;;; shortdoc.el --- Short function summaries  -*- lexical-binding: t -*-

;; Copyright (C) 2020-2022 Free Software Foundation, Inc.

;; Keywords: lisp, help
;; Package: emacs

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs 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
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; This package lists functions based on various groupings.
;;
;; For instance, `string-trim' and `mapconcat' are `string' functions,
;; so `M-x shortdoc RET string RET' will give an overview of functions
;; that operate on strings.
;;
;; The documentation groups are created with the
;; `define-short-documentation-group' macro.

;;; Code:

(require 'seq)
(require 'text-property-search)
(eval-when-compile (require 'cl-lib))

(defgroup shortdoc nil
  "Short documentation."
  :group 'lisp)

(defface shortdoc-heading
  '((t :inherit variable-pitch :height 1.3 :weight bold))
  "Face used for a heading."
  :version "28.1")

(defface shortdoc-section
  '((t :inherit variable-pitch))
  "Face used for a section.")

;;;###autoload
(progn
  (defvar shortdoc--groups nil)

  (defmacro define-short-documentation-group (group &rest functions)
    "Add GROUP to the list of defined documentation groups.
FUNCTIONS is a list of elements on the form:

  (FUNC
   :no-manual BOOL
   :args ARGS
   :eval EVAL
   :no-eval EXAMPLE-FORM
   :no-value EXAMPLE-FORM
   :no-eval* EXAMPLE-FORM
   :result RESULT-FORM
   :result-string RESULT-STRING
   :eg-result RESULT-FORM
   :eg-result-string RESULT-STRING)

FUNC is the function being documented.

NO-MANUAL should be non-nil if FUNC isn't documented in the
manual.

ARGS is optional list of function FUNC's arguments.  FUNC's
signature is displayed automatically if ARGS is not present.
Specifying ARGS might be useful where you don't want to document
some of the uncommon arguments a function might have.

While the `:no-manual' and `:args' property can be used for
any (FUNC ..) form, all of the other properties shown above
cannot be used simultaneously in such a form.

Here are some common forms with examples of properties that go
together:

1. Document a form or string, and its evaluated return value.
   (FUNC
    :eval EVAL)

If EVAL is a string, it will be inserted as is, and then that
string will be `read' and evaluated.

2. Document a form or string, but manually document its evaluation
   result.  The provided form will not be evaluated.

  (FUNC
   :no-eval EXAMPLE-FORM
   :result RESULT-FORM)   ;Use `:result-string' if value is in string form

Using `:no-value' is the same as using `:no-eval'.

Use `:no-eval*' instead of `:no-eval' where the successful
execution of the documented form depends on some conditions.

3. Document a form or string EXAMPLE-FORM.  Also manually
   document an example result.  This result could be unrelated to
   the documented form.

  (FUNC
   :no-eval EXAMPLE-FORM
   :eg-result RESULT-FORM) ;Use `:eg-result-string' if value is in string form

A FUNC form can have any number of `:no-eval' (or `:no-value'),
`:no-eval*', `:result', `:result-string', `:eg-result' and
`:eg-result-string' properties."
    (declare (indent defun))
    `(progn
       (setq shortdoc--groups (delq (assq ',group shortdoc--groups)
                                    shortdoc--groups))
       (push (cons ',group ',functions) shortdoc--groups))))

(define-short-documentation-group alist
  "Alist Basics"
  (assoc
   :eval (assoc 'foo '((foo . bar) (zot . baz))))
  (rassoc
   :eval (rassoc 'bar '((foo . bar) (zot . baz))))
  (assq
   :eval (assq 'foo '((foo . bar) (zot . baz))))
  (rassq
   :eval (rassq 'bar '((foo . bar) (zot . baz))))
  (assoc-string
   :eval (assoc-string "foo" '(("foo" . "bar") ("zot" "baz"))))
  "Manipulating Alists"
  (assoc-delete-all
   :eval (assoc-delete-all "foo" '(("foo" . "bar") ("zot" . "baz")) #'equal))
  (assq-delete-all
   :eval (assq-delete-all 'foo '((foo . bar) (zot . baz))))
  (rassq-delete-all
   :eval (rassq-delete-all 'bar '((foo . bar) (zot . baz))))
  (alist-get
   :eval (let ((foo '((bar . baz))))
           (setf (alist-get 'bar foo) 'zot)
           foo))
  "Misc"
  (assoc-default
   :eval (assoc-default "foobar" '(("foo" . baz)) #'string-match))
  (copy-alist
   :eval (let* ((old '((foo . bar)))
                (new (copy-alist old)))
           (eq old new)))
  ;; FIXME: Outputs "\.rose" for the symbol `.rose'.
  ;; (let-alist
  ;;     :eval (let ((colors '((rose . red)
  ;;                           (lily . white))))
  ;;             (let-alist colors
  ;;               (if (eq .rose 'red)
  ;;                   .lily))))
  )

