dotfiles/Emacs/.config/emacs/config.org

Emacs configuration

• Initial
  • Setup straight
  • Setup use package
  • Setup alpha and yes-or-no-p
  • Hs Minor mode
  • Set backup directory
  • Turn off the bars
  • Themes
  • Turn off startup buffer
• Emacs Mode-line
• Custom Functions
  • New line function
  • Generate tags
• General
• Evil
  • Evil default
  • Evil surround
  • Evil commentary
  • Evil mc
  • Evil collection
• Ivy
  • Ivy
  • Counsel
  • Counsel etags
• Avy
• Projectile
  • Counsel projectile
• Mail
  • Notmuch
  • Smtpmail
• Dired
• Hydra
• IBuffer
• Helpful
• Which-key
• Yasnippet
  • Yasnippet default
  • Yasnippet snippets
• Keychord
• Ripgrep
• Magit
• Company
• Elfeed
• Org mode
  • Org default with evil
  • Org superstar
  • Flyspell
• Window management
• Major modes and Programming
  • Smartparens
  • Show-paren-mode
  • Eldoc
  • Eglot
  • Flycheck
  • Activate tabs
  • C/C++
    • Clang format
  • Emacs lisp

Initial

Setup straight

Bootstrap of straight (from github)

(defvar bootstrap-version)
(let ((bootstrap-file
       (expand-file-name "straight/repos/straight.el/bootstrap.el" user-emacs-directory))
      (bootstrap-version 5))
  (unless (file-exists-p bootstrap-file)
    (with-current-buffer
        (url-retrieve-synchronously
         "https://raw.githubusercontent.com/raxod502/straight.el/develop/install.el"
         'silent 'inhibit-cookies)
      (goto-char (point-max))
      (eval-print-last-sexp)))
  (load bootstrap-file nil 'nomessage))

Setup use package

Straight clone use-package and state that all use-package statements implicity use straight.

(straight-use-package 'use-package)
(setq straight-use-package-by-default t)

Setup alpha and yes-or-no-p

This just sets the alpha to 85% and all yes or no questions to single letter responses.

(add-to-list 'default-frame-alist '(alpha . 85))
(fset 'yes-or-no-p 'y-or-n-p)

Hs Minor mode

Turn on hs minor mode for all prog-mode.

(add-hook 'prog-mode-hook #'hs-minor-mode)

Set backup directory

Set the backup directory to =user-emacs-directory=/saves so I don't get those annoying '~' files.

(setq backup-directory-alist `(("." . "~/.config/emacs/saves")))

Turn off the bars

Turn off all the bars, don't need them anymore!

(tool-bar-mode -1)
(scroll-bar-mode -1)
(menu-bar-mode -1)

Themes

Load my custom "Grayscale" theme (look at this file).

(load-theme 'Grayscale t)

Turn off startup buffer

(setq inhibit-startup-screen t)

Emacs Mode-line

Firstly, declare a variable for the number of spaces between each module in the modeline.

(defconst +modeline/sep-spaces 4 "Number of spaces separating modules.")

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.

(defconst +modeline/reserved-chars (list "[" "(") 
        "Characters that, when at the end of a module string, won't have the separator applied to them.")

Now declare a function that applies the separator with respect to the reserved characters to any one string.

(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-spaces collect " "))))))
    (error STR)))

Finally, set the mode-line-format.

(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)))

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, 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

  (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))))

Generate tags

For some reason, I can't seem to rely on the projectile-regenerate-tags function, so define my own.

Steps are as follows:

• Consider the root to be either default-directory or the projectile-project-root depending on if it's loaded and set.

• Start a process (shell command) by changing to root and executing ctags -Re

  (defun dx:generate-tags ()
    (interactive)
    (let ((root (if (bound-and-true-p projectile-project-root)
                    projectile-project-root
                  default-directory)))
      (start-process-shell-command "" nil (format "cd %s; ctags -Re ." root))))

General

Setup general, a good package for defining keys.

