doomemacs/docs/examples.org
Henrik Lissner 88bb045388
docs(*): replace all-the-icons with nerd-icons
Also colorizes the leading icon in notices.
2023-09-16 20:19:11 +02:00

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Examples

󰐃 Our documentation was designed to be read in Doom Emacs (M-x doom/help) or online at https://docs.doomemacs.org. Avoid reading it elsewhere (like Github), where it will be rendered incorrectly.

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:

If you're interested in adding to this document, read 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
(file-name-with-extension "some/file.cpp" "h")
some/file.h
file-name-concat
(file-name-concat user-emacs-directory "lisp" "file.el")
(file-name-concat "foo" "bar" "baz")
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!
;; 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 ()
    ...))
TODO add-transient-hook!
after!
;;; `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 ...)
appendq!
(let ((x '(a b c)))
  (appendq! x '(c d e))
  x)
(a b c c d e)
(let ((x '(a b c))
      (y '(c d e))
      (z '(f g)))
  (appendq! x y z '(h))
  x)
(a b c c d e f g h)
custom-set-faces!
(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)))
custom-theme-set-faces!
(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)))
TODO defer-feature!
TODO defer-until!
disable-packages!
;; Disable packages enabled by DOOM
(disable-packages! some-package second-package)
file-exists-p!
(file-exists-p! "init.el" doom-emacs-dir)
/home/hlissner/.emacs.d/init.el
(file-exists-p! (and (or "doesnotexist" "init.el")
                     "LICENSE")
                doom-emacs-dir)
/home/hlissner/.emacs.d/LICENSE
cmd!
(map! "C-j" (cmd! (newline) (indent-according-to-mode)))
cmd!!

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:

(map! "C-j" (cmd!! #'newline 5))

Or to create aliases for functions that behave differently:

(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))
cmds!
(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))
kbd!
(map! "," (kbd! "SPC")
      ";" (kbd! ":"))
lambda!
(mapcar (lambda! ((&key foo bar baz))
          (list foo bar baz))
        '((:foo 10 :bar 25)
          (:baz hello :boop nil)
          (:bar 42)))
fn!
(mapcar (fn! (symbol-name %)) '(hello world))
(seq-sort (fn! (string-lessp (symbol-name %1)
                             (symbol-name %2)))
          '(bonzo foo bar buddy doomguy baz zombies))
(format "You passed %d arguments to this function"
        (funcall (fn! (length %*)) :foo :bar :baz "hello" 123 t))
load!
;;; 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)
map!
(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)

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

;; 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))
pushnew!
(let ((list '(a b c)))
  (pushnew! list 'c 'd 'e)
  list)
(e d a b c)
prependq!
(let ((x '(a b c)))
  (prependq! x '(c d e))
  x)
(c d e a b c)
(let ((x '(a b c))
      (y '(c d e))
      (z '(f g)))
  (prependq! x y z '(h))
  x)
(c d e f g h a b c)
quiet!
;; Enters recentf-mode without extra output
(quiet! (recentf-mode +1))
remove-hook!
;; 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))
setq!
;; 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)
setq-hook!
;; 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)
unsetq-hook!
(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)
versionp!
(versionp! "25.3" > "27.1")
nil
(versionp! "28.0" <= emacs-version <= "28.1")
t

doom-modules

doom!
(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))
use-package!
;; 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)
package!
;; 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")))

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

profiles.el

This file can live in any of:

  • $DOOMDIR/profiles.el
  • $EMACSDIR/profiles.el
  • ~/.config/doom-profiles.el
  • ~/.doom-profiles.el

Here is an exhaustive example of all its syntax and capabilities:

;; -*- mode: emacs-lisp; -*-
((profile1
  ;; The permitted formats of each entry:
  (var . value)
  ("envvar" . value)
  (var :directive values...)

  ;; `user-emacs-directory' is often the first variable you want to set, so
  ;; Emacs knows where this profile lives. If you don't, it'll use the config
  ;; living in the default locations (~/.config/emacs or ~/.emacs.d).
  (user-emacs-directory . "~/another/emacs/config/")
  ;; If this is a Doom config, you'll also want to set `doom-user-dir', which
  ;; defaults to ~/.config/doom or ~/.doom.d:
  (doom-user-dir . "~/another/doom/config/")
  ;; If a CAR is a string, it is assumed you want to set an environment
  ;; variable. (Side-note: setting DOOMDIR will be unnecessary if you're setting
  ;; `doom-user-dir' above).
  ("DOOMDIR" . "~/another/doom/config/")

  ;; Doom profiles support a number of special directives. They are:
  ;;
  ;; (VAR :path SEGMENTS...) -- set VAR to an exapnded path built from SEGMENTS,
  ;; relative to `user-emacs-directory', unless an absolute path is in SEGMENTS.
  (doom-cache-dir :path doom-user-dir ".local/cache")
  (doom-data-dir  :path doom-user-dir ".local/data")
  (doom-state-dir :path doom-user-dir ".local/state")
  ;; (VAR :plist VALUE) -- use VALUE as a literal plist; ignoring any profile
  ;; directives that may be in it.
  (some-plist :plist (:foo bar :baz womp))
  ;; (VAR :eval FORMS...) -- use to evaluate arbitrary elisp forms. Note that
  ;; his runs early in early-init.el. It's wise to assume no APIs are available
  ;; or loaded, only the previous bindings in this profile.
  (doom-theme :eval (if (equal (system-name) "foo") 'doom-one 'doom-dracula))
  ;; Though discouraged, you may evaluate forms without a binding by using `_'.
  ;; You really should be doing this in the profile though...
  (_ :eval (message "Hello world!"))
  (_ :eval (with-eval-after-load 'company (setq-default company-idle-delay 2.0)))
  ;; (VAR :prepend FORMS...) or (VAR :append FORMS...) -- prepend or append the
  ;; evaluated result of each form in FORMS to VAR (a list). If VAR is undefined
  ;; at startup, it will be deferred until the variable is available.
  (load-path :prepend (expand-file-name "packages/" doom-user-dir))
  (load-path :prepend (expand-file-name "lisp/" doom-user-dir))
  (load-path :append  (expand-file-name "fallback/" doom-user-dir))
  (exec-path :prepend (expand-file-name "bin/" doom-user-dir))
  (auto-mode-alist :prepend '("\\.el\\'" . lisp-mode)))

 (profile2
  ...)

 (profile3
  ...))

.doomprofile

This file takes after the second level of profiles.el's format (see a more complete example in the previous section). For example:

;;; -*- mode: emacs-lisp -*-
;; A .doomprofile can be placed under an implicit profile. Same rules as
;; .doom-profiles.el, but one level deeper.

((var . value)
 ("envvar" . value)
 (var :directive values...))

TODO .doomrc

TODO .doomproject

TODO .doommodule

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
#!/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)))))
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:

        ((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)

    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 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:

    (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)))))

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

TODO say
#!/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)))
$ 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
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:

#!/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))))))
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:

(defcli! demacs (&rest args)
  (exit! :then (cons "emacs" args)))

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