:PROPERTIES:
:ID:       e103c1bc-be8e-4451-8e43-a93d9e35e692
:END:
#+title:    Examples
#+subtitle: Samples of Emacs/Doom dotfiles, concepts, and sub-projects
#+property: header-args:elisp :results pp

* Introduction
Examples speak louder than technical explanations, so this file exists to house
examples of Doom's (and Emacs') concepts, libraries, dotfiles, and more, for
your own reference. They are divided into Emacs-specific and Doom-specific
examples; where the former can also be useful to users who don't use Doom.

Some of Doom's components will read this file to generate documentation for you,
for example:

- Doom's [[doom-module:][:lang emacs-lisp]] module installs the [[doom-package:][elisp-demos]] package. This displays
  usage examples alongside documentation in [[doom-package:][help]] and [[doom-package:][helpful]] buffers (produced
  by =describe-*= and =helpful-*= commands; e.g. [[kbd:][<help> h f]]). Doom has extended
  this package to search this file as well.
- [[id:1b8b8fa9-6233-4ed8-95c7-f46f8e4e2592][Some Doom's CLI commands]] will emit documentation informed by Doom's org files,
  including this file.

If you're interested in adding to this document, read [[id:9ac0c15c-29e7-43f8-8926-5f0edb1098f0][the documentation section]]
of our contributing guide first.

* TODO Emacs
This section is dedicated to examples of concepts and libraries that can benefit
all Emacs users, whether or not they use Doom.

** TODO Emacs Lisp :demos:
**** file-name-with-extension
:PROPERTIES:
:added: 28.1
:END:
#+begin_src emacs-lisp
(file-name-with-extension "some/file.cpp" "h")
#+end_src

#+RESULTS:
: some/file.h

**** file-name-concat
:PROPERTIES:
:added: 28.1
:END:
#+begin_src emacs-lisp
(file-name-concat user-emacs-directory "lisp" "file.el")
#+end_src

#+begin_src emacs-lisp
(file-name-concat "foo" "bar" "baz")
#+end_src

#+RESULTS:
: foo/bar/baz

** TODO Templates
*** TODO Emacs package
*** TODO Dynamic module

* TODO Doom Emacs
This section is dedicated to examples of concepts and libraries only relevant to
Doom and its users. These are intended to be demonstrations, not substitutes for
documentation.

** TODO Emacs Lisp :demos:
*** doom-lib
**** add-hook!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp
;; With only one hook and one function, this is identical to `add-hook'. In that
;; case, use that instead.
(add-hook! 'some-mode-hook #'enable-something)

;; Adding many-to-many functions to hooks
(add-hook! some-mode #'enable-something #'and-another)
(add-hook! some-mode '(enable-something and-another))
(add-hook! '(one-mode-hook second-mode-hook) #'enable-something)
(add-hook! (one-mode second-mode) #'enable-something)

;; Appending and local hooks
(add-hook! (one-mode second-mode) :append #'enable-something)
(add-hook! (one-mode second-mode) :local #'enable-something)

;; With arbitrary forms
(add-hook! (one-mode second-mode) (setq v 5) (setq a 2))
(add-hook! (one-mode second-mode) :append :local (setq v 5) (setq a 2))

;; Inline named hook functions
(add-hook! '(one-mode-hook second-mode-hook)
  (defun do-something ()
    ...)
  (defun do-another-thing ()
    ...))
#+end_src

**** TODO add-transient-hook!
:PROPERTIES:
:added: 3.0.0-pre
:END:
**** after!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;;; `after!' will take:

;; An unquoted package symbol (the name of a package)
(after! helm ...)

;; An unquoted list of package symbols (i.e. BODY is evaluated once both magit
;; and git-gutter have loaded)
(after! (magit git-gutter) ...)

;; An unquoted, nested list of compound package lists, using any combination of
;; :or/:any and :and/:all
(after! (:or package-a package-b ...)  ...)
(after! (:and package-a package-b ...) ...)
(after! (:and package-a (:or package-b package-c) ...) ...)
;; (Without :or/:any/:and/:all, :and/:all are implied.)

