-mode-map "M" #'+mail/sync-mail)
  (evil-collection-notmuch-setup))
#+end_src
** Smtpmail
#+begin_src emacs-lisp
(use-package smtpmail
  :commands mail-send
  :after notmuch
  :custom
  ((smtpmail-smtp-server "mail.aryadevchavali.com")
   (smtpmail-smtp-user "aryadev")
   (smtpmail-smtp-service 587)
   (smtpmail-stream-type 'starttls))
  :init
  (setq send-mail-function #'smtpmail-send-it
        message-send-mail-function #'smtpmail-send-it))
#+end_src
** Org message
Org message allows for the use of org mode when composing mails,
generating HTML multipart emails. This integrates the WYSIWYG
experience into mail in Emacs while also providing powerful text
features with basically no learning curve (as long as you've already
learnt the basics of org).

#+begin_src emacs-lisp
(use-package org-msg
  :after notmuch
  :hook (message-mode-hook . org-msg-mode))
#+end_src
* Dired
Setup for dired. Firstly, as it's an inbuilt package don't let
straight try and download it. Make dired-hide-details-mode the
default mode when dired-mode, as it removes the clutter. Create a
keymap =dx:dired-map= which is bound to the prefix "C-c d", binding
useful dired functions. Setup evil collection for dired (even though
dired doesn't really conflict with evil, there are some black corners
I'd like to adjust)
#+begin_src emacs-lisp
(use-package dired
  :straight nil
  :hook (dired-mode-hook . dired-hide-details-mode)
  :after evil-collection
  :general
  (leader
    :infix "d"
    "f" #'find-dired
    "D" #'dired-other-window
    "d" #'dired-jump)
  :config
  (evil-collection-dired-setup))
#+end_src
* Hydra
Use hydras for stuff that I use often, currently buffer manipulation
#+begin_src emacs-lisp
(use-package hydra
  :after evil
  :init
  (defun dx:kill-defun ()
    "Mark defun then kill it."
    (interactive)
    (mark-defun)
    (delete-active-region t))

  (defun dx:paste-section ()
    "Paste the current kill-region content above section."
    (interactive)
    (open-line 1)
    (yank))

  :config
  (defhydra hydra-buffer (evil-normal-state-map "SPC b")
    "buffer-hydra"
    ("l" next-buffer)
    ("h" previous-buffer)
    ("c" kill-this-buffer))

  (defhydra hydra-goto-chg (evil-normal-state-map "g;")
    "goto-chg"
    (";" goto-last-change "goto-last-change")
    ("," goto-last-change-reverse "goto-last-change-reverse"))

