path: root/Emacs/.config/emacs/app.org

#+title: Applications for Emacs
#+author: Aryadev Chavali
#+description: Applications for my Emacs OS™
#+date: 2023-09-29
#+property: header-args:emacs-lisp :tangle app.el :comments link :results none
#+options: toc:nil
#+startup: noindent

Applications are greater than packages; they provide a set of
functionality to create an interface in Emacs.  Emacs comes with
applications and others may be installed.

* WIP Dashboard
:PROPERTIES:
:header-args:emacs-lisp: :tangle no
:END:
Dashboard creates a custom dashboard for Emacs that replaces the
initial startup screen in default Emacs.  It has a lot of customising
options.

Unfortunately not that useful, many things are easier to invoke
directly such as recent files or project changing.
#+begin_src emacs-lisp
(use-package dashboard
  :straight t
  :demand t
  :general
  (app-leader
    "b" #'dashboard-refresh-buffer)
  (:states '(normal motion emacs)
   :keymaps 'dashboard-mode-map
   "q" (proc (interactive) (kill-this-buffer)))
  (nmmap
    :keymaps 'dashboard-mode-map
    "r" #'dashboard-jump-to-recent-files
    "p" #'dashboard-jump-to-projects
    "}" #'dashboard-next-section
    "{" #'dashboard-previous-section)
  :init
  (setq initial-buffer-choice nil
        dashboard-banner-logo-title "Oreomacs"
        dashboard-center-content t
        dashboard-set-init-info t
        dashboard-startup-banner (no-littering-expand-etc-file-name "dashboard/logo.png")
        dashboard-set-footer t
        dashboard-set-navigator t
        dashboard-items '((projects . 5)
                          (recents . 5))
        dashboard-footer-messages (list
                                   "Collecting parentheses..."
                                   "Linking 'coffee_machine.o'..."
                                   "Uploading ip to hacker named 4chan..."
                                   "Dividing by zero..."
                                   "Solving 3-sat..."
                                   "Obtaining your health record..."
                                   (format "Recompiling Emacs for the %dth time..." (random 1000))
                                   "Escaping the cycle of samsara..."))
  :config
  (dashboard-setup-startup-hook))
#+end_src
* 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)
  :straight nil
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-eww-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
  :straight nil
  :defer t
  :commands (+calendar/copy-date +calendar/toggle-calendar)
  :display
  ("\\*Calendar\\*"
   (display-buffer-at-bottom)
   (inhibit-duplicate-buffer . t)
   (window-height . 0.17))
  :general
  (nmmap
    :keymaps 'calendar-mode-map
    "Y" #'+calendar/copy-date)
  (app-leader
    "d" #'+calendar/toggle-calendar)
  :config
  (defun +calendar/copy-date ()
    "Copy date under cursor into kill ring."
    (interactive)
    (if (use-region-p)
        (call-interactively #'kill-ring-save)
      (let ((date (calendar-cursor-to-date)))
        (when date
          (setq date (encode-time 0 0 0 (nth 1 date) (nth 0 date) (nth 2 date)))
          (kill-new (format-time-string "%Y-%m-%d" date))))))
  (+oreo/create-toggle-function
   +calendar/toggle-calendar
   "*Calendar*"
   calendar
   nil))
#+end_src
* Mail
Mail is a funny thing; most people use it just for business or
advertising and it's come out of use in terms of personal
communication in the west for the most part (largely due to "social"
media applications).  However, this isn't true for the open source and
free software movement who heavily use mail for communication.

Integrating mail into Emacs helps as I can send source code and
integrate it into my workflow just a bit better.
** Notmuch
#+begin_src emacs-lisp
(use-package notmuch
  :defer t
  :commands (notmuch +mail/flag-thread)
  :general
  (app-leader "m" #'notmuch)
  (nmap
    :keymaps 'notmuch-search-mode-map
    "f" #'+mail/flag-thread)
  :init
  (defconst +mail/signature "---------------\nAryadev Chavali")
  (defconst +mail/local-dir (concat user-emacs-directory ".mail/"))
  (setq notmuch-show-logo nil
        notmuch-search-oldest-first nil
        notmuch-hello-sections '(notmuch-hello-insert-saved-searches
                                 notmuch-hello-insert-alltags
                                 notmuch-hello-insert-recent-searches)
        notmuch-archive-tags '("-inbox" "-unread" "+archive")
        mail-signature +mail/signature
        mail-default-directory +mail/local-dir
        mail-source-directory +mail/local-dir
        message-signature +mail/signature
        message-auto-save-directory +mail/local-dir
        message-directory +mail/local-dir)