;; A common mistake is to pass it the names of major or minor modes, e.g.
(after! rustic-mode ...)
(after! python-mode ...)
;; But the code in them will never run! rustic-mode is in the `rustic' package
;; and python-mode is in the `python' package. This is what you want:
(after! rustic ...)
(after! python ...)
#+end_src
**** appendq!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp
(let ((x '(a b c)))
  (appendq! x '(c d e))
  x)
#+end_src

#+RESULTS:
: (a b c c d e)

#+begin_src emacs-lisp
(let ((x '(a b c))
      (y '(c d e))
      (z '(f g)))
  (appendq! x y z '(h))
  x)
#+end_src

#+RESULTS:
: (a b c c d e f g h)

**** custom-set-faces!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(custom-set-faces!
 '(outline-1 :weight normal)
 '(outline-2 :weight normal)
 '(outline-3 :weight normal)
 '(outline-4 :weight normal)
 '(outline-5 :weight normal)
 '(outline-6 :weight normal)
 '(default :background "red" :weight bold)
 '(region :background "red" :weight bold))

(custom-set-faces!
 '((outline-1 outline-2 outline-3 outline-4 outline-5 outline-6)
   :weight normal)
 '((default region)
   :background "red" :weight bold))

(let ((red-bg-faces '(default region)))
  (custom-set-faces!
   `(,(cl-loop for i from 0 to 6 collect (intern (format "outline-%d" i)))
     :weight normal)
   `(,red-bg-faces
     :background "red" :weight bold)))

;; You may utilise `doom-themes's theme API to fetch or tweak colors from their
;; palettes. No need to wait until the theme or package is loaded. e.g.
(custom-set-faces!
 `(outline-1 :foreground ,(doom-color 'red))
 `(outline-2 :background ,(doom-color 'blue)))
#+end_src

**** custom-theme-set-faces!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(custom-theme-set-faces! 'doom-one
 '(outline-1 :weight normal)
 '(outline-2 :weight normal)
 '(outline-3 :weight normal)
 '(outline-4 :weight normal)
 '(outline-5 :weight normal)
 '(outline-6 :weight normal)
 '(default :background "red" :weight bold)
 '(region :background "red" :weight bold))

(custom-theme-set-faces! '(doom-one-theme doom-one-light-theme)
 '((outline-1 outline-2 outline-3 outline-4 outline-5 outline-6)
   :weight normal)
 '((default region)
   :background "red" :weight bold))

(let ((red-bg-faces '(default region)))
  (custom-theme-set-faces! '(doom-one-theme doom-one-light-theme)
   `(,(cl-loop for i from 0 to 6 collect (intern (format "outline-%d" i)))
     :weight normal)
   `(,red-bg-faces
     :background "red" :weight bold)))

;; You may utilise `doom-themes's theme API to fetch or tweak colors from their
;; palettes. No need to wait until the theme or package is loaded. e.g.
(custom-theme-set-faces! 'doom-one
 `(outline-1 :foreground ,(doom-color 'red))
 `(outline-2 :background ,(doom-color 'blue)))
#+end_src

**** TODO defer-feature!
:PROPERTIES:
:added: 3.0.0-pre
:END:
**** TODO defer-until!
:PROPERTIES:
:added: 3.0.0-pre
:END:
**** disable-packages!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;; Disable packages enabled by DOOM
(disable-packages! some-package second-package)
#+end_src

**** file-exists-p!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp
(file-exists-p! "init.el" doom-emacs-dir)
#+end_src

#+RESULTS:
: /home/hlissner/.emacs.d/init.el

#+begin_src emacs-lisp
(file-exists-p! (and (or "doesnotexist" "init.el")
                     "LICENSE")
                doom-emacs-dir)
#+end_src

#+RESULTS:
: /home/hlissner/.emacs.d/LICENSE

**** cmd!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(map! "C-j" (cmd! (newline) (indent-according-to-mode)))
#+end_src

**** cmd!!
:PROPERTIES:
:added: 3.0.0-pre
:END:
When ~newline~ is passed a numerical prefix argument (=C-u 5 M-x newline=), it
inserts N newlines. We can use ~cmd!!~ to easily create a keybinds that bakes in
the prefix arg into the command call:

