#+title: Emacs configuration
#+author: Aryadev Chavali
#+description: My Emacs configuration
#+property: header-args:emacs-lisp :tangle config.el :comments link :results none
#+options: toc:nil

#+begin_center
My configuration for (a very specific form of) Emacs
#+end_center
#+latex: \clearpage
#+toc: headlines

* Basics
Firstly, 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

Let's set all yes or no questions to single letter responses.
#+begin_src emacs-lisp
(fset 'yes-or-no-p 'y-or-n-p)
#+end_src
Set the encoding to UTF-8-Unix by default.
#+begin_src emacs-lisp
(use-package emacs
  :straight nil
  :init
  (setq-default buffer-file-coding-system 'utf-8-unix
                save-buffer-coding-system 'utf-8-unix))
#+end_src

Setup no-littering, which cleans up many of the default directories in
Emacs.
#+begin_src emacs-lisp
(use-package no-littering
  :demand t
  :init
  (setq no-littering-etc-directory (expand-file-name ".config/"  user-emacs-directory)
        no-littering-var-directory (expand-file-name ".local/" user-emacs-directory)))
#+end_src
** File saves and custom file
Setup file saving and auto-revert-mode.  Along with that, setup the
custom-file to exist in the var-directory
#+begin_src emacs-lisp
(use-package emacs
  :straight nil
  :init
  (setq backup-directory-alist `(("." . ,(no-littering-expand-var-file-name "saves/")))
        global-auto-revert-non-file-buffers nil
        auto-revert-verbose nil)
  (setq custom-file (no-littering-expand-etc-file-name "custom.el"))
  :config
  (global-auto-revert-mode 1))
#+end_src
* Custom Functions
Functions that don't require a packages to work other than Emacs,
which means I can define them early and use them later.
** Toggle buffer
Like VSCode's toggling feature for just the terminal, but now for
anything I want.
#+begin_src emacs-lisp
(with-eval-after-load "window"
  (defmacro +oreo/create-toggle-function (func-name buf-name
                                                    buf-create
                                                    &optional accept-numeric)
    "Generate a function named FUNC-NAME that toggles the buffer with
name BUF-NAME, using BUF-CREATE to generate it if necessary.

BUF-NAME cannot be a regexp, it must be a fixed name."
    (let ((interactive-arg
           (if accept-numeric '(interactive "p") '(interactive)))
          (arguments
           (if accept-numeric '(&optional arg) nil))
          (buffer-name (if accept-numeric
                           `(if (= arg 1)
                                ,buf-name
                              (concat ,buf-name "<" (int-to-string arg) ">"))
                         buf-name))
          (buffer-create (if accept-numeric
                             `(if (= arg 1)
                                  (,buf-create)
                                (,buf-create arg))
                           `(,buf-create))))
      `(defun ,func-name ,arguments
         ,interactive-arg
         (let* ((buffer (or (get-buffer ,buffer-name)
                            ,buffer-create))
                (displayed (get-buffer-window buffer)))
           (cond (displayed
                  (select-window displayed)
                  (delete-window))
                 (t
                  (display-buffer buffer)
                  (select-window (get-buffer-window buffer)))))))))
#+end_src
** Auto-run command after-save-hook
Define a macro that can run a body of functionality on a given set of
files on after-save-hook.
#+begin_src emacs-lisp
(use-package simple
  :straight nil
  :config
  (defmacro +oreo/create-auto-save (func-name conditions &rest to-run)
    "Create a hook function with name FUNC-NAME such that when the
set of predicates CONDITIONS is satisfied evaluate TO-RUN after a
save."
    `(progn
       (defun ,func-name ()
         (interactive)
         (when ,conditions
           ,@to-run))
       (add-hook 'after-save-hook (quote ,func-name)))))
#+end_src
** Procedure
The ~lambda~ macro provides a function with possible arguments.  A
procedure is a type of form that takes no arguments. This macro
returns an anonymous function with no arguments with all the forms
provided.  It returns it in 'backquoted' form as that is the most
common use of this macro.

(You may notice ~proc~ is used where the return value doesn't matter).
#+begin_src emacs-lisp
(defmacro proc (&rest CDR)
  "For a given list of forms CDR, return a quoted non-argument
lambda."
  `(quote (lambda () ,@CDR)))
#+end_src
** sys-name-cond
A macro that acts as a switch case on ~(system-name)~ which allows
user to write machine specific code.  For me this is for my desktop,
laptop and any other machines that may require specific configuration.
#+begin_src emacs-lisp
(defmacro +oreo/sys-name-cond (&rest pairs)
  "Switch case on result of function `system-name'.

Each pair in PAIRS is typed as:
- (car pair) => string of system name to test.
- (cdr pair) => forms to evaluate."
  (let ((current-lisp))
    (while pairs
      (let* ((pair (car pairs))
             (name (car pair))
             (body (cdr pair)))
        (add-to-list
         'current-lisp
         `((string= ,name (system-name)) ,@body))
        (setq pairs (cdr pairs))))
    `(cond
      ,@current-lisp)))
#+end_src

In [[file:early-init.el][early-init.el]] I set the number of native-workers to 4, which isn't
necessarily optimal when loading/compiling the rest of this file
depending on the machine I use:
- On my laptop (=spiderboy=) I'd prefer to have it use 2-3 threads so I
  can actually use the rest of the laptop while waiting for
  compilation
- On my desktop (=oldboy=) I'd prefer to use 4-6 threads as I can
  afford more to get a much faster compilation as a result.
#+begin_src emacs-lisp
(+oreo/sys-name-cond
 ("spiderboy"
  (setq native-comp-async-jobs-number 3))
 ("oldboy"
  (setq native-comp-async-jobs-number 6)))
#+end_src
** Clean buffer list
Instead of cleaning my buffer list manually, just use this.  Preserves
any buffers in ~+oreo/keep-buffer~ and kills the rest.
#+begin_src emacs-lisp
(defconst +oreo/keep-buffers
  (list "config.org" "*scratch*"
        "*dashboard*" "*Messages*"
        "*Warnings*")
  "List of buffer names to preserve.")

(defun +oreo/clean-buffer-list ()
  "Kill all buffers except any with names in +oreo/keep-buffers."
  (interactive)
  (mapcar #'(lambda (buf)
         (if (not (member (buffer-name buf) +oreo/keep-buffers))
             (kill-buffer buf)))
     (buffer-list)))

#+end_src
* Aesthetics
Load my custom "personal-primary" theme which is stored in the Emacs
lisp folder (look at [[file:elisp/personal-primary-theme.el][this file]]).

I have an older version of this theme that uses a homogeneous colour
scheme ([[file:elisp/personal-theme.el][this file]])
#+begin_src emacs-lisp
(use-package custom
  :demand t
  :straight nil
  :init
  (setq custom-theme-directory (concat user-emacs-directory "elisp/"))
  :config
  (load-theme 'personal-primary t))
#+end_src

Set font size to 140 if on my desktop (oldboy) or 175 if on my laptop
(spiderboy).
#+begin_src emacs-lisp
(use-package faces
  :straight nil
  :config
  (+oreo/sys-name-cond
   ("spiderboy" (set-face-attribute 'default nil :height 175))
   ("oldboy" (set-face-attribute 'default nil :height 140))))
#+end_src

Turn off the startup buffer because I prefer [[Dashboard]], and write into
the scratch buffer some nice information about Emacs.
#+begin_src emacs-lisp
(use-package emacs
  :straight nil
  :init
  (setq inhibit-startup-screen t
        initial-scratch-message (format ";; Emacs v%s\n" emacs-version)
        ring-bell-function 'ignore))
#+end_src

Turn off blinking-cursor-mode as we will later be setting up hl-line,
which does a better job of indicating where the cursor is on screen.
#+begin_src emacs-lisp
(use-package frame
  :straight nil
  :config
  (blink-cursor-mode 0))
#+end_src

After turning off borders in my window manager, I tried turning off
the borders for Emacs.  Incredible, must be done.
#+begin_src emacs-lisp
(use-package fringe
  :after dashboard
  :straight nil
  :init
  (setq left-fringe-width 0
        right-fringe-width 0)
  :config
  (fringe-mode 0))
#+end_src
* Core packages
** 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 to the doom/spacemacs leader.
Local leader is bound to ~SPC ,~ and it's similar to doom/spacemacs
leader but doesn't try to fully assimilate the local-leader map
instead just picking stuff I think is useful.
#+begin_src emacs-lisp
(use-package general
  :demand t
  :config
  (general-def
    :states '(normal motion)
    "SPC"   nil)

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

  (general-create-definer local-leader
    :states '(normal motion)
    :prefix "SPC ,")

  (general-create-definer general-nmmap
    :states '(normal motion))

  (defalias 'nmmap #'general-nmmap)

  (general-evil-setup t))
#+end_src

Add bindings for ~+literate/~ namespace, allows for quick reloads.
#+begin_src emacs-lisp
(use-package general
  :general
  (leader
    :infix "q"
    "c" #'+literate/compile-config
    "l" #'+literate/load-config
    "d" #'delete-frame))
#+end_src
*** Some default binds in Emacs
#+begin_src emacs-lisp
(use-package emacs
  :straight nil
  :general
  (general-def
    "C-x d" #'delete-frame)

  (nmmap
    "C--" #'text-scale-decrease
    "C-=" #'text-scale-increase)

  (local-leader
    :keymaps 'override
    ";" #'browse-url-emacs)

  (leader
    "SPC" #'execute-extended-command
    "u"   #'universal-argument
    ";"   #'eval-expression
    ":"   (proc (interactive) (switch-to-buffer "*scratch*"))
    "!"   #'async-shell-command
    "qq"   #'save-buffers-kill-terminal
    "cF" (proc (interactive) (find-file "~/Code/")))

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

  (leader
    :infix "c"
    "j" #'next-error
    "k" #'previous-error
    "c" #'compile
    "C" #'recompile)

  (leader
    "si" #'imenu)

  (leader
    "h"   #'help-command))
#+end_src
** Evil
Evil (Emacs VI Layer) is a package that brings the Vi experience to
Emacs.  Packaged with it by default are:
- The modal system
- EX
- Vi mapping functions

This provides a lot of stuff for the average vim user moving to Emacs.
However there are many other packages surrounding evil that port even
greater functionality from vi to Emacs.  Surround, commenting,
multiple cursors and further support to other packages are configured
here.
*** Evil core
Setup the evil package, with some opinionated keybindings:

- Switch ~evil-upcase~ and ~evil-downcase~ because I use ~evil-upcase~
  more
- Switch ~evil-goto-mark~ and ~evil-goto-mark-line~ as I'd rather have
  the global one closer to the home row
- Use 'T' character as an action for transposing objects
#+begin_src emacs-lisp
(use-package evil
  :demand t
  :hook (after-init-hook . evil-mode)
  :general
  (nmmap
    "TAB" #'evil-jump-item
    "r"   #'evil-replace-state
    "zC"  #'hs-hide-level
    "'"   #'evil-goto-mark
    "`"   #'evil-goto-mark-line
    "C-w" #'evil-window-map
    "gu"  #'evil-upcase
    "gU"  #'evil-downcase
    "T"   nil)
  (nmmap
    :infix "T"
    "w" #'transpose-words
    "c" #'transpose-chars
    "s" #'transpose-sentences
    "p" #'transpose-paragraphs
    "e" #'transpose-sexps
    "l" #'transpose-lines)
  (vmap
    :keymaps '(emacs-lisp-mode-map lisp-interaction-mode-map)
    "gr" #'eval-region)
  (leader
    "w"  #'evil-window-map
    "wd" #'delete-frame)
  :init
  (setq evil-want-keybinding nil
        evil-split-window-below t
        evil-vsplit-window-right t
        evil-want-abbrev-expand-on-insert-exit t
        evil-undo-system #'undo-tree)
  :config
  (fset #'evil-window-vsplit #'make-frame))
#+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 multi cursor
Setup for multi cursors 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.
#+begin_src emacs-lisp
(use-package evil-mc
  :after evil
  :init
  (defvar evil-mc-key-map (make-sparse-keymap))
  :general
  (nmap
    :infix "gz"
    "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" #'evil-mc-make-cursor-here
    "r" #'evil-mc-resume-cursors
    "s" #'evil-mc-pause-cursors
    "u" #'evil-mc-undo-last-added-cursor)
  :config
  ;; (evil-mc-define-vars)
  ;; (evil-mc-initialize-vars)
  ;; (add-hook 'evil-mc-before-cursors-created #'evil-mc-pause-incompatible-modes)
  ;; (add-hook 'evil-mc-before-cursors-created #'evil-mc-initialize-active-state)
  ;; (add-hook 'evil-mc-after-cursors-deleted  #'evil-mc-teardown-active-state)
  ;; (add-hook 'evil-mc-after-cursors-deleted  #'evil-mc-resume-incompatible-modes)
  ;; (advice-add #'evil-mc-initialize-hooks :override #'ignore)
  ;; (advice-add #'evil-mc-teardown-hooks :override #'evil-mc-initialize-vars)
  ;; (advice-add #'evil-mc-initialize-active-state :before #'turn-on-evil-mc-mode)
  ;; (advice-add #'evil-mc-teardown-active-state :after #'turn-off-evil-mc-mode)
  ;; (add-hook 'evil-insert-state-entry-hook #'evil-mc-resume-cursors)
  (global-evil-mc-mode))
#+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
  :config
  (evil-collection-require 'dired))
#+end_src

** Completion
Emacs is a text based interface.  As a text based interface it heavily
leverages searches and user filters to manage input and provide
functionality.  Though the standard model of completion may be
desirable to some, it can be advanced through the use of 'completion
frameworks'.

These frameworks handle the input from the user for common commands
and provide a differing interface to the one Emacs comes with.  Most
of these completion frameworks provide a text based menu that is
actively filtered as more input is provided (progressive input
filtering).  Along with these frameworks come added functionality and
applications to integrate into the Emacs environment further.

One may say that when using a completion framework there is no point
in using any other framework as they encompasses so much of the
default functionality.  This is wrong: I'd argue that with a bit of
management and Emacs lisp it's totally possible to pick and mix your
options.  For small number selections (like finding files) use
something like Ido and for something larger like searching buffers use
ivy.

Along with frameworks, there is a configuration for the
completions-list, which is actually the original and default method of
completion within Emacs.  When you first install Emacs without a
config, any 'completing-read' function leverages the completions-list when
~TAB~ is used.

Though I believe Ido is a better completion system than the
completions-list, it still has it's place and can be used in tandem
with ido.
*** Amx
Amx is a fork of Smex that works to enhance the
execute-extended-command interface.  It also provides support for ido
or ivy (though I'm likely to use ido here) and allows you to switch
between them.

It provides a lot of niceties such as presenting the key bind when
looking for a command.

#+begin_src emacs-lisp
(use-package amx
  :config
  (amx-mode))
#+end_src
*** Orderless
Orderless sorting method for completion, probably one of the best
things ever.
#+begin_src emacs-lisp
(use-package orderless
  :after (ivy ido)
  :config
  (setf (alist-get t ivy-re-builders-alist) 'orderless-ivy-re-builder))
#+end_src
*** Ido
:PROPERTIES:
:header-args:emacs-lisp: :tangle no
:END:
Ido is a very old completion package that still works great to this
day.  Though it is limited in its scope (and may thus be called a
completion add-on rather than a full on framework), it is still a very
powerful package.  With the use of ido-completing-read+, it may be used
similarly to a fully fledged completion framework.

#+begin_src emacs-lisp
(use-package ido
  :demand t
  :general
  (general-def
    :keymaps '(ido-buffer-completion-map
               ido-file-completion-map
               ido-file-dir-completion-map
               ido-common-completion-map)
    (kbd "M-j")   #'ido-next-match
    (kbd "M-k")   #'ido-prev-match
    (kbd "C-x o") #'evil-window-up)
  :init
  (setq ido-decorations
        (list "{" "}" " \n" " ..." "[" "]" " [No match]" " [Matched]"
              " [Not readable]" " [Too big]" " [Confirm]")
        completion-styles '(flex partial-completion intials emacs22))
  (setq-default ido-enable-flex-matching t
                ido-enable-dot-prefix t
                ido-enable-regexp nil)
  (with-eval-after-load "magit"
    (setq magit-completing-read-function 'magit-ido-completing-read))
  :config
  (ido-mode)
  (ido-everywhere))
#+end_src
**** Ido ubiquitous
Ido completing-read+ is a package that extends the ido package to work
with more text based functions.
#+begin_src emacs-lisp
(use-package ido-completing-read+
  :after ido
  :config
  (ido-ubiquitous-mode +1))
#+end_src
*** Completions-list
#+begin_src emacs-lisp
(use-package simple
  :straight nil
  :general
  (nmmap
    :keymaps 'completion-list-mode-map
    "l"   #'next-completion
    "h"   #'previous-completion
    "ESC" #'delete-completion-window
    "q"   #'quit-window
    "RET" #'choose-completion)
  :config
  (with-eval-after-load "evil"
    (setq evil-emacs-state-modes (cl-remove-if
                                  #'(lambda (x) (eq 'completions-list-mode x))
                                  evil-emacs-state-modes))
    (add-to-list 'evil-normal-state-modes 'completions-list-mode)))
#+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 Core
Setup for ivy, in preparation for counsel.  Turn on ivy-mode just
after init.

Setup vim-like bindings for the minibuffer ("M-(j|k)" for down|up the
selection list).
#+begin_src emacs-lisp
(use-package ivy
  :defer t
  :hook (after-init-hook . ivy-mode)
  :general
  (general-def
    :keymaps  'ivy-minibuffer-map
    "C-j"     #'ivy-yank-symbol
    "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)
  (with-eval-after-load "amx"
    (setq amx-backend 'ivy)))
#+end_src
**** Counsel
Setup for counsel.  Load after ivy and helpful.

Along with that, set the help function and variable functions to their
helpful counterparts.
#+begin_src emacs-lisp
(use-package counsel
  :after ivy
  :general
  (leader
    "ss" #'counsel-grep-or-swiper
    "sr" #'counsel-rg
    "fr" #'counsel-recentf
    "ic" #'counsel-unicode-char)
  (general-def
    [remap describe-bindings]        #'counsel-descbinds
    [remap load-theme]               #'counsel-load-theme)
  :config
  (setq ivy-initial-inputs-alist nil
        counsel-describe-function-function #'helpful-callable
        counsel-describe-variable-function #'helpful-variable
        counsel-grep-swiper-limit 1500000
        ivy-re-builders-alist '((swiper . ivy--regex-plus)
                                (counsel-grep-or-swiper . ivy--regex-plus)
                                (counsel-rg . ivy--regex-plus)
                                (t . ivy--regex-ignore-order)))
  (counsel-mode))
#+end_src
**** Ivy posframe
This makes ivy minibuffer windows use child frames.  Very nice eyecandy.
#+begin_src emacs-lisp
(use-package ivy-posframe
  :hook (ivy-mode-hook . ivy-posframe-mode)
  :straight t
  :init
  (setq ivy-posframe-parameters
        '((left-fringe      . 0)
          (right-fringe     . 0)
          (background-color . "grey7")))

  (setq ivy-posframe-display-functions-alist
        '((t . ivy-posframe-display-at-window-center))))
#+end_src
**** Counsel etags
:PROPERTIES:
:header-args:emacs-lisp: :tangle no
:END:
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
*** Company
Company is the auto complete system I use.  I don't like having heavy
setups for company as it only makes it slower to use.  In this case,
just setup some evil binds for company.
#+begin_src emacs-lisp
(use-package company
  :straight t
  :hook
  (prog-mode-hook   . company-mode)
  (eshell-mode-hook . company-mode)
  :general
  (imap
    "C-SPC" #'company-complete)
  (general-def
    :states '(normal insert)
    "M-j" #'company-select-next
    "M-k" #'company-select-previous))
#+end_src
** Pretty symbols
Prettify symbols mode allows for users to declare 'symbols' that
replace text within certain modes.  For example, you may replace the
'for' word in c-mode for [[https://en.wikipedia.org/wiki/Universal_quantification][universal quantification]].  Though this may
seem like useless eye candy, it has aided my comprehension and speed
of recognition (recognising symbols is easier than words for many,
including me).

Now here I provide a macro +pretty/set-alist.  This macro works pretty
simply: given a mode hook, as well as a list of pairs typed (text to
substitute, symbol to replace with).  Then I add a hook to the given
mode, setting the prettify-symbols-alist to the symbols given.

I've declared it pretty high up into my config so that the rest of my
packages can leverage it.  Furthermore I've added a use-package
keyword which makes declaring this for language modes incredibly
easy.  Checkout my [[C/C++][C/C++]] configuration for an example.
#+begin_src emacs-lisp
(use-package prog-mode
  :straight nil
  :init
  (setq prettify-symbols-unprettify-at-point t)
  :config
  (with-eval-after-load "use-package-core"
    (add-to-list 'use-package-keywords ':pretty)
    (defun use-package-normalize/:pretty (_name-symbol _keyword args)
      args)

    (defun use-package-handler/:pretty (name _keyword args rest state)
      (use-package-concat
       (use-package-process-keywords name rest state)
       (let ((arg args)
             forms)
         (while arg
           (let* ((carg (car arg))
                  (mode (car carg))
                  (rest (cdr carg)))
             (add-to-list
              'forms
              `(add-hook
                ',mode
                (lambda ()
                  (setq prettify-symbols-alist ',rest)
                  (prettify-symbols-mode)))))
           (setq arg (cdr arg)))
         forms))))

  (defmacro +pretty/set-alist (mode &rest symbols)
    `(add-hook
      ',mode
      (lambda ()
        (setq prettify-symbols-alist ',symbols)
        (prettify-symbols-mode))))

  (defun +pretty/set-alist-f (mode symbols)
    `(+pretty/set-alist mode ,@symbols)))
#+end_src

Here's a collection of symbols I have currently that may be used
later.
#+begin_example
("null"   . "Ø")
("list"   . "ℓ")
("string" . "𝕊")
("true"   . "⊤")
("false"  . "⊥")
("char"   . "ℂ")
("int"    . "ℤ")
("float"  . "ℝ")
("!"      . "¬")
("&&"     . "∧")
("||"      . "∨")
("for"    . "∀")
("return" . "⟼")
("print"  . "ℙ")
("lambda" . "λ")
#+end_example
** 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.  Of course, anything and everything is
adaptable in Emacs, this behavior is no different.