  (defhydra hydra-code-manipulator (global-map "C-x c")
    "code-manip"
    ("j" evil-forward-section-begin)
    ("k" evil-backward-section-begin)
    ("m" mark-defun)
    ("d" dx:kill-defun)
    ("p" dx:paste-section)
    ("TAB" evil-toggle-fold)))
#+end_src
* IBuffer
#+begin_src emacs-lisp
(use-package ibuffer
  :after evil-collection
  :config
  (evil-collection-ibuffer-setup))
#+end_src
* Helpful
Basic setup, will be fully integrated in counsel.
#+begin_src emacs-lisp
(use-package helpful
  :commands (helpful-callable helpful-variable)
  :config
  (evil-define-key 'normal helpful-mode-map "q" #'quit-window))
#+end_src
* Which-key
Pretty simple, just activate after init.
#+begin_src emacs-lisp
(use-package which-key
  :after evil
  :config
  (which-key-mode))
#+end_src
* Yasnippet
Yasnippet is a great package for snippets, which I use heavily in
programming and org-mode. I setup here the global mode for yasnippet
and a collection of snippets for ease of use.
** Yasnippet default
Setup global mode after evil mode has been loaded
#+begin_src emacs-lisp
(use-package yasnippet
  :after evil
  :hook ((prog-mode-hook . yas-minor-mode)
         (text-mode-hook . yas-minor-mode))
  :general
  (leader
    "i" #'yas-insert-snippet)
  :config
  (yas-load-directory (concat user-emacs-directory "snippets")))
#+end_src
** Yasnippet snippets
Collection of snippets, activate after yasnippet has been loaded.
#+begin_src emacs-lisp
(use-package yasnippet-snippets
  :after yasnippet)
#+end_src
* Keychord
Keychord is only really here for this one chord I wish to define: "jk"
for exiting insert state. Otherwise, I don't really need it.
#+begin_src emacs-lisp
(use-package key-chord
  :after evil
  :config
  (key-chord-define evil-insert-state-map "jk" #'evil-normal-state)
  (key-chord-mode +1))
#+end_src
* Ripgrep
The ripgrep package provides utilities to grep projects and files for
strings via the rg tool. Though [[*Ivy][ivy]] comes with =counsel-rg= using it
makes me dependent on the ivy framework, and this configuration is
intentionally built to be modular and switchable.
#+begin_src emacs-lisp
(use-package rg
  :after evil
  :general
  (leader "r" #'rg)
  (:keymaps 'rg-mode-map
   "]]" #'rg-next-file
   "[[" #'rg-prev-file
   "q"  #'quit-window)
  :init
  (setq rg-group-result t
        rg-hide-command t
        rg-show-columns nil
        rg-show-header t
        rg-custom-type-aliases nil
        rg-default-alias-fallback "all"))
#+end_src
* Magit
Magit is *the* git porcelain for Emacs, which perfectly encapsulates
the git cli. In this case, I just need to setup the bindings for it.
As magit will definitely load after evil (as it must be run by a
binding, and evil will load after init), I can use evil-collection
freely.
#+begin_src emacs-lisp
(use-package magit
  :general
  (leader "g" #'magit-status))

(use-package evil-magit
  :after magit)
#+end_src
* Company
Company is the auto complete system I use. I don't like having heavy
setups for company, as it only makes it worse to use.  In this case,
just setup some evil binds for company
#+begin_src emacs-lisp
(use-package company
  :hook (prog-mode-hook . company-mode)
  :bind (("C-SPC" . company-complete)
         :map company-active-map
         ("M-j" . company-select-next)
         ("M-k" . company-select-previous)))
#+end_src
* Elfeed
Elfeed is the perfect RSS feed reader, integrated into Emacs
perfectly. I've got a set of feeds that I use for a large variety of
stuff, mostly media and entertainment. I've also bound "<leader> ar"
to elfeed for loading the system.
#+begin_src emacs-lisp
(use-package elfeed
  :general
  (leader "ar" #'elfeed)
  :init
  (setq +rss/feed-urls
        '(("Arch Linux"            "https://www.archlinux.org/feeds/news/" Linux)
          ("LEMMiNO"               "https://www.youtube.com/feeds/videos.xml?channel_id=UCRcgy6GzDeccI7dkbbBna3Q" YouTube Stories)
          ("Dark Sominium"         "https://www.youtube.com/feeds/videos.xml?channel_id=UC_e39rWdkQqo5-LbiLiU10g" YouTube Stories)
          ("Dark Sominium Music"   "https://www.youtube.com/feeds/videos.xml?channel_id=UCkLiZ_zLynyNd5fd62hg1Kw" YouTube Music)
          ("Nexpo"                 "https://www.youtube.com/feeds/videos.xml?channel_id=UCpFFItkfZz1qz5PpHpqzYBw" YouTube)
          ("Techquickie"           "https://www.youtube.com/feeds/videos.xml?channel_id=UC0vBXGSyV14uvJ4hECDOl0Q" YouTube)
          ("Captain Sinbad"        "https://www.youtube.com/feeds/videos.xml?channel_id=UC8XKyvQ5Ne_bvYbgv8LaIeg" YouTube)
          ("3B1B"                  "https://www.youtube.com/feeds/videos.xml?channel_id=UCYO_jab_esuFRV4b17AJtAw" YouTube)
          ("Fredrik Knusden"       "https://www.youtube.com/feeds/videos.xml?channel_id=UCbWcXB0PoqOsAvAdfzWMf0w" YouTube Stories)
          ("Barely Sociable"       "https://www.youtube.com/feeds/videos.xml?channel_id=UC9PIn6-XuRKZ5HmYeu46AIw" YouTube Stories)
          ("Atrocity Guide"        "https://www.youtube.com/feeds/videos.xml?channel_id=UCn8OYopT9e8tng-CGEWzfmw" YouTube Stories)
          ("Philip Defranco"       "https://www.youtube.com/feeds/videos.xml?channel_id=UClFSU9_bUb4Rc6OYfTt5SPw" YouTube News)
          ("Hacker News"           "http://morss.aryadevchavali.com/news.ycombinator.com/rss"                     Social)
          ("Hacker Factor"         "https://www.hackerfactor.com/blog/index.php?/feeds/index.rss2"                Social)
          ("BBC Top News"          "http://morss.aryadevchavali.com/feeds.bbci.co.uk/news/rss.xml"                News)
          ("BBC Tech News"         "http://morss.aryadevchavali.com/feeds.bbci.co.uk/news/technology/rss.xml"     News)))
  (setq elfeed-db-directory (concat user-emacs-directory "elfeed"))
  :config
  (evil-collection-elfeed-setup)
  (evil-define-key 'normal elfeed-search-mode-map "gr" #'elfeed-update)
  (evil-define-key 'normal elfeed-search-mode-map "s" #'elfeed-search-live-filter)
  (evil-define-key 'normal elfeed-search-mode-map "<return>" #'elfeed-search-show-entry)
  (setq elfeed-feeds (cl-map 'list #'(lambda (item) (append (list (nth 1 item)) (cdr (cdr item)))) +rss/feed-urls)))
#+end_src
* Eshell
Eshell is the integrated shell environment for Emacs. Though it isn't
necessarily *the best* shell, it really suits the 'integrated
computing environment' moniker that Emacs gets.

