#+title: Emacs configuration
#+author: Aryadev Chavali
#+description: My Emacs configuration
#+property: header-args:emacs-lisp :tangle config.el :comments link :results none
#+startup: noindent
#+options: toc:nil num:t
#+latex_header:\usepackage[margin=1.0in]{geometry}
#+latex_class: article
#+latex_class_options: [a4paper,12pt]

* Introduction
:PROPERTIES:
:header-args:emacs-lisp: :tangle config.el :results none
:END:
Welcome to my Emacs configuration.  You may be confused by the fact
it's a readable document with prose; this file serves as both
documentation *and* code.  Here's an example of some Emacs Lisp code:

#+begin_src emacs-lisp
;;; config.el --- Compiled configuration from config.org  -*- lexical-binding: t; -*-

;; Copyright (C) 2024  Aryadev Chavali

;; Author: Aryadev Chavali <aryadev@aryadevchavali.com>

;; This program is distributed in the hope that it will be useful, but WITHOUT
;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
;; FOR A PARTICULAR PURPOSE.  See the MIT License for details.

;; You may distribute and modify this code under the terms of the MIT License,
;; which you should have received a copy of along with this program.  If not,
;; please go to <https://opensource.org/license/MIT>.

;;; Commentary:
;; Welcome to my Emacs configuration.  This file is considered volatile i.e. any
;; edits made to this file will be overwritten if and when the configuration is
;; next compiled.

;; To propagate edits from this file back to the literate document, call
;; (org-babel-detangle).
;;; Code:
#+end_src

So how does this work?  [[file:elisp/literate.el][Literate]] is a
package that I designed myself which "compiles" my configuration and
links it all together.  This document is compiled by collecting all
the Emacs Lisp blocks, concatenating them then writing it to
=config.el=, which is loaded as a standard Emacs Lisp file afterwards.
So all the prose is ignored in the final document.

This allows the document to act as both /source code/ and
/documentation/ at once.  Pretty cool, right?  This style of coding is
called /literate programming/.  Donald Knuth
[[https://en.wikipedia.org/wiki/Literate_programming][really liked]]
the idea and I see why.

Some details about the configuration:
+ The ordering of sections is relevant: packages defined earlier can
  be utilised by later packages
+ Sections tagged with =WAIT= are not compiled into the final document
  (using :PROPERTIES:), usually with some explanation.
+ Some sections are essentially blog posts, so you may just want to
  read the tangled output via ~(org-babel-tangle)~
* Basics
Let's setup a few absolute essentials:
+ My name and mail address
+ File encoding (no "\r" characters at the end of lines, please)
+ Where to store backup files (~backup-directory-alist~)
+ Auto refresh buffers when a change occurs (~auto-revert-mode~)
+ Yes or no questions are less painful (~y-or-n-p~)
+ Make the "kill ring" work seamlessly with the clipboard
+ Deleting files or directories "trashes" them instead
+ Font size based on the machine
+ Disable mouse usage where possible
+ Ensure when compiling the Emacs configuration, we only get messages
  for really bad stuff

#+begin_src emacs-lisp
(use-package emacs
  :demand t
  :init
  (setq user-full-name "Aryadev Chavali"
        user-mail-address "aryadev@aryadevchavali.com"
        buffer-file-coding-system 'utf-8-unix
        save-buffer-coding-system 'utf-8-unix
        backup-directory-alist `(("." . ,(no-littering-expand-var-file-name "saves/")))
        global-auto-revert-non-file-buffers t
        auto-revert-verbose nil
        auto-revert-use-notify nil
        select-enable-clipboard t
        delete-by-moving-to-trash t
        use-file-dialog nil
        use-dialog-box nil
        warning-minimum-level :emergency)
  :config
  (fset 'yes-or-no-p 'y-or-n-p)
  (global-auto-revert-mode)
  (set-face-attribute 'default nil :height
                      (pcase (system-name)
                        ("ravenmaiden" 130)
                        (_ 120))))
#+end_src
* Custom functionality and libraries
This is custom Lisp I've written to help me out throughout the
configuration.  Note that because it's setup so early I can use it
throughout the file.
** dash
Dash is an external library that provides a ton of Emacs Lisp
functions that make it a bit nicer to use.
#+begin_src emacs-lisp
(use-package dash
  :straight t
  :demand t)
#+end_src
** Procedure
An anonymous function (~lambda~) which takes no arguments is a
"procedure".  This macro generates procedures, with the parameters of
the macro being the body of the procedure.  The function is returned
quoted (as data rather than code), as that is the most common use of
this macro.
#+begin_src emacs-lisp
(defmacro proc (&rest BODY)
  "For a given list of forms BODY, return a quoted 0 argument
lambda."
  `(function (lambda nil ,@BODY)))
#+end_src
** Automatically run a command on saving
Sometimes you want a command to run when a file is saved, a classic
example being compiling a project after saving.  To run a command
after saving, one may write the command as an Emacs Lisp function and
add it to the ~after-save-hook~ which essentially subscribes that
function to the ~after-save~ event.  We can encapsulate these steps
in one macro, which is defined here.

#+begin_src emacs-lisp
(use-package simple
  :defer t
  :config
  (defmacro create-auto-save (CONDITIONS &rest TO-RUN)
    "Create a hook for after-save, where on CONDITIONS being met
TO-RUN is evaluated."
    `(add-hook 'after-save-hook
               (proc
                (interactive)
                (when ,CONDITIONS ,@TO-RUN)))))
#+end_src
** Clean buffer list
Clean all buffers except for those in ~clean-buffers-keep~.

#+begin_src emacs-lisp
(defconst clean-buffers-keep
  (list "config.org" "*scratch*"
        "*dashboard*" "*Messages*"
        "*Warnings*" "*eshell*")
  "List of buffer names to preserve.")

(defun clean-buffers ()
  "Kill all buffers except any with names in CLEAN-BUFFERS-KEEP."
  (interactive)
  (let ((should-not-kill
         #'(lambda (buf)
             (member (buffer-name buf)
                     clean-buffers-keep))))
    (-->
     (buffer-list)
     (cl-remove-if should-not-kill it)
     (mapc #'kill-buffer it))))
#+end_src
** Custom window management
Generally speaking, applications that have some windowing features do
not have a lot of options for how those windows are placed.  Emacs has
a window management system unlike any other piece of software I have
ever used with some incredible capabilities.  Unfortunately, as a
result, it is quite complex to use.

The big idea is this table, ~display-buffer-alist~, which associates
regular expressions with "actions".  The regular expressions are for
the name of buffers, and the actions are how the buffer should be
displayed.  And there are a *lot* of ways to display buffers.

Here's an example record:
#+begin_src lisp
'("config.org"
  (display-buffer-in-side-window)
  (side . bottom))
#+end_src

This matches any buffer named =config.org=, displaying the buffer in a
side window to the bottom.

What I configure here is a ~use-package~ keyword, ~:display~, which
will allow me to write associations in ~display-buffer-alist~ really
easily.

2024-04-23: Found this option ~switch-to-buffer-obey-display-actions~
which makes manual buffer switches obey the same constraints via
~display-buffer-alist~ as creating the buffer automatically.

#+begin_src emacs-lisp
(use-package window
  :demand t
  :init
  (setq switch-to-buffer-obey-display-actions nil)
  (with-eval-after-load "use-package-core"
    (add-to-list 'use-package-keywords ':display)
    (defun use-package-normalize/:display (_name-symbol _keyword args)
      "Normalise args for use in handler.
Don't do anything to the args here."
      args)

    (defun use-package-handler/:display (name _keyword args rest state)
      (use-package-concat
       (use-package-process-keywords name rest state)
       (mapcar
        #'(lambda (arg)
            `(add-to-list 'display-buffer-alist
                          ',arg))
        args)))))
#+end_src

Here's some ~:display~ records for buffers that don't really have
configuration anywhere else in the file.  These serve as good examples
on how to use the keyword.

#+begin_src emacs-lisp
(use-package window
  :defer t
  :display
  ("\\*Process List\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  ("\\*Async Shell Command\\*"
   (display-buffer-at-bottom)
   (window-height . 0.25)))
#+end_src
** add-to-list multiple times
I want to be able to add multiple items to a list in a single
expression.  Here's a macro to do that for me.

#+begin_src emacs-lisp
(defmacro add-multiple-to-list (listvar &rest elements)
  (cons
   'progn
   (cl-loop for element in elements
            collect `(cl-pushnew ,element ,listvar))))
#+end_src
** Setting number of native jobs
Emacs has a native compilation capability to make things /even
faster/.  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 machines, which have 8 process throughput (4 cores + hyper
threading), 6-7 workers makes much more sense.  On a machine I've
never used before, 3 seems to be a reasonable default.

#+begin_src emacs-lisp
(use-package comp
  :init
  (setq native-comp-async-jobs-number
        (pcase (system-name)
          ("ravenmaiden" 6)
          (_ 3))))
#+end_src
* Essential packages
External and internal packages absolutely necessary for the rest of
this configuration.
** General - Bindings package
Vanilla Emacs has the ~bind-key~ function (and the ~bind-key*~ macro)
for this, but [[*Evil - Vim Emulation][Evil]] has it's own
~evil-define-key~.  I'd like a unified interface for using both, which
is why I use =general=.  General provides a set of very useful macros
for defining keys in a variety of different situations.  One may
redefine any key in any keymap, bind over different Evil states, add
=which-key= documentation, create so-called "definers" which act as
wrapper macros over some pre-defined configuration, etc, all at the
same time.

Here I setup the rough outline of how bindings should be made in the
global scope, namely:
+ Use "SPC" as a "leader", the root of all general bindings
+ Use "\" as a local-leader, the root of all major mode specific
  bindings
+ A few "definers" for the different sub bindings for the leader key
+ ~nmmap~ macro, for defining keys under both normal and motion
  states.

#+begin_src emacs-lisp
(use-package general
  :straight t
  :demand t
  :config
  ;; General which key definitions for leaders
  (general-def
    :states '(normal motion)
    "SPC"   'nil
    "\\"    '(nil :which-key "Local leader")
    "SPC a" '(nil :which-key "Applications")
    "SPC b" '(nil :which-key "Buffers")
    "SPC c" '(nil :which-key "Code")
    "SPC d" '(nil :which-key "Directories")
    "SPC f" '(nil :which-key "Files")
    "SPC i" '(nil :which-key "Insert")
    "SPC m" '(nil :which-key "Modes")
    "SPC r" '(nil :which-key "Tabs")
    "SPC s" '(nil :which-key "Search")
    "SPC t" '(nil :which-key "Shell")
    "SPC q" '(nil :which-key "Quit/Literate"))

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

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

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

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

  (general-create-definer shell-leader
    :states '(normal motion)
    :keymaps 'override
    :prefix "SPC t")

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

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

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

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

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

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

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

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

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

  (defalias 'nmmap #'general-nmmap)

  (general-evil-setup t))
#+end_src
*** Some binds for Emacs
Here are some bindings for Emacs using general and the definers
created previously.  Here I bind stuff I don't care to make a separate
heading for, so it serves as both a dumping ground and as a great
set of examples on how to use general.

#+begin_src emacs-lisp
(use-package emacs
  :init
  ;; this is for `duplicate-dwim'
  (setq duplicate-line-final-position -1)
  :general
  ("C-x d" #'delete-frame)

  (:keymaps 'help-map
   "l" #'find-library)

  (nmmap
    :keymaps 'override
    "M-%" #'replace-regexp-as-diff
    "M-o" #'duplicate-dwim
    "M-;" #'comment-dwim
    "gC"  #'comment-dwim
    "g="  #'align-regexp
    "C--" #'text-scale-decrease
    "C-=" #'text-scale-increase
    "C-+" #'text-scale-adjust)

  (leader
    "SPC" '(execute-extended-command :which-key "M-x")
    "R"   `(revert-buffer :which-key "Revert buffer")
    ":"   `(,(proc (interactive) (switch-to-buffer "*scratch*"))
            :which-key "Switch to *scratch*")
    "!"   '(async-shell-command :which-key "Async shell command")
    "h"   '(help-command :which-key "Help"))

  (mode-leader
    "t" `(,(proc (interactive) (+oreo/load-theme))
          :which-key "Reload current theme")
    "T" `(,(proc (interactive) (+oreo/switch-theme))
          :which-key "Iterate through themes"))

  (code-leader
    "F" `(,(proc (interactive) (find-file "~/Code/"))
          :which-key "Open ~/Code/"))

  (search-leader
    "i" #'imenu)

  (file-leader
    "f" #'find-file
    "P" (proc (interactive)
              (find-file (concat user-emacs-directory "config.org")))
    "F" #'find-file-other-window
    "t" #'find-file-other-tab
    "v" #'add-file-local-variable
    "s" #'save-buffer)

  (insert-leader
    "c" #'insert-char)

  (dir-leader
    "v" #'add-dir-local-variable)

  (buffer-leader
    "b" #'switch-to-buffer
    "d" #'kill-current-buffer
    "c" #'kill-buffer-and-window
    "K" #'kill-buffer
    "j" #'next-buffer
    "k" #'previous-buffer
    "D" #'clean-buffers)

  (quit-leader
    "p" #'straight-pull-package
    "b" #'straight-rebuild-package
    "q" #'save-buffers-kill-terminal
    "c" #'+literate/compile-config
    "C" #'+literate/clean-config
    "l" #'+literate/load-config))
#+end_src
** Evil - Vim emulation
My editor journey started off with Vim rather than Emacs, so my brain
has imprinted on its style.  Emacs is super extensible so there exists
a package for porting Vim's modal editing style to Emacs, called evil
(Emacs Vi Layer).

However there are a lot of packages in Vim that provide greater
functionality, for example tpope's "vim-surround".  Emacs has these
capabilities out of the box, but there are further packages which
integrate them into Evil.  These are setup later in [[*Evil
additions][Evil additions]].

Setup the evil package, with some opinionated settings:
+ Switch ~evil-upcase~ and ~evil-downcase~ because I use ~evil-upcase~
  more
+ Use 'T' character as an action for "transposing objects"
  + Swapping any two textual "objects" seems like a natural thing in
    Vim considering the "verb-object" model most motions follow, but
    by default Vim doesn't have the ability to do so.  But Emacs can,
    hence I can set these up.
+ Allow the Evil cursor to traverse End of Lines like the Emacs cursor
+ Do not move the cursor when exiting insert mode.
#+begin_src emacs-lisp
(use-package evil
  :straight t
  :demand t
  :init
  (setq evil-split-window-below t
        evil-vsplit-window-right t
        evil-undo-system #'undo-tree
        evil-move-beyond-eol t
        evil-move-cursor-back nil
        evil-want-abbrev-expand-on-insert-exit t
        evil-want-minibuffer t
        evil-want-keybinding nil
        evil-want-Y-yank-to-eol t)
  :config
  (evil-mode)
  :general
  (leader
    "w"  '(evil-window-map :which-key "Window")
    "wT" #'window-swap-states
    "wd" #'evil-window-delete
    "w;" #'make-frame)

  (nmmap
    "K"   #'man
    "TAB" #'evil-jump-item
    "r"   #'evil-replace-state
    "zC"  #'hs-hide-level
    "zO"  #'hs-show-all)

  (general-def
    :keymaps 'override
    :states '(normal motion visual)
    "gu"  #'evil-upcase
    "gU"  #'evil-downcase
    "M-y" #'yank-pop
    "T"   'nil)

  (general-def
    :keymaps 'override
    :states '(normal motion visual)
    :infix "T"
    "w" #'transpose-words
    "c" #'transpose-chars
    "s" #'transpose-sentences
    "p" #'transpose-paragraphs
    "e" #'transpose-sexps
    "l" #'transpose-lines))
#+end_src
** Text Completion
Emacs is a text based interface.  All commands use textual input,
operate on text and produce text as output.  A classic command is
~execute-extended-command~, which takes a command name as input then
executes it.  Input is taken from the /minibuffer/.