#+begin_src emacs-lisp :eval no
(map! "C-j" (cmd!! #'newline 5))
#+end_src

Or to create aliases for functions that behave differently:

#+begin_src emacs-lisp :eval no
(fset 'insert-5-newlines (cmd!! #'newline 5))

;; The equivalent of C-u M-x org-global-cycle, which resets the org document to
;; its startup visibility settings.
(fset 'org-reset-global-visibility (cmd!! #'org-global-cycle '(4))
#+end_src

**** cmds!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(map! :i [tab] (cmds! (and (modulep! :editor snippets)
                           (bound-and-true-p yas-minor-mode)
                           (yas-maybe-expand-abbrev-key-filter 'yas-expand))
                      #'yas-expand
                      (modulep! :completion company +tng)
                      #'company-indent-or-complete-common)
      :m [tab] (cmds! (and (bound-and-true-p yas-minor-mode)
                           (evil-visual-state-p)
                           (or (eq evil-visual-selection 'line)
                               (not (memq (char-after) (list ?\( ?\[ ?\{ ?\} ?\] ?\))))))
                      #'yas-insert-snippet
                      (and (modulep! :editor fold)
                           (save-excursion (end-of-line) (invisible-p (point))))
                      #'+fold/toggle
                      (fboundp 'evil-jump-item)
                      #'evil-jump-item))
#+end_src

**** kbd!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(map! "," (kbd! "SPC")
      ";" (kbd! ":"))
#+end_src

**** lambda!
#+begin_src emacs-lisp
(mapcar (lambda! ((&key foo bar baz))
          (list foo bar baz))
        '((:foo 10 :bar 25)
          (:baz hello :boop nil)
          (:bar 42)))
#+end_src

**** fn!
#+begin_src emacs-lisp
(mapcar (fn! (symbol-name %)) '(hello world))
#+end_src

#+begin_src emacs-lisp
(seq-sort (fn! (string-lessp (symbol-name %1)
                             (symbol-name %2)))
          '(bonzo foo bar buddy doomguy baz zombies))
#+end_src

#+begin_src emacs-lisp
(format "You passed %d arguments to this function"
        (funcall (fn! (length %*)) :foo :bar :baz "hello" 123 t))
#+end_src

**** load!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;;; Lets say we're in ~/.doom.d/config.el
(load! "lisp/module")                  ; loads ~/.doom.d/lisp/module.el
(load! "somefile" doom-emacs-dir)      ; loads ~/.emacs.d/somefile.el
(load! "anotherfile" doom-user-dir)    ; loads ~/.doom.d/anotherfile.el

;; If you don't want a `load!' call to throw an error if the file doesn't exist:
(load! "~/.maynotexist" nil t)
#+end_src

**** map!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(map! :map magit-mode-map
      :m  "C-r" 'do-something           ; C-r in motion state
      :nv "q" 'magit-mode-quit-window   ; q in normal+visual states
      "C-x C-r" 'a-global-keybind
      :g "C-x C-r" 'another-global-keybind  ; same as above

      (:when IS-MAC
        :n "M-s" 'some-fn
        :i "M-o" (cmd! (message "Hi"))))

(map! (:when (modulep! :completion company) ; Conditional loading
        :i "C-@" #'+company/complete
        (:prefix "C-x"                       ; Use a prefix key
          :i "C-l" #'+company/whole-lines)))

(map! (:when (modulep! :lang latex)    ; local conditional
        (:map LaTeX-mode-map
          :localleader                  ; Use local leader
          :desc "View" "v" #'TeX-view)) ; Add which-key description
      :leader                           ; Use leader key from now on
      :desc "Eval expression" ";" #'eval-expression)
#+end_src

These are side-by-side comparisons, showing how to bind keys with and without
~map!~:

#+begin_src emacs-lisp :eval no
;; bind a global key
(global-set-key (kbd "C-x y") #'do-something)
(map! "C-x y" #'do-something)

;; bind a key on a keymap
(define-key emacs-lisp-mode-map (kbd "C-c p") #'do-something)
(map! :map emacs-lisp-mode-map "C-c p" #'do-something)