(define-short-documentation-group string
  "Making Strings"
  (make-string
   :args (length init)
   :eval "(make-string 5 ?x)")
  (string
   :eval "(string ?a ?b ?c)")
  (concat
   :eval (concat "foo" "bar" "zot"))
  (string-join
   :no-manual t
   :eval (string-join '("foo" "bar" "zot") " "))
  (mapconcat
   :eval (mapconcat (lambda (a) (concat "[" a "]"))
                    '("foo" "bar" "zot") " "))
  (string-pad
   :eval (string-pad "foo" 5)
   :eval (string-pad "foobar" 5)
   :eval (string-pad "foo" 5 ?- t))
  (mapcar
   :eval (mapcar #'identity "123"))
  (format
   :eval (format "This number is %d" 4))
  "Manipulating Strings"
  (substring
   :eval (substring "foobar" 0 3)
   :eval (substring "foobar" 3))
  (string-limit
   :eval (string-limit "foobar" 3)
   :eval (string-limit "foobar" 3 t)
   :eval (string-limit "foobar" 10)
   :eval (string-limit "fo好" 3 nil 'utf-8))
  (truncate-string-to-width
   :eval (truncate-string-to-width "foobar" 3)
   :eval (truncate-string-to-width "你好bar" 5))
  (split-string
   :eval (split-string "foo bar")
   :eval (split-string "|foo|bar|" "|")
   :eval (split-string "|foo|bar|" "|" t))
  (split-string-and-unquote
   :eval (split-string-and-unquote "foo \"bar zot\""))
  (split-string-shell-command
   :eval (split-string-shell-command "ls /tmp/'foo bar'"))
  (string-lines
   :eval (string-lines "foo\n\nbar")
   :eval (string-lines "foo\n\nbar" t))
  (string-replace
   :eval (string-replace "foo" "bar" "foozot"))
  (replace-regexp-in-string
   :eval (replace-regexp-in-string "[a-z]+" "_" "*foo*"))
  (string-trim
   :args (string)
   :doc "Trim STRING of leading and trailing white space."
   :eval (string-trim " foo "))
  (string-trim-left
   :eval (string-trim-left "oofoo" "o+"))
  (string-trim-right
   :eval (string-trim-right "barkss" "s+"))
  (string-truncate-left
   :no-manual t
   :eval (string-truncate-left "longstring" 8))
  (string-remove-suffix
   :no-manual t
   :eval (string-remove-suffix "bar" "foobar"))
  (string-remove-prefix
   :no-manual t
   :eval (string-remove-prefix "foo" "foobar"))
  (string-chop-newline
   :eval (string-chop-newline "foo\n"))
  (string-clean-whitespace
   :eval (string-clean-whitespace " foo   bar   "))
  (string-fill
   :eval (string-fill "Three short words" 12)
   :eval (string-fill "Long-word" 3))
  (reverse
   :eval (reverse "foo"))
  (substring-no-properties
   :eval (substring-no-properties (propertize "foobar" 'face 'bold) 0 3))
  (try-completion
   :eval (try-completion "foo" '("foobar" "foozot" "gazonk")))
  "Unicode Strings"
  (string-glyph-split
   :eval (string-glyph-split "Hello, 👼🏻🧑🏼‍🤝‍🧑🏻"))
  (string-glyph-compose
   :eval (string-glyph-compose "Å"))
  (string-glyph-decompose
   :eval (string-glyph-decompose "Å"))
  "Predicates for Strings"
  (string-equal
   :eval (string-equal "foo" "foo"))
  (string-equal-ignore-case
   :eval (string-equal-ignore-case "foo" "FOO"))
  (eq
   :eval (eq "foo" "foo"))
  (eql
   :eval (eql "foo" "foo"))
  (equal
   :eval (equal "foo" "foo"))
  (cl-equalp
   :eval (cl-equalp "Foo" "foo"))
  (stringp
   :eval "(stringp ?a)")
  (string-empty-p
   :no-manual t
   :eval (string-empty-p ""))
  (string-blank-p
   :no-manual t
   :eval (string-blank-p " \n"))
  (string-lessp
   :eval (string-lessp "foo" "bar")
   :eval (string-lessp "pic4.png" "pic32.png")
   :eval (string-lessp "1.1" "1 2"))
  (string-greaterp
   :eval (string-greaterp "foo" "bar"))
  (string-version-lessp
   :eval (string-version-lessp "pic4.png" "pic32.png")
   :eval (string-version-lessp "1.1" "1 2"))
  (string-collate-lessp
   :eval (string-collate-lessp "1.1" "1 2"))
  (string-prefix-p
   :eval (string-prefix-p "foo" "foobar"))
  (string-suffix-p
   :eval (string-suffix-p "bar" "foobar"))
  "Case Manipulation"
  (upcase
   :eval (upcase "foo"))
  (downcase
   :eval (downcase "FOObar"))
  (capitalize
   :eval (capitalize "foo bar zot"))
  (upcase-initials
   :eval (upcase-initials "The CAT in the hAt"))
  "Converting Strings"
  (string-to-number
   :eval (string-to-number "42")
   :eval (string-to-number "deadbeef" 16))
  (number-to-string
   :eval (number-to-string 42))
  "Data About Strings"
  (length
   :eval (length "foo")
   :eval (length "avocado: 🥑"))
  (string-width
   :eval (string-width "foo")
   :eval (string-width "avocado: 🥑"))
  (string-pixel-width
   :eval (string-pixel-width "foo")
   :eval (string-pixel-width "avocado: 🥑"))
  (string-search
   :eval (string-search "bar" "foobarzot"))
  (assoc-string
   :eval (assoc-string "foo" '(("a" 1) (foo 2))))
  (seq-position
   :eval "(seq-position \"foobarzot\" ?z)"))

(define-short-documentation-group file-name
  "File Name Manipulation"
  (file-name-directory
   :eval (file-name-directory "/tmp/foo")
   :eval (file-name-directory "/tmp/foo/"))
  (file-name-nondirectory
   :eval (file-name-nondirectory "/tmp/foo")
   :eval (file-name-nondirectory "/tmp/foo/"))
  (file-name-sans-versions
   :args (filename)
   :eval (file-name-sans-versions "/tmp/foo~"))
  (file-name-extension
   :eval (file-name-extension "/tmp/foo.txt"))
  (file-name-sans-extension
   :eval (file-name-sans-extension "/tmp/foo.txt"))
  (file-name-with-extension
   :eval (file-name-with-extension "foo.txt" "bin")
   :eval (file-name-with-extension "foo" "bin"))
  (file-name-base
   :eval (file-name-base "/tmp/foo.txt"))
  (file-relative-name
   :eval (file-relative-name "/tmp/foo" "/tmp"))
  (file-name-split
   :eval (file-name-split "/tmp/foo")
   :eval (file-name-split "foo/bar"))
  (make-temp-name
   :eval (make-temp-name "/tmp/foo-"))
  (file-name-concat
   :eval (file-name-concat "/tmp/" "foo")
   :eval (file-name-concat "/tmp" "foo")
   :eval (file-name-concat "/tmp" "foo" "bar/" "zot")
   :eval (file-name-concat "/tmp" "~"))
  (expand-file-name
   :eval (expand-file-name "foo" "/tmp/")
   :eval (expand-file-name "foo" "/tmp///")
   :eval (expand-file-name "foo" "/tmp/foo/.././")
   :eval (expand-file-name "~" "/tmp/"))
  (substitute-in-file-name
   :eval (substitute-in-file-name "$HOME/foo"))
  "Directory Functions"
  (file-name-as-directory
   :eval (file-name-as-directory "/tmp/foo"))
  (directory-file-name
   :eval (directory-file-name "/tmp/foo/"))
  (abbreviate-file-name
   :no-eval (abbreviate-file-name "/home/some-user")
   :eg-result "~some-user")
  (file-name-parent-directory
   :eval (file-name-parent-directory "/foo/bar")
   :eval (file-name-parent-directory "/foo/")
   :eval (file-name-parent-directory "foo/bar")
   :eval (file-name-parent-directory "foo"))
  "Quoted File Names"
  (file-name-quote
   :args (name)
   :eval (file-name-quote "/tmp/foo"))
  (file-name-unquote
   :args (name)
   :eval (file-name-unquote "/:/tmp/foo"))
  "Predicates"
  (file-name-absolute-p
   :eval (file-name-absolute-p "/tmp/foo")
   :eval (file-name-absolute-p "foo"))
  (directory-name-p
   :eval (directory-name-p "/tmp/foo/"))
  (file-name-quoted-p
   :eval (file-name-quoted-p "/:/tmp/foo")))