A critical component of this interaction is text completion: given a
list of options and some user input, try to find an option that best
fits it.  Out of the box, Emacs provides the ~completions-list~ to
help with selecting an option given some initial input, which can be
activated when the minibuffer is active using ~TAB~.  This is quite a
handy interface on its own, but we can do much better.

So called "text completion frameworks" remodel the interaction with
the minibuffer to improve certain aspects of it.  Emacs provides two
such packages out of the box: ido and icomplete.  They both eschew the
~completions-list~, instead providing an incrementally adjusted list
of results based on the current input within the minibuffer itself.
IDO only covers a few text based commands, such as ~find-file~, while
~IComplete~ covers essentially all of them.

In terms of external packages, there exist a few.  I used Ivy for a
few year, partially from the inertia of my Doom Emacs configuration.
I then moved to ~icomplete~, then to ~vertico~.  The move to these
more minimal frameworks come from a similar school of thought as the
Unix Philosophy, but for Emacs' packages: do one thing and do it well.
While Ivy is a very good piece of software, certain aspects are done
better by standalone packages built for that purpose (such as
[[*rg][rg]]).  ~vertico~ or ~icomplete~ are packages that only care
about the minibuffer and making interactions with it more pleasant,
and they do a great job at that.
*** Minibuffer
As described before, the minibuffer is the default text input/output
mechanism.  Here are some basic binds that I need to work effectively
in it.
+ By default, the minibuffer is in insert state, with Escape going to
  normal state. M-escape allows quick exits from the minibuffer while
  in insert state
+ In normal state, escape exits the minibuffer
+ ~M-{j, k}~ for selecting elements
+ ~C-M-j~ for forcing the minibuffer to accept on the current
  selection
+ ~<backtab>~ (shift + TAB) to switch to the completions list
#+begin_src emacs-lisp
(use-package minibuffer
  :demand t
  :init
  (setq enable-recursive-minibuffers t)
  :general
  (imap
    :keymaps 'minibuffer-local-map
    "M-<escape>" #'abort-minibuffers)
  (nmap
    :keymaps 'minibuffer-local-map
    "<escape>"  #'abort-minibuffers)
  (general-def
    :states '(normal insert)
    :keymaps 'minibuffer-local-map
    "<backtab>" #'switch-to-completions
    "RET"       #'exit-minibuffer
    "M-j"       #'next-line-or-history-element
    "M-k"       #'previous-line-or-history-element))
#+end_src

I can also save the history of the minibuffer to make it easier to
replicate previous inputs.
#+begin_src emacs-lisp
(use-package savehist
  :defer t
  :config
  (savehist-mode t))
#+end_src
*** Completions-list
The list of completions that comes by default with the minibuffer when
forcing it to complete some input.  Here I just make some binds to
make that selection easier.

#+begin_src emacs-lisp
(use-package simple
  :demand t
  :display
  ("\\*Completions\\*"
   (display-buffer-in-side-window)
   (window-height . 0.3)
   (side . bottom))
  :general
  (nmmap
    :keymaps 'completion-list-mode-map
    "l"         #'next-completion
    "h"         #'previous-completion
    "q"         #'quit-window
    "RET"       #'choose-completion
    "<backtab>" #'switch-to-minibuffer)
  :init
  (with-eval-after-load "evil"
    (evil-set-initial-state 'completion-list-mode 'normal)))
#+end_src
*** Vertico
Vertico is a minimalist text completion framework for the minibuffer.
It's configuration is /so/ similar to IComplete that I essentially
copy-pasted it, and it does a great job.  It's quite fast as well,
outperforming ~icomplete~ consistently when displaying results.
#+begin_src emacs-lisp
(use-package vertico
  :straight t
  :demand t
  :init
  (setq vertico-count 8
        vertico-cycle t)
  :config
  (vertico-mode)
  :general
  (general-def
    :state '(normal insert)
    :keymaps 'vertico-map
    "M-j" #'vertico-next
    "M-k" #'vertico-previous
    "RET" #'vertico-exit
    "TAB" #'minibuffer-complete
    "SPC" #'self-insert-command))
#+end_src
*** Consult
Consult provides some improved replacements for certain inbuilt
functions, and a few extensions as well.  If we consider ivy/counsel
to be two separate packages, ivy being the completion framework and
counsel the extension package using ivy, consult would be the latter.
Unlike counsel, however, it isn't dependent on any one completion
framework making it more extensible and easier to use in different
situations.

#+begin_src emacs-lisp
(use-package consult
  :straight t
  :init
  (setq consult-preview-excluded-buffers t
        consult-preview-excluded-files '(".*"))
  :general
  (:states '(normal insert motion visual emacs)
   [remap imenu]            #'consult-imenu
   [remap switch-to-buffer] #'consult-buffer)
  (leader
    "'" #'consult-register)
  (search-leader
    "s" #'consult-line)
  :config
  (defun consult-line-isearch-history (&rest _)
    "Add latest `consult-line' search pattern to the isearch history.

This allows n and N to continue the search after `consult-line' exits.

From https://jmthornton.net/blog/p/consult-line-isearch-history, taken
2024-10-10 03:58 BST."
    (when (and (bound-and-true-p evil-mode)
               (eq evil-search-module 'isearch)
               consult--line-history)
      (let* ((pattern (car consult--line-history))
             (regexp (if (string-prefix-p "\\_" pattern)
                         (substring pattern 2)
                       pattern)))
        (add-to-history 'regexp-search-ring regexp)
        (setq evil-ex-search-pattern (evil-ex-pattern regexp t nil nil))
        (setq evil-ex-search-direction 'forward))))

  (advice-add #'consult-line :after #'consult-line-isearch-history))
#+end_src
*** Orderless
Orderless sorting method for completion, probably one of the best
things ever.

#+begin_src emacs-lisp
(use-package orderless
  :straight t
  :after vertico
  :config
  (setq completion-styles '(orderless substring basic)
        completion-category-defaults nil
        completion-category-overrides
        '((file (styles flex partial-completion substring)))))
#+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
  :defer t
  :straight t
  :hook
  ((prog-mode-hook eshell-mode-hook)   . company-mode)
  :general
  (imap
    :keymaps 'company-mode-map
    "C-SPC" #'company-complete
    "C-@"   #'company-complete
    "M-j"   #'company-select-next
    "M-k"   #'company-select-previous))
#+end_src
** Hydra
Hydra is a great package by =abo-abo= (yes the same guy who made ivy
and swiper).  Though not absolutely essential it provides an easy
interface option for keybindings which enhances their discoverability
and ease of use.  There are two use-package declarations here: one for
~hydra~ itself, and the other for ~use-package-hydra~ which provides
the keyword ~:hydra~ in use-package declarations.

#+begin_src emacs-lisp
(use-package hydra
  :straight t)

(use-package use-package-hydra
  :straight t)
#+end_src
* Aesthetics
General look and feel of Emacs, perhaps the most important of all the
sections here.
** Themes
I have both a dark and light theme for differing situations.  Here I
configure a timer which ensures I have a light theme during the day
and dark theme at night.  I wrote my own themes by copying stuff I
like from other themes then modifying them.  The dark theme is in
[[file:elisp/personal-solarized-theme.el][this file]] and the light
theme is in [[file:elisp/personal-light-theme.el][this file]].

#+begin_src emacs-lisp
(use-package custom
  :defer t
  :commands (+oreo/load-theme)
  :hook (after-init-hook . +oreo/load-theme)
  :init
  (setq custom-theme-directory (concat user-emacs-directory "elisp/"))
  (defvar +oreo/theme-list `(personal-light personal-solarized))
  (defvar +oreo/theme 1)
  :config
  (defun +oreo/disable-other-themes ()
    "Disable all other themes in +OREO/THEME-LIST excluding
+OREO/THEME."
    (cl-loop
     for theme in +oreo/theme-list
     for i from 0
     if (not (= i +oreo/theme))
     do (disable-theme theme)))

  (defun +oreo/load-theme ()
    "Load +OREO/THEME, disabling all other themes to reduce conflict."
    (mapc #'disable-theme custom-enabled-themes)
    (+oreo/disable-other-themes)
    (load-theme (nth +oreo/theme +oreo/theme-list) t))

  (defun +oreo/switch-theme ()
    "Flip between different themes set in +OREO/THEME-ALIST."
    (setq +oreo/theme (mod (+ 1 +oreo/theme) (length +oreo/theme-list)))
    (+oreo/load-theme))

  (+oreo/load-theme))
#+end_src
** Startup screen
The default startup screen is quite bad in all honesty.  While for a
first time user it can be very helpful in running the tutorial and
finding more about Emacs, for someone who's already configured it
there isn't much point.

The scratch buffer is created at boot.  When the splash screen isn't
enabled, it is the first buffer a user sees.  By default, it is in
~lisp-interaction-mode~, which allows one to prototype Emacs Lisp
code.

I mostly use the scratch buffer to hold snippets of code and to write
text (usually then copy-pasted into other applications).  So
~text-mode~ is a good fit for that.

2024-06-04: I use to load [[*Org mode][org-mode]] in the scratch
buffer and it added 2 seconds of load time, so let's just use
fundamental mode and call it a day.

#+begin_src emacs-lisp
(use-package emacs
  :defer t
  :init
  (setq inhibit-startup-screen t
        inhibit-startup-echo-area-message user-login-name
        initial-major-mode 'text-mode
        initial-scratch-message ""
        ring-bell-function 'ignore)
  :config
  (add-hook 'after-init-hook
            (proc
             (with-current-buffer "*scratch*"
               (goto-char (point-max))
               (-->
                (emacs-init-time)
                (format "Emacs v%s - %s\n" emacs-version it)
                (insert it))))))
#+end_src
** Blinking cursor
Configure the blinking cursor.

#+begin_src emacs-lisp
(use-package frame
  :defer t
  :init
  (setq blink-cursor-delay 0.2)
  :config
  (blink-cursor-mode))
#+end_src
** Mode line
The mode line is the little bar at the bottom of the buffer, just
above the minibuffer.  It can store essentially any text, but
generally details about the current buffer (such as name, major mode,
etc) is placed there.

The default mode-line is... disgusting.  It displays information in an
unintelligible format and seems to smash together a bunch of
information without much care for ordering.  Most heartbreaking is
that *anything* can seemingly append new information to it without any
purview, which is *REALLY* annoying.  It can be very overstimulating
to look at, without even being that immediately informative.

I've got a custom Emacs lisp package
([[file:elisp/better-mode-line.el][here]]) which sets up the default
mode line as a set of 3 segments: left, centre and right.  It pads out
the mode line with space strings to achieve this.

#+begin_src emacs-lisp
(use-package better-mode-line
  :load-path "elisp/"
  :demand t
  :init
  (defun +mode-line/evil-state ()
    "Returns either \"E\" if no evil-state is defined or the first character
of the evil state capitalised"
    (with-eval-after-load "evil"
      (if (bound-and-true-p evil-state)
          (-->
           (format "%s" evil-state)
           (substring it 0 1)
           (upcase it))
        "E")))

  (setq better-mode-line/left-segment
        '("    "                           ;; Left padding
          (:eval
           (when (mode-line-window-selected-p)
             '("%l:%c"                     ;; Line and column count
               "     "
               "%p"                        ;; Percentage into buffer
               "["                         ;; Evil state
               (:eval
                (+mode-line/evil-state))
               "]"))))
        better-mode-line/centre-segment
        '("%+"                             ;; Buffer state (changed or not)
          "%b"                             ;; Buffer name
          "("                              ;; Major mode
          (:eval (format "%s" major-mode))
          ")")
        better-mode-line/right-segment
        '((:eval
           (when (mode-line-window-selected-p)
             (format "%s %s"
                     (if (project-current) ;; Name of current project (if any)
                         (project-name
                          (project-current))
                       "")
                     (if vc-mode           ;; Project and Git branch
                         vc-mode
                       ""))
             ))
          mode-line-misc-info              ;; Any other information
          (:eval                           ;; Compilation mode errors
           (if (eq major-mode 'compilation-mode)
               compilation-mode-line-errors))
          "    "                           ;; Right padding
          ))
  :config
  (better-mode-line/setup-mode-line))
#+end_src
** Fringes
Turning off borders in my window manager was a good idea, so I should
adjust the borders for Emacs, so called fringes.  However, some things
like [[info:emacs#Compilation Mode][Compilation Mode]] do require
fringes to provide arrows on the left side of the window.  Hence I
provide a minimal fringe style with only 10 pixels on the left
provided.

#+begin_src emacs-lisp
(fringe-mode (cons 10 0))
#+end_src
** Scrolling
When scrolling, editors generally try to keep the cursor on screen.
Emacs has some variables which ensure the cursor is a certain number
of lines above the bottom of the screen and below the top of the
screen when scrolling.  Here I set the margin to 8 (so it'll start
correcting at 8) and scroll-conservatively to the same value so it'll
keep the cursor centred.

I also setup the ~pixel-scroll-mode~ to make scrolling nicer looking.

#+begin_src emacs-lisp
(use-package emacs
  :init
  (setq scroll-conservatively 8
        scroll-margin 8
        pixel-dead-time nil
        pixel-scroll-precision-use-momentum nil
        pixel-resolution-fine-flag t
        fast-but-imprecise-scrolling t)
  :config
  (pixel-scroll-mode t)
  (pixel-scroll-precision-mode t))
#+end_src
** Display line numbers
I don't really like line numbers, I find them similar to
[[*Fringes][fringes]] (useless space), but at least it provides some
information.  Sometimes it can help with doing repeated commands so a
toggle option is necessary.

#+begin_src emacs-lisp
(use-package display-line-numbers
  :defer t
  :hook ((prog-mode-hook text-mode-hook) . display-line-numbers-mode)
  :commands display-line-numbers-mode
  :general
  (mode-leader
    "l" #'display-line-numbers-mode)
  :init
  (setq-default display-line-numbers-type 'relative))
#+end_src
** Pulsar
Similar to how [[*Evil goggles][Evil goggles]] highlights Evil
actions, pulsar provides more highlighting capabilities.  Made by my
favourite Greek philosopher, Prot.
#+begin_src emacs-lisp
(use-package pulsar
  :straight t
  :init
  (setq pulsar-face 'pulsar-cyan
        pulsar-pulse-functions
        '(next-buffer
          previous-buffer
          fill-paragraph
          drag-stuff-right
          drag-stuff-left
          drag-stuff-up
          drag-stuff-down
          evil-goto-first-line
          evil-goto-line
          evil-scroll-down
          evil-scroll-up
          evil-scroll-page-down
          evil-scroll-page-up
          evil-window-left
          evil-window-right
          evil-window-up
          evil-window-down
          evil-forward-paragraph
          evil-backward-paragraph
          evil-fill-and-move
          evil-join
          org-forward-paragraph
          org-backward-paragraph
          org-fill-paragraph))
  :config
  (pulsar-global-mode 1))
#+end_src
** Zoom
Zoom provides a very useful capability: dynamic resizing of windows
based on which one is active.  I prefer larger font sizes but make it
too large and it's difficult to have multiple buffers side by side.
This package allows larger font sizes and still have multiple buffers
side by side.

#+begin_src emacs-lisp
(use-package zoom
  :straight t
  :defer t
  :hook (after-init-hook . zoom-mode)
  :init
  (setq zoom-size '(90 . 25)))
#+end_src
** Hide mode line
Custom minor mode to toggle the mode line.  Check it out at
[[file:elisp/hide-mode-line.el][elisp/hide-mode-line.el]].