;; unbind a key defined elsewhere
(define-key lua-mode-map (kbd "SPC m b") nil)
(map! :map lua-mode-map "SPC m b" nil)

;; bind multiple keys
(global-set-key (kbd "C-x x") #'do-something)
(global-set-key (kbd "C-x y") #'do-something-else)
(global-set-key (kbd "C-x z") #'do-another-thing)
(map! "C-x x" #'do-something
      "C-x y" #'do-something-else
      "C-x z" #'do-another-thing)

;; bind global keys in normal mode
(evil-define-key* 'normal 'global
  (kbd "C-x x") #'do-something
  (kbd "C-x y") #'do-something-else
  (kbd "C-x z") #'do-another-thing)
(map! :n "C-x x" #'do-something
      :n "C-x y" #'do-something-else
      :n "C-x z" #'do-another-thing)

;; or on a deferred keymap
(evil-define-key 'normal emacs-lisp-mode-map
  (kbd "C-x x") #'do-something
  (kbd "C-x y") #'do-something-else
  (kbd "C-x z") #'do-another-thing)
(map! :map emacs-lisp-mode-map
      :n "C-x x" #'do-something
      :n "C-x y" #'do-something-else
      :n "C-x z" #'do-another-thing)

;; or multiple maps
(dolist (map (list emacs-lisp-mode go-mode-map ivy-minibuffer-map))
  (evil-define-key '(normal insert) map
    "a" #'a
    "b" #'b
    "c" #'c))
(map! :map (emacs-lisp-mode go-mode-map ivy-minibuffer-map)
      :ni "a" #'a
      :ni "b" #'b
      :ni "c" #'c)

;; or in multiple states (order of states doesn't matter)
(evil-define-key* '(normal visual) emacs-lisp-mode-map (kbd "C-x x") #'do-something)
(evil-define-key* 'insert emacs-lisp-mode-map (kbd "C-x x") #'do-something-else)
(evil-define-key* '(visual normal insert emacs) emacs-lisp-mode-map (kbd "C-x z") #'do-another-thing)
(map! :map emacs-lisp-mode
      :nv   "C-x x" #'do-something      ; normal+visual
      :i    "C-x y" #'do-something-else ; insert
      :vnie "C-x z" #'do-another-thing) ; visual+normal+insert+emacs

;; You can nest map! calls:
(evil-define-key* '(normal visual) emacs-lisp-mode-map (kbd "C-x x") #'do-something)
(evil-define-key* 'normal go-lisp-mode-map (kbd "C-x x") #'do-something-else)
(map! (:map emacs-lisp-mode :nv "C-x x" #'do-something)
      (:map go-lisp-mode    :n  "C-x x" #'do-something-else))
#+end_src

**** pushnew!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp
(let ((list '(a b c)))
  (pushnew! list 'c 'd 'e)
  list)
#+end_src

#+RESULTS:
: (e d a b c)

**** prependq!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp
(let ((x '(a b c)))
  (prependq! x '(c d e))
  x)
#+end_src

#+RESULTS:
: (c d e a b c)

#+begin_src emacs-lisp
(let ((x '(a b c))
      (y '(c d e))
      (z '(f g)))
  (prependq! x y z '(h))
  x)
#+end_src

#+RESULTS:
: (c d e f g h a b c)

**** quiet!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;; Enters recentf-mode without extra output
(quiet! (recentf-mode +1))
#+end_src
**** remove-hook!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;; With only one hook and one function, this is identical to `remove-hook'. In
;; that case, use that instead.
(remove-hook! 'some-mode-hook #'enable-something)

;; Removing N functions from M hooks
(remove-hook! some-mode #'enable-something #'and-another)
(remove-hook! some-mode #'(enable-something and-another))
(remove-hook! '(one-mode-hook second-mode-hook) #'enable-something)
(remove-hook! (one-mode second-mode) #'enable-something)

;; Removing buffer-local hooks
(remove-hook! (one-mode second-mode) :local #'enable-something)