(define-short-documentation-group file
  "Inserting Contents"
  (insert-file-contents
   :no-eval (insert-file-contents "/tmp/foo")
   :eg-result ("/tmp/foo" 6))
  (insert-file-contents-literally
   :no-eval (insert-file-contents-literally "/tmp/foo")
   :eg-result ("/tmp/foo" 6))
  (find-file
   :no-eval (find-file "/tmp/foo")
   :eg-result-string "#<buffer foo>")
  "Predicates"
  (file-symlink-p
   :no-eval (file-symlink-p "/tmp/foo")
   :eg-result t)
  (file-directory-p
   :no-eval (file-directory-p "/tmp")
   :eg-result t)
  (file-regular-p
   :no-eval (file-regular-p "/tmp/foo")
   :eg-result t)
  (file-exists-p
   :no-eval (file-exists-p "/tmp/foo")
   :eg-result t)
  (file-readable-p
   :no-eval (file-readable-p "/tmp/foo")
   :eg-result t)
  (file-writeable-p
   :no-eval (file-writeable-p "/tmp/foo")
   :eg-result t)
  (file-accessible-directory-p
   :no-eval (file-accessible-directory-p "/tmp")
   :eg-result t)
  (file-executable-p
   :no-eval (file-executable-p "/bin/cat")
   :eg-result t)
  (file-newer-than-file-p
   :no-eval (file-newer-than-file-p "/tmp/foo" "/tmp/bar")
   :eg-result nil)
  (file-has-changed-p
   :no-eval (file-has-changed-p "/tmp/foo")
   :eg-result t)
  (file-equal-p
   :no-eval (file-equal-p "/tmp/foo" "/tmp/bar")
   :eg-result nil)
  (file-in-directory-p
   :no-eval (file-in-directory-p "/tmp/foo" "/tmp/")
   :eg-result t)
  (file-locked-p
   :no-eval (file-locked-p "/tmp/foo")
   :eg-result nil)
  "Information"
  (file-attributes
   :no-eval* (file-attributes "/tmp"))
  (file-truename
   :no-eval (file-truename "/tmp/foo/bar")
   :eg-result "/tmp/foo/zot")
  (file-chase-links
   :no-eval (file-chase-links "/tmp/foo/bar")
   :eg-result "/tmp/foo/zot")
  (vc-responsible-backend
   :args (file &optional no-error)
   :no-eval (vc-responsible-backend "/src/foo/bar.c")
   :eg-result Git)
  (file-acl
   :no-eval (file-acl "/tmp/foo")
   :eg-result "user::rw-\ngroup::r--\nother::r--\n")
  (file-extended-attributes
   :no-eval* (file-extended-attributes "/tmp/foo"))
  (file-selinux-context
   :no-eval* (file-selinux-context "/tmp/foo"))
  (locate-file
   :no-eval (locate-file "syslog" '("/var/log" "/usr/bin"))
   :eg-result "/var/log/syslog")
  (executable-find
   :no-eval (executable-find "ls")
   :eg-result "/usr/bin/ls")
  "Creating"
  (make-temp-file
   :no-eval (make-temp-file "/tmp/foo-")
   :eg-result "/tmp/foo-ZcXFMj")
  (make-nearby-temp-file
   :no-eval (make-nearby-temp-file "/tmp/foo-")
   :eg-result "/tmp/foo-xe8iON")
  (write-region
   :no-value (write-region (point-min) (point-max) "/tmp/foo"))
  "Directories"
  (make-directory
   :no-value (make-directory "/tmp/bar/zot/" t))
  (directory-files
   :no-eval (directory-files "/tmp/")
   :eg-result ("." ".." ".ICE-unix" ".Test-unix"))
  (directory-files-recursively
   :no-eval (directory-files-recursively "/tmp/" "\\.png\\'")
   :eg-result ("/tmp/foo.png" "/tmp/zot.png" "/tmp/bar/foobar.png"))
  (directory-files-and-attributes
   :no-eval* (directory-files-and-attributes "/tmp/foo"))
  (file-expand-wildcards
   :no-eval (file-expand-wildcards "/tmp/*.png")
   :eg-result ("/tmp/foo.png" "/tmp/zot.png")
   :no-eval (file-expand-wildcards "/*/foo.png")
   :eg-result ("/tmp/foo.png" "/var/foo.png"))
  (locate-dominating-file
   :no-eval (locate-dominating-file "foo.png" "/tmp/foo/bar/zot")
   :eg-result "/tmp/foo.png")
  (copy-directory
   :no-value (copy-directory "/tmp/bar/" "/tmp/barcopy"))
  (delete-directory
   :no-value (delete-directory "/tmp/bar/"))
  "File Operations"
  (rename-file
   :no-value (rename-file "/tmp/foo" "/tmp/newname"))
  (copy-file
   :no-value (copy-file "/tmp/foo" "/tmp/foocopy"))
  (delete-file
   :no-value (delete-file "/tmp/foo"))
  (make-empty-file
   :no-value (make-empty-file "/tmp/foo"))
  (make-symbolic-link
   :no-value (make-symbolic-link "/tmp/foo" "/tmp/foosymlink"))
  (add-name-to-file
   :no-value (add-name-to-file "/tmp/foo" "/tmp/bar"))
  (set-file-modes
   :no-value "(set-file-modes \"/tmp/foo\" #o644)")
  (set-file-times
   :no-value (set-file-times "/tmp/foo"))
  "File Modes"
  (set-default-file-modes
   :no-value "(set-default-file-modes #o755)")
  (default-file-modes
    :no-eval (default-file-modes)
    :eg-result-string "#o755")
  (file-modes-symbolic-to-number
   :no-eval (file-modes-symbolic-to-number "a+r")
   :eg-result-string "#o444")
  (file-modes-number-to-symbolic
   :eval "(file-modes-number-to-symbolic #o444)")
  (set-file-extended-attributes
   :no-eval (set-file-extended-attributes
             "/tmp/foo" '((acl . "group::rxx")))
   :eg-result t)
  (set-file-selinux-context
   :no-eval (set-file-selinux-context
             "/tmp/foo" '(unconfined_u object_r user_home_t s0))
   :eg-result t)
  (set-file-acl
   :no-eval (set-file-acl "/tmp/foo" "group::rxx")
   :eg-result t))