  (defun +mail/sync-mail ()
    "Sync mail via mbsync."
    (interactive)
    (start-process-shell-command "" nil "mbsync -a"))
  (defun +mail/trash-junk ()
    "Delete any mail in junk"
    (interactive)
    (start-process-shell-command "" nil "notmuch search --output=files --format=text0 tag:deleted tag:spam tag:trash tag:junk | xargs -r0 rm"))
  :config
  (defun +mail/flag-thread (&optional unflag beg end)
    (interactive (cons current-prefix-arg (notmuch-interactive-region)))
    (notmuch-search-tag
     (notmuch-tag-change-list '("-inbox" "+flagged") unflag) beg end)
    (when (eq beg end)
      (notmuch-search-next-thread)))
  (advice-add #'notmuch-poll-and-refresh-this-buffer :before
#'+mail/sync-mail)
  (advice-add #'notmuch-poll-and-refresh-this-buffer :after
#'+mail/trash-junk)
  (with-eval-after-load "evil-collection"
    (evil-collection-notmuch-setup)))
#+end_src
** Smtpmail
#+begin_src emacs-lisp
(use-package smtpmail
  :after notmuch
  :commands mail-send
  :custom
  (smtpmail-smtp-server "mail.aryadevchavali.com")
  (smtpmail-smtp-user "aryadev")
  (smtpmail-smtp-service 587)
  (smtpmail-stream-type 'starttls)
  :init
  (setq send-mail-function #'smtpmail-send-it
        message-send-mail-function #'smtpmail-send-it))
#+end_src
* Dired
Setup for dired.  Make dired-hide-details-mode the default mode when
using dired-mode, as it removes the clutter.  Setup evil collection
for dired (even though dired doesn't really conflict with evil, there
are some corners I'd like to adjust).
#+begin_src emacs-lisp
(use-package dired
  :straight nil
  :commands (dired find-dired)
  :hook
  (dired-mode-hook              . auto-revert-mode)
  (dired-mode-hook              . dired-hide-details-mode)
  :init
  (setq-default dired-listing-switches "-AFBlu --group-directories-first"
                dired-omit-files "^\\."
                dired-dwim-target t)
  (with-eval-after-load "evil-collection"
    (evil-collection-dired-setup))
  :general
  (nmmap
    :keymaps 'dired-mode-map
    "T" #'dired-create-empty-file
    "H" #'dired-up-directory
    "L" #'dired-find-file)
  (dir-leader
    "f" #'find-dired
    "d" #'dired
    "D" #'dired-other-frame
    "i" #'image-dired
    "p" `((proc (interactive)
                (dired "~/Text/PDFs/"))
          :which-key "Open PDFs"))
  :config
  (defun +dired/insert-all-subdirectories ()
    "Insert all subdirectories currently viewable."
    (interactive)
    (dired-mark-directories nil)
    (dolist #'dired-insert-subdir (dired-get-marked-files))
    (dired-unmark-all-marks))

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

  (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)

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

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

#+begin_src emacs-lisp
(use-package fd-dired
  :after dired
  :straight t
  :general
  (dir-leader
    "g" #'fd-dired))
#+end_src
* Xwidget
Xwidget is a package which allows for the insertion of arbitrary
xwidgets into Emacs through buffers.  It must be compiled into Emacs
so you might need to customise your install.  One of its premier uses
is in navigating the web which it provides through the function
~xwidget-webkit-browse-url~.  This renders a fully functional web
browser within Emacs.

Though I am not to keen on using Emacs to browse the web /via/ xwidget
(EWW does a good job on its own), I am very interested in its
capability to render pages with JavaScript, as it may come of use when
doing web development.  I can see the results of work very quickly
without switching windows all within Emacs.
** Xwidget Core
#+begin_src emacs-lisp
(use-package xwidget
  :straight nil
  :general
  (app-leader
    "u" #'xwidget-webkit-browse-url)
  (nmmap
    :keymaps 'xwidget-webkit-mode-map
    "q"         #'quit-window
    "h"         #'xwidget-webkit-scroll-backward
    "j"         #'xwidget-webkit-scroll-up
    "k"         #'xwidget-webkit-scroll-down
    "l"         #'xwidget-webkit-scroll-forward
    "+"         #'xwidget-webkit-zoom-in
    "-"         #'xwidget-webkit-zoom-out
    (kbd "C-f") #'xwidget-webkit-scroll-up
    (kbd "C-b") #'xwidget-webkit-scroll-down
    "H"         #'xwidget-webkit-back
    "L"         #'xwidget-webkit-forward
    "gu"        #'xwidget-webkit-browse-url
    "gr"        #'xwidget-webkit-reload
    "gg"        #'xwidget-webkit-scroll-top
    "G"         #'xwidget-webkit-scroll-bottom))
#+end_src
** Xwidget Extensions
Define a function ~+xwidget/render-file~ that reads a file name and
presents it in an xwidget.  If the current file is an HTML file, ask
if user wants to open current file.  Bind it to ~aU~ in the leader.