#+begin_src emacs-lisp
(use-package hide-mode-line
  :load-path "elisp/"
  :defer t
  :general
  (mode-leader
    "m" #'global-hide-mode-line-mode))
#+end_src
** Olivetti
Olivetti provides a focus mode for Emacs, which makes it look a bit
nicer.  It uses margins by default and centres using fill-column.  I
actually really like olivetti mode particularly with my [[*Mode
line][centred mode-line]], so I also define a global minor mode which
enables it in all but the minibuffer.

#+begin_src emacs-lisp
(use-package olivetti
  :straight t
  :defer t
  :general
  (mode-leader
    "o" #'olivetti-global-mode)
  :init
  (setq-default olivetti-body-width nil
                olivetti-minimum-body-width 100
                olivetti-style nil)
  :config
  (define-globalized-minor-mode olivetti-global-mode olivetti-mode
    (lambda nil (unless (or (minibufferp)
                     (string= (buffer-name) "*which-key*"))
           (olivetti-mode 1)))))
#+end_src
** All the Icons
Nice set of icons, for even more emojis.

#+begin_src emacs-lisp
(use-package all-the-icons
  :straight t
  :defer t
  :general
  (insert-leader
    "e" #'all-the-icons-insert))
#+end_src
** Pretty symbols
Prettify symbols mode allows users to declare "symbols" that replace
text within certain modes.  It's eye candy in most cases, but can aid
comprehension for symbol heavy languages.

This configures a ~use-package~ keyword which makes declaring pretty
symbols for language modes incredibly easy.  Checkout my [[*Emacs
lisp][Emacs lisp]] configuration for an example.

#+begin_src emacs-lisp
(use-package prog-mode
  :demand t
  :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)
       (mapcar
        #'(lambda (arg)
            (let ((mode (car arg))
                  (rest (cdr arg)))
              `(add-hook
                ',mode
                #'(lambda nil
                    (setq prettify-symbols-alist ',rest)
                    (prettify-symbols-mode)))))
        args)))))
#+end_src

Here's a collection of keywords and possible associated symbols for
any prog language of choice.  Mostly for reference and copying.

#+begin_example
("null"     . "Ø")
("list"     . "ℓ")
("string"   . "𝕊")
("char"     . "ℂ")
("int"      . "ℤ")
("float"    . "ℝ")
("!"        . "¬")
("for"      . "Σ")
("return"   . "≡")
("reduce"   . "↓")
("map"      . "→")
("some"     . "∃")
("every"    . "∃")
("lambda"   . "λ")
("function" . "ƒ")
("<="       . "≤")
(">="       . "≥")
#+end_example
* Text packages
Standard packages and configurations for dealing with text, usually
prose.
** Flyspell
Flyspell allows me to spell check text documents.  I use it primarily
in org mode, as that is my preferred prose writing software, but I
also need it in commit messages and so on, thus it should really hook
into text-mode.

#+begin_src emacs-lisp
(use-package flyspell
  :defer t
  :hook ((org-mode-hook text-mode-hook) . flyspell-mode)
  :general
  (nmmap
    :keymaps 'text-mode-map
    "M-C" #'flyspell-correct-word-before-point
    "M-c" #'flyspell-auto-correct-word)
  (mode-leader
    "s" #'flyspell-mode))
#+end_src
** Whitespace
I hate inconsistencies in whitespace.  If I'm using tabs, I better be
using them everywhere, and if I'm using whitespace, it better be well
formed.  Furthermore, hard character limits are important (enforced by
[[*Filling and displaying fills][auto-fill-mode]]) which is why I like
to have some kind of highlighting option.

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 that need the help.

#+begin_src emacs-lisp
(use-package whitespace
  :defer t
  :general
  (nmmap
    "M--"   #'whitespace-cleanup)
  (mode-leader
    "w" #'whitespace-mode)
  :hook
  (before-save-hook  . whitespace-cleanup)
  ((c-mode-hook c++-mode-hook haskell-mode-hook python-mode-hook
                org-mode-hook text-mode-hook js-mode-hook
                nasm-mode-hook)
   . whitespace-mode)
  :init
  (setq whitespace-line-column nil
        whitespace-style '(face empty spaces tabs newline trailing
                                lines-char tab-mark)))
#+end_src
** Filling and displaying fills
The fill-column is the number of characters that should be in a single
line of text before doing a hard wrap.  The default case is 80
characters for that l33t Unix hard terminal character limit.  I like
different fill-columns for different modes: text modes should really
use 70 fill columns while code should stick to 80.

#+begin_src emacs-lisp
(use-package emacs
  :hook
  (text-mode-hook . auto-fill-mode)
  ((c-mode-hook c++-mode-hook haskell-mode-hook python-mode-hook
                org-mode-hook text-mode-hook js-mode-hook)
   . display-fill-column-indicator-mode)
  :init
  (setq-default fill-column 80)
  (add-hook 'text-mode-hook  (proc (setq-local fill-column 70))))
#+end_src
** Visual line mode
When dealing with really long lines I have a specific taste.  I don't
want text to just go off the screen, such that I have to move the
cursor forward in the line to see later content - I want line
wrapping.  Emacs provides ~truncate-lines~ for line wrapping but it
cuts words, which isn't very nice as that cut word spans two lines.
Instead I want Emacs to cut by word, which is where visual-line-mode
comes in.  Since I may experience really long lines anywhere, it
should be enabled globally.

#+begin_src emacs-lisp
(use-package emacs
  :demand t
  :config
  (global-visual-line-mode t))
#+end_src
** Show-paren-mode
When the cursor is over a parenthesis, highlight the other member of
the pair.

#+begin_src emacs-lisp
(use-package paren
  :hook (prog-mode-hook . show-paren-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
  :straight t
  :defer t
  :hook
  (prog-mode-hook . smartparens-mode)
  (text-mode-hook . smartparens-mode)
  :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
** Powerthesaurus
Modern package for thesaurus in Emacs with a transient + hydra.
#+begin_src emacs-lisp
(use-package powerthesaurus
  :defer t
  :straight t
  :general
  (search-leader
    "w" #'powerthesaurus-transient))
#+end_src
** lorem ipsum
Sometimes you need placeholder text for some UI or document.  Pretty
easy to guess what text I'd use.

#+begin_src emacs-lisp
(use-package lorem-ipsum
  :straight t
  :general
  (insert-leader
    "p" #'lorem-ipsum-insert-paragraphs))
#+end_src
** Auto insert
Allows inserting text immediately upon creating a new buffer with a
given name, similar to template.  Supports skeletons for inserting
text.  To make it easier for later systems to define their own auto
inserts, I define a ~use-package~ keyword (~:auto-insert~) which
allows one to define an entry for ~auto-insert-alist~.

#+begin_src emacs-lisp
(use-package autoinsert
  :demand t
  :hook (after-init-hook . auto-insert-mode)
  :config
  (with-eval-after-load "use-package-core"
    (add-to-list 'use-package-keywords ':auto-insert)
    (defun use-package-normalize/:auto-insert (_name-symbol _keyword args)
      args)
    (defun use-package-handler/:auto-insert (name _keyword args rest state)
      (use-package-concat
       (use-package-process-keywords name rest state)
       (mapcar
        #'(lambda (arg)
            `(add-to-list
              'auto-insert-alist
              ',arg))
        args)))))
#+end_src
* Programming packages
Packages that help with programming.
** 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

Eldoc box makes the help buffer a hovering box instead of printing it
in the minibuffer.  A lot cleaner.

2024-05-31: Eldoc box is a bit useless now that I'm not using frames.
I prefer the use of the minibuffer for printing documentation now.

#+begin_src emacs-lisp
(use-package eldoc
  :defer t
  :hook (prog-mode-hook . eldoc-mode)
  :init
  (global-eldoc-mode 1)
  :general
  (leader
    "h>" #'eldoc-doc-buffer))
#+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.  Many times Flycheck is annoying when checking a
program, particularly one which isn't finished yet.

#+begin_src emacs-lisp
(use-package flycheck
  :straight t
  :defer t
  :commands (flycheck-mode flycheck-list-errors)
  :general
  (mode-leader
    "f" #'flycheck-mode)
  (code-leader
    "x" #'flycheck-list-errors
    "j" #'flycheck-next-error
    "k" #'flycheck-previous-error)
  :display
  ("\\*Flycheck.*"
   (display-buffer-at-bottom)
   (window-height . 0.25))
  :init
  (setq-default flycheck-check-syntax-automatically
                '(save idle-change mode-enabled)
                flycheck-idle-change-delay 1.0
                flycheck-buffer-switch-check-intermediate-buffers t
                flycheck-display-errors-delay 0.25)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-flycheck-setup)))
#+end_src
** Eglot
Eglot is package to communicate with LSP servers for better
programming capabilities.  Interactions with a server provide results
to the client, done through JSON.

NOTE: Emacs 28.1 comes with better JSON parsing, which makes Eglot
much faster.

2023-03-26: I've found Eglot to be useful sometimes, but many of the
projects I work on don't require a heavy server setup to efficiently
edit and check for errors; Emacs provides a lot of functionality.  So
by default I've disabled it, using =M-x eglot= to startup the LSP
server when I need it.

2024-06-27: In projects where I do use eglot and I know I will need it
regardless of file choice, I prefer setting it at the dir-local level
via an eval form.  So I add to the safe values for the eval variable
to be set.

#+begin_src emacs-lisp
(use-package eglot
  :defer t
  :general
  (code-leader
    :keymaps 'eglot-mode-map
    "f" #'eglot-format
    "a" #'eglot-code-actions
    "R" #'eglot-reconnect)
  :init
  (setq eglot-auto-shutdown t
        eglot-stay-out-of '(flymake)
        eglot-ignored-server-capabilities '(:documentHighlightProvider
                                            :documentOnTypeFormattingProvider
                                            :inlayHintProvider))
  (add-to-list 'safe-local-variable-values '(eval eglot-ensure)))
#+end_src
** Indentation
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/use-tabs ()
  (interactive)
  (setq-local indent-tabs-mode t))
#+end_src
** Highlight todo items
TODO items are highlighted in org-mode, but not necessarily in every
mode.  This minor mode highlights all TODO like items via a list of
strings to match.  It also configures faces to use when highlighting.
I hook it to prog-mode.

#+begin_src emacs-lisp
(use-package hl-todo
  :straight t
  :after prog-mode
  :hook (prog-mode-hook . hl-todo-mode)
  :init
  (setq hl-todo-keyword-faces
        '(("TODO"  . "#E50000")
          ("WIP"   . "#ffa500")
          ("NOTE"  . "#00CC00")
          ("FIXME" . "#d02090"))))
#+end_src
** Hide-show mode
Turn on ~hs-minor-mode~ for all prog-mode.  This provides folds for
free.

#+begin_src emacs-lisp
(use-package hideshow
  :defer t
  :hook (prog-mode-hook . hs-minor-mode))
#+end_src
** Aggressive indenting
Essentially my dream editing experience: when I type stuff in, try and
indent it for me on the fly.  Just checkout the
[[https://github.com/Malabarba/aggressive-indent-mode][page]], any
description I give won't do it justice.

#+begin_src emacs-lisp
(use-package aggressive-indent
  :straight t
  :hook (python-mode-hook     . aggressive-indent-mode)
  :hook (emacs-lisp-mode-hook . aggressive-indent-mode)
  :hook (lisp-mode-hook       . aggressive-indent-mode))
#+end_src
** Compilation
Compilation mode is an incredibly useful subsystem of Emacs which
allows one to run arbitrary commands.  If those commands produce
errors (particularly errors that have a filename, column and line)
compilation-mode can colourise these errors and help you navigate to
them.

Here I add some bindings and a filter which colourises the output of
compilation mode for ANSI escape sequences; the eyecandy is certainly
nice but it's very useful when dealing with tools that use those codes
so you can actually read the text.

#+begin_src emacs-lisp
(use-package compile
  :defer t
  :display
  ("\\*compilation\\*"
   (display-buffer-reuse-window display-buffer-at-bottom)
   (window-height . 0.3)
   (reusable-frames . t))
  :hydra
  (move-error-hydra
   (:hint nil) "Hydra for moving between errors"
   ("j" #'next-error)
   ("k" #'previous-error))
  :general
  (leader
    "j" #'move-error-hydra/next-error
    "k" #'move-error-hydra/previous-error)
  (code-leader
    "c" #'compile
    "r" #'recompile)
  (nmap
    "M-r" #'recompile)
  (:keymaps 'compilation-mode-map
   "g" nil) ;; by default this is recompile
  (nmmap
    :keymaps 'compilation-mode-map
    "c" #'recompile)
  :init
  (setq compilation-scroll-output 'first-error
        compilation-context-lines nil
        next-error-highlight 'fringe-arrow)
  :config
  (add-hook 'compilation-filter-hook #'ansi-color-compilation-filter))
#+end_src
** xref
Find definitions, references and general objects using tags without
external packages.  Provided out of the box with Emacs, but requires a
way of generating a =TAGS= file for your project (look at
[[*Project.el][Project.el]] for my way of doing so).  A critical
component in a minimal setup for programming without heavier systems
like [[*Eglot][Eglot]].

#+begin_src emacs-lisp
(use-package xref
  :defer t
  :display
  ("\\*xref\\*"
   (display-buffer-at-bottom)
   (inhibit-duplicate-buffer . t)
   (window-height . 0.3))
  :general
  (code-leader
    "t" '(nil :which-key "Tags"))
  (code-leader
    :infix "t"
    "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
    "r" #'xref-query-replace-in-results
    "gr" #'xref-revert-buffer
    "q" #'quit-window))
#+end_src
** Project.el
An out of the box system for managing projects.  Where possible we
should try to use Emacs defaults, so when setting up on a new computer
it takes a bit less time.

Here I:
+ Bind ~project-prefix-map~ to "<leader>p"
+ write a TAGS command, mimicking projectile's one, so I can quickly
  generate them.
  + Bind that to "<leader>pr"

#+begin_src emacs-lisp
(use-package project
  :defer t
  :general
  (:keymaps 'project-prefix-map
   "r" #'+project/generate-tags)
  (leader
    "p" `(,project-prefix-map :which-key "Project"))
  :config
  (defun +project/command (folder)
    (format "ctags -Re -f %sTAGS %s*"
            folder folder))

  (defun +project/root ()
    (if (project-current)
        (project-root (project-current))
      default-directory))

  (defun +project/generate-tags ()
    (interactive)
    (set-process-sentinel
     (start-process-shell-command
      "PROJECT-GENERATE-TAGS"
      "*tags*"
      (+project/command (+project/root)))
     (lambda (p event)
       (when (string= event "finished\n")
         (message "Finished generating tags!")
         (visit-tags-table (format "%sTAGS" (+project/root))))))))
#+end_src
** devdocs
When man pages aren't enough, you need some documentation lookup
system (basically whenever your using anything but C/C++/Bash).
[[https://devdocs.io][Devdocs]] is a great little website that
provides a ton of documentation sets.  There's an Emacs package for it
which works well and downloads documentation sets to my machine, which
is nice.

#+begin_src emacs-lisp
(use-package devdocs
  :straight t
  :defer t
  :general
  (file-leader
    "d" #'devdocs-lookup))
#+end_src
** rainbow-delimiters
Makes colours delimiters (parentheses) based on their depth in an
expression.  Rainbow flag in your Lisp source code.

#+begin_src emacs-lisp
(use-package rainbow-delimiters
  :defer t
  :straight t
  :general
  (mode-leader "r" #'rainbow-delimiters-mode)
  :hook
  ((lisp-mode-hook emacs-lisp-mode-hook racket-mode-hook) . rainbow-delimiters-mode))
#+end_src
** Licensing
Loads [[file:elisp/license.el][license.el]] for inserting licenses.
Licenses are important for distribution and attribution to be defined
clearly.