;; Removing arbitrary forms (must be exactly the same as the definition)
(remove-hook! (one-mode second-mode) (setq v 5) (setq a 2))
#+end_src
**** setq!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp
;; Each of these have a setter associated with them, which must be triggered in
;; order for their new values to have an effect.
(setq! evil-want-Y-yank-to-eol nil
       evil-want-C-u-scroll nil
       evil-want-C-d-scroll nil)
#+end_src
**** setq-hook!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;; Set multiple variables after a hook
(setq-hook! 'markdown-mode-hook
  line-spacing 2
  fill-column 80)

;; Set variables after multiple hooks
(setq-hook! '(eshell-mode-hook term-mode-hook)
  hscroll-margin 0)
#+end_src

**** unsetq-hook!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(unsetq-hook! 'markdown-mode-hook line-spacing)

;; Removes the following variable hook
(setq-hook! 'markdown-mode-hook line-spacing 2)

;; Removing N variables from M hooks
(unsetq-hook! some-mode enable-something and-another)
(unsetq-hook! some-mode (enable-something and-another))
(unsetq-hook! '(one-mode-hook second-mode-hook) enable-something)
(unsetq-hook! (one-mode second-mode) enable-something)
#+end_src
**** versionp!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp
(versionp! "25.3" > "27.1")
#+end_src

#+RESULTS:
: nil

#+begin_src emacs-lisp
(versionp! "28.0" <= emacs-version <= "28.1")
#+end_src

#+RESULTS:
: t

*** doom-modules
**** doom!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
(doom! :completion
       company
       ivy
       ;;helm

       :tools
       (:if IS-MAC macos)
       docker
       lsp

       :lang
       (cc +lsp)
       (:cond ((string= system-name "work-pc")
               python
               rust
               web)
              ((string= system-name "writing-pc")
               (org +dragndrop)
               ruby))
       (:if IS-LINUX
           (web +lsp)
         web)

       :config
       literate
       (default +bindings +smartparens))
#+end_src

**** use-package!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;; Use after-call to load package before hook
(use-package! projectile
  :after-call (pre-command-hook after-find-file dired-before-readin-hook))

;; defer recentf packages one by one
(use-package! recentf
  :defer-incrementally easymenu tree-widget timer
  :after-call after-find-file)

;; This is equivalent to :defer-incrementally (abc)
(use-package! abc
  :defer-incrementally t)
#+end_src

**** package!
:PROPERTIES:
:added: 3.0.0-pre
:END:
#+begin_src emacs-lisp :eval no
;; To install a package that can be found on ELPA or any of the sources
;; specified in `straight-recipe-repositories':
(package! evil)
(package! js2-mode)
(package! rainbow-delimiters)

;; To disable a package included with Doom (which will no-op all its `after!'
;; and `use-package!' blocks):
(package! evil :disable t)
(package! rainbow-delimiters :disable t)

;; To install a package from a github repo
(package! so-long :recipe (:host github :repo "hlissner/emacs-so-long"))

;; If a package is particularly big and comes with submodules you don't need,
;; you can tell the package manager not to clone the repo recursively:
(package! ansible :recipe (:nonrecursive t))

;; To pin a package to a specific commit:
(package! evil :pin "e7bc39de2f9")
;; ...or branch:
(package! evil :recipe (:branch "stable"))
;; To unpin a pinned package:
(package! evil :pin nil)

;; If you share your config between two computers, and don't want bin/doom
;; refresh to delete packages used only on one system, use :ignore
(package! evil :ignore (not (equal system-name "my-desktop")))
#+end_src

*** doom-cli
**** TODO defcli!
**** TODO defcli-alias!
**** TODO defcli-obsolete!
**** TODO defcli-stub!
**** TODO defcli-autoload!
**** TODO defcli-group!
**** TODO exit!
**** TODO call!
**** TODO run!
**** TODO sh!
**** TODO sh!!
**** TODO git!
**** TODO def-cli-context-get
**** TODO def-cli-context-put
**** TODO def-cli-context-find-option
**** TODO def-cli-call
**** TODO def-cli-exit
**** TODO def-cli-load
**** TODO def-cli-load-all
**** TODO doom-cli-find
**** TODO doom-cli-get
**** TODO doom-cli-prop
**** TODO doom-cli-subcommands
**** TODO doom-cli-aliases
*** TODO lib/files.el
**** TODO doom-path
**** TODO doom-glob
**** TODO doom-dir
**** TODO doom-files-in
**** TODO doom-file-cookie-p
**** TODO file-exists-p!
**** TODO doom-file-size
**** TODO doom-file-line-count
**** TODO doom-directory-size
**** TODO doom-file-read
**** TODO doom-file-write
**** TODO with-file-contents!