(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)))
    
  (general-create-definer leader
    :states 'normal
    :keymaps 'override
    :prefix "SPC")
    
  (leader
    "!"   #'async-shell-command
    "SPC" #'execute-extended-command
    "u"   #'universal-argument
    "si"  #'imenu
    "h"   #'help-command)
    
  (leader
    :infix "b"
    "d" #'kill-this-buffer
    "i" #'ibuffer
    "b" #'switch-to-buffer)

  (leader
    :infix "c"
    "f" #'(lambda () (interactive) (find-file "~/Code/")))

  (leader
    :infix "f"
    "f" #'find-file
    "s" #'save-buffer
    "p" #'(lambda () (interactive) (find-file (concat user-emacs-directory "config.org")))))

Evil

Evil default

Setup the evil package, with some basic keybinds. Also declare a leader-map at "SPC".

(use-package evil
  :init
  (setq evil-want-keybinding nil)
  :config
  (evil-mode +1)
  (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))

Evil surround

(use-package evil-surround
  :after evil
  :config
  (global-evil-surround-mode))

Evil commentary

(use-package evil-commentary
  :after evil
  :config
  (evil-commentary-mode))

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.

(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
  (defvar evil-mc-key-map (make-sparse-keymap))
  (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)))

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.

(use-package evil-collection
  :after evil)

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.

(use-package ivy
  :hook (after-init . ivy-mode)
  :after evil-collection
  :bind (:map ivy-minibuffer-map 
         ("M-j" . ivy-next-line-or-history)
         ("M-k" . ivy-previous-line-or-history)
         :map ivy-switch-buffer-map
         ("M-j" . ivy-next-line-or-history)
         ("M-k" . ivy-previous-line-or-history))
  :general
  (:keymaps 'ivy-minibuffer-map
   "C-c C-e" #'ivy-occur)
  :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
        ivy-initial-inputs-alist nil)
  (evil-collection-ivy-setup))

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.

(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)
  :config
  (setq ivy-initial-inputs-alist nil)
  (setq counsel-describe-function-function #'helpful-callable
        counsel-describe-variable-function #'helpful-variable))

Counsel etags

Counsel etags allows me to search generated tag files for tags. I already have a function defined here 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.

(use-package counsel-etags
 :after counsel
 :general
 (leader "st" #'counsel-etags-find-tag))

Avy

Setup avy with leader.

(use-package avy
  :after evil
  :general
  (leader
    :infix "s"
    "l" #'avy-goto-line
    "g" #'avy-goto-char-2))

Projectile

Setup projectile, along with the tags command. Also bind "C-c C-p" to the projectile command map for quick access.

(use-package projectile
  :after evil
  :hook (prog-mode . projectile-mode)
  :general
  (leader "p" #'projectile-command-map)
  :init
  (setq projectile-tags-command "ctags -Re -f \"%s\" %s \"%s\"")
  :config
  (projectile-global-mode))

Counsel projectile

Counsel projectile provides the ivy interface to projectile commands, which is really useful.

(use-package counsel-projectile
  :after (projectile counsel)
  :config
  (counsel-projectile-mode +1))

Mail

Notmuch

(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-collection-notmuch-setup))

Smtpmail

(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))

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)

(use-package dired
  :straight nil
  :hook (dired-mode . 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))

Hydra

Use hydras for stuff that I use often, currently buffer manipulation

(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"
    ("j" next-buffer)
    ("k" previous-buffer)
    ("c" kill-this-buffer))

  (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)))

IBuffer

(use-package ibuffer
  :after evil-collection
  :config
  (evil-collection-ibuffer-setup))

Helpful

Basic setup, will be fully integrated in counsel.

(use-package helpful
  :commands (helpful-callable helpful-variable)
  :config
  (evil-define-key 'normal helpful-mode-map "q" #'quit-window))

Which-key

Pretty simple, just activate after init.

(use-package which-key
  :hook (after-init . which-key-mode))

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

(use-package yasnippet
  :after evil
  :hook ((prog-mode . yas-minor-mode)
         (text-mode . yas-minor-mode))
  :general
  (leader
    "i" #'yas-insert-snippet))

Yasnippet snippets

Collection of snippets, activate after yasnippet has been loaded.

(use-package yasnippet-snippets
  :after yasnippet)

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.

(use-package key-chord
  :after evil
  :config
  (key-chord-define evil-insert-state-map "jk" #'evil-normal-state)
  (key-chord-mode +1))

Ripgrep

The ripgrep package provides utilities to grep projects and files for strings via the rg tool. Though 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.