#+begin_src emacs-lisp
(use-package license
  :demand t
  :load-path "elisp/"
  :general
  (insert-leader
    "l" #'+license/insert-copyright-notice
    "L" #'+license/insert-complete-license))
#+end_src
** diff mode
Oh diffs; the way of the ancient ones.  Nowadays we use our newfangled
"pull requests" and "cool web interfaces" to manage changes in our
code repositories, but old school projects use patches to make code
changes.  They're a pain to distribute and can be very annoying to use
when applying them to code.  Even then I somewhat like patches, if
only for their simplicity.

[[https://git.aryadevchavali.com/dwm][dwm]] uses patches for adding
new features and Emacs has great functionality to work with patches
effectively.  Here I configure ~diff-mode~, which provides most of
this cool stuff, to be a bit more ergonomic with ~evil~.

#+begin_src emacs-lisp
(use-package diff-mode
  :general
  (nmmap
    :keymaps 'diff-mode-map
    "}" #'diff-hunk-next
    "{" #'diff-hunk-prev
    "RET" #'diff-goto-source))
#+end_src
* Org mode
Org is, at its most basic, a markup language.  =org-mode= is a major
mode for Emacs to interpret org buffers.  org-mode provides a lot of
capabilities, some are:
+ A complete table based spreadsheet system, with formulas (including
  [[*Calculator][calc-mode]] integration)
+ Code blocks with proper syntax highlighting and editing experience
  + Evaluation
  + Export of code blocks to a variety of formats
  + Export of code blocks to a code file (so called "tangling", which
    is what occurs in this document)
+ Feature complete scheduling system with [[*Calendar][calendar]]
  integration
  + A clock-in system to time tasks
+ TODO system
+ Export to a variety of formats or make your own export engine using
  the org AST.
+ Inline $\LaTeX$, with the ability to render the fragments on
  demand within the buffer
+ Links to a variety of formats:
  + Websites (via http or https)
  + FTP
  + SSH
  + Files (even to a specific line)
  + Info pages

I'd argue this is a bit more than a markup language.  Like
[[*Magit][Magit]], some use Emacs just for this system.
** Org Essentials
Org has a ton of settings to tweak, which change your experience quite
a bit.  Here are mine, but this took a lot of just reading other
people's configurations and testing.  I don't do a good job of
explaining how this works in all honesty, but it works well for me so
I'm not very bothered.

+ By default =~/Text= is my directory for text files.  I actually have
  a repository that manages this directory for agenda files and other
  documents
+ Indentation in file should not be allowed, i.e. text indentation, as
  that forces other editors to read it a certain way as well.  It's
  obtrusive hence it's off.
+ Org startup indented is on by default as most documents do benefit
  from the indentation, but I do turn it off for some files via
  ~#+startup:noindent~
+ When opening an org document there can be a lot of headings, so I
  set folding to just content
+ Org documents can also have a lot of latex previews, which make
  opening some after a while a massive hassle.  If I want to see the
  preview, I'll do it myself, so turn it off.
+ Org manages windowing itself, to some extent, so I set those options
  to be as unobtrusive as possible
+ Load languages I use in =src= blocks in org-mode (Emacs-lisp for
  this configuration, C and Python)

#+begin_src emacs-lisp
(use-package org
  :defer t
  :init
  (setq org-directory "~/Text/"
        org-adapt-indentation nil
        org-indent-mode nil
        org-startup-indented nil
        org-startup-folded 'showeverything
        org-startup-with-latex-preview nil
        org-imenu-depth 10
        org-src-window-setup 'current-window
        org-indirect-buffer-display 'current-window
        org-link-frame-setup '((vm . vm-visit-folder-other-frame)
                               (vm-imap . vm-visit-imap-folder-other-frame)
                               (file . find-file))
        org-babel-load-languages '((emacs-lisp . t)
                                   (lisp . t)
                                   (shell . t))))
#+end_src
** Org Latex
Org mode has deep integration with latex, can export to PDF and even
display latex fragments in the document directly.  I setup the
pdf-process, code listing options via minted and the format options
for latex fragments.

#+begin_src emacs-lisp
(use-package org
  :defer t
  :init
  (setq org-format-latex-options
        '(:foreground default :background "Transparent" :scale 2
          :html-foreground "Black" :html-background "Transparent"
          :html-scale 1.0 :matchers ("begin" "$1" "$" "$$" "\\(" "\\["))
        org-latex-src-block-backend '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
        (list (concat "latexmk -f -bibtex -pdf "
                      "-shell-escape -%latex -interaction=nonstopmode "
                      "-output-directory=%o %f"))
        org-latex-minted-options
        '(("style" "colorful")
          ("linenos")
          ("frame" "single")
          ("mathescape")
          ("fontfamily" "courier")
          ("samepage" "false")
          ("breaklines" "true")
          ("breakanywhere" "true"))))
#+end_src
** 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
  :init
  (setq org-edit-src-content-indentation 0
        org-eldoc-breadcrumb-separator " → "
        org-enforce-todo-dependencies t
        org-export-backends '(ascii html latex odt icalendar)
        org-fontify-quote-and-verse-blocks t
        org-fontify-whole-heading-line t
        org-footnote-auto-label t
        org-hide-emphasis-markers nil
        org-hide-leading-stars t
        org-image-actual-width nil
        org-imenu-depth 10
        org-link-descriptive nil
        org-priority-faces '((?A . error) (?B . warning) (?C . success))
        org-refile-targets '((nil . (:maxlevel . 2)))
        org-tags-column 0
        org-todo-keywords '((sequence "TODO" "WIP" "DONE")
                            (sequence "PROJ" "WAIT" "COMPLETE"))
        org-use-sub-superscripts '{}))
#+end_src
** Org Core Functionality
Hooks, prettify-symbols and records for auto insertion.

#+begin_src emacs-lisp
(use-package org
  :defer t
  :hook
  (org-mode-hook . prettify-symbols-mode)
  :display
  ("\\*Org Src.*"
   (display-buffer-same-window))
  :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
A load of bindings for org-mode which binds together a lot of
functionality.  It's best to read it yourself; to describe it is to
write the code.

#+begin_src emacs-lisp
(use-package org
  :defer t
  :config
  (with-eval-after-load "consult"
    (general-def
      :keymaps 'org-mode-map
      [remap consult-imenu] #'consult-outline))
  :general
  (file-leader
    "l" #'org-store-link
    "i" #'org-insert-last-stored-link)
  (code-leader
    :keymaps 'emacs-lisp-mode-map
    "D" #'org-babel-detangle)
  (local-leader
    :state '(normal motion)
    :keymaps 'org-src-mode-map
    "o" #'org-edit-src-exit)
  (local-leader
    :keymaps 'org-mode-map
    "l" '(nil :which-key "Links")
    "'" '(nil :which-key "Tables")
    "c" '(nil :which-key "Clocks")
    "r" #'org-refile
    "d" #'org-date-from-calendar
    "t" #'org-todo
    "," #'org-priority
    "T" #'org-babel-tangle
    "i" #'org-insert-structure-template
    "p" #'org-latex-preview
    "s" #'org-property-action
    "e" #'org-export-dispatch
    "o" #'org-edit-special
    "O" #'org-open-at-point)
  (local-leader
    :keymaps 'org-mode-map
    :infix "l"
    "i" #'org-insert-link
    "l" #'org-open-at-point
    "f" #'org-footnote-action)
  (local-leader
    :keymaps 'org-mode-map
    :infix "'"
    "a" #'org-table-align
    "c" #'org-table-create
    "f" #'org-table-edit-formulas
    "t" #'org-table-toggle-coordinate-overlays
    "s" #'org-table-sum
    "e" #'org-table-calc-current-TBLFM
    "E" #'org-table-eval-formula))
#+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
  :defer t
  :init
  (defconst +org/agenda-root "~/Text/"
    "Root directory for all agenda files")
  (setq org-agenda-files (list (expand-file-name +org/agenda-root))
        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
        org-agenda-start-with-entry-text-mode nil)
  :config
  (evil-set-initial-state 'org-agenda-mode 'normal)
  :general
  (file-leader
    "a" `(,(proc (interactive)
                 (find-file (completing-read "Enter directory: " org-agenda-files nil t)))
          :which-key "Open agenda directory"))
  (app-leader
    "a" #'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 capture
Org capture provides a system for quickly "capturing" some information
into an org file.  A classic example is creating a new TODO in a
todo file, where the bare minimum to record one is:
+ where was it recorded?
+ when was it recorded?
+ what is it?
Org capture provides a way to do that seamlessly without opening the
todo file directly.

#+begin_src emacs-lisp
(use-package org-capture
  :defer t
  :init
  (setq
   org-default-notes-file (concat org-directory "todo.org")
   org-capture-templates
   '(("t" "Todo" entry
      (file "")
      "* TODO %?
%T
%a")
     ("q" "Quote" entry
      (file "quotes.org")
      "* %^{Title: }
,#+caption: %^{Origin: } %t
,#+begin_quote
%?
,#+end_quote")))
  :general
  (leader
    "C" #'org-capture)
  (nmmap
    :keymaps 'org-capture-mode-map
    "ZZ" #'org-capture-finalize
    "ZR" #'org-capture-refile
    "ZQ" #'org-capture-kill))
#+end_src
** WIP Org clock-in
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
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
  :general
  (local-leader
    :keymaps 'org-mode-map
    :infix "c"
    "d" #'org-clock-display
    "c" #'org-clock-in
    "o" #'org-clock-out
    "r" #'org-clock-report))
#+end_src
** WAIT Org ref
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
For bibliographic stuff in $\LaTeX$ export.

#+begin_src emacs-lisp
(use-package org-ref
  :straight t
  :defer t
  :init
  (setq bibtex-files '("~/Text/bibliography.bib")
        bibtex-completion-bibliography '("~/Text/bibliography.bib")
        bibtex-completion-additional-search-fields '(keywords)))
#+end_src
*** Org ref ivy integration
Org ref requires ivy-bibtex to work properly with ivy, so we need to
set that up as well

#+begin_src emacs-lisp
(use-package ivy-bibtex
  :straight t
  :after org-ref
  :config
  (require 'org-ref-ivy))
#+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
  :straight t
  :hook
  (message-mode-hook . org-msg-mode)
  (notmuch-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
  :straight t
  :defer t
  :hook (org-mode-hook . evil-org-mode)
  :general
  (nmmap
    :keymaps 'org-mode-map
    "TAB" #'org-cycle))
#+end_src
** WAIT Org reveal
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
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
  :straight t
  :defer t
  :init
  (setq org-reveal-root "https://cdn.jsdelivr.net/npm/reveal.js"
        org-reveal-theme "sky"))
#+end_src
** Org bookmark
I maintain a bookmarks file at =~/Text/bookmarks.org=.  I would like
the ability to construct new bookmarks and open bookmarks.  They may
be either articles I want to read, useful information documents or
just straight up youtube videos.  So I wrote a
[[file:elisp/org-bookmark.el][library]] myself which does the
appropriate dispatching and work for me.  Pretty sweet!

Also I define a template for org-capture here for bookmarks and add it
to the list ~org-capture-templates~.

#+begin_src emacs-lisp
(use-package org-bookmark
  :defer t
  :load-path "elisp/"
  :general
  (file-leader
    "b" #'org-bookmark/open-bookmark)
  :init
  (with-eval-after-load "org-capture"
    (add-to-list
     'org-capture-templates
     '("b" "Bookmark" entry
       (file "bookmarks.org")
       "* %? :bookmark:
%T
%^{url|%x}p
"
       ))))
#+end_src
* Languages
For a variety of (programming) languages Emacs comes with default
modes but this configures them as well as pulls any modes Emacs
doesn't come with.
** Makefile
Defines an auto-insert for Makefiles.  Assumes C but it's very easy to
change it for C++.

#+begin_src emacs-lisp
(use-package make-mode
  :defer t
  :auto-insert
  (("[mM]akefile\\'" . "Makefile skeleton")
   ""
	 "CC=gcc
OUT=main.out
LIBS=
ARGS=

RELEASE=0
GFLAGS=-Wall -Wextra -Werror -Wswitch-enum -std=c11
DFLAGS=-ggdb -fsanitize=address -fsanitize=undefined
RFLAGS=-O3
DEPFLAGS=-MT $@ -MMD -MP -MF
ifeq ($(RELEASE), 1)
CFLAGS=$(GFLAGS) $(RFLAGS)
else
CFLAGS=$(GFLAGS) $(DFLAGS)
endif

SRC=src
DIST=build
CODE=$(addprefix $(SRC)/, ) # add source files here
OBJECTS=$(CODE:$(SRC)/%.c=$(DIST)/%.o)
DEPDIR:=$(DIST)/dependencies
DEPS:=$(CODE:$(SRC)/%.c=$(DEPDIR):%.d) $(DEPDIR)/main.d

.PHONY: all
all: $(OUT)

$(OUT): $(DIST)/$(OUT)

$(DIST)/$(OUT): $(OBJECTS) $(DIST)/main.o | $(DIST)
	$(CC) $(CFLAGS) $^ -o $@ $(LIBS)

$(DIST)/%.o: $(SRC)/%.c | $(DIST) $(DEPDIR)
	$(CC) $(CFLAGS) $(DEPFLAGS) $(DEPDIR)/$*.d -c $< -o $@ $(LIBS)

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

.PHONY:
clean:
	rm -rfv $(DIST)/*

$(DIST):
	mkdir -p $(DIST)

$(DEPDIR):
	mkdir -p $(DEPDIR)

-include $(DEPS)
"
   _))
#+end_src
** WAIT SQL
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
The default SQL package provides support for connecting to common
database types (sqlite, mysql, etc) for auto completion and query
execution.  I don't use SQL currently but whenever I need it it's
there.

#+begin_src emacs-lisp
(use-package sql
  :defer t
  :init
  (setq sql-display-sqli-buffer-function nil))
#+end_src
** WAIT Ada
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
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 and a language server to do the hard work.

#+begin_src emacs-lisp
(use-package ada-mode
  :load-path "elisp/"
  :defer t
  :config
  (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
  :defer t
  :mode ("\\.bin" "\\.out"))
#+end_src
** NASM
#+begin_src emacs-lisp
(use-package nasm-mode
  :straight t
  :defer t
  :mode ("\\.asm" . nasm-mode))
#+end_src
** C/C++
Setup for C and C++ modes, using Emacs' default package: cc-mode.
*** cc-mode
Tons of stuff, namely:
+ ~auto-fill-mode~ for 80 char limit
+ Some keybindings to make evil statement movement easy
+ Lots of pretty symbols
+ Indenting options and a nice (for me) code style for C
+ Auto inserts to get a C file going

#+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
   "{" #'c-beginning-of-defun
   "}" #'c-end-of-defun)
  :init
  (setq-default c-basic-offset 2)
  (setq-default c-auto-newline nil)
  (setq-default c-default-style '((other . "user")))
  (defun +cc/copyright-notice ()
    (let* ((lines (split-string (+license/copyright-notice) "\n"))
           (copyright-line (car lines))
           (rest (cdr lines)))
      (concat
       "* "
       copyright-line
       "\n"
       (mapconcat
        #'(lambda (x)
            (if (string= x "")
                ""
              (concat " * " x)))
        rest
        "\n"))))
  :auto-insert
  (("\\.c\\'" . "C skeleton")
   ""
   "/" (+cc/copyright-notice) "\n\n"
   " * Created: " (format-time-string "%Y-%m-%d") "\n"
   " * Author: " user-full-name "\n"
   " * Description: " _ "\n"
   " */\n"
   "\n")
  (("\\.cpp\\'" "C++ skeleton")
   ""
   "/" (+cc/copyright-notice) "\n\n"
   " * Created: " (format-time-string "%Y-%m-%d") "\n"
   " * Author: " user-full-name "\n"
   " * Description: " _ "\n"
   " */\n"
   "\n")
  (("\\.\\([Hh]\\|hh\\|hpp\\|hxx\\|h\\+\\+\\)\\'" . "C / C++ header")
   (replace-regexp-in-string "[^A-Z0-9]" "_"
                             (string-replace "+" "P"
                                             (upcase
                                              (file-name-nondirectory buffer-file-name))))
   "/" (+cc/copyright-notice) "\n\n"
   " * Created: " (format-time-string "%Y-%m-%d") "\n"
   " * Author: " user-full-name "\n"
   " * Description: " _ "\n"
   " */\n\n"
   "#ifndef " str n "#define " str "\n\n" "\n\n#endif")
  :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 is a program that formats C/C++ files.  It's highly
configurable and quite fast.  I have a root configuration in my
Dotfiles (check it out
[[file:~/Dotfiles/ClangFormat/).clang-format][here]].