It may be argued that Emacs integrates within itself many of the
functionalities that one would use within a shell or terminal. Stuff
like compilation, file management, large scale text manipulation could
be done through Emacs' own tools (=compile=, =dired= and =occur= come
to mind). However, I'd argue that eshell's greatest ability comes from
it's separation (or perhaps better phrased, *integration*) of two
'parsers': the Lisp parser and the Shell parser. With these parsers
you can mix and match at will for use in the shell, which grants
greater power than many shells I know of.

Setup a function that /toggles/ the eshell window rather than
just opening it via =+dx/toggle-buffer=.

#+begin_src emacs-lisp
(use-package eshell
  :general
  (leader
    "tt" #'+shell/toggle-eshell)
  :init
  (setq eshell-cmpl-ignore-case t
  eshell-cd-on-directory t)
  :config
  (defun +shell/toggle-eshell ()
    (interactive)
    (+dx/toggle-buffer "*eshell*" #'eshell)))

#+end_src
* Window management
Window management is really important. I find the default window
handling of Emacs incredibly annoying: sometimes consuming my windows,
sometimes creating new ones. So, as Emacs is the ultimate editor, I
want to configure and fine tune the window management of Emacs.
#+begin_src emacs-lisp
(setq display-buffer-alist
      '(("\\*Org Src.*"
         (display-buffer-same-window))
        ("\\*e?shell\\*"
         (display-buffer-at-bottom)
         (window-height . 0.25))
        ("\\*[Hh]elp.*"
         (display-buffer-at-bottom)
         (inhibit-duplicate-buffer . t)
         (window-height . 0.25))
        ("magit:.*"
         (display-buffer-same-window)
         (inhibit-duplicate-buffer . t))
        ("magit-diff:.*"
         (display-buffer-below-selected))
        ("magit-log:.*"
         (display-buffer-same-window))
        ("\\*compilation\\*"
         (display-buffer-at-bottom)
         (window-height . 0.25))
        ("\\*Flycheck.*"
         (display-buffer-at-bottom)
         (window-height . 0.25))
        ("\\*rg.*"
         (display-buffer-at-bottom)
         (window-height . 0.25))
        ("\\*Python\\*"
         (display-buffer-at-bottom)
         (window-height . 0.25))
        ("\\*Org Export.*"
         (display-buffer-at-bottom)
         (window-height . 0.25))
        ("\\*Async Shell Command\\*"
         (display-buffer-at-bottom)
         (window-height . 0.25))
        ))
#+end_src
* Text modes
** Flyspell
Flyspell allows me to quickly spell check text documents. I use
flyspell primarily in org mode, as that is my preferred prose writing
software, but I also need it in commit messages and so on. So
flyspell-mode should be hooked to text-mode.
#+begin_src emacs-lisp
(use-package flyspell
  :hook (text-mode-hook . flyspell-mode))
#+end_src