(define-short-documentation-group hash-table
  "Hash Table Basics"
  (make-hash-table
   :no-eval (make-hash-table)
   :result-string "#s(hash-table ...)")
  (puthash
   :no-eval (puthash 'key "value" table))
  (gethash
   :no-eval (gethash 'key table)
   :eg-result "value")
  (remhash
   :no-eval (remhash 'key table)
   :result nil)
  (clrhash
   :no-eval (clrhash table)
   :result-string "#s(hash-table ...)")
  (maphash
   :no-eval (maphash (lambda (key value) (message value)) table)
   :result nil)
  "Other Hash Table Functions"
  (hash-table-p
   :eval (hash-table-p 123))
  (copy-hash-table
   :no-eval (copy-hash-table table)
   :result-string "#s(hash-table ...)")
  (hash-table-count
   :no-eval (hash-table-count table)
   :eg-result 15)
  (hash-table-size
   :no-eval (hash-table-size table)
   :eg-result 65))

(define-short-documentation-group list
  "Making Lists"
  (make-list
   :eval (make-list 5 'a))
  (cons
   :eval (cons 1 '(2 3 4)))
  (list
   :eval (list 1 2 3))
  (number-sequence
   :eval (number-sequence 5 8))
  (ensure-list
   :eval (ensure-list "foo")
   :eval (ensure-list '(1 2 3)))
  "Operations on Lists"
  (append
   :eval (append '("foo" "bar") '("zot")))
  (copy-tree
   :eval (copy-tree '(1 (2 3) 4)))
  (flatten-tree
   :eval (flatten-tree '(1 (2 3) 4)))
  (car
   :eval (car '(one two three))
   :eval (car '(one . two))
   :eval (car nil))
  (cdr
   :eval (cdr '(one two three))
   :eval (cdr '(one . two))
   :eval (cdr nil))
  (last
   :eval (last '(one two three)))
  (butlast
   :eval (butlast '(one two three)))
  (nbutlast
   :eval (nbutlast (list 'one 'two 'three)))
  (nth
   :eval (nth 1 '(one two three)))
  (nthcdr
   :eval (nthcdr 1 '(one two three)))
  (take
   :eval (take 3 '(one two three four)))
  (ntake
   :eval (ntake 3 (list 'one 'two 'three 'four)))
  (elt
   :eval (elt '(one two three) 1))
  (car-safe
   :eval (car-safe '(one two three)))
  (cdr-safe
   :eval (cdr-safe '(one two three)))
  (push
   :no-eval* (push 'a list))
  (pop
   :no-eval* (pop list))
  (setcar
   :no-eval (setcar list 'c)
   :result c)
  (setcdr
   :no-eval (setcdr list (list c))
   :result '(c))
  (nconc
   :eval (nconc (list 1) (list 2 3 4)))
  (delq
   :eval (delq 2 (list 1 2 3 4))
   :eval (delq "a" (list "a" "b" "c" "d")))
  (delete
   :eval (delete 2 (list 1 2 3 4))
   :eval (delete "a" (list "a" "b" "c" "d")))
  (remove
   :eval (remove 2 '(1 2 3 4))
   :eval (remove "a" '("a" "b" "c" "d")))
  (delete-dups
   :eval (delete-dups (list 1 2 4 3 2 4)))
  "Mapping Over Lists"
  (mapcar
   :eval (mapcar #'list '(1 2 3)))
  (mapcan
   :eval (mapcan #'list '(1 2 3)))
  (mapc
   :eval (mapc #'insert '("1" "2" "3")))
  (reduce
   :eval (reduce #'+ '(1 2 3)))
  (mapconcat
   :eval (mapconcat #'identity '("foo" "bar") "|"))
  "Predicates"
  (listp
   :eval (listp '(1 2 3))
   :eval (listp nil)
   :eval (listp '(1 . 2)))
  (consp
   :eval (consp '(1 2 3))
   :eval (consp nil))
  (proper-list-p
   :eval (proper-list-p '(1 2 3))
   :eval (proper-list-p nil)
   :eval (proper-list-p '(1 . 2)))
  (null
   :eval (null nil))
  (atom
   :eval (atom 'a))
  (nlistp
   :eval (nlistp '(1 2 3))
   :eval (nlistp t)
   :eval (nlistp '(1 . 2)))
  "Finding Elements"
  (memq
   :eval (memq 2 '(1 2 3))
   :eval (memq 2.0 '(1.0 2.0 3.0))
   :eval (memq "b" '("a" "b" "c")))
  (member
   :eval (member 2 '(1 2 3))
   :eval (member "b" '("a" "b" "c")))
  (remq
   :eval (remq 2 '(1 2 3 2 4 2))
   :eval (remq "b" '("a" "b" "c")))
  (memql
   :eval (memql 2.0 '(1.0 2.0 3.0)))
  (member-ignore-case
   :eval (member-ignore-case "foo" '("bar" "Foo" "zot")))
  "Association Lists"
  (assoc
   :eval (assoc 'b '((a 1) (b 2))))
  (rassoc
   :eval (rassoc '2 '((a . 1) (b . 2))))
  (assq
   :eval (assq 'b '((a 1) (b 2)))
   :eval (assq "a" '(("a" 1) ("b" 2))))
  (rassq
   :eval (rassq '2 '((a . 1) (b . 2))))
  (assoc-string
   :eval (assoc-string "foo" '(("a" 1) (foo 2))))
  (alist-get
   :eval (alist-get 2 '((1 . a) (2 . b))))
  (assoc-default
   :eval (assoc-default 2 '((1 . a) (2 . b) #'=)))
  (copy-alist
   :eval (copy-alist '((1 . a) (2 . b))))
  (assq-delete-all
   :eval (assq-delete-all 2 (list '(1 . a) '(2 . b) '(2 . c))))
  (assoc-delete-all
   :eval (assoc-delete-all "b" (list '("a" . a) '("b" . b) '("b" . c))))
  "Property Lists"
  (plist-get
   :eval (plist-get '(a 1 b 2 c 3) 'b))
  (plist-put
   :no-eval (setq plist (plist-put plist 'd 4))
   :eq-result (a 1 b 2 c 3 d 4))
  (plist-member
   :eval (plist-member '(a 1 b 2 c 3) 'b))
  "Data About Lists"
  (length
   :eval (length '(a b c)))
  (length<
   :eval (length< '(a b c) 1))
  (length>
   :eval (length> '(a b c) 1))
  (length=
   :eval (length= '(a b c) 3))
  (safe-length
   :eval (safe-length '(a b c))))