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

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

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

The killer benefits of eshell (which would appeal to Emacs users) are
a direct result of eshell being written in Emacs lisp:
- incredible 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

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

Lisp evaluator: works on braced expressions, evaluating them as Lisp
expressions (e.g. ~(message "Hello, World!\n")~).  Any returned
objects are printed.  This makes eshell a LISP REPL!

External evaluator: works within curly braces, evaluating them via
some external shell process (like sh) (e.g. ~{echo "Hello,
world!\n"}~).  This makes eshell a (kinda dumb) terminal emulator!

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

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

  (defun eshell/goto (&rest args)
    "Use `read-directory-name' to change directories."
    (eshell/cd (list (read-directory-name "Enter directory to go to:")))))
#+end_src
** Eshell change directory quickly
~eshell/goto~ is a better ~cd~ for eshell.  However it is really just
a plaster over a bigger issue for my workflow; many times I want
eshell to be present in the current directory of the buffer I am
using.

#+begin_src emacs-lisp
(use-package eshell
  :straight nil
  :general
  (shell-leader
    "T" #'+eshell/current-buffer)
  :config
  (defun +eshell/current-buffer ()
    (interactive)
    (let  ((dir (if buffer-file-name
                    (file-name-directory buffer-file-name)
                  (if default-directory
                      default-directory
                    nil)))
           (buf (eshell)))
      (if dir
          (with-current-buffer buf
            (eshell/cd dir)
            (eshell-send-input))
        (message "Could not switch eshell: buffer is not real file")))))
#+end_src
* Elfeed
Elfeed is the perfect RSS feed reader, integrated into Emacs
perfectly.  I've got a set of feeds that I use for a large variety of
stuff, mostly media and entertainment.  I've also bound "<leader> ar"
to elfeed for loading the system.
#+begin_src emacs-lisp
(use-package elfeed
  :general
  (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/"
           Linux)
          ("LEMMiNO"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCRcgy6GzDeccI7dkbbBna3Q"
           YouTube Stories)
          ("The Onion"
           "https://www.theonion.com/rss"
           Social)
          ("Stack exchange"
           "http://morss.aryadevchavali.com/stackexchange.com/feeds/questions"
           Social)
          ("Dark Sominium"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UC_e39rWdkQqo5-LbiLiU10g"
           YouTube Stories)
          ("Dark Sominium Music"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCkLiZ_zLynyNd5fd62hg1Kw"
           YouTube Music)
          ("Nexpo"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCpFFItkfZz1qz5PpHpqzYBw"
           YouTube)
          ("Techquickie"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UC0vBXGSyV14uvJ4hECDOl0Q"
           YouTube)
          ("3B1B"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCYO_jab_esuFRV4b17AJtAw"
           YouTube)
          ("Fredrik Knusden"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCbWcXB0PoqOsAvAdfzWMf0w"
           YouTube Stories)
          ("Barely Sociable"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UC9PIn6-XuRKZ5HmYeu46AIw"
           YouTube Stories)
          ("Atrocity Guide"
           "https://www.youtube.com/feeds/videos.xml?channel_id=UCn8OYopT9e8tng-CGEWzfmw"
           YouTube Stories)
          ("Hacker News"
           "http://morss.aryadevchavali.com/news.ycombinator.com/rss"
           Social)
          ("Hacker Factor"
           "https://www.hackerfactor.com/blog/index.php?/feeds/index.rss2"
           Social)
          ("BBC Top News"
           "http://morss.aryadevchavali.com/feeds.bbci.co.uk/news/rss.xml"
           News)
          ("BBC Tech News"
           "http://morss.aryadevchavali.com/feeds.bbci.co.uk/news/technology/rss.xml"
           News)))
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-elfeed-setup))
  (setq elfeed-feeds (cl-map 'list #'(lambda (item)
                                       (append (list (nth 1 item)) (cdr (cdr item))))
                             +rss/feed-urls)))
#+end_src
* Magit
Magit is *the* git porcelain for Emacs, which perfectly encapsulates
the git cli.  In this case I just need to setup the bindings for it.
As magit will definitely load after evil (as it must be run by a
binding, and evil will load after init), I can use evil-collection
freely.  Also, define an auto insert for commit messages so that I
don't need to write everything myself.