As I use ivy I'd like the flyspell correct interface (which allow for
corrections to real words) to use ivy.
#+begin_src emacs-lisp
(use-package flyspell-correct-ivy
  :after flyspell
  :general
  (general-def
    :states '(normal insert)
    :map flyspell-mode-map
    "M-a" #'flyspell-correct-at-point
    "M-A" #'ispell-word))
#+end_src
** Set auto-fill-mode for all text-modes
Auto fill mode is nice for most text modes, 80 char limit is great.
#+begin_src emacs-lisp
(add-hook 'text-mode-hook #'auto-fill-mode)
#+end_src
** Delete a sentence in auto fill
In long lines via truncate lines, deleting till the end of the
sentence was easy via vim motions. However, the same action is
difficult with auto-fill-mode where sentences are separated through
(potentially several) newlines which makes vim motions
difficult. Thus, I propose some form of functionality which allows you
to:

- Find the next closest period denoting the end of the sentence
- Delete the region between the point of invocation and the found period

This essentially does the same task as vim motion based deletion, but
can handle the newlines. To not trample on the toes of any package,
I'll set it to "M-d" (kill-word), the most inoffensive binding
possible which is still mnemonic.

First, the function. I'll use search-forward (from zap* lib) to find
the period. Then auto-fill to make it look nice.
#+begin_src emacs-lisp
(defun +text/delete-till-sentence ()
  "Delete all text from current point to the next closest period."
  (interactive)
  (set-mark-command nil)
  (search-forward ". ")
  (kill-region (region-beginning) (region-end))
  (fill-paragraph))
#+end_src

Now, the binding
#+begin_src emacs-lisp
(general-def
  :states '(normal insert)
  (kbd "M-d") #'+text/delete-till-sentence)
#+end_src
* Org
** Org default with evil
Setup for org mode, currently basically nothing. Has evil-org for
evil bindings.

Also setup a lot of variables, particularly for latex exports.
#+begin_src emacs-lisp
(use-package org
  :hook (org-mode-hook . yas-minor-mode)
  :bind (:map org-mode-map
              ([remap imenu] . counsel-org-goto))
  :custom
  ((org-edit-src-content-indentation 0)
   (org-src-window-setup 'current-window)
   (org-indirect-buffer-display 'current-window)
   (org-eldoc-breadcrumb-separator " → ")
   (org-enforce-todo-dependencies t)
   (org-fontify-quote-and-verse-blocks t)
   (org-fontify-whole-heading-line t)
   (org-footnote-auto-label 'plain)
   (org-hide-leading-stars t)
   (org-hide-emphasis-markers nil)
   (org-image-actual-width nil)
   (org-priority-faces '((?A . error) (?B . warning) (?C . success)))
   (org-startup-indented t)
   (org-tags-column 0)
   (org-todo-keywords
    '((sequence "TODO" "WAIT" "DONE")
      (sequence "PROJ" "WAIT" "COMPLETE")))
   (org-use-sub-superscripts '{})
   (org-latex-listings 'minted)
   (org-babel-load-languages '((emacs-lisp . t)
                               (C . t)))
   (org-latex-packages-alist '(("" "minted")))
   (org-latex-pdf-process '("%latex -interaction nonstopmode -shell-escape -output-directory %o %f"
                            "%latex -interaction nonstopmode -shell-escape -output-directory %o %f"
                            "%latex -interaction nonstopmode -shell-escape -output-directory %o %f"))
   (org-latex-minted-options '(("style" "xcode")
                               ("linenos")
                               ("frame" "single")
                               ("mathescape")
                               ("fontfamily" "courier")
                               ("samepage" "false")
                               ("breaklines" "true")
                               ("breakanywhere" "true")
                               ))))