Clang format comes inbuilt with clang/LLVM, so it's quite likely to be
on your machine.

#+begin_src emacs-lisp
(use-package clang-format
  :load-path "/usr/share/clang/"
  :defer t
  :after cc-mode
  :commands (+code/clang-format-region-or-buffer
             clang-format-mode)
  :general
  (code-leader
    :keymaps '(c-mode-map c++-mode-map)
    "f" #'clang-format-buffer)
  :config
  (define-minor-mode clang-format-mode
    "On save formats the current buffer via clang-format."
    :lighter nil
    (let ((save-func (proc (interactive)
                           (clang-format-buffer))))
      (if clang-format-mode
          (add-hook 'before-save-hook save-func nil t)
        (remove-hook 'before-save-hook save-func t))))
  (defun +code/clang-format-region-or-buffer ()
    (interactive)
    (if (mark)
        (clang-format-region (region-beginning) (region-end))
      (clang-format-buffer))))
#+end_src
*** cc org babel
To ensure org-babel executes language blocks of C/C++, I need to load
it as an option in ~org-babel-load-languages~.

#+begin_src emacs-lisp
(use-package org
  :after cc-mode
  :init
  (org-babel-do-load-languages
   'org-babel-load-languages
   '((C . t))))
#+end_src
*** cc compile fsan
Sanitisers are a blessing for C/C++.  An additional runtime on top of
the executable which catches stuff like undefined behaviour or memory
leaks make it super easy to see where and how code is failing.
However, by default, Emacs' compilation-mode doesn't understand the
logs =fsanitize= makes so you usually have to manually deal with it
yourself.

Compilation mode uses regular expressions to figure out whether
something is an error and how to navigate to the file where that error
is located.  So adding support for =-fsanitize= is as simple as making
a regular expression which captures file names and digits

#+begin_src emacs-lisp
(use-package compile
  :after cc-mode
  :config
  (add-to-list 'compilation-error-regexp-alist-alist
               `(fsan ,(rx (and
                            line-start "    #" digit " 0x" (1+ hex) " in "
                            (1+ (or word "_")) " "
                            (group (seq (* any) (or ".c" ".cpp" ".h" ".hpp"))) ":"
                            (group (+ digit))))

                      1 2))
  (add-to-list 'compilation-error-regexp-alist
               'fsan))
#+end_src
** Markdown
Why use Markdown when you have org-mode?  Because LSP servers
sometimes format their documentation as markdown, which
[[*Eglot][Eglot]] can use to provide nicer views on docs!
#+begin_src emacs-lisp
(use-package markdown-mode
  :defer t
  :straight t)
#+end_src
** WAIT D
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
D is a systems level programming language with C-style syntax.  I
think it has some interesting ideas such as a toggleable garbage
collector.  Here I just install the D-mode package, enable ~org-babel~
execution of d-mode blocks and alias ~D-mode~ with ~d-mode~.

#+begin_src emacs-lisp
(use-package d-mode
  :defer t
  :straight t
  :config
  (fset 'D-mode 'd-mode)
  (with-eval-after-load "org-mode"
    (setf (alist-get 'd org-babel-load-languages) t)))
#+end_src
** WAIT Rust
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
Rust is the systems programming language that also does web stuff and
CLI programs and basically tries to be a jack of all trades.  It's got
some interesting stuff but most importantly it's very new, so everyone
must learn it, right?

#+begin_src emacs-lisp
(use-package rust-mode
  :straight t
  :defer t
  :general
  (code-leader
    :keymaps 'rust-mode-map
    "f" #'rust-format-buffer)
  (local-leader
    :keymaps 'rust-mode-map
    "c" #'rust-run-clippy)
  :init
  (setq rust-format-on-save t)
  (with-eval-after-load "eglot"
    (add-to-list 'eglot-server-programs '(rust-mode "rust-analyzer"))))
#+end_src
** WAIT Racket
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
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
  :defer t
  :hook (racket-mode-hook . racket-xp-mode)
  :display
  ("\\*Racket REPL*"
   (display-buffer-at-bottom)
   (window-height . 0.3))
  :init
  (setq racket-documentation-search-location 'local)
  :general
  (nmap
    :keymaps 'racket-describe-mode-map
    "q" #'quit-window)
  (nmap
    :keymaps 'racket-mode-map
    "gr" #'racket-eval-last-sexp)
  (local-leader
    :keymaps '(racket-mode-map racket-repl-mode-map)
    "d" #'racket-repl-describe)
  (local-leader
    :keymaps 'racket-mode-map
    "r" #'racket-run
    "i" #'racket-repl
    "e" #'racket-send-definition
    "sr" #'racket-send-region
    "sd" #'racket-send-definition))
#+end_src
** WAIT CSharp
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
Haven't used C# in a while, but Emacs is alright for it with
omnisharp.

#+begin_src emacs-lisp
(use-package csharp-mode
  :defer t)
#+end_src
** WAIT Java
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
I kinda dislike Java, but if necessary I will code in it.  Just setup
a style and some pretty symbols.  You can use LSP to get cooler
features to be fair.

#+begin_src emacs-lisp
(use-package ob-java
  :defer t
  :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
** WAIT Haskell
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
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.  However, my preferred
functional language is still unfortunately Lisp so no extra brownie
points there.

Here I configure the REPL for Haskell via the
~haskell-interactive-mode~.  I also load my custom package
[[file:elisp/haskell-multiedit.el][haskell-multiedit]] which allows a
user to create temporary ~haskell-mode~ buffers that, upon completion,
will run in the REPL.  Even easier than making your own buffer.

#+begin_src emacs-lisp
(use-package haskell-mode
  :straight t
  :defer t
  :hook
  (haskell-mode-hook . haskell-indentation-mode)
  (haskell-mode-hook . interactive-haskell-mode)
  :display
  ("\\*haskell.**\\*"
   (display-buffer-at-bottom)
   (window-height . 0.3))
  :general
  (shell-leader
    "h" #'haskell-interactive-bring)
  (local-leader
    :keymaps 'haskell-mode-map
    "c" #'haskell-compile
    "t" #'haskell-process-do-type)
  (nmmap
    :keymaps 'haskell-mode-map
    "C-c C-c" #'haskell-process-load-file)
  (local-leader
    :keymaps 'haskell-interactive-mode-map
    "c" #'haskell-interactive-mode-clear)
  (imap
    :keymaps 'haskell-interactive-mode-map
    "M-k" #'haskell-interactive-mode-history-previous
    "M-j" #'haskell-interactive-mode-history-next)
  :init
  (setq haskell-interactive-prompt "[λ] "
        haskell-interactive-prompt-cont "{λ} "
        haskell-interactive-popup-errors nil
        haskell-stylish-on-save t
        haskell-process-type 'auto)
  :config
  (load (concat user-emacs-directory "elisp/haskell-multiedit.el")))
#+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.  Here I also setup org-babel for python
source code blocks.

#+begin_src emacs-lisp
(use-package python
  :defer t
  :general
  (nmmap
    :keymaps 'python-mode-map
    "C-M-x" #'python-shell-send-defun)
  (local-leader
    :keymaps 'python-mode-map
    "c" #'python-check)
  (local-leader
    :keymaps 'python-mode-map
    :infix "e"
    "e" #'python-shell-send-statement
    "r" #'python-shell-send-region
    "f" #'python-shell-send-buffer)
  :pretty
  (python-mode-hook
   ("None"   . "Ø")
   ("list"   . "ℓ")
   ("List"   . "ℓ")
   ("str"    . "𝕊")
   ("!"      . "¬")
   ("for"    . "∀")
   ("print"  . "φ")
   ("lambda" . "λ")
   ("reduce" . "↓")
   ("map"    . "→")
   ("return" . "≡")
   ("yield"  . "≈"))
  :init
  (setq python-indent-offset 4)
  :config
  (with-eval-after-load "org-mode"
    (setf (alist-get 'python org-babel-load-languages) t)))
#+end_src
*** Python shell
Setup for python shell, including a toggle option

#+begin_src emacs-lisp
(use-package python
  :defer t
  :commands +python/toggle-repl
  :general
  (shell-leader
    "p" #'run-python)
  :hook
  (inferior-python-mode-hook . company-mode)
  :display
  ("\\*Python\\*"
   (display-buffer-at-bottom)
   (window-height . 0.3)))
#+end_src
** YAML
YAML is a data language which is useful for config files.

#+begin_src emacs-lisp
(use-package yaml-mode
  :defer t
  :straight t)
#+end_src
** HTML/CSS/JS
Firstly, web mode for consistent colouring of syntax.

#+begin_src emacs-lisp
(use-package web-mode
  :straight t
  :defer t
  :mode ("\\.html" . 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
*** Emmet
Emmet for super speed code writing.

#+begin_src emacs-lisp
(use-package emmet-mode
  :straight t
  :defer t
  :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
*** HTML Auto insert
An auto-insert for HTML buffers, which just adds some nice stuff.

#+begin_src emacs-lisp
(use-package web-mode
  :defer t
  :auto-insert
  (("\\.html\\'" . "HTML Skeleton")
   ""
   "<!doctype html>
<html lang=''>
  <head>
    <meta charset='utf-8'>
    <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'/>
  </head>
  <body>
"
   _
   "     </body>
</html>"))
#+end_src
*** Javascript Mode
A better mode for JavaScript that also has automatic integration with
eglot.

#+begin_src emacs-lisp
(use-package js
  :defer t
  :mode ("\\.js" . js-mode)
  :hook (js-mode-hook . auto-fill-mode)
  :init
  (setq js-indent-level 2))
#+end_src
*** Typescript
A language that adds a build step to JavaScript projects for "static"
typing.  It's nice because it adds good auto completion.

#+begin_src emacs-lisp
(use-package typescript-mode
  :straight t
  :defer t
  :init
  (setq typescript-indent-level 2))
#+end_src
** Scheme
Another Lisp but simpler than the rest.  A beauty of engineering and
fun to write programs in.  Here I setup ~geiser~, which is the
premiere way to interact with scheme REPLs.

#+begin_src emacs-lisp
(use-package geiser
  :defer t
  :straight t
  :display
  ("\\*Geiser.*"
   (display-buffer-reuse-mode-window display-buffer-at-bottom)
   (window-height . 0.3))
  :general
  (shell-leader
    "S" #'geiser)
  (local-leader
    :keymaps 'scheme-mode-map
    "t"  #'geiser
    "m"  #'geiser-doc-look-up-manual
    "d" #'geiser-doc-symbol-at-point)
  (local-leader
    :keymaps 'scheme-mode-map
    :infix "e"
    "e" #'geiser-eval-last-sexp
    "b" #'geiser-eval-buffer
    "d" #'geiser-eval-definition
    "r" #'geiser-eval-region)
  :init
  (with-eval-after-load "evil"
    (evil-set-initial-state 'geiser-debug-mode-map 'emacs)))

(use-package geiser-guile
  :defer t
  :straight t)
#+end_src
** WAIT Ocaml
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
*** Ocaml Setup
Firstly, install ~opam~ and ~ocaml~.  Then run the following script:
#+begin_src sh
opam install tuareg ocamlformat odoc utop merlin user-setup;
opam user-setup install;
mv ~/.emacs.d/opam-user-setup.el ~/.config/emacs/elisp;
rm -rf ~/.emacs.d ~/.emacs;
#+end_src

This sets up the necessary packages (particularly Emacs Lisp) and some
configuration that ensures Emacs is consistent with the user
installation.  Notice the moving of =opam-user-setup.el= into
=~/.config/emacs/elisp=, which we'll use to setup the ocaml
experience.
*** Ocaml Configuration
Here I load the =opam-user-setup= package setup earlier, with some
neat tips from the default =~/.emacs= generated by ~opam user-setup
install~.
#+begin_src emacs-lisp
(use-package opam-user-setup
  :defer t
  :load-path "elisp/"
  :mode ("\\.ml" . tuareg-mode)
  :hook (tuareg-mode-hook . whitespace-mode)
  :display
  ("\\*utop\\*"
   (display-buffer-at-bottom)
   (window-height . 0.3))
  :general
  (code-leader
    :keymaps 'tuareg-mode-map
    "f" #'+ocaml/format-buffer)
  :config
  (defun +ocaml/format-buffer ()
    (interactive)
    (when (eq major-mode 'tuareg-mode)
      (let ((name (buffer-file-name (current-buffer)))
            (format-str "ocamlformat -i --enable-outside-detected-project %s"))
        (save-buffer)
        (set-process-sentinel (start-process-shell-command "ocamlformat" "*ocamlformat*"
                                                           (format format-str name))
                              (lambda (p event)
                                (when (string= event "finished\n")
                                  (revert-buffer nil t)
                                  (message "[ocamlformat] Finished.")))))))
  (add-to-list 'compilation-error-regexp-alist-alist
               `(ocaml
                 "[Ff]ile \\(\"\\(.*?\\)\", line \\(-?[0-9]+\\)\\(, characters \\(-?[0-9]+\\)-\\([0-9]+\\)\\)?\\)\\(:\n\\(\\(Warning .*?\\)\\|\\(Error\\)\\):\\)?"
                 2 3 (5 . 6) (9 . 11) 1 (8 compilation-message-face)))
  (add-to-list 'compilation-error-regexp-alist
               'ocaml)
  :general
  (local-leader
    :keymaps 'tuareg-mode-map
    "u" #'utop)
  (local-leader
    :keymaps 'tuareg-mode-map
    :infix "e"
    "r" #'utop-eval-region
    "e" #'utop-eval-phrase
    "b" #'utop-eval-buffer))

(use-package merlin-eldoc
  :straight t
  :after opam-user-setup
  :hook
  (tuareg-mode-hook . merlin-eldoc-setup)
  :init
  (setq merlin-eldoc-occurrences nil))
#+end_src
** Common Lisp
Common Lisp is a dialect of Lisp, the most /common/ one around.  Emacs
comes with builtin Lisp support, of course, and it's really good in
comparison to literally everything else.  However, I wish it had a
better REPL...
*** WAIT Sly
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
Enter /SLY/.  Sly is a fork of /SLIME/ and is *mandatory* for lisp
development on Emacs.

Here I just setup Sly to use ~sbcl~.