Here I create a use-package extension that manages the whole ordeal of
adding a new record to the display-buffer-alist, a useful abstraction
that makes it easy to manage the various buffers created by packages.
#+begin_src emacs-lisp
(use-package window
  :straight nil
  :general
  (leader
    :infix "b"
    "b" #'switch-to-buffer
    "d" #'kill-current-buffer
    "K" #'kill-buffer
    "j" #'next-buffer
    "k" #'previous-buffer
    "D" #'+oreo/clean-buffer-list)
  :init
  (with-eval-after-load "use-package-core"
    (add-to-list 'use-package-keywords ':display)
    (defun use-package-normalize/:display (_name-symbol _keyword args)
      args)

    (defun use-package-handler/:display (name _keyword args rest state)
      (use-package-concat
       (use-package-process-keywords name rest state)
       (let ((arg args)
             forms)
         (while arg
           (add-to-list 'forms
                        `(add-to-list 'display-buffer-alist
                                      ',(car arg)))
           (setq arg (cdr arg)))
         forms)))))
#+end_src
*** Setup some display records
Using the ~:display~ keyword, setup up some ~display-buffer-alist~
records.  This is mostly for packages that aren't really configured
(like [[info:woman][woman]]) or packages that were configured before (like [[Ivy][Ivy]]).
#+begin_src emacs-lisp
(use-package window
  :straight nil
  :defer t
  :display
  ("\\*\\(Wo\\)?Man.*"
   (display-buffer-at-bottom)
   (window-height . 0.25))

  ("\\*Process List\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25))

  ("\\*\\(Ido \\)?Completions\\*"
   (display-buffer-in-side-window)
   (window-height . 0.25)
   (side . bottom))

  ("\\*ivy-occur.*"
   (display-buffer-at-bottom)
   (window-height . 0.25))

  ("\\*Async Shell Command\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25)))
#+end_src
** Auto typing
Snippets are a system by which pieces of code can be inserted via
prefixes.  For example, an 'if' snippet would work by first inserting
the word 'if' then pressing some _expansion key_ such as TAB.  This
will insert a set of text that may be have some components that need
to be further filled by the user.

The popular solution is 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.

However, Emacs provides its own 'auto typing' facilities.  Abbrevs and
skeletons make up the popular solution within Emacs default.  Abbrevs
are for simple expressions wherein there is only one user input (say,
getting today's time which only requires you asking for it).  They
provide a lot of inbuilt functionality and are quite useful.
Skeletons, on the other hand, are for higher level insertions
*** Abbrevs
Just define a few abbrevs for various date-time operations.  Also
define a macro that will assume a function for the expansion, helping
with abstracting a few things away.
#+begin_src emacs-lisp
(use-package abbrev
  :straight nil
  :hook
  (prog-mode-hook . abbrev-mode)
  (text-mode-hook . abbrev-mode)
  :init
  (defmacro +autotyping/deff-abbrev (ABBREV-TABLE ABBREV EXPANSION)
    "Wraps around define-abbrev to fill in some repeated stuff
when expansion is a function."
    `(define-abbrev
       ,ABBREV-TABLE
       ,ABBREV
       ""
       (proc (insert ,EXPANSION))))

  (setq save-abbrevs nil)
  :config
  (+autotyping/deff-abbrev
   global-abbrev-table
   "sdate"
   (format-time-string "%Y-%m-%d" (current-time)))

  (+autotyping/deff-abbrev
   global-abbrev-table
   "stime"
   (format-time-string "%H:%M:%S" (current-time)))

  (+autotyping/deff-abbrev
   text-mode-abbrev-table
   "sday"
   (format-time-string "%A" (current-time)))

  (+autotyping/deff-abbrev
   text-mode-abbrev-table
   "smon"
   (format-time-string "%B" (current-time))))
#+end_src
*** Skeletons
Defining some basic skeletons and a macro to help generate an abbrev
as well.
#+begin_src emacs-lisp
(use-package skeleton
  :straight nil
  :after abbrev
  :config
  (defmacro +autotyping/gen-skeleton-abbrev (mode abbrev &rest skeleton)
    (let* ((table          (intern (concat (symbol-name mode) "-abbrev-table")))
           (skeleton-name  (intern (concat "+skeleton/" (symbol-name mode) "/" abbrev))))
      `(progn
         (define-skeleton
           ,skeleton-name
           ""
           ,@skeleton)
         (define-abbrev ,table
           ,abbrev
           ""
           ',skeleton-name)))))
#+end_src
*** Auto insert
#+begin_src emacs-lisp
(use-package autoinsert
  :straight nil
  :hook (after-init-hook . auto-insert-mode)
  :config
  (add-to-list
   'auto-insert-alist
   '(("\\.html\\'" . "HTML Skeleton")
     ""
     "<!doctype html>
<html class='no-js' lang=''>
  <head>
    <meta charset='utf-8'>
    <meta http-equiv='x-ua-compatible' content='ie=edge'>
    <title>"(read-string "Enter title: ") | """</title>
    <meta name='description' content='" (read-string "Enter description: ") | "" "'>
    <meta name='author' content='"user-full-name"'/>
    <meta name='viewport' content='width=device-width, initial-scale=1'>

    <link rel='apple-touch-icon' href='/apple-touch-icon.png'>
    <link rel='shortcut icon' href='/favicon.ico'/>
    <!-- Place favicon.ico in the root directory -->

  </head>
  <body>
    <!--[if lt IE 8]>
      <p class='browserupgrade'>
      You are using an <strong>outdated</strong> browser. Please
      <a href='http://browsehappy.com/'>upgrade your browser</a> to improve
      your experience.
      </p>
    <![endif]-->
"
     _
"     </body>
</html>"))
  (add-to-list
   'auto-insert-alist
   '(("Makefile" . "Makefile skeleton")
     ""
     "CC=g++
CFLAGS=-Wall -ggdb
OBJECTS=main.o
OUT=main
ARGS=

%.o: %.cpp
  $(CC) $(CFLAGS) -c $^ -o $@

$(OUT): $(OBJECTS)
  $(CC) $(CFLAGS) $^ -o $@

.PHONY:
clean:
  rm -rfv $(OUT) $(OBJECTS)

.PHONY: run
run: $(OUT)
  ./$^ $(ARGS)

.PHONY: memcheck
memcheck: $(OUT)
  sh /etc/profile.d/debuginfod.sh && valgrind --leak-check=full -s --tool=memcheck ./$^ $(ARGS)"
     _)))
#+end_src
*** 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
    "ii" #'yas-insert-snippet)
  :config
  (yas-load-directory (no-littering-expand-etc-file-name "yasnippet/snippets")))
#+end_src
** Mode line
A mode line in an editor can provide a LOT of information, or very
little.  I customised the Emacs modeline to give me a bit of info,
~telephone-line~ to give me a lot.
*** Emacs Mode-line
Check out [[*Telephone-line][this package]] for my current modeline.

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-misc-info
               mode-line-end-spaces)))
#+end_src
*** Telephone-line
:PROPERTIES:
:header-args:emacs-lisp: :tangle no
:END:
Telephone-line is a mode-line package for Emacs which prioritises
extensibility.  It also looks much nicer than the default mode line
with colouring and a ton of presentations to choose from.
#+begin_src emacs-lisp
(use-package telephone-line
  :init
  (defface +telephone/position-face '((t (:foreground "red" :background "grey10"))) "")
  (defface +telephone/mode-face '((t (:foreground "white" :background "dark green"))) "")
  (defface +telephone/file-info-face '((t (:foreground "white" :background "Dark Blue"))) "")
  :custom
  (telephone-line-faces
   '((evil      . telephone-line-modal-face)
     (modal     . telephone-line-modal-face)
     (ryo       . telephone-line-ryo-modal-face)
     (accent    . (telephone-line-accent-active . telephone-line-accent-inactive))
     (nil         . (mode-line                    . mode-line-inactive))
     (position  . (+telephone/position-face     . mode-line-inactive))
     (mode      . (+telephone/mode-face         . mode-line-inactive))
     (file-info . (+telephone/file-info-face    . mode-line-inactive))))
  (telephone-line-primary-left-separator    'telephone-line-halfcos-left)
  (telephone-line-secondary-left-separator  'telephone-line-halfcos-hollow-left)
  (telephone-line-primary-right-separator   'telephone-line-identity-right)
  (telephone-line-secondary-right-separator 'telephone-line-identity-hollow-right)
  (telephone-line-height 24)
  (telephone-line-evil-use-short-tag nil)
  :config
  (telephone-line-defsegment +telephone/buffer-or-filename ()
    (cond
     ((buffer-file-name)
      (if (and (fboundp 'projectile-project-name)
             (fboundp 'projectile-project-p)
             (projectile-project-p))
          (list ""
                (funcall (telephone-line-projectile-segment) face)
                (propertize
                 (concat "/"
                         (file-relative-name (file-truename (buffer-file-name))
                                             (projectile-project-root)))
                 'help-echo (buffer-file-name)))
        (buffer-file-name)))
     (t (buffer-name))))

  (telephone-line-defsegment +telephone/get-position ()
    `(,(concat "%lL:%cC"
               (if (not mark-active)
                   ""
                 (format " | %dc" (- (+ 1 (region-end)) (region-beginning)))))))