(define-short-documentation-group vector
  "Making Vectors"
  (make-vector
   :eval (make-vector 5 "foo"))
  (vector
   :eval (vector 1 "b" 3))
  "Operations on Vectors"
  (vectorp
   :eval (vectorp [1])
   :eval (vectorp "1"))
  (vconcat
   :eval (vconcat '(1 2) [3 4]))
  (append
   :eval (append [1 2] nil))
  (length
   :eval (length [1 2 3]))
  (seq-reduce
   :eval (seq-reduce #'+ [1 2 3] 0))
  (seq-subseq
   :eval (seq-subseq [1 2 3 4 5] 1 3)
   :eval (seq-subseq [1 2 3 4 5] 1))
  "Mapping Over Vectors"
  (mapcar
   :eval (mapcar #'identity [1 2 3]))
  (mapc
   :eval (mapc #'insert ["1" "2" "3"])))

(define-short-documentation-group regexp
  "Matching Strings"
  (replace-regexp-in-string
   :eval (replace-regexp-in-string "[a-z]+" "_" "*foo*"))
  (string-match-p
   :eval (string-match-p "^[fo]+" "foobar"))
  "Looking in Buffers"
  (re-search-forward
   :no-eval (re-search-forward "^foo$" nil t)
   :eg-result 43)
  (re-search-backward
   :no-eval (re-search-backward "^foo$" nil t)
   :eg-result 43)
  (looking-at-p
   :no-eval (looking-at-p "f[0-9]")
   :eg-result t)
  "Match Data"
  (match-string
   :eval (and (string-match "^\\([fo]+\\)b" "foobar")
              (match-string 0 "foobar")))
  (match-beginning
   :no-eval (match-beginning 1)
   :eg-result 0)
  (match-end
   :no-eval (match-end 1)
   :eg-result 3)
  (save-match-data
    :no-eval (save-match-data ...))
  "Replacing Match"
  (replace-match
   :no-eval (replace-match "new")
   :eg-result nil)
  (match-substitute-replacement
   :no-eval (match-substitute-replacement "new")
   :eg-result "new")
  (replace-regexp-in-region
   :no-value (replace-regexp-in-region "[0-9]+" "Num \\&"))
  "Utilities"
  (regexp-quote
   :eval (regexp-quote "foo.*bar"))
  (regexp-opt
   :eval (regexp-opt '("foo" "bar")))
  (regexp-opt-depth
   :eval (regexp-opt-depth "\\(a\\(b\\)\\)"))
  (regexp-opt-charset
   :eval (regexp-opt-charset '(?a ?b ?c ?d ?e)))
  "The `rx' Structured Regexp Notation"
  (rx
   :eval (rx "IP=" (+ digit) (= 3 "." (+ digit))))
  (rx-to-string
   :eval (rx-to-string '(| "foo" "bar")))
  (rx-define
   :no-eval "(and (rx-define haskell-comment (seq \"--\" (zero-or-more nonl)))
       (rx haskell-comment))"
   :result "--.*")
  (rx-let
   :eval "(rx-let ((comma-separated (item) (seq item (0+ \",\" item)))
           (number (1+ digit))
           (numbers (comma-separated number)))
    (rx \"(\" numbers \")\"))"
   :result "([[:digit:]]+\\(?:,[[:digit:]]+\\)*)")
  (rx-let-eval
   :eval "(rx-let-eval
      '((ponder (x) (seq \"Where have all the \" x \" gone?\")))
    (rx-to-string
     '(ponder (or \"flowers\" \"cars\" \"socks\"))))"
   :result "\\(?:Where have all the \\(?:\\(?:car\\|flower\\|sock\\)s\\) gone\\?\\)"))