#+begin_src emacs-lisp
(use-package sly
  :defer t
  :straight t
  :init
  (setq inferior-lisp-program "sbcl"
        sly-lisp-loop-body-forms-indentation 0)
  :display
  ("\\*sly-db"
   (display-buffer-at-bottom)
   (window-height . 0.5))
  ("\\*sly-"
   (display-buffer-at-bottom)
   (window-height . 0.3))
  :config
  (evil-set-initial-state 'sly-db-mode 'normal)
  (with-eval-after-load "org"
    (setq-default org-babel-lisp-eval-fn #'sly-eval))
  (with-eval-after-load "company"
    (add-hook 'sly-mrepl-hook #'company-mode))
  :general
  (shell-leader
    "s" #'sly)
  (nmap
    :keymaps 'lisp-mode-map
    "gr" #'sly-eval-buffer
    "gd" #'sly-edit-definition
    "gR" #'sly-who-calls)
  (local-leader
    :keymaps 'lisp-mode-map
    "a" '(sly-apropos :which-key "Apropos")
    "d" '(sly-describe-symbol :which-key "Describe symbol")
    "D" '(sly-documentation-lookup :which-key "Lookup on lispworks")
    "l" '(sly-load-file :which-key "Load file")
    "c" '(sly-compile-defun :which-key "Compile defun")
    "C" '(sly-compile-file :which-key "Compile file")
    "S" '(sly-mrepl-sync :which-key "Sync REPL"))
  (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)
  (nmap
    :keymaps 'sly-mrepl-mode-map
    "M-j" #'sly-mrepl-next-input-or-button
    "M-k" #'sly-mrepl-previous-input-or-button)
  (local-leader
    :keymaps 'sly-mrepl-mode-map
    "s" '(sly-mrepl-shortcut :which-key "Shortcut"))
  (nmap
    :keymaps 'sly-db-mode-map
    "\C-i" 'sly-db-cycle
    "g?" 'describe-mode
    "S" 'sly-db-show-frame-source
    "e" 'sly-db-eval-in-frame
    "d" 'sly-db-pprint-eval-in-frame
    "D" 'sly-db-disassemble
    "i" 'sly-db-inspect-in-frame
    "gj" 'sly-db-down
    "gk" 'sly-db-up
    (kbd "C-j") 'sly-db-down
    (kbd "C-k") 'sly-db-up
    "]]" 'sly-db-details-down
    "[[" 'sly-db-details-up
    (kbd "M-j") 'sly-db-details-down
    (kbd "M-k") 'sly-db-details-up
    "gg" 'sly-db-beginning-of-backtrace
    "G" 'sly-db-end-of-backtrace
    "t" 'sly-db-toggle-details
    "gr" 'sly-db-restart-frame
    "I" 'sly-db-invoke-restart-by-name
    "R" 'sly-db-return-from-frame
    "c" 'sly-db-continue
    "s" 'sly-db-step
    "n" 'sly-db-next
    "o" 'sly-db-out
    "b" 'sly-db-break-on-return
    "a" 'sly-db-abort
    "q" 'sly-db-quit
    "A" 'sly-db-break-with-system-debugger
    "B" 'sly-db-break-with-default-debugger
    "P" 'sly-db-print-condition
    "C" 'sly-db-inspect-condition
    "g:" 'sly-interactive-eval
    "0" 'sly-db-invoke-restart-0
    "1" 'sly-db-invoke-restart-1
    "2" 'sly-db-invoke-restart-2
    "3" 'sly-db-invoke-restart-3
    "4" 'sly-db-invoke-restart-4
    "5" 'sly-db-invoke-restart-5
    "6" 'sly-db-invoke-restart-6
    "7" 'sly-db-invoke-restart-7
    "8" 'sly-db-invoke-restart-8
    "9" 'sly-db-invoke-restart-9)
  (nmap
    :keymaps 'sly-inspector-mode-map
    "q" #'sly-inspector-quit))
#+end_src
*** WAIT Sly-ASDF
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
ASDF is the package declaration system that _most_ Common Lisp
programmers use.  Here's a package which integrates some stuff into
SLY for ASDF.

#+begin_src emacs-lisp
(use-package sly-asdf
  :straight t
  :after sly)
#+end_src
*** Emacs lisp
Ligatures and bindings for (Emacs) Lisp.  Pretty self declarative.

#+begin_src emacs-lisp
(use-package elisp-mode
  :defer t
  :pretty
  (lisp-mode-hook
   ("lambda" . "λ")
   ("nil"    . "Ø")
   ("<="     . "≤")
   (">="     . "≥")
   ("defun"  . "ƒ")
   ("loop"   . "Σ")
   ("mapcar" . "→")
   ("reduce" . "↓")
   ("some"   . "∃")
   ("every"  . "∀"))
  (emacs-lisp-mode-hook
   ("lambda" . "λ")
   ("nil"    . "Ø")
   ("defun"  . "ƒ")
   ("mapcar" . "→"))
  :general
  (:states '(normal motion visual)
   :keymaps '(emacs-lisp-mode-map
              lisp-mode-map
              lisp-interaction-mode-map)
   ")" #'sp-next-sexp
   "(" #'sp-previous-sexp)
  (nmmap
    :keymaps '(emacs-lisp-mode-map lisp-interaction-mode-map)
    "gr" #'eval-buffer)
  (vmap
    :keymaps '(emacs-lisp-mode-map lisp-interaction-mode-map)
    "gr" #'eval-region)
  (local-leader
    :keymaps '(emacs-lisp-mode-map lisp-interaction-mode-map)
    "e" #'eval-last-sexp
    "f" #'eval-defun))
#+end_src
*** WIP Hydra like Lispy
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
A [[*Hydra][Hydra]] which uses the ~Lispy~ package (by
abo-abo) to create a set of motions that allow movement around a lisp
file easily.

2024-04-18: Still working on this, quite rough around the edges.

#+begin_src emacs-lisp
(use-package lispy
  :after (lisp-mode elisp-mode)
  :hydra
  (hydra-lispy
   nil "Move around quickly in Lisp"
   ("h" #'lispy-left)
   ("j" ("t" #'lispy-teleport)
    #'lispy-down)
   ("k" #'lispy-up)
   ("l" #'lispy-right)
   ("d" #'lispy-different)
   ("u" #'lispy-flow)
   ("o" #'lispy-oneline)
   ("m" #'lispy-multiline)
   ("N" #'lispy-narrow)
   ("W" #'lispy-widen)
   ("c" #'lispy-clone)
   ("fp" #'lispy-ace-paren)
   ("fs" #'lispy-ace-symbol :exit t)
   ("H" #'lispy-slurp)
   ("L" #'lispy-barf)
   ("M-h" #'lispy-move-left)
   ("M-j" #'lispy-move-down)
   ("M-k" #'lispy-move-up)
   ("M-l" #'lispy-move-right)
   ("C-g" nil))
  :general
  (nmmap
    :keymaps '(emacs-lisp-mode-map lisp-mode-map)
    "." #'hydra-lispy/body))
#+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
  :defer t
  :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
* Applications
Emacs is an operating system, now with a good text editor through
[[*Evil - Vim emulation][Evil]].  Let's configure some apps for it.
** EWW
Emacs Web Wowser is the inbuilt text based web browser for Emacs.  It
can render images and basic CSS styles but doesn't have a JavaScript
engine, which makes sense as it's primarily a text interface.

#+begin_src emacs-lisp
(use-package eww
  :defer t
  :general
  (app-leader
    "w" #'eww)
  (nmmap
    :keymaps 'eww-mode-map
    "w" #'evil-forward-word-begin
    "Y" #'eww-copy-page-url)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-eww-setup)))
#+end_src
** Magit
Magit is *the* git porcelain for Emacs, which perfectly encapsulates
the git CLI.  It's so good that some people are use Emacs just for it.
It's difficult to describe it well without using it and it integrates
so well with Emacs that there is very little need to use the git CLI
ever.

In this case I just need to setup the bindings for it.  Also, define
an auto insert for commit messages so that I don't need to write
everything myself.

#+begin_src emacs-lisp
(use-package transient
  :defer t
  :straight (:host github :repo "magit/transient" :tag "v0.7.5"))

(use-package magit
  :straight (:host github :repo "magit/magit" :tag "v4.1.0")
  :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-dispatch :which-key "Magit"))
  (code-leader
    "b" #'magit-blame)
  :init
  (setq vc-follow-symlinks t
        magit-blame-echo-style 'lines
        magit-copy-revision-abbreviated t)
  :config
  (with-eval-after-load "evil"
    (evil-set-initial-state 'magit-status-mode 'motion))
  (with-eval-after-load "evil-collection"
    (evil-collection-magit-setup)))
#+end_src
** Calendar
Calendar is a simple inbuilt application 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
  :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)
  (app-leader
    "d" #'calendar)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-calendar-setup))
  (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)))))))
#+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.  There are a few
ways of doing this, both in built and via package.
*** Notmuch
Notmuch is an application for categorising some local mail system.
It's really fast, has tons of customisable functionality and has good
integration with Emacs.  I use ~mbsync~ separately to pull my mail
from the remote server.

#+begin_src emacs-lisp
(use-package notmuch
  :straight t
  :defer t
  :commands (notmuch +mail/flag-thread)
  :general
  (app-leader "m" #'notmuch)
  (nmap
    :keymaps 'notmuch-search-mode-map
    "f" #'+mail/flag-thread)
  :init
  (defconst +mail/local-dir (no-littering-expand-var-file-name "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")
        message-auto-save-directory +mail/local-dir
        message-directory +mail/local-dir)
  (with-eval-after-load "evil-collection"
    (evil-collection-notmuch-setup))
  :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))))
#+end_src
*** Smtpmail
Setup the smtpmail package, which is used when sending mail.  Mostly
custom configuration for integration with other parts of Emacs' mail
system.

#+begin_src emacs-lisp
(use-package smtpmail
  :defer t
  :commands mail-send
  :init
  (setq-default
   smtpmail-smtp-server "mail.aryadevchavali.com"
   smtpmail-smtp-user "aryadev"
   smtpmail-smtp-service 587
   smtpmail-stream-type 'starttls
   send-mail-function #'smtpmail-send-it
   message-send-mail-function #'smtpmail-send-it))
#+end_src
*** Mail signature using fortune
Generate a mail signature using the ~fortune~ executable.  Pretty
cool!

#+begin_src emacs-lisp
(use-package fortune
  :init
  (setq fortune-dir "/usr/share/fortune"
        fortune-file "/usr/share/fortune/cookie")
  :config
  (defvar +mail/signature "---------------\nAryadev Chavali\n---------------\n%s")
  (defun +mail/make-signature ()
    (interactive)
    (format +mail/signature
            (with-temp-buffer
              (let ((fortune-buffer-name (current-buffer)))
                (fortune-in-buffer t)
                (if (bolp) (delete-char -1))
                (buffer-string)))))
  (add-hook 'message-setup-hook
            (lambda nil (setq message-signature (+mail/make-signature)))))
#+end_src
** Dired
Dired: Directory editor for Emacs.  An incredibly nifty piece of
software which deeply integrates with Emacs as a whole.  I can't think
of a better file management tool than this.

Here I setup dired with a few niceties
+ Hide details by default (no extra stuff from ~ls~)
+ Omit dot files by default (using ~dired-omit-mode~)
+ If I have two dired windows open, moving or copying files in one
  dired instance will automatically target the other dired window
  (~dired-dwim~)
+ If opening an application on a PDF file, suggest ~zathura~
+ Examine all the subdirectories within the same buffer
  (~+dired/insert-all-subdirectories~)

#+begin_src emacs-lisp
(use-package dired
  :defer t
  :commands (dired find-dired)
  :hook
  (dired-mode-hook . auto-revert-mode)
  (dired-mode-hook . dired-hide-details-mode)
  (dired-mode-hook . dired-omit-mode)
  :init
  (setq-default dired-listing-switches "-AFBlu --group-directories-first"
                dired-omit-files "^\\." ; dotfiles
                dired-omit-verbose nil
                dired-dwim-target t
                dired-kill-when-opening-new-dired-buffer t)
  (with-eval-after-load "evil-collection"
    (evil-collection-dired-setup))
  :general
  (nmmap
    :keymaps 'dired-mode-map
    "SPC"   nil
    "SPC ," nil
    "("     #'dired-hide-details-mode
    ")"     #'dired-omit-mode
    "T"     #'dired-create-empty-file
    "H"     #'dired-up-directory
    "L"     #'dired-find-file)
  (leader
    "D" #'dired-jump)
  (dir-leader
    "f" #'find-dired
    "d" #'dired
    "D" #'dired-other-window
    "i" #'image-dired
    "b" `(,(proc (interactive)
                 (dired "~/Text/Books/"))
          :which-key "Open Books"))
  (local-leader
    :keymaps 'dired-mode-map
    "i" #'dired-maybe-insert-subdir
    "I" #'+dired/insert-all-subdirectories
    "o" #'dired-omit-mode
    "k" #'dired-prev-subdir
    "j" #'dired-next-subdir
    "K" #'dired-kill-subdir
    "m" #'dired-mark-files-regexp
    "u" #'dired-undo)
  :config
  (add-multiple-to-list dired-guess-shell-alist-user
                        '("\\.pdf\\'"    "zathura")
                        '("\\.epub\\'"   "zathura")
                        '("\\.jpg\\'"    "feh")
                        '("\\.png\\'"    "feh")
                        '("\\.webm\\'"   "mpv")
                        '("\\.mp[34]\\'" "mpv")
                        '("\\.mkv\\'"    "mpv"))
  (defun +dired/insert-all-subdirectories ()
    "Insert all subdirectories currently viewable."
    (interactive)
    (dired-mark-directories nil)
    (mapc #'dired-insert-subdir (dired-get-marked-files))
    (dired-unmark-all-marks)))
#+end_src
*** image-dired
Image dired is a little cherry on top for Dired: the ability to look
through swathes of images in a centralised fashion while still being
able to do all the usual dired stuff as well is really cool.

#+begin_src emacs-lisp
(use-package dired
  :defer t
  :init
  (setq image-dired-external-viewer "nsxiv")
  :general
  (nmmap
    :keymaps 'image-dired-thumbnail-mode-map
    "h"   #'image-dired-backward-image
    "l"   #'image-dired-forward-image
    "j"   #'image-dired-next-line
    "k"   #'image-dired-previous-line
    "H"   #'image-dired-display-previous
    "L"   #'image-dired-display-next
    "RET" #'image-dired-display-this
    "m"   #'image-dired-mark-thumb-original-file
    "q"   #'quit-window))
#+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
  :straight t
  :after dired
  :general
  (dir-leader
    "g" #'fd-dired))
#+end_src
*** wdired
Similar to [[*(Rip)grep][wgrep]] =wdired= provides
the ability to use Emacs motions and editing on file names.  This
makes stuff like mass renaming and other file management tasks way
easier than even using the mark based system.

#+begin_src emacs-lisp
(use-package wdired
  :after dired
  :hook (wdired-mode-hook . undo-tree-mode)
  :general
  (nmmap
    :keymaps 'dired-mode-map
    "W" #'wdired-change-to-wdired-mode)
  (nmmap
    :keymaps 'wdired-mode-map
    "ZZ" #'wdired-finish-edit
    "ZQ" #'wdired-abort-changes)
  :config
  (eval-after-load "evil"
    ;; 2024-09-07: Why does evil-set-initial-state returning a list of modes for
    ;; normal state make eval-after-load evaluate as if it were an actual
    ;; expression?
    (progn (evil-set-initial-state 'wdired-mode 'normal)
           nil)))
#+end_src
*** dired-rsync
Rsync is a great way of transferring files around *nix machines, and I
use dired for all my file management concerns.  So I should be able to
rsync stuff around if I want.

#+begin_src emacs-lisp
(use-package dired-rsync
  :straight t
  :after dired
  :general
  (nmmap
    :keymaps 'dired-mode-map
    "M-r" #'dired-rsync))
#+end_src
** EShell
*** Why EShell?
EShell is an integrated shell environment for Emacs, written in Emacs
Lisp.  Henceforth I will argue that it is the best shell/command
interpreter to use in Emacs, so good that you should eschew any second
class terminal emulators (~term~, ~shell~, etc).