  (setq-default
   telephone-line-lhs '((mode telephone-line-major-mode-segment)
                        (file-info telephone-line-input-info-segment)
                        (position +telephone/get-position)
                        (accent   +telephone/buffer-or-filename
                                  telephone-line-process-segment))
   telephone-line-rhs '((accent telephone-line-flycheck-segment telephone-line-misc-info-segment
                                telephone-line-projectile-segment)
                        (file-info telephone-line-filesize-segment)
                        (evil  telephone-line-evil-tag-segment)))
  (telephone-line-mode))
#+end_src
** Olivetti
Olivetti provides a focus mode for Emacs, which makes it look a bit
nicer with fringes.  I also define ~+olivetti-mode~ which will
remember and clear up any window configurations on the frame, then
when turned off will reinsert them - provides a nice way to quickly
focus on a buffer.
#+begin_src emacs-lisp
(use-package olivetti
  :commands (+olivetti-mode)
  :general
  (leader
    "to" #'+olivetti-mode)
  :init
  (setq-default olivetti-body-width 0.6)
  (setq olivetti-style nil)
  (add-hook 'olivetti-mode-on-hook  (proc (interactive) (text-scale-increase 1)))
  (add-hook 'olivetti-mode-off-hook (proc (interactive) (text-scale-decrease 1)))
  :config
  (defun +olivetti-mode ()
    (interactive)
    (if (not olivetti-mode)
        (progn
          (window-configuration-to-register 1)
          (delete-other-windows)
          (setq +olivetti/prev-mode-line mode-line-format)
          (setq mode-line-format nil)
          (olivetti-mode t))
      (jump-to-register 1)
      (setq mode-line-format +olivetti/prev-mode-line)
      (olivetti-mode 0))))
#+end_src
* Small packages
** ISearch
#+begin_src emacs-lisp
(use-package isearch
  :straight nil
  :general
  (:keymaps 'isearch-mode-map
     "M-s" #'isearch-repeat-forward))
#+end_src
** Info
#+begin_src emacs-lisp
(use-package info
  :straight nil
  :general
  (nmmap
    :keymaps 'Info-mode-map
    "h" #'evil-backward-char
    "k" #'evil-previous-line
    "l" #'evil-forward-char
    "H" #'Info-history-back
    "L" #'Info-history-forward))
#+end_src
** Display line numbers
I don't like using this mode by default, but I'd like to configure it
if possible.  Line numbers are a necessary evil a lot of times, and
it's useful for presentations.
#+begin_src emacs-lisp
(use-package display-line-numbers
  :straight nil
  :commands display-line-numbers-mode
  :general
  (leader
    "tl" #'display-line-numbers-mode)
  :init
  (setq-default display-line-numbers-type 'relative))
#+end_src
** xref
Find definitions, references using tags for free!  Such an underrated
utility, particularly now that I'm not using Eglot (in some sense,
returning to the nature of Emacs).  All you need is a way of
generating tags, probably a make recipe.
#+begin_src emacs-lisp
(use-package xref
  :straight nil
  :display
  ("\\*xref\\*"
   (display-buffer-at-bottom)
   (inhibit-duplicate-buffer . t)
   (window-height . 0.25))
  :general
  (leader
    :infix "ct"
    "t" #'xref-find-apropos
    "d" #'xref-find-definitions
    "r" #'xref-find-references)
  (nmmap
    :keymaps 'xref--xref-buffer-mode-map
    "RET" #'xref-goto-xref
    "J" #'xref-next-line
    "K" #'xref-prev-line
    "g" #'xref-revert-buffer
    "q" #'quit-window))
#+end_src
** Hl-line
Hl-line is a useful tool, best line indicator in the game.
#+begin_src emacs-lisp
(use-package hl-line
  :defer t
  :hook (text-mode-hook . hl-line-mode))
#+end_src
** Recentf
Recentf makes it easy to
#+begin_src emacs-lisp
(use-package recentf
  :straight nil
  :hook (emacs-startup-hook . recentf-mode))
#+end_src
** Projectile
Setup projectile, along with the tags command.
#+begin_src emacs-lisp
(use-package projectile
  :after evil
  :hook (emacs-startup-hook . projectile-mode)
  :general
  (leader "p" #'projectile-command-map)
  :init
  (setq projectile-tags-command "ctags -Re -f \"%s\" %s \"%s\""))
#+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
** Avy
Setup avy with leader.  As I use ~avy-goto-char-timer~ a lot, use the
~C-s~ bind which replaces isearch.  Switch isearch to M-s in case I
need to use it.
#+begin_src emacs-lisp
(use-package avy
  :after evil
  :general
  (leader
    :infix "s"
    "l" #'avy-goto-line)
  (nmmap
    (kbd "C-s") #'avy-goto-char-timer
    (kbd "M-s") #'isearch-forward))
#+end_src
** Ace window
Though evil provides a great many features in terms of window
management, much greater than what's easily available in Emacs, ace
window can provide some nicer chords for higher management of windows
(closing, switching, etc).

#+begin_src emacs-lisp
(use-package ace-window
  :after evil
  :custom
  (aw-keys '(?a ?s ?d ?f ?g ?h ?j ?k ?l))
  :general
 (nmmap
    [remap evil-window-next] #'ace-window))
#+end_src
** Helpful
Basic setup that replaces commands and configures
~display-buffer-alist~ for helpful.
#+begin_src emacs-lisp
(use-package helpful
  :after ivy
  :commands (helpful-callable helpful-variable)
  :general
  (general-def
    [remap describe-function] #'helpful-callable
    [remap describe-variable] #'helpful-variable
    [remap describe-key]      #'helpful-key)
  :display
  ("\\*[Hh]elp.*"
   (display-buffer-at-bottom)
   (inhibit-duplicate-buffer . t)
   (window-height . 0.25))
  :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
  :config
  (which-key-mode))
#+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))
#+end_src
** (Rip)grep
Grep is likely one of the most important programs ever invented; a
must-have tool for any Linux users inventory.  It is a searching
utility that allows one to search files for certain regex patterns.
The fact that there have been so many attempts to replace grep (with
limited success) only goes to show how important its general function
is to people.

Ripgrep is a grep-like utility written in Rust.  It subsumes not only
the ability to search a given file but also to search multiple files
within a directory (which is usually only done by composing the
program find with grep to search multiple files).  It is incredibly
fast by virtue of its regex optimisations and the use of ignore files
such as ~.gitignore~ to filter files when searching.

Grep has default Emacs utilities that use a ~compilation~ style buffer
to search a variety of differing data sets.  ~grep~ searches files,
~rgrep~ searches in a directory using the ~find~ binary and ~zgrep~
searches archives.  This is a great solution for most computer
environments as basically all of them will have grep and find
installed.  Even when you ~ssh~ into a remote machine, they're likely
to have these tools.

The ripgrep package provides utilities to ripgrep projects and files
for strings via the rg binary.  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.  Of
course, this requires installing the rg binary which is available in
most repositories nowadays.
*** Grep
#+begin_src emacs-lisp
(use-package grep
  :display
  ("grep\\*"
   (display-buffer-reuse-window)
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :straight nil
  :general
  (leader
    "sd" #'rgrep))
#+end_src
*** rg
#+begin_src emacs-lisp
(use-package rg
  :after grep
  :general
  (leader
    "sR" #'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"
        rg-buffer-name "*ripgrep*"))
#+end_src
** All the Icons
Nice set of icons with a great user interface to manage them.
#+begin_src emacs-lisp
(use-package all-the-icons
  :straight t
  :defer t
  :commands (all-the-icons-insert)
  :general
  (leader
    "ie" #'all-the-icons-insert))

#+end_src
* Applications
** Dashboard
Dashboard creates a custom dashboard for Emacs that replaces the
initial startup screen in default Emacs.
#+begin_src emacs-lisp
(use-package dashboard
  :straight t
  :demand t
  :general
  (leader
    "ab" #'dashboard-refresh-buffer)
  (:states '(normal motion emacs)
   :keymaps 'dashboard-mode-map
   "q" (proc (interactive) (kill-this-buffer)))
  (nmmap
    :keymaps 'dashboard-mode-map
    "r" #'dashboard-jump-to-recent-files
    "p" #'dashboard-jump-to-projects
    "}" #'dashboard-next-section
    "{" #'dashboard-previous-section)
  :init
  (setq initial-buffer-choice nil
        dashboard-banner-logo-title "Oreomacs"
        dashboard-center-content t
        dashboard-set-init-info t
        dashboard-startup-banner (no-littering-expand-etc-file-name "dashboard/logo.png")
        dashboard-set-footer t
        dashboard-set-navigator t
        dashboard-items '((projects . 5)
                          (recents . 5)))
  :config
  (dashboard-setup-startup-hook))
#+end_src
** EWW
#+begin_src emacs-lisp
(use-package eww
  :defer t
  :straight nil
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-eww-setup)))
#+end_src
** Calendar
Calendar is a simple inbuilt application within Emacs that helps with
date functionalities.  I add functionality to copy dates from the
calendar to the kill ring and bind it to "Y".
#+begin_src emacs-lisp
(use-package calendar
  :straight nil
  :defer t
  :commands (+calendar/copy-date +calendar/toggle-calendar)
  :display
  ("\\*Calendar\\*"
   (display-buffer-at-bottom)
   (inhibit-duplicate-buffer . t)
   (window-height . 0.17))
  :general
  (nmmap
    :keymaps 'calendar-mode-map
   "Y" #'+calendar/copy-date)
  (leader
    "ad" #'+calendar/toggle-calendar)
  :config
  (defun +calendar/copy-date ()
    "Copy date under cursor into kill ring."
    (interactive)
    (if (use-region-p)
        (call-interactively #'kill-ring-save)
      (let ((date (calendar-cursor-to-date)))
        (when date
          (setq date (encode-time 0 0 0 (nth 1 date) (nth 0 date) (nth 2 date)))
          (kill-new (format-time-string "%Y-%m-%d" date))))))
  (+oreo/create-toggle-function
   +calendar/toggle-calendar
   "*Calendar*"
   calendar
   nil))
#+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
(use-package notmuch
  :defer t
  :commands (notmuch +mail/flag-thread)
  :general
  (leader "am" #'notmuch)
  (nmap
    :keymaps 'notmuch-search-mode-map
    "f" #'+mail/flag-thread)
  :init
  (defconst +mail/signature "---------------\nAryadev Chavali")
  (defconst +mail/local-dir (concat user-emacs-directory ".mail/"))
  (setq notmuch-show-logo nil
        notmuch-search-oldest-first nil
        notmuch-hello-sections '(notmuch-hello-insert-saved-searches
                                 notmuch-hello-insert-alltags
                                 notmuch-hello-insert-recent-searches)
        notmuch-archive-tags '("-inbox" "-unread" "+archive")
        mail-signature +mail/signature
        mail-default-directory +mail/local-dir
        mail-source-directory +mail/local-dir
        message-signature +mail/signature
        message-auto-save-directory +mail/local-dir
        message-directory +mail/local-dir)