** TODO Configuration files
*** TODO doomprofiles.el
*** TODO =.doomrc=
*** TODO =.doomproject=
*** TODO =.doommodule=
*** TODO =.doomprofile=
** TODO Templates
*** TODO User configuration
*** TODO Module
*** TODO Project
*** TODO Theme
*** TODO Command-line interface
**** Unix utilities, rewritten as Doom scripts
To show off the syntax and capabilities of Doom's CLI framework, here are some
popular scripts ported to doomscripts for reference. They will all operate under
these assumptions:

1. The script lives somewhere in your =$PATH=,
2. =$EMACSDIR/bin/doomscript= lives in your =$PATH=.
3. The script is executable,
4. The script's filename matches the first argument of ~run!~ (by convention,
   not a requirement),

***** ~mkdir~
#+begin_src emacs-lisp :eval no
#!/usr/bin/env doomscript

(defcli! mkdir
    ((mode     ("-m" "--mode" mode))
     (parents? ("-p" "--parents"))
     (verbose? ("-v" "--verbose"))
     &args directories)
  "Create the DIRECTORIES, if do not already exist.

Mandatory arguments to long options are mandatory for short options too.

OPTIONS:
  -m, --mode
    set file mode (as in chmod), not a=rwx - umask.
  -p, --parents
    no error if existing, make parent directories as needed, with their file
    modes unaffected by any `-m' option.
  -v, --verbose
    print a message for each created directory

AUTHOR:
  Original program by David MacKenzie. Doomscript port by Henrik Lissner.

SEE ALSO:
  `mkdir(2)`

  Full documentation <https://www.gnu.org/software/coreutils/mkdir>
  or available locally via: info '(coreutils) mkdir invocation'

  Packaged by https://nixos.org
  Copyright © 2022 Free Software Foundation, Inc.
  License  GPLv3+:  GNU  GPL  version 3 or later <https://gnu.org/li‐
  censes/gpl.html>.
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law."
  (dolist (dir directories)
    (unless (file-directory-p dir)
      (make-directory dir parents?)
      (when mode
        (set-file-modes dir mode))
      (when verbose?
        (print! "mkdir: created directory '%s'" dir)))))
#+end_src

****** Notes
- Docstrings for Doom CLIs recognize indented sections with a capitalized
  heading followed by a colon (like ~SEE ALSO:~, ~OPTIONS:~, etc). They will be
  appended to the --help output for this command. ~OPTIONS~ and ~ARGUMENTS~ are
  special, in that they decorate pre-existing documentation for referenced
  options/arguments.

- The options were documented in the CLI's docstring, instead of inline like so:

  #+begin_src emacs-lisp
      ((mode     ("-m" "--mode" mode) "set file modes (as in chmod), not a=rwx - umask.")
       (parents? ("-p" "--parents") "no error if existing, make parent directories as needed, with their file modes unaffected by any `-m' option.")
       (verbose? ("-v" "--verbose") "print a message for each created directory")
       &args directories)
  #+end_src

  Either is acceptable, but for long docs like this, it's better suited to the
  docstring. If both were present, Doom's help docs would have concatenated them
  (separated by two newlines).