(use-package evil-org
  :hook (org-mode-hook . evil-org-mode))
#+end_src
** Org fragtog
Toggle latex fragments in org mode so you get fancy maths symbols. I
use latex a bit in org mode as it is the premier way of getting
mathematical symbols and text rendered and compiled, but org mode >
latex.

As Org mode has the ability to accept arbitrary inputs of Latex
(through escaped (square) brackets), allowing me to observe how they
look is nice to have.
#+begin_src emacs-lisp
(use-package org-fragtog
  :hook (org-mode-hook . org-fragtog-mode))
#+end_src
** Org pretty tables
Make the default ASCII tables of org mode pretty with
#+begin_src emacs-lisp
(use-package org-pretty-table-mode
  :straight (org-pretty-table-mode :type git :host github :repo "Fuco1/org-pretty-table")
  :hook org-mode-hook)
#+end_src
** Org pretty tags
#+begin_src emacs-lisp
(use-package org-pretty-tags
  :hook (org-mode-hook . org-pretty-tags-mode))
#+end_src
** Org superstar
Org superstar adds cute little unicode symbols for headers, much
better than the default asterisks.
#+begin_src emacs-lisp
(use-package org-superstar
  :hook (org-mode-hook . org-superstar-mode))
#+end_src
* Major modes and Programming
Setups for common major modes and languages. Here are some basic
packages for programming first
** Smartparens
Smartparens is a smarter electric-parens, it's much more aware of
stuff and easier to use.
#+begin_src emacs-lisp
(use-package smartparens
  :hook (prog-mode-hook . smartparens-mode)
  :hook (text-mode-hook . smartparens-mode)
  :after evil
  :config
  (setq sp-highlight-pair-overlay nil
        sp-highlight-wrap-overlay t
        sp-highlight-wrap-tag-overlay t)

  (let ((unless-list '(sp-point-before-word-p
                       sp-point-after-word-p
                       sp-point-before-same-p)))
    (sp-pair "'"  nil :unless unless-list)
    (sp-pair "\"" nil :unless unless-list))
  (sp-local-pair sp-lisp-modes "(" ")" :unless '(:rem sp-point-before-same-p))
  (require 'smartparens-config))
#+end_src
** Show-paren-mode
Show parenthesis for Emacs
#+begin_src emacs-lisp
(add-hook 'prog-mode-hook #'show-paren-mode)
#+end_src
** Eldoc
Eldoc presents documentation to the user upon placing ones cursor upon
any symbol. This is very useful when programming as it:
- presents the arguments of functions while writing calls for them
- presents typing and documentation of variables

#+begin_src emacs-lisp
(use-package eldoc
  :hook (prog-mode-hook . eldoc-mode))