  (defun +mail/sync-mail ()
    "Sync mail via mbsync."
    (interactive)
    (start-process-shell-command "" nil "mbsync -a"))
  (defun +mail/trash-junk ()
    "Delete any mail in junk"
    (interactive)
    (start-process-shell-command "" nil "notmuch search --output=files --format=text0 tag:deleted tag:spam tag:trash tag:junk | xargs -r0 rm"))
  :config
  (defun +mail/flag-thread (&optional unflag beg end)
    (interactive (cons current-prefix-arg (notmuch-interactive-region)))
    (notmuch-search-tag
     (notmuch-tag-change-list '("-inbox" "+flagged") unflag) beg end)
    (when (eq beg end)
      (notmuch-search-next-thread)))
  (advice-add #'notmuch-poll-and-refresh-this-buffer :before
              #'+mail/sync-mail)
  (advice-add #'notmuch-poll-and-refresh-this-buffer :after
              #'+mail/trash-junk)
  (with-eval-after-load "evil-collection"
    (evil-collection-notmuch-setup)))
#+end_src
*** Smtpmail
#+begin_src emacs-lisp
(use-package smtpmail
  :after notmuch
  :commands mail-send
  :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
** Dired
Setup for dired.  Make dired-hide-details-mode the default mode when
using dired-mode, as it removes the clutter.  Setup evil collection
for dired (even though dired doesn't really conflict with evil, there
are some corners I'd like to adjust).
#+begin_src emacs-lisp
(use-package dired
  :defer t
  :straight nil
  :commands (dired find-dired)
  :init
  (setq-default dired-listing-switches "-AFBl --group-directories-first"
                dired-omit-files "^\\.")
  (defvar +dired/omit-mode nil)
  (defun +dired/omit-dot-files ()
    (interactive)
    (setq-local +dired/omit-mode (not +dired/omit-mode))
    (dired-omit-mode (if +dired/omit-mode 1 -1))
    (revert-buffer))
  :hook
  (dired-mode-hook              . dired-hide-details-mode)
  (dired-mode-hook              . auto-revert-mode)
  (dired-hide-details-mode-hook . +dired/omit-dot-files)
  :general
  (nmmap
    :keymaps 'dired-mode-map
    "T" #'dired-create-empty-file)
  (leader
    :infix "d"
    "w" #'wdired-change-to-wdired-mode
    "f" #'find-dired
    "d" #'dired
    "D" #'dired-other-frame
    "l" (proc (interactive) (find-dired "~/Text/PDFs/" "-iname 'cs[0-9][0-9][0-9].pdf' -or -iname 'ma[0-9][0-9][0-9]*.pdf'")))
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-dired-setup))

  (defun +dired/insert-all-subdirectories ()
    "Insert all subdirectories currently viewable."
    (interactive)
    (dired-mark-directories nil)
    (mapcar #'dired-insert-subdir (dired-get-marked-files))
    (dired-unmark-all-marks))

  (nmmap
    :keymaps 'dired-mode-map
    "SPC"   nil
    "SPC ," nil)

  (local-leader
    :keymaps 'dired-mode-map
    "l" #'dired-maybe-insert-subdir
    "m" #'dired-mark-files-regexp
    "u" #'dired-undo))
#+end_src

*** fd-dired
Uses fd for finding file results in a directory: ~find-dired~ ->
~fd-dired~.

#+begin_src emacs-lisp
(use-package fd-dired
  :after dired
  :straight t
  :general
  (leader
    "dF" #'fd-dired))
#+end_src
** Xwidget
Xwidget is a package (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 web pages which include JavaScript,
as it may come of use when doing web development.  I can see the
results of work very quickly without switching windows or workspaces.
*** Xwidget Core
#+begin_src emacs-lisp
(use-package xwidget
  :straight nil
  :display
  ("\\*xwidget.*"
   (display-buffer-pop-up-frame))
  :general
  (leader "au" #'xwidget-webkit-browse-url)
  (nmmap
    :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
    "+"         #'xwidget-webkit-zoom-in
    "-"         #'xwidget-webkit-zoom-out
    (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
*** Xwidget Extensions
Define a function ~+xwidget/render-file~ that reads a file name and
presents it in an xwidget.  If the current file is an HTML file, ask
if user wants to open current file.  Bind it to ~aU~ in the leader.

Also define a function ~+xwidget/search-query~ that first asks the
user what search engine they want to use ([[https://duckduckgo.com][Duck Duck Go]] and [[https://devdocs.io][DevDocs]]
currently) then asks for a query, which it parses then presents in an
xwidget window.  Bind to ~as~ in the leader.
#+begin_src emacs-lisp
(use-package xwidget
  :straight nil
  :commands (+xwidget/render-file +xwidget/search)
  :general
  (leader
    "aU" #'+xwidget/render-file
    "as" #'+xwidget/search)
  :config
  (setenv "WEBKIT_FORCE_SANDBOX" "0")
  (defun +xwidget/render-file (&optional FORCE)
    "Find file (or use current file) and render in xwidget."
    (interactive)
    (cond
     ((and (not FORCE) (or (string= (replace-regexp-in-string ".*.html"
                                                           "html" (buffer-name)) "html")
                        (eq major-mode 'web-mode)
                        (eq major-mode 'html-mode))) ; If in html file
      (if (y-or-n-p "Open current file?: ") ; Maybe they want to open a separate file
          (xwidget-webkit-browse-url (format "file://%s" (buffer-file-name)))
        (+xwidget/render-file t))) ; recurse and open file via prompt
     (t
      (xwidget-webkit-browse-url
       (format "file://%s" (read-file-name "Enter file to open: "))))))

  (defun +xwidget/search ()
    "Run a search query on some search engine and display in
xwidget."
    (interactive)
    (let* ((engine (completing-read "Engine: " '("duckduckgo.com" "devdocs.io") nil t))
           (query-raw (read-string "Enter query: "))
           (query
            (cond
             ((string= engine "duckduckgo.com") query-raw)
             ((string= engine "devdocs.io") (concat "_ " query-raw)))))
      (xwidget-webkit-browse-url (concat "https://" engine "/?q=" query)))))
#+end_src
** Eshell
*** Why Eshell?
Eshell is the integrated shell environment for Emacs.  I argue that it
is the best shell/command interpreter to use in Emacs.

Eshell is unlike the alternatives in Emacs as it's a /shell/ first,
not a terminal emulator. It has the ability to spoof some aspects of a
terminal emulator (through the shell parser), but it is NOT a terminal
emulator.

I'd say the killer benefits of eshell (which would appeal to Emacs
users) are due to eshell being written in Emacs lisp:
- incredible integration with Emacs utilities (such as ~dired~,
  ~find-file~, any read functions, to name a few)
- very extensible, easy to write new commands which leverage Emacs
  commands as well as external utilities
- agnostic of platform: "eshell/cd" will call the underlying change
  directory function for you, so commands will (usually) mean the same
  thing regardless of platform
  - this means as long as Emacs runs, you can run eshell

However, my favourite feature of eshell is the set of evaluators that
run on command input.  Some of the benefits listed above come as a
result of this powerful feature. These evaluators are describe below.

Lisp evaluator: works on braced expressions, evaluating them as Lisp
expressions.  Any returned objects are printed.  This makes eshell an
Emacs Lisp REPL!

External evaluator: works within curly braces, evaluating them via
some external shell process (like sh).  This makes eshell a (dumb)
terminal emulator!

The alias evaluator is the top level evaluator.  It is the main
evaluator for each expression given to eshell.  When given an
expression it tries to evaluate it by testing against these conditions
(going to the next if it doesn't find it):
- it's an alias defined by the user or in the ~eshell/~ namespace of
  functions (simplest evaluator)
- it's some form of lisp expression (lisp evaluator)
- it's an external command (bash evaluator)

Essentially, you get the best of both Emacs and external shell
programs *ALL WITHIN* Emacs for free.
*** Eshell functionality
Bind some evil-like movements for easy shell usage, and a toggle
function to pull up the eshell quickly.
#+begin_src emacs-lisp
(use-package eshell
  :commands +shell/toggle-eshell
  :general
  (leader
    "tt" #'+shell/toggle-eshell)
  :init
  (add-hook
   'eshell-mode-hook
   (proc
    (interactive)
    (general-def
      :states '(normal insert)
      :keymaps 'eshell-mode-map
      "M-l" (proc (interactive) (eshell/clear)
      "M-j" #'eshell-next-matching-input-from-input
      "M-k" #'eshell-previous-matching-input-from-input)
    (local-leader
      :keymaps 'eshell-mode-map
      "c" (proc (interactive) (eshell/clear)
                   (recenter))
      "k" #'eshell-kill-process))))
  :config
  (+oreo/create-toggle-function
   +shell/toggle-eshell
   "*eshell*"
   eshell
   t))
#+end_src
*** Eshell pretty symbols and display
Pretty symbols and a display record.
#+begin_src emacs-lisp
(use-package eshell
  :pretty
  (eshell-mode-hook
   ("lambda"  . "λ")
   ("numberp" . "ℤ")
   ("t"       . "⊨")
   ("nil"     . "Ø"))
  :display
  ("\\*e?shell\\*" ; for general shells as well
   (display-buffer-at-bottom)
   (window-height . 0.25)))
#+end_src
*** Eshell variables and aliases
Set some sane defaults, a banner and a prompt.  The prompt checks for
a git repo in the current directory and provides some extra
information in that case (in particular, branch name and if there any
changes that haven't been committed).

Also add ~eshell/goto~, which is actually a command accessible from
within eshell (this is because ~eshell/*~ creates an accessible
function within eshell with name ~*~).  ~eshell/goto~ makes it easier
to change directories by using Emacs to provide an interface (which is
much faster than ~cd ..; ls -l~).
#+begin_src emacs-lisp
(use-package eshell
  :config
  (defun +eshell/get-git-properties ()
    (let* ((git-branch (shell-command-to-string "git branch"))
           (is-repo (string= (if (string= git-branch "") ""
                               (substring git-branch 0 1)) "*")))
      (if (not is-repo)
          ""
        (concat
         "("
         (nth 2 (split-string git-branch "\n\\|\\*\\| "))
         "<"
         (if (string= "" (shell-command-to-string "git status | grep 'up to date'"))
             "×"
           "✓")
         ">)"))))
  (setq eshell-cmpl-ignore-case t
        eshell-cd-on-directory t
        eshell-banner-message (concat (shell-command-to-string "figlet eshell") "\n")
        eshell-prompt-function
        (proc
         (let ((properties (+eshell/get-git-properties)))
           (concat
            properties
            (format "[%s]\n" (abbreviate-file-name (eshell/pwd)))
            "λ ")))
        eshell-prompt-regexp "^λ ")

  (defun eshell/goto (&rest args)
    "Use `read-directory-name' to change directories."
    (eshell/cd (list (read-directory-name "Enter directory to go to:")))))
#+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)
  (nmmap
    :keymaps 'elfeed-search-mode-map
    "gr"       #'elfeed-update
    "s"        #'elfeed-search-live-filter
    "<return>" #'elfeed-search-show-entry)
  :init
  (setq elfeed-db-directory (no-littering-expand-var-file-name "elfeed/"))
  (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)
          ("The Onion"
           "https://www.theonion.com/rss"
           Social)
          ("Stack exchange"
           "http://morss.aryadevchavali.com/stackexchange.com/feeds/questions"
           Social)
          ("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)
          ("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)
          ("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)))
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-elfeed-setup))
  (setq elfeed-feeds (cl-map 'list #'(lambda (item)
                                       (append (list (nth 1 item)) (cdr (cdr item))))
                             +rss/feed-urls)))
#+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.  Also, define an auto insert for commit messages so that I
don't need to write everything myself.