EShell is unlike the other alternatives in Emacs as it's a /shell/
first, not a terminal emulator (granted, with the ability to spoof
some aspects of a terminal emulator).

The killer benefits of EShell (which would appeal particularly to an
Emacs user) are a direct consequence of EShell being written in Emacs
Lisp:
- strong integration with Emacs utilities (such as ~dired~,
  ~find-file~, any read functions, etc)
- 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 can run on an operating system, one
    may run EShell
- mixing of Lisp and shell commands, with piping!

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
consequence of this powerful feature.

The main evaluator for any expression for EShell evaluates an
expression by testing the first symbol against different namespaces.
The namespaces are ordered such that if a symbol is not found in one,
the next namespace is tested.  These namespaces are:
- alias (defined in the [[file:.config/eshell/aliases][aliases
  file]])
- "built-in" command i.e. in the ~eshell/~ namespace of functions
- external command
- Lisp function

You can direct EShell to use these latter two namespaces: any
expression delimited by parentheses is considered a Lisp expression,
and any expression delimited by curly braces is considered an external
command.  You may even pipe the results of one into another, allowing
a deeper level of integration between Emacs Lisp and the shell!
*** EShell basics
Setup some niceties of any shell program and some evil-like movements
for easy shell usage, both in and out of insert mode.

NOTE: This mode doesn't allow you to set maps the normal way; you need
to set keybindings on eshell-mode-hook, otherwise it'll just overwrite
them.

#+begin_src emacs-lisp
(use-package eshell
  :defer t
  :display
  ("\\*eshell\\*"
   (display-buffer-same-window)
   (reusable-frames . t))
  :init
  (defun +eshell/banner-message ()
    (concat (shell-command-to-string "fortune") "\n"))

  (setq eshell-cmpl-ignore-case t
        eshell-cd-on-directory t
        eshell-cd-shows-directory nil
        eshell-highlight-prompt nil
        eshell-banner-message '(+eshell/banner-message))

  (defun +eshell/good-clear ()
    (interactive)
    (eshell/clear-scrollback)
    (eshell-send-input))

  (add-hook
   'eshell-mode-hook
   (defun +eshell/--setup-keymap nil
     (interactive)
     (general-def
       :states '(normal insert visual)
       :keymaps 'eshell-mode-map
       "M-j" #'eshell-next-prompt
       "M-k" #'eshell-previous-prompt
       "C-j" #'eshell-next-matching-input-from-input
       "C-k" #'eshell-previous-matching-input-from-input)

     (local-leader
       :keymaps 'eshell-mode-map
       "g" (proc (interactive)
                 (let ((buffer (current-buffer)))
                   (eshell/goto)
                   (with-current-buffer buffer
                     (eshell-send-input))))
       "l" (proc (interactive)
                 (eshell-return-to-prompt)
                 (insert "ls")
                 (eshell-send-input))
       "c" #'+eshell/good-clear
       "k" #'eshell-kill-process))))
#+end_src
*** EShell prompt
Here I use my external library
[[file:elisp/eshell-prompt.el][eshell-prompt]], which provides a
dynamic prompt for EShell.  Current features include:
- Git repository details (with difference from remote and number of
  modified files)
- Current date and time
- A coloured prompt character which changes colour based on the exit
  code of the previous command

NOTE: I don't defer this package because it doesn't use any EShell
internals without autoloading.

#+begin_src emacs-lisp
(use-package eshell-prompt
  :load-path "elisp/"
  :config
  (setq eshell-prompt-function #'+eshell-prompt/make-prompt))
#+end_src
*** EShell additions
Using my external library
[[file:elisp/eshell-additions.el][eshell-additions]], I get a few new
internal EShell commands and a command to open EShell at the current
working directory.

NOTE: I don't defer this package because it must be loaded *before*
EShell is.  This is because any ~eshell/*~ functions need to be loaded
before launching it.
#+begin_src emacs-lisp
(use-package eshell-additions
  :demand t
  :load-path "elisp/"
  :general
  (shell-leader
    "t" #'+eshell/open)
  (leader
    "T" #'+eshell/at-cwd
    "E" #'eshell-command))
#+end_src
*** EShell syntax highlighting
This package external package adds syntax highlighting to EShell
(disabling it for remote work).  Doesn't require a lot of config
thankfully.

#+begin_src emacs-lisp
(use-package eshell-syntax-highlighting
  :straight t
  :after eshell
  :hook (eshell-mode-hook . eshell-syntax-highlighting-mode))
#+end_src
** VTerm
There are a few times when EShell doesn't cut it, particularly in the
domain of TUI applications like ~cfdisk~.  Emacs comes by default with
some terminal emulators that can run a system wide shell like SH or
ZSH (~shell~ and ~term~ for example), but they're pretty terrible.
~vterm~ is an external package using a shared library for terminal
emulation, and is much better than the default Emacs stuff.

Since my ZSH configuration enables vim emulation, using ~evil~ on top
of it would lead to some weird states.  Instead, use the Emacs state
so vim emulation is completely controlled by the shell.
#+begin_src emacs-lisp
(use-package vterm
  :straight t
  :general
  (shell-leader
    "v" #'vterm)
  :init
  (with-eval-after-load "evil"
    (evil-set-initial-state 'vterm-mode 'emacs)))
#+end_src
** (Rip)grep
Grep is a great piece of software, a necessary tool in any Linux
user's inventory.  Out of the box Emacs has a family of functions
utilising grep which present results in a
[[*Compilation][compilation]] buffer: ~grep~ searches files, ~rgrep~
searches files in a directory using the ~find~ program and ~zgrep~
searches archives.

Ripgrep is a program that attempts to perform better than grep, and it
does.  This is because of many optimisations, such as reading
=.gitignore= to exclude certain files from being searched.  The
ripgrep package provides utilities to search projects and files.  Of
course, this requires installing the rg binary which is available in
most distribution nowadays.
*** Grep
#+begin_src emacs-lisp
(use-package grep
  :defer t
  :display
  ("^\\*grep.*"
   (display-buffer-reuse-window display-buffer-at-bottom)
   (window-height . 0.35)
   (reusable-frames . t))
  :general
  (search-leader
    "g" #'grep-this-file
    "c" #'grep-config-file
    "d" #'rgrep)
  (nmmap
    :keymaps 'grep-mode-map
    "0" #'evil-beginning-of-line
    "q" #'quit-window
    "i" #'wgrep-change-to-wgrep-mode
    "c" #'recompile)
  (nmmap
    :keymaps 'wgrep-mode-map
    "q"  #'evil-record-macro
    "ZZ" #'wgrep-finish-edit
    "ZQ" #'wgrep-abort-changes)
  :config
  ;; Without this wgrep doesn't work properly
  (evil-set-initial-state 'grep-mode 'normal)

  (defun grep-file (query filename)
    (grep (format "grep --color=auto -nIiHZEe \"%s\" -- %s"
                  query filename)))

  (defun grep-this-file ()
    (interactive)
    (let ((query (read-string "Search for: ")))
      (if (buffer-file-name (current-buffer))
          (grep-file query (buffer-file-name (current-buffer)))
        (let ((temp-file (make-temp-file "temp-grep")))
          (write-region (point-min) (point-max) temp-file)
          (grep-file query temp-file)))))

  (defun grep-config-file ()
    (interactive)
    (let ((query (read-string "Search for: " "^[*]+ .*")))
      (grep-file query (concat user-emacs-directory "config.org")))))
#+end_src
*** rg
#+begin_src emacs-lisp
(use-package rg
  :straight t
  :defer t
  :commands (+rg/project-todo)
  :display
  ("^\\*\\*ripgrep\\*\\*"
   (display-buffer-reuse-window display-buffer-at-bottom)
   (window-height . 0.35))
  :general
  (search-leader
    "r" #'rg)
  (:keymaps 'project-prefix-map
   "t" `(+rg/project-todo :which-key "Project TODOs"))
  (nmmap
    :keymaps 'rg-mode-map
    "c"  #'rg-recompile
    "C"  #'rg-rerun-toggle-case
    "]]" #'rg-next-file
    "[[" #'rg-prev-file
    "q"  #'quit-window
    "i"  #'wgrep-change-to-wgrep-mode)
  :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*")
  :config
  (defun +rg/project-todo ()
    (interactive)
    (rg "TODO" "*"
        (if (project-current)
            (project-root (project-current))
          default-directory)))
  (evil-set-initial-state 'rg-mode 'normal))
#+end_src
** WAIT Elfeed
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
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
  :straight t
  :general
  (app-leader "r" #'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/"
           News Technology)
          ("The Onion"
           "https://www.theonion.com/rss"
           Social)
          ("Protesilaos Stavrou"
           "https://www.youtube.com/@protesilaos"
           YouTube Technology)
          ("Tsoding Daily"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCrqM0Ym_NbK1fqeQG2VIohg"
           YouTube Technology)
          ("Tsoding"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCrqM0Ym_NbK1fqeQG2VIohg"
           YouTube Technology)
          ("Nexpo"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCpFFItkfZz1qz5PpHpqzYBw"
           YouTube Stories)
          ("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"
           "https://news.ycombinator.com/rss"
           Social News Technology)
          ("Hacker Factor"
           "https://www.hackerfactor.com/blog/index.php?/feeds/index.rss2"
           Social)))
  :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))

  (advice-add  'elfeed-search-show-entry :after #'+elfeed/dispatch-entry)

  (defun +elfeed/dispatch-entry (entry)
    "Process each type of entry differently.
  e.g., you may want to open HN entries in eww."
    (let ((url (elfeed-entry-link entry)))
      (pcase url
        ((pred (string-match-p "https\\:\\/\\/www.youtube.com\\/watch"))
         (mpv-play-url url))
        (_ (eww url))))))
#+end_src
** IBuffer
IBuffer is the dired of buffers.  Nothing much else to be said.

#+begin_src emacs-lisp
(use-package ibuffer
  :defer t
  :general
  (buffer-leader
    "i" #'ibuffer)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-ibuffer-setup)))
#+end_src
** Proced
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)

Core Proced config, just a few bindings and evil collection setup.

#+begin_src emacs-lisp
(use-package proced
  :defer t
  :general
  (app-leader
    "p" #'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 5)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-proced-setup)))
#+end_src
** Calculator
~calc-mode~ is a calculator system within Emacs that provides a
diverse array of mathematical operations.  It uses reverse polish
notation, but there is a standard infix algebraic notation mode so
don't be too shocked.  It can do a surprising amount of stuff, such
as:
+ finding derivatives/integrals of generic equations
+ matrix operations
+ finding solutions for equations, such as for finite degree multi
  variable polynomials

Perhaps most powerful is ~embedded-mode~.  This allows one to perform
computation within a non ~calc-mode~ buffer.  Surround any equation
with dollar signs and call ~(calc-embedded)~ with your cursor on it to
compute it.  It'll replace the equation with the result it computed.
This is obviously incredibly useful; I don't even need to leave the
current buffer to perform some quick mathematics in it.

#+begin_src emacs-lisp
(use-package calc
  :defer t
  :display
  ("*Calculator*"
   (display-buffer-at-bottom)
   (window-height . 0.2))
  :general
  (app-leader
    "c" #'calc-dispatch)
  :init
  (setq calc-algebraic-mode t)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-calc-setup)))
#+end_src
** Zone
Emacs' out of the box screensaver software.

#+begin_src emacs-lisp
(use-package zone
  :defer t
  :commands (zone)
  :general
  (leader
    "z" #'zone)
  :init

  (setq zone-programs
        [zone-pgm-drip
         zone-pgm-drip-fretfully]))
#+end_src
** (Wo)man
Man pages are the user manuals for most software on Linux.  Of course,
Emacs comes out of the box with a renderer for man pages and some
searching capabilities.

2023-08-17: `Man-notify-method' is the reason the `:display' record
doesn't work here.  I think it's to do with how Man pages are rendered
or something, but very annoying as it's a break from standards!

2024-10-08: Man pages are rendered via a separate process, which is
why this is necessary.

#+begin_src emacs-lisp
(use-package man
  :defer t
  :init
  (setq Man-notify-method 'thrifty)
  :display
  ("\\*Man.*"
   (display-buffer-reuse-mode-window display-buffer-same-window)
   (mode . Man-mode))
  :general
  (file-leader
    "m" #'man) ;; kinda like "find man page"
  (nmmap
    :keymaps 'Man-mode-map
    "RET" #'man-follow))
#+end_src
** Info
Info is GNU's attempt at better man pages.  Most Emacs packages have
info pages so I'd like nice navigation options.

#+begin_src emacs-lisp
(use-package info
  :defer t
  :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
    "C-j" #'Info-forward-node
    "C-k" #'Info-backward-node
    "RET" #'Info-follow-nearest-node
    "m"   #'Info-menu
    "C-o" #'Info-history-back
    "s"   #'Info-search
    "S"   #'Info-search-case-sensitively
    "i"   #'Info-index
    "a"   #'info-apropos
    "gj"  #'Info-next
    "gk"  #'Info-prev
    "g?"  #'Info-summary
    "q"   #'quit-window)
  :init
  (with-eval-after-load "evil"
    (evil-set-initial-state 'Info-mode 'normal)))
#+end_src
** WAIT gif-screencast
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
Little application that uses =gifsicle= to make essentially videos of
Emacs.  Useful for demonstrating features.