(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"))

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.

(use-package magit
  :general
  (leader "g" #'magit-status))

(use-package evil-magit
  :after magit)

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

(use-package company
  :hook (prog-mode . company-mode)
  :bind (("C-SPC" . company-complete)
         :map company-active-map
         ("M-j" . company-select-next)
         ("M-k" . company-select-previous)))

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 "C-c r" to elfeed for loading the system.

(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)))

Org mode

Org default with evil

Setup for org mode, currently basically nothing. Has evil-org for evil bindings.

(use-package org
  :hook (org-mode . 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-entities-user '(("flat"  "\\flat" nil "" "" "266D" "♭") ("sharp" "\\sharp" nil "" "" "266F" "♯")))
   (org-fontify-quote-and-verse-blocks t)
   (org-fontify-whole-heading-line t)
   (org-footnote-auto-label 'plain)
   (org-hide-leading-stars t)
   (org-image-actual-width nil)
   (org-priority-faces '((?A . error) (?B . warning) (?C . success)))
   (org-startup-indented t)
   (org-tags-column 0)
   (org-use-sub-superscripts '{})))

(use-package evil-org
  :hook (org-mode . evil-org-mode))

Org superstar

(use-package org-superstar
  :hook (org-mode . org-superstar-mode))

Flyspell

(use-package flyspell
  :hook (org-mode . flyspell-mode))

(use-package flyspell-correct-ivy
  :after flyspell
  :bind (:map org-mode-map
              ("C-c C-a" . flyspell-correct-at-point)))

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.

(setq display-buffer-alist
      '(("\\*e?shell\\*"
         (display-buffer-in-side-window)
         (window-height . 0.25)
         (side . bottom)
         (slot . 0))
        ("\\*[Hh]elp.*"
         (display-buffer-in-side-window)
         (window-height . 0.25)
         (side . bottom)
         (slot . 1))
        ("magit:.*"
         (display-buffer-in-side-window)
         (side . right)
         (slot . -1)
         (window-width . 0.5))
        ("magit-diff:.*"
         (display-buffer-in-side-window)
         (side . right)
         (window-width . 0.5))
        ("magit-log:.*"
         (display-buffer-in-side-window)
         (side . right)
         (window-width . 0.5))
        ("\\*compilation\\*"
         (display-buffer-in-side-window)
         (side . bottom)
         (slot . -1)
         (window-height . 0.25))
        ("\\*Flycheck.*"
         (display-buffer-in-side-window)
         (side . bottom)
         (window-height . 0.25)
         (slot . 0))
        ("\\*rg.*"
         (display-buffer-in-side-window)
         (side . bottom)
         (window-height . 0.25)
         (slot . 1))
        ))

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.

(use-package smartparens
  :hook (prog-mode . 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))

Show-paren-mode

Show parenthesis for Emacs

(add-hook 'prog-mode-hook #'show-paren-mode)

Eldoc

(use-package eldoc
  :hook (prog-mode . eldoc-mode))

(use-package eldoc-box
  :hook (eldoc-mode . eldoc-box-hover-mode))

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.

(use-package eglot
  :hook (c++-mode . eglot-ensure)
  :hook (c-mode . eglot-ensure)
  :bind (:map eglot-mode-map
              ("<f2>" . eglot-rename)
              ("C-c C-A" . eglot-code-actions)
              ("C-c C-f" . eglot-format))
  :config
  (add-to-list 'eglot-server-programs '((c-mode c++-mode) "clangd")))

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.

(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)))

Activate tabs

Set tabs to nil by default, with normal tab size set to 2.

(setq-default indent-tabs-mode nil
              tab-width 2)

Add a function to activate tabs mode.

(defun dx:activate-tabs ()
  (interactive)
  (setq indent-tabs-mode t))

C/C++

Setup for C and C++ modes via the cc-mode package. Firstly hook the C and C++ modes to activate tabs. Then set the offset to 2, and the general style to user. Finally, add a user style that mimics the Microsoft guidelines for C# (open braces everywhere).

(use-package cc-mode
  :hook (c-mode   . dx:activate-tabs)
  :hook (c++-mode . 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 . +)))))

Clang format

use-package clang-format for ease of use formatting, binding to "C-c '" for both C and C++ mode maps.

(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))

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))))