(define-short-documentation-group sequence
  "Sequence Predicates"
  (seq-contains-p
   :eval (seq-contains-p '(a b c) 'b)
   :eval (seq-contains-p '(a b c) 'd))
  (seq-every-p
   :eval (seq-every-p #'numberp '(1 2 3)))
  (seq-empty-p
   :eval (seq-empty-p []))
  (seq-set-equal-p
   :eval (seq-set-equal-p '(1 2 3) '(3 1 2)))
  (seq-some
   :eval (seq-some #'cl-evenp '(1 2 3)))
  "Building Sequences"
  (seq-concatenate
   :eval (seq-concatenate 'vector '(1 2) '(c d)))
  (seq-copy
   :eval (seq-copy '(a 2)))
  (seq-into
   :eval (seq-into '(1 2 3) 'vector))
  "Utility Functions"
  (seq-count
   :eval (seq-count #'numberp '(1 b c 4)))
  (seq-elt
   :eval (seq-elt '(a b c) 1))
  (seq-random-elt
   :no-eval (seq-random-elt '(a b c))
   :eg-result c)
  (seq-find
   :eval (seq-find #'numberp '(a b 3 4 f 6)))
  (seq-position
   :eval (seq-position '(a b c) 'c))
  (seq-positions
   :eval (seq-positions '(a b c a d) 'a)
   :eval (seq-positions '(a b c a d) 'z)
   :eval (seq-positions '(11 5 7 12 9 15) 10 #'>=))
  (seq-length
   :eval (seq-length "abcde"))
  (seq-max
   :eval (seq-max [1 2 3]))
  (seq-min
   :eval (seq-min [1 2 3]))
  (seq-first
   :eval (seq-first [a b c]))
  (seq-rest
   :eval (seq-rest '[1 2 3]))
  (seq-reverse
   :eval (seq-reverse '(1 2 3)))
  (seq-sort
   :eval (seq-sort #'> '(1 2 3)))
  (seq-sort-by
   :eval (seq-sort-by (lambda (a) (/ 1.0 a)) #'< '(1 2 3)))
  "Mapping Over Sequences"
  (seq-map
   :eval (seq-map #'1+ '(1 2 3)))
  (seq-map-indexed
   :eval (seq-map-indexed (lambda (a i) (cons i a)) '(a b c)))
  (seq-mapcat
   :eval (seq-mapcat #'upcase '("a" "b" "c") 'string))
  (seq-do
   :no-eval (seq-do (lambda (a) (insert a)) '("foo" "bar"))
   :eg-result ("foo" "bar"))
  (seq-do-indexed
   :no-eval (seq-do-indexed
             (lambda (a index) (message "%s:%s" index a))
             '("foo" "bar"))
   :eg-result nil)
  (seq-reduce
   :eval (seq-reduce #'* [1 2 3] 2))
  "Excerpting Sequences"
  (seq-drop
   :eval (seq-drop '(a b c) 2))
  (seq-drop-while
   :eval (seq-drop-while #'numberp '(1 2 c d 5)))
  (seq-filter
   :eval (seq-filter #'numberp '(a b 3 4 f 6)))
  (seq-keep
   :eval (seq-keep #'cl-digit-char-p '(?6 ?a ?7)))
  (seq-remove
   :eval (seq-remove #'numberp '(1 2 c d 5)))
  (seq-remove-at-position
   :eval (seq-remove-at-position '(a b c d e) 3)
   :eval (seq-remove-at-position [a b c d e] 0))
  (seq-group-by
   :eval (seq-group-by #'cl-plusp '(-1 2 3 -4 -5 6)))
  (seq-union
   :eval (seq-union '(1 2 3) '(3 5)))
  (seq-difference
   :eval (seq-difference '(1 2 3) '(2 3 4)))
  (seq-intersection
   :eval (seq-intersection '(1 2 3) '(2 3 4)))
  (seq-partition
   :eval (seq-partition '(a b c d e f g h) 3))
  (seq-subseq
   :eval (seq-subseq '(a b c d e) 2 4))
  (seq-take
   :eval (seq-take '(a b c d e) 3))
  (seq-split
   :eval (seq-split [0 1 2 3 5] 2))
  (seq-take-while
   :eval (seq-take-while #'cl-evenp [2 4 9 6 5]))
  (seq-uniq
   :eval (seq-uniq '(a b d b a c))))

(define-short-documentation-group buffer
  "Buffer Basics"
  (current-buffer
   :no-eval (current-buffer)
   :eg-result-string "#<buffer shortdoc.el>")
  (bufferp
   :eval (bufferp 23))
  (buffer-live-p
   :no-eval (buffer-live-p some-buffer)
   :eg-result t)
  (buffer-modified-p
   :eval (buffer-modified-p (current-buffer)))
  (buffer-name
   :eval (buffer-name))
  (window-buffer
   :eval (window-buffer))
  "Selecting Buffers"
  (get-buffer-create
   :no-eval (get-buffer-create "*foo*")
   :eg-result-string "#<buffer *foo*>")
  (pop-to-buffer
   :no-eval (pop-to-buffer "*foo*")
   :eg-result-string "#<buffer *foo*>")
  (with-current-buffer
      :no-eval* (with-current-buffer buffer (buffer-size)))
  "Points and Positions"
  (point
   :eval (point))
  (point-min
   :eval (point-min))
  (point-max
   :eval (point-max))
  (pos-bol
   :eval (pos-bol))
  (pos-eol
   :eval (pos-eol))
  (bolp
   :eval (bolp))
  (eolp
   :eval (eolp))
  (line-beginning-position
   :eval (line-beginning-position))
  (line-end-position
   :eval (line-end-position))
  (buffer-size
   :eval (buffer-size))
  (bobp
   :eval (bobp))
  (eobp
   :eval (eobp))
  "Moving Around"
  (goto-char
   :no-eval (goto-char (point-max))
   :eg-result 342)
  (search-forward
   :no-eval (search-forward "some-string" nil t)
   :eg-result 245)
  (re-search-forward
   :no-eval (re-search-forward "some-s.*g" nil t)
   :eg-result 245)
  (forward-line
   :no-eval (forward-line 1)
   :eg-result 0
   :no-eval (forward-line -2)
   :eg-result 0)
  "Strings from Buffers"
  (buffer-string
   :no-eval* (buffer-string))
  (buffer-substring
   :eval (buffer-substring (point-min) (+ (point-min) 10)))
  (buffer-substring-no-properties
   :eval (buffer-substring-no-properties (point-min) (+ (point-min) 10)))
  (following-char
   :no-eval (following-char)
   :eg-result 67)
  (preceding-char
   :no-eval (preceding-char)
   :eg-result 38)
  (char-after
   :eval (char-after 45))
  (char-before
   :eval (char-before 13))
  (get-byte
   :no-eval (get-byte 45)
   :eg-result-string "#xff")
  "Altering Buffers"
  (delete-region
   :no-value (delete-region (point-min) (point-max)))
  (erase-buffer
   :no-value (erase-buffer))
  (delete-line
   :no-value (delete-line))
  (insert
   :no-value (insert "This string will be inserted in the buffer\n"))
  (subst-char-in-region
   :no-eval "(subst-char-in-region (point-min) (point-max) ?+ ?-)")
  (replace-string-in-region
   :no-value (replace-string-in-region "foo" "bar"))
  "Locking"
  (lock-buffer
   :no-value (lock-buffer "/tmp/foo"))
  (unlock-buffer
   :no-value (unlock-buffer)))