#+begin_src emacs-lisp
(use-package magit
  :defer t
  :display
  ("magit:.*"
   (display-buffer-same-window)
   (inhibit-duplicate-buffer . t))
  ("magit-diff:.*"
   (display-buffer-below-selected))
  ("magit-log:.*"
   (display-buffer-same-window))
  :general
  (leader "g" #'magit-status)
  :init
  (setq vc-follow-symlinks t)
  (with-eval-after-load "autoinsert"
    (define-auto-insert '("COMMIT_EDITMSG" , "Commit")
      '(nil
        "(" (read-string "Enter feature/module: ") ")"
        (read-string "Enter simple description: ") "\n\n"
        _)))
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-magit-setup)))
#+end_src
** IBuffer
#+begin_src emacs-lisp
(use-package ibuffer
  :general
  (leader
    "bi" #'ibuffer)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-ibuffer-setup)))
#+end_src
** Processes
Emacs has two systems for process management:
+ proced: a general 'top' like interface which allows general
  management of linux processes
+ list-processes: a specific Emacs based system that lists processes
  spawned by Emacs (similar to a top for Emacs specifically)

*** Proced
Core proced config, just a few bindings and evil collection setup.
#+begin_src emacs-lisp
(use-package proced
  :straight nil
  :general
  (leader
    "ap" #'proced)
  (nmap
    :keymaps 'proced-mode-map
    "za" #'proced-toggle-auto-update)
  :display
  ("\\*Proced\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :init
  (setq proced-auto-update-interval 0.5)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-proced-setup)))
#+end_src

Along with that I setup the package ~proced-narrow~ which allows
further filtering of the process list.
#+begin_src emacs-lisp
(use-package proced-narrow
  :straight t
  :after proced
  :general
  (nmap
    :keymaps 'proced-mode-map
    "%" #'proced-narrow))
#+end_src
** Calculator
Surprise, surprise Emacs comes with a calculator.

Greater surprise, this thing is over powered beyond just simple
calculation:
- Matrix calculations
- Generalised calculus operations
- Equation solvers for n-degree multi-variable polynomials
- Embedded mode!

~calc-mode~ is a calculator system within Emacs that provides a
diverse array of mathematical operations.  It uses reverse polish
notation to do calculations (though there is a standard infix
algebraic notation mode).

#+begin_src emacs-lisp
(use-package calc
  :straight nil
  :display
  ("*Calculator*"
   (display-buffer-at-bottom)
   (window-height . 0.18))
  :general
  (leader
    "ac" #'calc-dispatch
    "tc" #'calc-embedded)
  :init
  (setq calc-algebraic-mode t)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-calc-setup)))
#+end_src
*** Calctex
~calc-mode~ also has a 3rd party package called ~calctex~. It renders
mathematical expressions within calc as if they were rendered in TeX.
You can also copy the expressions in their TeX forms, which is pretty
useful when writing a paper.  I've set a very specific lock on this
repository as it's got quite a messy work-tree and this commit seems to
work for me given the various TeX utilities installed via Arch.

#+begin_src emacs-lisp
(use-package calctex
  :after calc
  :straight (calctex :type git :host github :repo "johnbcoughlin/calctex")
  :hook (calc-mode-hook . calctex-mode))
#+end_src
** Ledger
#+begin_src emacs-lisp
(use-package ledger-mode
  :defer t)

(use-package evil-ledger
  :after ledger-mode)
#+end_src
** Zone
:PROPERTIES:
:header-args:emacs-lisp: :tangle no
:END:
Of course Emacs has a cool screensaver software.

#+begin_src emacs-lisp
(use-package zone-matrix
  :straight t
  :after dashboard
  :init
  (setq zone-programs
        [zone-pgm-jitter
         zone-pgm-putz-with-case
         zone-pgm-dissolve
         zone-pgm-whack-chars
         zone-pgm-drip
         zone-pgm-rat-race
         zone-pgm-random-life
         zone-matrix
         ])
  :config
  (zone-when-idle 15))
#+end_src
* Major modes, programming and text
Setups for common major modes and languages.
** Text Configuration
Standard packages and configurations for the text-mode.
*** 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)
  :general
  (nmmap
    :keymaps 'text-mode-map
    (kbd "M-C") #'flyspell-correct-word-before-point
    (kbd "M-c") #'flyspell-auto-correct-word))
#+end_src
*** Undo tree
Undo tree is a system for handling the history of any buffer.  It
provides a very nice 'tree' visualiser (hence the name) for revisions
of a file or buffer, and allows you to move around different versions
at once, without using a VCS like git (all in Emacs).
#+begin_src emacs-lisp
(use-package undo-tree
  :straight t
  :hook (after-init-hook . global-undo-tree-mode)
  :general
  (leader
    "tu" #'undo-tree-visualize))
#+end_src
*** Whitespace
Deleting whitespace, highlighting when going beyond the 80th character
limit, all good stuff.  I don't want to highlight whitespace for
general mode categories (Lisp shouldn't really have an 80 character
limit), so set it for specific modes need the help.
#+begin_src emacs-lisp
(use-package whitespace
  :straight nil
  :general
  (nmmap
    "M--"   #'whitespace-cleanup)
  (leader
    "ts" #'whitespace-mode)
  :hook
  (before-save-hook  . whitespace-cleanup)
  (c-mode-hook       . whitespace-mode)
  (c++-mode-hook     . whitespace-mode)
  (haskell-mode-hook . whitespace-mode)
  (python-mode-hook  . whitespace-mode)
  :init
  (setq whitespace-style '(face lines-tail spaces tabs tab-mark trailing newline)
        whitespace-line-column 80))
#+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
*** Smartparens
Smartparens is a smarter electric-parens, it's much more aware of
context and easier to use.
#+begin_src emacs-lisp
(use-package smartparens
  :hook
  (prog-mode-hook . smartparens-mode)
  (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
** Programming Configuration
*** 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
  :straight nil
  :hook (prog-mode-hook . eldoc-mode)
  :init
  (global-eldoc-mode 1))

(use-package eldoc-box
  :hook (eldoc-mode-hook . eldoc-box-hover-mode)
  :init
  (setq eldoc-box-position-function #'eldoc-box--default-upper-corner-position-function
        eldoc-box-clear-with-C-g t))
#+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
  :after project
  :defer t
  :general
  (leader
    :keymaps 'eglot-mode-map
    :infix "c"
    "f" #'eglot-format
    "a" #'eglot-code-actions
    "r" #'eglot-rename
    "R" #'eglot-reconnect)
  ;; :init
  ;; (setq eglot-stay-out-of '(flymake))
  :config
  (add-to-list 'eglot-server-programs '((c++-mode c-mode) "clangd"))
  (add-to-list 'eglot-server-programs `(csharp-mode "~/.local/src/omnisharp-roslyn/run" "-lsp")))
#+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 flycheck-list-errors)
  :hook
  (prog-mode-hook . flycheck-mode)
  :general
  (leader
    "tf" #'flycheck-mode
    "cx" #'flycheck-list-errors
    "cJ" #'flycheck-next-error
    "cK" #'flycheck-previous-error)
  :display
  ("\\*Flycheck.*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-flycheck-setup)))
#+end_src
*** Tabs and spaces
By default, turn off tabs and set the tab width to two.
#+begin_src emacs-lisp
(setq-default indent-tabs-mode nil
              tab-width 2)
#+end_src

However, if necessary later, define a function that may activate tabs locally.
#+begin_src emacs-lisp
(defun +oreo/activate-tabs ()
  (interactive)
  (setq-local indent-tabs-mode t))
#+end_src
*** Compilation
Colourising the compilation buffer so ANSI colour codes get computed.
#+begin_src emacs-lisp
(use-package compile
  :defer t
  :straight nil
  :display
  ("\\*compilation\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :config
  (defun +compile/colourise ()
    "Colourise the emacs compilation buffer."
    (interactive)
    (let ((inhibit-read-only t))
      (ansi-color-apply-on-region (point-min) (point-max))))
  (add-hook 'compilation-filter-hook #'+compile/colourise))
#+end_src
*** Highlight todo items
TODO items are highlighted in org buffers, but not necessarily in
every buffer.  This minor mode highlights all TODO like items via a
list of strings to match.  It also configures faces to use when
highlighting.

#+begin_src emacs-lisp
(use-package hl-todo
  :after prog-mode
  :hook (prog-mode-hook . hl-todo-mode)
  :init
  (setq hl-todo-keyword-faces
        '(("TODO"  . "#E50000")
          ("WAIT"  . "#00CC00")
          ("FIXME" . "#d02090")))
  )
#+end_src
** Hide-show mode
Turn on ~hs-minor-mode~ for all prog-mode.
#+begin_src emacs-lisp
(use-package hideshow
  :straight nil
  :hook (prog-mode-hook . hs-minor-mode))
#+end_src
** PDF
PDFs are a format for (somewhat) immutable text and reports with great
formatting options.  Though Emacs isn't my favourite application for
viewing PDFs (I highly recommend [[https://pwmt.org/projects/zathura/][Zathura]]), similar to most things with
Emacs, having a PDF viewer builtin can be a very useful asset.

For example if I were editing an org document which I was eventually
compiling into a PDF, my workflow would be much smoother with a PDF
viewer within Emacs that I can open on another pane.
*** PDF tools
~pdf-tools~ provides the necessary functionality for viewing PDFs.
There is no proper PDF viewing without this package.
~evil-collection~ provides a setup for this mode, so use that.
#+begin_src emacs-lisp
(use-package pdf-tools
  :mode ("\\.[pP][dD][fF]" . pdf-view-mode)
  :straight t
  :display
  ("^.*pdf$"
   (display-buffer-same-window)
   (inhibit-duplicate-buffer . t))
  :config
  (pdf-tools-install-noverify)
  (with-eval-after-load "evil-collection"
    (evil-collection-pdf-setup)))
#+end_src
*** PDF grep
PDF grep is a Linux tool that allows for searches against PDFs similar
to standard grep (but for PDFs!).
#+begin_src emacs-lisp
(use-package pdfgrep
  :after pdf-tools
  :hook (pdf-view-mode-hook . pdfgrep-mode)
  :general
  (nmap
    :keymaps 'pdf-view-mode-map
    "M-g"    #'pdfgrep))
#+end_src
** SQL
#+begin_src emacs-lisp
(use-package sql
  :straight nil
  :init
  (setq sql-display-sqli-buffer-function nil))
#+end_src
** Ada
Check out [[file:elisp/ada-mode.el][ada-mode*]], my custom ~ada-mode~ that replaces the default one.
This mode just colourises stuff, and uses eglot to do the important
stuff.

#+begin_src emacs-lisp
(load-file (concat user-emacs-directory "elisp/ada-mode.el"))
(with-eval-after-load "eglot"
  (add-hook 'ada-mode-hook #'eglot))
#+end_src
** NHexl
Hexl-mode is the inbuilt package within Emacs to edit hex and binary
format buffers.  There are a few problems with hexl-mode though,
including an annoying prompt on /revert-buffer/.