#+begin_src emacs-lisp
(use-package magit
  :defer t
  :display
  ("magit:.*"
   (display-buffer-same-window)
   (inhibit-duplicate-buffer . t))
  ("magit-diff:.*"
   (display-buffer-below-selected))
  ("magit-log:.*"
   (display-buffer-same-window))
  :general
  (leader
    "g" '(magit-dispatch :which-key "Magit")
    "vf" '(magit-file-dispatch :which-key "Magit file")
    "vb" '(magit-blame :which-key "Magit blame"))
  (code-leader
    "b" #'magit-blame)
  :auto-insert
  (("COMMIT_EDITMSG" . "Commit skeleton")
   ""
   "(" (read-string "Enter feature/module: ") ")"
   (read-string "Enter simple description: ") "\n\n")
  :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
* IBuffer
#+begin_src emacs-lisp
(use-package ibuffer
  :general
  (buffer-leader
    "i" #'ibuffer)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-ibuffer-setup)))
#+end_src
* Processes
Emacs has two systems for process management:
+ proced: a general 'top' like interface which allows general
  management of linux processes
+ list-processes: a specific Emacs based system that lists processes
  spawned by Emacs (similar to a top for Emacs specifically)

** Proced
Core proced config, just a few bindings and evil collection setup.
#+begin_src emacs-lisp
(use-package proced
  :straight nil
  :general
  (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 0.5)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-proced-setup)))
#+end_src

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

Greater surprise, this thing is over powered.  It can perform the
following (and more):
- Matrix calculations
- Generalised calculus operations
- Equation solvers for n-degree multi-variable polynomials
- Embedded mode (check below)!

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

Embedded mode allows computation with the current buffer as the echo
area.  This basically means I can compute stuff within a buffer
without invoking calc directly: $1 + 2\rightarrow_{\text{calc-embed}} 3$.

#+begin_src emacs-lisp
(use-package calc
  :straight nil
  :display
  ("*Calculator*"
   (display-buffer-at-bottom)
   (window-height . 0.18))
  :general
  (app-leader
    "c" #'calc-dispatch)
  (mode-leader
    "c" #'calc-embedded)
  :init
  (setq calc-algebraic-mode t)
  :config
  (with-eval-after-load "evil-collection"
    (evil-collection-calc-setup)))
#+end_src
** WIP Calctex
:PROPERTIES:
:header-args:emacs-lisp: :tangle no
:END:
~calc-mode~ also has a 3rd party package called ~calctex~. It renders
mathematical expressions within calc as if they were rendered in TeX.
You can also copy the expressions in their TeX forms, which is pretty
useful when writing a paper.  I've set a very specific lock on this
repository as it's got quite a messy work-tree and this commit seems to
work for me given the various TeX utilities installed via Arch.

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

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

#+begin_src emacs-lisp
(use-package zone-matrix
  :straight t
  :after dashboard
  :init
  (setq zone-programs
        [zone-pgm-jitter
         zone-pgm-putz-with-case
         zone-pgm-dissolve
         zone-pgm-whack-chars
         zone-pgm-drip
         zone-pgm-rat-race
         zone-pgm-random-life
         zone-matrix
         ])
  :config
  (zone-when-idle 15))
#+end_src
* (Wo)man
Man pages are the user manuals for most software on Linux.  Really
useful when writing code for Un*x systems, though they can be very
verbose.

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!
#+begin_src emacs-lisp
(use-package man
  :demand t
  :straight nil
  :init
  (setq Man-notify-method 'pushy)
  :display
  ("^\\*Man.*"
   (display-buffer-reuse-mode-window display-buffer-same-window))
  :general
  (file-leader
    "m" #'man) ;; kinda like "find man page"
  (nmmap
    :keymaps 'Man-mode-map
    "RET" #'man-follow))
#+end_src
* gif-screencast
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