(define-short-documentation-group overlay
  "Predicates"
  (overlayp
   :no-eval (overlayp some-overlay)
   :eg-result t)
  "Creation and Deletion"
  (make-overlay
   :args (beg end &optional buffer)
   :no-eval (make-overlay 1 10)
   :eg-result-string "#<overlay from 1 to 10 in *foo*>")
  (delete-overlay
   :no-eval (delete-overlay foo)
   :eg-result t)
  "Searching Overlays"
  (overlays-at
   :no-eval (overlays-at 15)
   :eg-result-string "(#<overlay from 1 to 10 in *foo*>)")
  (overlays-in
   :no-eval (overlays-in 1 30)
   :eg-result-string "(#<overlay from 1 to 10 in *foo*>)")
  (next-overlay-change
   :no-eval (next-overlay-change 1)
   :eg-result 20)
  (previous-overlay-change
   :no-eval (previous-overlay-change 30)
   :eg-result 20)
  "Overlay Properties"
  (overlay-start
   :no-eval (overlay-start foo)
   :eg-result 1)
  (overlay-end
   :no-eval (overlay-end foo)
   :eg-result 10)
  (overlay-put
   :no-eval (overlay-put foo 'happy t)
   :eg-result t)
  (overlay-get
   :no-eval (overlay-get foo 'happy)
   :eg-result t)
  (overlay-buffer
   :no-eval (overlay-buffer foo))
  "Moving Overlays"
  (move-overlay
   :no-eval (move-overlay foo 5 20)
   :eg-result-string "#<overlay from 5 to 20 in *foo*>"))

(define-short-documentation-group process
  (make-process
   :no-eval (make-process :name "foo" :command '("cat" "/tmp/foo"))
   :eg-result-string "#<process foo>")
  (processp
   :eval (processp t))
  (delete-process
   :no-value (delete-process process))
  (kill-process
   :no-value (kill-process process))
  (set-process-sentinel
   :no-value (set-process-sentinel process (lambda (proc string))))
  (process-buffer
   :no-eval (process-buffer process)
   :eg-result-string "#<buffer *foo*>")
  (get-buffer-process
   :no-eval (get-buffer-process buffer)
   :eg-result-string "#<process foo>")
  (process-live-p
   :no-eval (process-live-p process)
   :eg-result t))

(define-short-documentation-group number
  "Arithmetic"
  (+
   :args (&rest numbers)
   :eval (+ 1 2)
   :eval (+ 1 2 3 4))
  (-
   :args (&rest numbers)
   :eval (- 3 2)
   :eval (- 6 3 2))
  (*
   :args (&rest numbers)
   :eval (* 3 4 5))
  (/
   :eval (/ 10 5)
   :eval (/ 10 6)
   :eval (/ 10.0 6)
   :eval (/ 10.0 3 3))
  (%
   :eval (% 10 5)
   :eval (% 10 6))
  (mod
   :eval (mod 10 5)
   :eval (mod 10 6)
   :eval (mod 10.5 6))
  (1+
   :eval (1+ 2))
  (1-
   :eval (1- 4))
  "Predicates"
  (=
   :args (number &rest numbers)
   :eval (= 4 4)
   :eval (= 4.0 4.0)
   :eval (= 4 5 6 7))
  (eq
   :eval (eq 4 4)
   :eval (eq 4.0 4.0))
  (eql
   :eval (eql 4 4)
   :eval (eql 4 "4")
   :eval (eql 4.0 4.0))
  (/=
   :eval (/= 4 4))
  (<
   :args (number &rest numbers)
   :eval (< 4 4)
   :eval (< 1 2 3))
  (<=
   :args (number &rest numbers)
   :eval (<= 4 4)
   :eval (<= 1 2 3))
  (>
   :args (number &rest numbers)
   :eval (> 4 4)
   :eval (> 1 2 3))
  (>=
   :args (number &rest numbers)
   :eval (>= 4 4)
   :eval (>= 1 2 3))
  (zerop
   :eval (zerop 0))
  (cl-plusp
   :eval (cl-plusp 0)
   :eval (cl-plusp 1))
  (cl-minusp
   :eval (cl-minusp 0)
   :eval (cl-minusp -1))
  (cl-oddp
   :eval (cl-oddp 3))
  (cl-evenp
   :eval (cl-evenp 6))
  (natnump
   :eval (natnump -1)
   :eval (natnump 23))
  (bignump
   :eval (bignump 4)
   :eval (bignump (expt 2 90)))
  (fixnump
   :eval (fixnump 4)
   :eval (fixnump (expt 2 90)))
  (floatp
   :eval (floatp 5.4))
  (integerp
   :eval (integerp 5.4))
  (numberp
   :eval (numberp "5.4"))
  (cl-digit-char-p
   :eval (cl-digit-char-p ?5 10)
   :eval (cl-digit-char-p ?f 16))
  "Operations"
  (max
   :args (number &rest numbers)
   :eval (max 7 9 3))
  (min
   :args (number &rest numbers)
   :eval (min 7 9 3))
  (abs
   :eval (abs -4))
  (float
   :eval (float 2))
  (truncate
   :eval (truncate 1.2)
   :eval (truncate -1.2)
   :eval (truncate 5.4 2))
  (floor
   :eval (floor 1.2)
   :eval (floor -1.2)
   :eval (floor 5.4 2))
  (ceiling
   :eval (ceiling 1.2)
   :eval (ceiling -1.2)
   :eval (ceiling 5.4 2))
  (round
   :eval (round 1.2)
   :eval (round -1.2)
   :eval (round 5.4 2))
  (random
   :eval (random 6))
  "Bit Operations"
  (ash
   :eval (ash 1 4)
   :eval (ash 16 -1))
  (logand
   :no-eval "(logand #b10 #b111)"
   :result-string "#b10")
  (logior
   :eval (logior 4 16))
  (logxor
   :eval (logxor 4 16))
  (lognot
   :eval (lognot 5))
  (logcount
   :eval (logcount 5))
  "Floating Point"
  (isnan
   :eval (isnan 5.0))
  (frexp
   :eval (frexp 5.7))
  (ldexp
   :eval (ldexp 0.7125 3))
  (logb
   :eval (logb 10.5))
  (ffloor
   :eval (ffloor 1.2))
  (fceiling
   :eval (fceiling 1.2))
  (ftruncate
   :eval (ftruncate 1.2))
  (fround
   :eval (fround 1.2))
  "Standard Math Functions"
  (sin
   :eval (sin float-pi))
  (cos
   :eval (cos float-pi))
  (tan
   :eval (tan float-pi))
  (asin
   :eval (asin float-pi))
  (acos
   :eval (acos float-pi))
  (atan
   :eval (atan float-pi))
  (exp
   :eval (exp 4))
  (log
   :eval (log 54.59))
  (expt
   :eval (expt 2 16))
  (sqrt
   :eval (sqrt -1)))