#+begin_src emacs-lisp
(use-package gif-screencast
  :straight t
  :general
  (app-leader
    "x" #'gif-screencast-start-or-stop)
  :init
  (setq gif-screencast-output-directory (expand-file-name "~/Media/emacs/")))
#+end_src
** Image-mode
Image mode, for viewing images.  Supports tons of formats, easy to use
and integrates slickly into image-dired.  Of course,

#+begin_src emacs-lisp
(use-package image-mode
  :defer t
  :general
  (nmmap
    :keymaps 'image-mode-map
    "+" #'image-increase-size
    "-" #'image-decrease-size
    "a" #'image-toggle-animation
    "p+" #'image-increase-speed
    "p-" #'image-increase-speed
    "h" #'image-backward-hscroll
    "j" #'image-next-line
    "k" #'image-previous-line
    "l" #'image-forward-hscroll))
#+end_src
** empv
Emacs MPV bindings, with very cool controls for queuing files for
playing.
#+begin_src emacs-lisp
(use-package empv
  :straight t
  :defer t
  :init
  (setq empv-audio-dir (expand-file-name "~/Media/audio")
        empv-video-dir (expand-file-name "~/Media/videos")
        empv-audio-file-extensions (list "mp3" "ogg" "wav" "m4a"
                                         "flac" "aac" "opus")
        empv-video-file-extensions (list "mkv" "mp4" "avi" "mov"
                                         "webm"))
  :hydra
  (empv-hydra
   nil "Hydra for EMPV"
   ("(" #'empv-chapter-prev
    "chapter-prev" :column "playback")
   (")" #'empv-chapter-next
    "chapter-next" :column "playback")
   ("0" #'empv-volume-up
    "volume-up" :column "playback")
   ("9" #'empv-volume-down
    "volume-down" :column "playback")
   ("[" #'empv-playback-speed-down
    "playback-speed-down" :column "playback")
   ("]" #'empv-playback-speed-up
    "playback-speed-up" :column "playback")
   ("_" #'empv-toggle-video
    "toggle-video" :column "playback")
   ("q" #'empv-exit
    "exit" :column "playback")
   ("s" #'empv-seek
    "seek" :column "playback")
   ("t" #'empv-toggle
    "toggle" :column "playback")
   ("x" #'empv-chapter-select
    "chapter-select" :column "playback")
   ("N" #'empv-playlist-prev
    "playlist-prev" :column "playlist")
   ("C" #'empv-playlist-clear
    "playlist-clear" :column "playlist")
   ("n" #'empv-playlist-next
    "playlist-next" :column "playlist")
   ("p" #'empv-playlist-select
    "playlist-select" :column "playlist")
   ("S" #'empv-playlist-shuffle
    "playlist-shuffle" :column "playlist")
   ("a" #'empv-play-audio
    "play-audio" :column "play")
   ("R" #'empv-play-random-channel
    "play-random-channel" :column "play")
   ("d" #'empv-play-directory
    "play-directory" :column "play")
   ("f" #'empv-play-file
    "play-file" :column "play")
   ("o" #'empv-play-or-enqueue
    "play-or-enqueue" :column "play")
   ("r" #'empv-play-radio
    "play-radio" :column "play")
   ("v" #'empv-play-video
    "play-video" :column "play")
   ("i" #'empv-display-current
    "display-current" :column "misc")
   ("l" #'empv-log-current-radio-song-name
    "log-current-radio-song-name" :column "misc")
   ("c" #'empv-copy-path
    "copy-path" :column "misc")
   ("Y" #'empv-youtube-last-results
    "youtube-last-results" :column "misc")
   ("y" #'empv-youtube
    "youtube" :column "misc"))
  :general
  (app-leader
    "e" #'empv-hydra/body))
#+end_src
** Grand Unified Debugger (GUD)
GUD is a system for debugging, hooking into processes and
providing an interface to the user all in Emacs.  Here I define a
hydra which provides a ton of the useful =gud= keybindings that exist
in an Emacs-only map.
#+begin_src emacs-lisp
(use-package gud
  :general
  :after hydra
  :hydra
  (gud-hydra
   (:hint nil) "Hydra for GUD"
   ("<"   #'gud-up "Up"
    :column "Control Flow")
   (">"   #'gud-down "Down"
    :column "Control Flow")
   ("b"   #'gud-break "Break"
    :column "Breakpoints")
   ("d"   #'gud-remove "Remove"
    :column "Breakpoints")
   ("f"   #'gud-finish "Finish"
    :column "Control Flow")
   ("J"   #'gud-jump "Jump"
    :column "Control Flow")
   ("L"   #'gud-refresh "Refresh"
    :column "Misc")
   ("n"   #'gud-next "Next"
    :column "Control Flow")
   ("p"   #'gud-print "Print"
    :column "Misc")
   ("c"   #'gud-cont "Cont"
    :column "Control Flow")
   ("s"   #'gud-step "Step"
    :column "Control Flow")
   ("t"   #'gud-tbreak "Tbreak"
    :column "Control Flow")
   ("u"   #'gud-until "Until"
    :column "Control Flow")
   ("v"   #'gud-go "Go"
    :column "Control Flow")
   ("w"   #'gud-watch "Watch"
    :column "Breakpoints")
   ("TAB" #'gud-stepi "Stepi"
    :column "Control Flow"))
  :general
  (code-leader "d" #'gud-hydra/body
    "D" #'gud-gdb))
#+end_src
** WAIT esup
:PROPERTIES:
:header-args:emacs-lisp: :tangle no :results none
:END:
I used to be able to just use
[[file:elisp/profiler-dotemacs.el][profile-dotemacs.el]], when my
Emacs config was smaller, but now it tells me very little information
about where my setup is inefficient due to the literate config.  Just
found this ~esup~ thing and it works perfectly, exactly how I would
prefer getting this kind of information.  It runs an external Emacs
instance and collects information from it, so it doesn't require
restarting Emacs to profile, and I can compile my configuration in my
current instance to test it immediately.

2023-10-16: Unless I'm doing some optimisations or tests, I don't
really need this in my config at all times.  Enable when needed.

#+begin_src emacs-lisp
(use-package esup
  :straight t
  :defer t
  :general
  (leader
    "qe" #'esup))
#+end_src
* Miscellaneous
** Evil additions
Additional packages that add the functionality of plugins in Vim I
really liked, as well as some new stuff.
*** Evil surround
A port for vim-surround, providing the ability to mutate delimiters
around some text.

#+begin_src emacs-lisp
(use-package evil-surround
  :after evil
  :straight t
  :config
  (global-evil-surround-mode))
#+end_src
*** Evil commentary
A port of vim-commentary, providing generalised commenting of objects.

#+begin_src emacs-lisp
(use-package evil-commentary
  :after evil
  :straight t
  :config
  (evil-commentary-mode))
#+end_src
*** Evil multi cursor
Setup for multi cursors in Evil mode, which is a bit of very nice
functionality.  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
  :straight t
  :init
  (defvar evil-mc-key-map (make-sparse-keymap))
  :general
  (nmap
    :infix "gz"
    "m" 'evil-mc-make-all-cursors
    "u" 'evil-mc-undo-last-added-cursor
    "q" 'evil-mc-undo-all-cursors
    "s" 'evil-mc-pause-cursors
    "r" 'evil-mc-resume-cursors
    "f" 'evil-mc-make-and-goto-first-cursor
    "l" 'evil-mc-make-and-goto-last-cursor
    "h" 'evil-mc-make-cursor-here
    "j" 'evil-mc-make-cursor-move-next-line
    "k" 'evil-mc-make-cursor-move-prev-line
    "N" 'evil-mc-skip-and-goto-next-cursor
    "P" 'evil-mc-skip-and-goto-prev-cursor
    "n" 'evil-mc-skip-and-goto-next-match
    "p" 'evil-mc-skip-and-goto-prev-match
    "I" 'evil-mc-make-cursor-in-visual-selection-beg
    "A" 'evil-mc-make-cursor-in-visual-selection-end
    "d" #'evil-mc-make-and-goto-next-match)
  :config
  (global-evil-mc-mode))
#+end_src
*** Evil multi edit
Evil-ME provides a simpler parallel editing experience within the same
buffer.  I use it in-tandem with Evil-MC, where I use Evil-ME for
textual changes and Evil-MC for more complex motions.

#+begin_src emacs-lisp
(use-package evil-multiedit
  :straight t
  :defer t
  :init
  (setq evil-multiedit-scope 'visible)
  :general
  (:states '(normal visual)
   :keymaps 'override
   "M-e" #'evil-multiedit-match-and-next
   "M-E" #'evil-multiedit-match-and-prev))
#+end_src
*** Evil collection
Provides a community based set of keybindings for most modes in
Emacs.  I don't necessarily like all my modes having these bindings
though, as I may disagree with some.  So I use it in a mode to mode basis.

#+begin_src emacs-lisp
(use-package evil-collection
  :straight t
  :after evil)
#+end_src
*** Evil number
Increment/decrement a number at point like Vim does, but use bindings
that don't conflict with Emacs default.

#+begin_src emacs-lisp
(use-package evil-numbers
  :straight t
  :defer t
  :general
  (nmmap
    "+" #'evil-numbers/inc-at-pt
    "-" #'evil-numbers/dec-at-pt))
#+end_src
*** Evil goggles
Make it easier to notice edits and changes using Vim motions!
#+begin_src emacs-lisp
(use-package evil-goggles
  :straight t
  :after evil
  :init
  (setq evil-goggles-duration 0.1
        evil-goggles-blocking-duration 0.1
        evil-goggles-async-duration 0.9
        evil-goggles-default-face 'pulsar-cyan)
  :config
  (evil-goggles-mode)
  (evil-goggles-use-diff-faces))
#+end_src
** Save place
Saves current place in a buffer permanently, so on revisiting the file
(even in a different Emacs instance) you go back to the place you were
at last.

#+begin_src emacs-lisp
(use-package saveplace
  :demand t
  :config
  (save-place-mode))
#+end_src
** Tabs
Tabs in vscode are just like buffers in Emacs but way slower and
harder to use.  Tabs in Emacs are essentially window layouts, similar
to instances in Tmux.  With this setup I can use tabs quite
effectively.

#+begin_src emacs-lisp
(use-package tab-bar
  :defer t
  :hook (after-init-hook . tab-bar-mode)
  :init
  (setq tab-bar-close-button-show nil
        tab-bar-format '(tab-bar-format-history
                         tab-bar-format-tabs tab-bar-separator)
        tab-bar-show 1
        tab-bar-auto-width t
        tab-bar-auto-width-max '((100) 20)
        tab-bar-auto-width-min '((20) 2))
  :general
  (tab-leader
    "R" #'tab-rename
    "c" #'tab-close
    "d" #'tab-close
    "f" #'tab-detach
    "h" #'tab-move-to
    "j" #'tab-next
    "k" #'tab-previous
    "l" #'tab-move
    "n" #'tab-new
    "r" #'tab-switch
    "w" #'tab-window-detach))
#+end_src
** Registers
Emacs comes by default with the notion of "registers".  Registers are
essentially an alist of symbols mapped to some Lisp object, which
can be easily accessed and manipulated.  Some common use cases of
registers are:
+ Marking locations in a file to quickly go to (using Emacs' in-built
  notion of marks)
+ Copying and pasting text without the clipboard (essentially even
  more clipboards)
+ Creating number counters (usually for macros)

Of course, Vim has its own notion of registers which are frankly much
less capable than Emacs.  Evil emulates this limited notion of
registers, but I prefer Emacs' hence the configuration here.

#+begin_src emacs-lisp
(use-package register
  :config
  (defmacro +register/jump-to (reg)
    `(proc (interactive)
           (jump-to-register ,reg)))
  :general
  (nmmap
    "m"   #'point-to-register
    "'"   #'jump-to-register
    "g1"  (+register/jump-to ?1)
    "g2"  (+register/jump-to ?2)
    "g3"  (+register/jump-to ?3)
    "g4"  (+register/jump-to ?4)
    "g5"  (+register/jump-to ?5)
    "g6"  (+register/jump-to ?6)
    "g7"  (+register/jump-to ?7)
    "g8"  (+register/jump-to ?8)
    "g9"  (+register/jump-to ?9)))
#+end_src
** Recentf
Recentf provides a method of keeping track of recently opened files.

#+begin_src emacs-lisp
(use-package recentf
  :defer t
  :hook (after-init-hook . recentf-mode)
  :general
  (file-leader
    "r" #'recentf))
#+end_src
** Memory-report
New feature of Emacs-29, gives a rough report of memory usage with
some details.  Useful to know on a long Emacs instance what could be
eating up memory.

#+begin_src emacs-lisp
(use-package memory-report
  :defer t
  :general
  (leader
    "qm" #'memory-report))
#+end_src
** Helpful
Helpful provides a modern interface for some common help commands.  I
replace ~describe-function~, ~describe-variable~ and ~describe-key~ by
their helpful counterparts.

#+begin_src emacs-lisp
(use-package helpful
  :straight t
  :defer t
  :commands (helpful-callable helpful-variable)
  :general
  ([remap describe-function] #'helpful-callable
   [remap describe-variable] #'helpful-variable
   [remap describe-key]      #'helpful-key)
  :display
  ("\\*helpful.*"
   (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
** Avy and Ace
Avy is a package that provides "jump" functions.  Given some input,
the current buffer is scanned and any matching candidates are given a
tag which the user can input to perform some action (usually moving
the cursor to that point).
*** Avy core
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
  :straight t
  :defer t
  :general
  (nmmap
    :keymaps 'override
    "C-s" #'avy-goto-char-timer
    "M-s" #'isearch-forward
    "gp"  #'avy-copy-region
    "gP"  #'avy-move-region
    "gl"  #'avy-goto-line
    "gw"  #'avy-goto-word-1))
#+end_src
*** Ace window
Though evil provides a great many features in terms of window
management, ace window can provide some nicer chords for higher
management of windows (closing, switching, etc).

#+begin_src emacs-lisp
(use-package ace-window
  :straight t
  :defer t
  :custom
  (aw-keys '(?a ?s ?d ?f ?g ?h ?j ?k ?l))
  :general
  (nmmap
    [remap evil-window-next] #'ace-window))
#+end_src
*** Ace link
Avy-style link following!

#+begin_src emacs-lisp
(use-package ace-link
  :straight t
  :defer t
  :general
  (nmmap
    :keymaps 'override
    "gL" #'ace-link))
#+end_src
** Drag Stuff
Drag stuff around, like my favourite russian programmer (Tsoding).
Useful mechanism which works better than any vim motion.

#+begin_src emacs-lisp
(use-package drag-stuff
  :straight t
  :defer t
  :general
  (nmmap
    "C-M-h" #'drag-stuff-left
    "C-M-j" #'drag-stuff-down
    "C-M-k" #'drag-stuff-up
    "C-M-l" #'drag-stuff-right))
#+end_src
** Separedit
Edit anything anywhere all at once!

#+begin_src emacs-lisp
(use-package separedit
  :defer t
  :straight t
  :general
  (leader "e" #'separedit)
  :init
  (setq separedit-default-mode 'org-mode
        separedit-remove-trailing-spaces-in-comment t))
#+end_src
** Undo tree
Undo tree sits on top of Emacs' undo capabilities.  It provides a nice
visual for the history of a buffer and is a great way to produce
branches of edits.  This history may be saved to and loaded from the
disk, which makes Emacs a quasi version control system in and of
itself.  The only feature left is describing changes...

#+begin_src emacs-lisp
(use-package undo-tree
  :demand t
  :straight t
  :general
  (leader
    "u" #'undo-tree-visualize)
  :init
  (setq undo-tree-auto-save-history t
        undo-tree-history-directory-alist backup-directory-alist)
  :config
  (global-undo-tree-mode))
#+end_src
** Searching common directories
Using [[file:elisp/search.el][search.el]] I can search a set of
directories particularly efficiently.

#+begin_src emacs-lisp
(use-package search
  :defer t
  :load-path "elisp/"
  :general
  (search-leader
    "a" #'+search/search-all)
  (file-leader
    "p" #'+search/find-file))
#+end_src
** 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
  :defer t
  :hook
  (prog-mode-hook . abbrev-mode)
  (text-mode-hook . abbrev-mode)
  :init
  (defmacro +abbrev/define-abbrevs (abbrev-table &rest abbrevs)
    `(progn
       ,@(mapcar #'(lambda (abbrev)
                `(define-abbrev
                   ,abbrev-table
                   ,(car abbrev)
                   ""
                   (proc (insert ,(cadr abbrev)))))
            abbrevs)))
  (setq save-abbrevs nil)
  :config
  (+abbrev/define-abbrevs
   global-abbrev-table
   ("sdate"
    (format-time-string "%Y-%m-%d" (current-time)))
   ("stime"
    (format-time-string "%H:%M:%S" (current-time)))
   ("sday"
    (format-time-string "%A" (current-time)))
   ("smon"
    (format-time-string "%B" (current-time)))))
#+end_src
** Yasnippet
Look at the snippets [[file:../.config/yasnippet/snippets/][folder]]
for all snippets I've got.

#+begin_src emacs-lisp
(use-package yasnippet
  :straight t
  :defer t
  :hook
  (prog-mode-hook . yas-minor-mode)
  (text-mode-hook . yas-minor-mode)
  :general
  (insert-leader
    "i" #'yas-insert-snippet)
  :config
  (yas-load-directory (no-littering-expand-etc-file-name
                       "yasnippet/snippets")))
#+end_src
** Amx
Amx is a fork of Smex that works to enhance the
~execute-extended-command~ interface.  It provides a lot of niceties
such as presenting the key bind when looking for a command.

#+begin_src emacs-lisp
(use-package amx
  :straight t
  :demand t
  :init
  (setq amx-backend 'auto)
  :config
  (amx-mode))
#+end_src