Thus, nhexl-mode!  It comes with a few other improvements. Check out
the [[https://elpa.gnu.org/packages/nhexl-mode.html][page]] yourself.
#+begin_src emacs-lisp
(use-package nhexl-mode
  :straight t
  :mode "\\.bin")
#+end_src
** Org
*** Org Core Variables
Tons of variables for org-mode, including a ton of latex ones.  Can't
really explain because it sets up quite a lot of local stuff.  Also I
copy pasted the majority of this, tweaking it till it felt good.  Doom
Emacs was very helpful here.
#+begin_src emacs-lisp
(use-package org
  :defer t
  :custom
  (org-directory "~/Text")
  (org-edit-src-content-indentation 0)
  (org-goto-interface 'outline)
  (org-src-window-setup 'current-window)
  (org-indirect-buffer-display 'current-window)
  (org-export-backends '(ascii html latex odt))
  (org-imenu-depth 10)
  (org-link-frame-setup '((vm . vm-visit-folder-other-frame)
                          (vm-imap . vm-visit-imap-folder-other-frame)
                          (gnus . org-gnus-no-new-news)
                          (file . find-file-other-frame)
                          (wl . wl-other-frame)))
  (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-startup-with-latex-preview t)
  (org-startup-folded 'content)
  (org-tags-column 0)
  (org-todo-keywords
   '((sequence "TODO" "DONE")
     (sequence "PROJ" "WAIT" "COMPLETE")))
  (org-use-sub-superscripts '{})
  (org-babel-load-languages '((emacs-lisp . t)
                              (lisp . t)
                              (C . t)
                              (python . t)
                              (shell . t)))
  (org-format-latex-options '(:foreground default :background default :scale 2
                              :html-foreground "Black" :html-background "Transparent"
                              :html-scale 1.0 :matchers ("begin" "$1" "$" "$$" "\\(" "\\[")))
  (org-latex-listings 'minted)
  (org-latex-minted-langs '((emacs-lisp "common-lisp")
                            (ledger "text")
                            (cc "c++")
                            (cperl "perl")
                            (shell-script "bash")
                            (caml "ocaml")))
  (org-latex-packages-alist '(("" "minted")))
  (org-latex-pdf-process
   '("latexmk -pdf -bibtex -f -shell-escape %f"))
  (org-latex-minted-options '(("style" "xcode")
                              ("linenos")
                              ("frame" "single")
                              ("mathescape")
                              ("fontfamily" "courier")
                              ("samepage" "false")
                              ("breaklines" "true")
                              ("breakanywhere" "true")
                              )))
#+end_src
*** Org Core Functionality
Hooks, prettify-symbols and records for auto insertion.
#+begin_src emacs-lisp
(use-package org
  :hook
  (org-mode-hook . prettify-symbols-mode)
  :display
  ("\\*Org Src.*"
   (display-buffer-same-window))
  :pretty
  (org-mode-hook
   ("#+begin_src" . "≫")
   ("#+end_src"   . "≪"))
  :init
  (with-eval-after-load "autoinsert"
    (define-auto-insert '("\\.org\\'" . "Org skeleton")
      '("Enter title: "
        "#+title: " str | (buffer-file-name) "\n"
        "#+author: " (read-string "Enter author: ") | user-full-name "\n"
        "#+description: " (read-string "Enter description: ") | "Description" "\n"
        "#+date: " (format-time-string "%Y-%m-%d" (current-time)) "\n"
        "* " _))))
#+end_src
*** Org Core Bindings
Some bindings for org mode.
#+begin_src emacs-lisp
(use-package org
  :after counsel
  :config
  (defun +org/swiper-goto ()
    (interactive)
    (swiper "^\\* "))
  :general
  (leader
    "fw" #'org-capture
    "fl" #'org-store-link
    "fi" #'org-insert-last-stored-link)
  (nmmap
    :keymaps 'org-mode-map
    [remap imenu] #'+org/swiper-goto)
  (local-leader
    :keymaps 'org-mode-map
    :infix "l"
    "i" #'org-insert-link
    "l" #'org-open-at-point)
  (local-leader
    :keymaps 'org-mode-map
    "t" #'org-todo
    "i" #'org-insert-structure-template
    "p" #'org-latex-preview
    "s" #'org-property-action
    "e" #'org-export-dispatch
    "o" #'org-edit-special))
#+end_src
*** Org agenda
Org agenda provides a nice viewing for schedules.  With org mode it's
a very tidy way to manage your time.
#+begin_src emacs-lisp
(use-package org-agenda
  :after (org evil)
  :straight nil
  :init
  (defconst +org/agenda-root "~/Text"
    "Root directory for all agenda files")
  (setq org-agenda-files (list (expand-file-name +org/agenda-root) (expand-file-name (concat +org/agenda-root "/Notes")) (expand-file-name "~/Projects/lpv/"))
        org-agenda-window-setup 'current-window
        org-agenda-skip-deadline-prewarning-if-scheduled t
        org-agenda-skip-scheduled-if-done t
        org-agenda-skip-deadline-if-done t)
  :config
  (evil-set-initial-state 'org-agenda-mode 'normal)
  :general
  (leader
    "fa" (proc (interactive) (find-file (completing-read "Enter directory: " org-agenda-files nil t)))
    "aa" #'org-agenda)
  (nmmap
    :keymaps 'org-agenda-mode-map
    "zd" #'org-agenda-day-view
    "zw" #'org-agenda-week-view
    "zm" #'org-agenda-month-view
    "gd" #'org-agenda-goto-date
    "RET" #'org-agenda-switch-to
    "J" #'org-agenda-later
    "K" #'org-agenda-earlier
    "t" #'org-agenda-todo
    "." #'org-agenda-goto-today
    "," #'org-agenda-goto-date
    "q" #'org-agenda-quit
    "r" #'org-agenda-redo))
#+end_src
*** Org clock-in
Org provides a nice timekeeping system that allows for managing how
much time is taken per task.  It even has an extensive reporting
system to see how much time you spend on specific tasks or overall.
#+begin_src emacs-lisp
(use-package org-clock
  :after org
  :straight nil
  :init
  (defvar +org/clock-out-toggle-report nil
    "Non-nil means update the first clock report in the file every
time a clock out occurs.")
  :config
  (advice-add #'org-clock-out
              :after
              (proc (interactive)
                    (if +org/clock-out-toggle-report
                        (org-clock-report t))))
  :general
  (local-leader
    :keymaps 'org-mode-map
    :infix "c"
    "c" #'org-clock-in
    "o" #'org-clock-out
    "r" #'org-clock-report
    "t" (proc (interactive)
              (setq-local +org/clock-out-toggle-report
                          (not +org/clock-out-toggle-report)))))
#+end_src
*** Org on save
If ~+org/compile-to-pdf-on-save-p~ is non-nil, then compile to
\(\LaTeX\) and run an async process to compile it to a PDF.  Doesn't
make Emacs hang (like ~org-latex-export-to-pdf~) and doesn't randomly
crash (like the async handler for org-export).  Works really well with
~pdf-view-mode~.
#+begin_src emacs-lisp
(use-package org
  :init
  (defvar +org/compile-to-pdf-on-save-p
    nil
    "Non-nil to activate compile functionality.")
  :general
  (local-leader
    :keymaps 'org-mode-map
    "C" (proc (interactive)
              (if (+org/compile-to-pdf-on-save-f)
                  (setq-local +org/compile-to-pdf-on-save-p nil)
                (setq-local +org/compile-to-pdf-on-save-p t))))
  :config
  (+oreo/create-auto-save
   +org/compile-to-pdf-on-save-f
   (and (eq major-mode 'org-mode) +org/compile-to-pdf-on-save-p)
   (start-process-shell-command "" "*pdflatex*" (concat "pdflatex -shell-escape "
                                                        (org-latex-export-to-latex)))))
#+end_src
*** Org ref
#+begin_src emacs-lisp
(use-package org-ref
  :straight t
  :after org
  :init
  (setq bibtex-files '("~/Text/bibliography.bib")
        bibtex-completion-bibliography '("~/Text/bibliography.bib")
        bibtex-completion-additional-search-fields '(keywords)))
#+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 with 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
  :hook (message-mode-hook . org-msg-mode)
  :config
  (setq org-msg-options "html-postamble:nil H:5 num:nil ^:{} toc:nil author:nil email:nil \\n:t tex:dvipng"
        org-msg-greeting-name-limit 3)

  (add-to-list 'org-msg-enforce-css
               '(img latex-fragment-inline
                     ((transform . ,(format "translateY(-1px) scale(%.3f)"
                                            (/ 1.0 (if (boundp 'preview-scale)
                                                       preview-scale 1.4))))
                      (margin . "0 -0.35em")))))
#+end_src
*** Org for evil
Evil org for some nice bindings.
#+begin_src emacs-lisp
(use-package evil-org
  :hook (org-mode-hook . evil-org-mode))
#+end_src
*** Org reveal
Org reveal allows one to export org files as HTML presentations via
reveal.js.  Pretty nifty and it's easy to use.
#+begin_src emacs-lisp
(use-package ox-reveal
  :after org
  :init
  (setq org-reveal-root "https://cdn.jsdelivr.net/npm/reveal.js"
        org-reveal-theme "sky"))
#+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 rendered, but org mode > latex.