(use-package eldoc-box
  :hook (eldoc-mode-hook . eldoc-box-hover-mode)
  :custom
  ((eldoc-box-position-function #'eldoc-box--default-upper-corner-position-function)
   (eldoc-box-clear-with-C-g t))
  :config
  (advice-add #'evil-force-normal-state :before #'eldoc-box-quit-frame))
#+end_src
** Eglot
Eglot is a library of packages to communicate with LSP servers for
better programming capabilities. Interactions with a server provide
results to the client, done through JSON.
#+begin_src emacs-lisp
(use-package eglot
  :hook (c++-mode-hook . eglot-ensure)
  :hook (c-mode-hook . eglot-ensure)
  :bind (:map eglot-mode-map
         ("<f2>" . eglot-rename))
  :general
  (leader
    :keymaps '(eglot-mode-map)
    :infix "c"
    "f" #'eglot-format
    "a" #'eglot-code-actions
    "r" #'eglot-rename)
  :config
  (add-to-list 'eglot-server-programs '((c-mode c++-mode) "clangd")))
#+end_src
** Flycheck
Flycheck is the checking system for Emacs. I don't necessarily like
having all my code checked all the time, so I haven't added a hook to
prog-mode as it would be better for me to decide when I want checking
and when I don't.
#+begin_src emacs-lisp
(use-package flycheck
  :commands flycheck-mode
  :config
  (defun +flycheck/list-errors-load-flycheck ()
    "Load flycheck if not available, then list errors."
    (interactive)
    (when (not (or flycheck-mode global-flycheck-mode))
      (flycheck-mode))
    (flycheck-list-errors)))
#+end_src
** Activate tabs
Set tabs to nil by default, with normal tab size set to 2.
#+begin_src emacs-lisp
(setq-default indent-tabs-mode nil
              tab-width 2)
#+end_src

Add a function to activate tabs mode for any modes you want tabs in.
#+begin_src emacs-lisp
(defun dx:activate-tabs ()
  (interactive)
  (setq indent-tabs-mode t))
#+end_src
** C/C++
Setup for C and C++ modes via the cc-mode package.

C and C++ are great languages for general purpose programming. Though
lisp is more aesthetically and mentally pleasing, they get the job
done. Furthermore, they provide speed and finer control in trade of
aesthetics and security-based abstractions.

When writing C/C++ code, I use folds and section manipulation quite a
bit so observing folds is quite important for me when considering a
codebase. Thus, I observed the two main styles of brace placement and
how they do folds.

#+begin_src c :tangle no
if (cond) {...}
#+end_src
vs
#+begin_src c :tangle no
if (cond)
{....}
#+end_src

I don't print my code, nor am I absolutely pressed for screen real
estate in terms of height (such that newlines matter). Width matters
to me as I do use Emacs multiplexing capabilities often. Thus, with
these in mind the open brace style is a better option than the
opposing style.

Also, with large code bases consistency is important. I personally use
tabs as they are more accessible: anyone can set their tab width such
that it best suits them. Furthermore, tabs produce smaller source
files. However, this isn't set in stone and I will return to no tabs
when needed in projects.

#+begin_src emacs-lisp
(use-package cc-mode
  :hook (c-mode-hook   . dx:activate-tabs)
  :hook (c++-mode-hook . dx:activate-tabs)
  :init
  (setq-default c-basic-offset 2)
  (setq c-default-style '((java-mode . "java")
                          (awk-mode . "awk")
                          (other . "user")))
  :config
  (c-add-style
   "user"
   '((c-basic-offset . 2)
     (c-comment-only-line-offset . 0)
     (c-hanging-braces-alist (brace-list-open)
                             (brace-entry-open)
                             (substatement-open after)
                             (block-close . c-snug-do-while)
                             (arglist-cont-nonempty))
     (c-cleanup-list brace-else-brace)
     (c-offsets-alist
      (statement-block-intro . +)
      (knr-argdecl-intro . 0)
      (substatement-open . 0)
      (substatement-label . 0)
      (access-label . 0)
      (label . 0)
      (statement-cont . +)))))
#+end_src
*** Clang format
Clang format for when:
- eglot isn't working/I'm not running it
- eglot format is bad

#+begin_src emacs-lisp
(use-package clang-format
  :after cc-mode
  :config
  (bind-key "C-c '" #'clang-format-region c-mode-map)
  (bind-key "C-c '" #'clang-format-region c++-mode-map))
#+end_src
** HTML/CSS/JS
Firstly, web mode for consistent colouring of syntax.
#+begin_src emacs-lisp
(use-package web-mode
  :mode ("\\.html" . web-mode)
  :mode ("\\.js"   . web-mode)
  :mode ("\\.css"  . web-mode)
  :custom
  ((web-mode-markup-indent-offset 2)
   (web-mode-css-indent-offset 2)))
#+end_src