- The ~mode~ option takes one argument, a chmod mask. I indicate this with
  ~"`MODE'"~. This is a special syntax for highlighting arguments in the help
  docs of this command. If I had used a symbol, instead (one of the predefined
  types in [[var:][doom-cli-argument-value-types]]), I would've gotten free type-checking
  and error handling, but there is no predefined type for chmod masks (yet), so
  I'd have to do my own checks:

  #+begin_src emacs-lisp :eval no
  (defcli! mkdir
      ((mode     ("-m" "--mode" "`MODE'"))
       (parents? ("-p" "--parents"))
       (verbose? ("-v" "--verbose"))
       &args directories)
    (unless (string-match-p "^[0-9]\\{3,4\\}$" mode)
      (user-error "Invalid mode: %s" mode))
    (setq mode (string-to-number mode 8))
    (dolist (dir directories)
      (unless (file-directory-p dir)
        (make-directory dir parents?)
        (when mode
          (set-file-modes dir mode))
        (when verbose?
          (print! "mkdir: created directory '%s'" dir)))))
  #+end_src

  That said, set-file-modes will throw its own type error, but it likely won't
  be as user friendly.

***** TODO ~say~
#+begin_src emacs-lisp :eval no
#!/usr/bin/env doomscript

(defcli! say
    ((name ("--speaker" name) "Who is speaking?")
     &args args)
  "This command repeats what you say to it.

It serves as an example of the bare minimum you need to write a Doom-based CLI.
Naturally, it could be more useful; it could process more complex options and
arguments, call other Doom CLIs, read/write data from files or over networks --
but that can wait for more complicated examples.

ARGUMENTS:
  ARGS
    The message to be repeated back at you.

OPTIONS:
  --speaker
    If not specified, it is assumed that Emacs is speaking."
  (print! "%s says: %S"
          (or name "Emacs")
          (string-join args " ")))

(run! "say" (cdr (member "--" argv)))
#+end_src

#+begin_src bash :eval no
$ say hello world
Emacs says: "Hello world"
$ say --speaker Henrik "I've doomed us all"
Henrik says: "I've doomed us all"
$ say --help
TODO
#+end_src

***** emacs
This isn't useful, but it should hopefully demonstrate the full spectrum of
Doom's CLI, by reimplementing a subset of ~emacs~'s options and arguments (and
none of its documentation). It will simply forward them to the real program
afterwards.

Since I don't want to override the real ~emacs~ in the ~$PATH~, I'll just call
it ~demacs~:

#+begin_src emacs-lisp :eval no
#!/usr/bin/env doomscript

(defcli! demacs
    ((cd ("--chdir" dir))
     (quick?     ("-Q" "--quick"))
     (no-init?   ("-q" "--no-init-file"))
     (no-slisp?  ("-nsl" "--no-site-lisp"))
     (no-sfile?  ("--no-site-file"))
     (initdir    ("--init-directory" dir))
     (batch?     ("--batch"))
     (batch      (("-l" "--load" (file) ...))
                 (("-e" "--eval" (form) ...))
                 (("-f" "--funcall" (fn) ...))
                 (("-L" "--directory" (dir) ...))
                 (("--kill")))
     (script     ("--script" (file)))
     &args (args (file linecol)))
  "Demacs is a thin wrapper around Emacs, made to demo of Doom's CLI Framework.

Since documentation isn't the focus of this example, this is all you'll get!"
  (cond (script (load script))
        (batch?
         (dolist (do batch)
           (pcase do
             (`(,(or "-l" "--load") . ,file) (load file))
             (`(,(or "-e" "--eval") . ,form) (eval (read form) t))
             (`(,(or "-f" "--funcall") . ,fn) (funcall (read fn)))
             (`("--kill" . t) (kill-emacs 0)))))
        ((exit! :then (cons "emacs"
                            (append (if quick '("-Q"))
                                    (if no-init? '("-q"))
                                    (if no-slisp? '("-nsl"))
                                    (if no-sfile? '("--no-site-file"))
                                    (if initdir `("--init-directory" ,initdir))
                                    args))))))
#+end_src

****** Notes
There's a lot of (intentional) redundancy here, for posterity. A *much* simpler
(and more reliable) version of this command would've looked like this:

#+begin_src emacs-lisp
(defcli! demacs (&rest args)
  (exit! :then (cons "emacs" args)))
#+end_src

But that wouldn't demonstrate enough. Though, it wouldn't forward ~--version~ or
~--help~ either.

** TODO Use cases
*** TODO Note-taking
*** TODO Game development
*** TODO Web development
*** TODO Emacs as your terminal