Delimited environments are aplenty, escaped brackets and dollar signs
are my favourite.  Here's a snippet:
$\int_{-\infty}^{\infty}e^{-x^2}dx = \sqrt{\pi}$.
#+begin_src emacs-lisp
(use-package org-fragtog
  :hook (org-mode-hook . org-fragtog-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
** C/C++
Setup for C and C++ modes via the cc-mode package.  C and C++ are
great languages for general purpose programming.  My preferred choice
when I want greater control over memory management.
*** cc-mode
#+begin_src emacs-lisp
(use-package cc-mode
  :defer t
  :hook
  (c-mode-hook   . auto-fill-mode)
  (c++-mode-hook . auto-fill-mode)
  :general
  (:keymaps '(c-mode-map c++-mode-map)
   :states '(normal motion visual)
   "(" #'c-beginning-of-statement
   ")" #'c-end-of-statement)
  :pretty
  (c-mode-hook
   ("puts"    . "φ")
   ("fputs"   . "ϕ")
   ("printf"  . "ω")
   ("fprintf" . "Ω")
   ("NULL"    . "Ø")
   ("true"    . "⊨")
   ("false"   . "⊭")
   ("!"       . "¬")
   ("&&"      . "⋀")
   ("||"      . "⋁")
   ("for"     . "∀")
   ("return"  . "⟼"))
  (c++-mode-hook
   ("nullptr" . "Ø")
   ("string"  . "𝕊")
   ("vector"  . "ℓ")
   ("puts"    . "φ")
   ("fputs"   . "ϕ")
   ("printf"  . "ω")
   ("fprintf" . "Ω")
   ("NULL"    . "Ø")
   ("true"    . "⊨")
   ("false"   . "⊭")
   ("!"       . "¬")
   ("&&"      . "⋀")
   ("||"      . "⋁")
   ("for"     . "∀")
   ("return"  . "⟼"))
  :init
  (setq-default c-basic-offset 2)
  (setq-default c-auto-newline nil)
  (setq-default c-default-style '((other . "user")))

  (with-eval-after-load "autoinsert"
    (define-auto-insert
      '("\\.c\\'" . "C skeleton")
      '(""
        "/* " (file-name-nondirectory (buffer-file-name (current-buffer))) "\n"
        " * Created: " (format-time-string "%Y-%m-%d") "\n"
        " * Author: " user-full-name "\n"
        " */\n"
        "\n"
        _))

    (define-auto-insert
      '("\\.cpp\\'" . "C++ skeleton")
      '(""
        "/* " (file-name-nondirectory (buffer-file-name (current-buffer))) "\n"
        " * Created: " (format-time-string "%Y-%m-%d") "\n"
        " * Author: " user-full-name "\n"
        " */\n"
        "\n"
        _)))
  :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 . +)
      (substatement-open . 0)
      (access-label . -)
      (inline-open  . 0)
      (label . 0)
      (statement-cont . +)))))
#+end_src
*** Clang format
Clang format comes inbuilt with clang, so download that before using
this.  Formats C/C++ files depending on a format (checkout the Clang
format [[file:~/Dotfiles/ClangFormat/.clang-format][config file]] in my dotfiles).

#+begin_src emacs-lisp
(use-package clang-format
  :straight nil
  :load-path "/usr/share/clang/"
  :after cc-mode
  :commands (+code/clang-format-region-or-buffer)
  :general
  (leader
    :keymaps '(c-mode-map c++-mode-map)
    "cf" #'+code/clang-format-region-or-buffer)
  :config
  (defvar +code/clang-format-automatically t
    "Automatically call clang-format every time save occurs in C/C++
buffer")

  (+oreo/create-auto-save
   +code/clang-format-on-save
   (and +code/clang-format-automatically
        (or (eq major-mode 'c-mode)
            (eq major-mode 'c++-mode)))
   (clang-format-buffer))

  (defun +code/clang-format-region-or-buffer ()
    (interactive)
    (if (mark)
        (clang-format-region (region-beginning) (region-end))
      (clang-format-buffer))))
#+end_src
** Racket
A scheme with lots of stuff inside it.  Using it for a language design
book so it's useful to have some Emacs binds for it.
#+begin_src emacs-lisp
(use-package racket-mode
  :straight t
  :hook (racket-mode-hook . racket-xp-mode)
  :display
  ("\\*Racket.*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :general
  (local-leader
    :keymaps 'racket-mode-map
    "r" #'racket-run
    "i" #'racket-repl
    "sr" #'racket-send-region
    "sd" #'racket-send-definition))
#+end_src
** CSharp
:PROPERTIES:
:header-args:emacs-lisp: :tangle no
:END:
I sometimes use C# when I'm bored or if I'm trying out a language
feature.  However, if I desperately needed an easy way to make a
fast-ish API server or some kinda industrial level project then C#
would probably be the language I would reach for.
#+begin_src emacs-lisp
(use-package csharp-mode
  :defer t
  :pretty
  (csharp-mode-hook
   ("null"      . "∅")
   ("string"    . "𝕊")
   ("List"      . "ℓ")
   ("WriteLine" . "φ")
   ("Write"     . "ω")
   ("true"      . "⊨")
   ("false"     . "⊭")
   ("!"         . "¬")
   ("&&"        . "⋀")
   ("||"        . "⋁")
   ("for"       . "∀")
   ("return"    . "⟼")))
#+end_src
** Java
I kinda dislike Java, but if necessary I will code in it.  Might have
to use an IDE for the cooler features, but use Emacs for editing.
Just setup a style and some pretty symbols.
#+begin_src emacs-lisp
(use-package ob-java
  :straight nil
  :pretty
  (java-mode-hook
   ("println" . "φ")
   ("printf"  . "ω")
   ("null"    . "Ø")
   ("true"    . "⊨")
   ("false"   . "⊭")
   ("!"       . "¬")
   ("&&"      . "⋀")
   ("||"      . "⋁")
   ("for"     . "∀")
   ("return"  . "⟼"))
  :config
  (with-eval-after-load "cc-mode"
    (c-add-style
     "java"
     '((c-basic-offset . 4)
       (c-comment-only-line-offset 0 . 0)
       (c-offsets-alist
        (inline-open . 0)
        (topmost-intro-cont . +)
        (statement-block-intro . +)
        (knr-argdecl-intro . 5)
        (substatement-open . 0)
        (substatement-label . +)
        (label . +)
        (statement-case-open . +)
        (statement-cont . +)
        (arglist-intro . c-lineup-arglist-intro-after-paren)
        (arglist-close . c-lineup-arglist)
        (brace-list-intro first c-lineup-2nd-brace-entry-in-arglist c-lineup-class-decl-init-+ +)
        (access-label . 0)
        (inher-cont . c-lineup-java-inher)
        (func-decl-cont . c-lineup-java-throws))))
    (add-to-list 'c-default-style '(java-mode . "java")))

  (with-eval-after-load "abbrev"
    (define-abbrev-table 'java-mode-abbrev-table nil)
    (add-hook 'java-mode-hook
              (proc (setq-local local-abbrev-table java-mode-abbrev-table)))))
#+end_src
** Haskell
Haskell is a static lazy functional programming language (what a
mouthful).  It's quite a beautiful language and really learning it will
change the way you think about programming.

Here I configure the REPL for Haskell via the
~haskell-interactive-mode~ as well.
#+begin_src emacs-lisp
(use-package haskell-mode
  :hook
  (haskell-mode-hook . haskell-indentation-mode)
  (haskell-mode-hook . interactive-haskell-mode)
  :custom
  (haskell-interactive-prompt "[λ] ")
  (haskell-interactive-prompt-cont "{λ} ")
  (haskell-interactive-popup-errors nil)
  (haskell-stylish-on-save nil)
  (haskell-process-type 'stack-ghci)
  :general
  (leader
    "th" #'+shell/toggle-haskell-repl)
  :display
  ("\\*haskell.**\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :config
  (load (concat user-emacs-directory "elisp/haskell-multiedit.el"))
  (+oreo/create-toggle-function
   +shell/toggle-haskell-repl
   "*haskell*"
   haskell-interactive-bring
   nil))
#+end_src
** Python
Works well for python.  If you have ~pyls~ it should be on your path, so
just run eglot if you need.  But an LSP server is not necessary for a
lot of my time in python.
#+begin_src emacs-lisp
(use-package python
  :defer t
  :straight nil
  :pretty
  (python-mode-hook
   ("None"   . "Ø")
   ("list"   . "ℓ")
   ("List"   . "ℓ")
   ("str"    . "𝕊")
   ("True"   . "⊨")
   ("False"  . "⊭")
   ("!"      . "¬")
   ("&&"     . "⋀")
   ("||"     . "⋁")
   ("for"    . "∀")
   ("print"  . "φ")
   ("lambda" . "λ")
   ("return" . "⟼")
   ("yield"  . "⟻"))
  :init
  (setq python-indent-offset 4))
#+end_src
*** Python shell
Setup for python shell, including a toggle option
#+begin_src emacs-lisp
(use-package python
  :straight nil
  :commands +python/toggle-repl
  :general
  (leader
    "tp" #'+shell/python-toggle-repl)
  :display
  ("\\*Python\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :config
  (+oreo/create-toggle-function
   +shell/python-toggle-repl
   "*Python*"
   run-python
   nil))
#+end_src
** YAML
YAML is a data language which is useful for config files.
#+begin_src emacs-lisp
(use-package yaml-mode
  :straight t)
#+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-code-indent-offset 2)
   (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
  (imap
    :keymaps 'emmet-mode-keymap
    "TAB" #'emmet-expand-line
    "M-j" #'emmet-next-edit-point
    "M-k" #'emmet-prev-edit-point))
#+end_src
** Typescript
Kinda expressive, interesting.
#+begin_src emacs-lisp
(use-package typescript-mode
  :defer t
  :init
  (setq typescript-indent-level 2))
#+end_src
** Common Lisp
Common Lisp is a dialect of Lisp, the most /common/ one around.  Emacs
comes with builtin Lisp support of course, but a REPL would be nice.

Enter /SLY/.  Sly is a fork of /SLIME/ and is *mandatory* for lisp
development on Emacs.

#+begin_src emacs-lisp
(use-package sly
  :straight t
  :init
  (setq inferior-lisp-program "sbcl")
  :display
  ("\\*sly-db"
   (display-buffer-at-bottom)
   (window-height . 0.5))
  ("\\*sly-"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :config
  (evil-set-initial-state 'sly-db-mode 'emacs)
  (+oreo/create-toggle-function
   +shell/toggle-sly
   "*sly-mrepl for sbcl*"
   sly-mrepl
   nil)
  :general
  ; general binds
  (nmap
    :keymaps '(lisp-mode-map sly-mrepl-mode-map)
    "gr" #'sly-eval-buffer
    "gd" #'sly-edit-definition
    "gR" #'sly-who-calls)

  (leader
    "tS" #'+shell/toggle-sly)
  (local-leader
    :keymaps '(lisp-mode-map sly-mrepl-mode-map)
    "s" #'+shell/toggle-sly
    "c" #'sly-compile-file
    "a" #'sly-apropos
    "d" #'sly-describe-symbol)
  (local-leader
    :keymaps 'lisp-mode-map
    :infix "e"
    "b" #'sly-eval-buffer
    "e" #'sly-eval-last-expression
    "f" #'sly-eval-defun
    "r" #'sly-eval-region)
  ; sly binds
  (nmap
    :keymaps 'sly-inspector-mode-map
    "q" #'sly-inspector-quit))
#+end_src
*** Lisp indent function
Add a new lisp indent function which indents newline lists more
appropriately.
#+begin_src emacs-lisp
(use-package lisp-mode
  :straight nil
  :pretty
  (lisp-mode-hook
   ("lambda"  . "λ")
   ("t"       . "⊨")
   ("nil"     . "Ø")
   ("and"     . "⋀")
   ("or"      . "⋁")
   ("defun"   . "ƒ")
   ("for"     . "∀")
   ("mapc"    . "∀")
   ("mapcar"  . "∀"))
  :general
  (:states '(normal motion visual)
   :keymaps '(emacs-lisp-mode-map lisp-mode-map)
   ")" #'sp-next-sexp
   "(" #'sp-previous-sexp)
  :config
  (defun +oreo/lisp-indent-function (indent-point state)
    (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))))))))
  (setq-default lisp-indent-function #'+oreo/lisp-indent-function))
#+end_src