Then emmet for super speed
#+begin_src emacs-lisp
(use-package emmet-mode
  :hook (web-mode-hook . emmet-mode)
  :general
  (general-def
    :states 'insert
    :keymaps 'emmet-mode-keymap
    "TAB" #'emmet-expand-line
    "M-j" #'emmet-next-edit-point
    "M-k" #'emmet-prev-edit-point))
#+end_src
** Emacs lisp
Add a new lisp indent function which indents newline lists more
appropriately.
#+begin_src emacs-lisp
(with-eval-after-load "lisp-mode"
  (defun +modded/lisp-indent-function (indent-point state)
    "This function is the normal value of the variable `lisp-indent-function'.
The function `calculate-lisp-indent' calls this to determine
if the arguments of a Lisp function call should be indented specially.
INDENT-POINT is the position at which the line being indented begins.
Point is located at the point to indent under (for default indentation);
STATE is the `parse-partial-sexp' state for that position.
If the current line is in a call to a Lisp function that has a non-nil
property `lisp-indent-function' (or the deprecated `lisp-indent-hook'),
it specifies how to indent.  The property value can be:
,* `defun', meaning indent `defun'-style
  \(this is also the case if there is no property and the function
  has a name that begins with \"def\", and three or more arguments);
,* an integer N, meaning indent the first N arguments specially
  (like ordinary function arguments), and then indent any further
  arguments like a body;
,* a function to call that returns the indentation (or nil).
  `lisp-indent-function' calls this function with the same two arguments
  that it itself received.
This function returns either the indentation to use, or nil if the
Lisp function does not specify a special indentation."
    (let ((normal-indent (current-column))
          (orig-point (point)))
      (goto-char (1+ (elt state 1)))
      (parse-partial-sexp (point) calculate-lisp-indent-last-sexp 0 t)
      (cond
       ;; car of form doesn't seem to be a symbol, or is a keyword
       ((and (elt state 2)
             (or (not (looking-at "\\sw\\|\\s_"))
                 (looking-at ":")))
        (if (not (> (save-excursion (forward-line 1) (point))
                    calculate-lisp-indent-last-sexp))
            (progn (goto-char calculate-lisp-indent-last-sexp)
                   (beginning-of-line)
                   (parse-partial-sexp (point)
                                       calculate-lisp-indent-last-sexp 0 t)))
        ;; Indent under the list or under the first sexp on the same
        ;; line as calculate-lisp-indent-last-sexp.  Note that first
        ;; thing on that line has to be complete sexp since we are
        ;; inside the innermost containing sexp.
        (backward-prefix-chars)
        (current-column))
       ((and (save-excursion
               (goto-char indent-point)
               (skip-syntax-forward " ")
               (not (looking-at ":")))
             (save-excursion
               (goto-char orig-point)
               (looking-at ":")))
        (save-excursion
          (goto-char (+ 2 (elt state 1)))
          (current-column)))
       (t
        (let ((function (buffer-substring (point)
                                          (progn (forward-sexp 1) (point))))
              method)
          (setq method (or (function-get (intern-soft function)
                                         'lisp-indent-function)
                           (get (intern-soft function) 'lisp-indent-hook)))
          (cond ((or (eq method 'defun)
                     (and (null method)
                          (> (length function) 3)
                          (string-match "\\`def" function)))
                 (lisp-indent-defform state indent-point))
                ((integerp method)
                 (lisp-indent-specform method state
                                       indent-point normal-indent))
                (method
                 (funcall method indent-point state))))))))
  (add-hook 'emacs-lisp-mode-hook #'(lambda () (interactive) (setq-local lisp-indent-function #'+modded/lisp-indent-function))))
#+end_src