(define-short-documentation-group text-properties
  "Examining Text Properties"
  (get-text-property
   :eval (get-text-property 0 'foo (propertize "x" 'foo t)))
  (get-char-property
   :eval (get-char-property 0 'foo (propertize "x" 'foo t)))
  (get-pos-property
   :eval (get-pos-property 0 'foo (propertize "x" 'foo t)))
  (get-char-property-and-overlay
   :eval (get-char-property-and-overlay 0 'foo (propertize "x" 'foo t)))
  (text-properties-at
   :eval (text-properties-at (point)))
  "Changing Text Properties"
  (put-text-property
   :eval (let ((s "abc")) (put-text-property 0 1 'foo t s) s)
   :no-eval (put-text-property (point) (1+ (point)) 'face 'error))
  (add-text-properties
   :no-eval (add-text-properties (point) (1+ (point)) '(face error)))
  (remove-text-properties
   :no-eval (remove-text-properties (point) (1+ (point)) '(face nil)))
  (remove-list-of-text-properties
   :no-eval (remove-list-of-text-properties (point) (1+ (point)) '(face font-lock-face)))
  (set-text-properties
   :no-eval (set-text-properties (point) (1+ (point)) '(face error)))
  (add-face-text-property
   (add-face-text-property START END '(:foreground "green")))
  (propertize
   :eval (propertize "foo" 'face 'italic 'mouse-face 'bold-italic))
  "Searching for Text Properties"
  (next-property-change
   :no-eval (next-property-change (point) (current-buffer)))
  (previous-property-change
   :no-eval (previous-property-change (point) (current-buffer)))
  (next-single-property-change
   :no-eval (next-single-property-change (point) 'face (current-buffer)))
  (previous-single-property-change
   :no-eval (previous-single-property-change (point) 'face (current-buffer)))
  ;; TODO: There are some more that could be added here.
  (text-property-search-forward
   :no-eval (text-property-search-forward 'face nil t))
  (text-property-search-backward
   :no-eval (text-property-search-backward 'face nil t)))

(define-short-documentation-group keymaps
  "Defining keymaps"
  (define-keymap
    :no-eval (define-keymap "C-c C-c" #'quit-buffer))
  (defvar-keymap
      :no-eval (defvar-keymap my-keymap "C-c C-c" #'quit-buffer))
  "Setting keys"
  (keymap-set
   :no-eval (keymap-set map "C-c C-c" #'quit-buffer))
  (keymap-local-set
   :no-eval (keymap-local-set "C-c C-c" #'quit-buffer))
  (keymap-global-set
   :no-eval (keymap-global-set "C-c C-c" #'quit-buffer))
  (keymap-unset
   :no-eval (keymap-unset map "C-c C-c"))
  (keymap-local-unset
   :no-eval (keymap-local-unset "C-c C-c"))
  (keymap-global-unset
   :no-eval (keymap-global-unset "C-c C-c"))
  (keymap-substitute
   :no-eval (keymap-substitute map "C-c C-c" "M-a"))
  (keymap-set-after
   :no-eval (keymap-set-after map "<separator-2>" menu-bar-separator))
  "Predicates"
  (keymapp
   :eval (keymapp (define-keymap)))
  (key-valid-p
   :eval (key-valid-p "C-c C-c")
   :eval (key-valid-p "C-cC-c"))
  "Lookup"
  (keymap-lookup
   :eval (keymap-lookup (current-global-map) "C-x x g")))

;;;###autoload
(defun shortdoc-display-group (group &optional function same-window)
  "Pop to a buffer with short documentation summary for functions in GROUP.
If FUNCTION is non-nil, place point on the entry for FUNCTION (if any).
If SAME-WINDOW, don't pop to a new window."
  (interactive (list (completing-read "Show summary for functions in: "
                                      (mapcar #'car shortdoc--groups))))
  (when (stringp group)
    (setq group (intern group)))
  (unless (assq group shortdoc--groups)
    (error "No such documentation group %s" group))
  (funcall (if same-window
               #'pop-to-buffer-same-window
             #'pop-to-buffer)
           (format "*Shortdoc %s*" group))
  (let ((inhibit-read-only t)
        (prev nil))
    (erase-buffer)
    (shortdoc-mode)
    (button-mode)
    (mapc
     (lambda (data)
       (cond
        ((stringp data)
         (setq prev nil)
         (unless (bobp)
           (insert "\n"))
         (insert (propertize
                  (concat (substitute-command-keys data) "\n\n")
                  'face 'shortdoc-heading
                  'shortdoc-section t)))
        ;; There may be functions not yet defined in the data.
        ((fboundp (car data))
         (when prev
           (insert (make-separator-line)))
         (setq prev t)
         (shortdoc--display-function data))))
     (cdr (assq group shortdoc--groups))))
  (goto-char (point-min))
  (when function
    (text-property-search-forward 'shortdoc-function function t)
    (beginning-of-line)))

;;;###autoload
(defalias 'shortdoc #'shortdoc-display-group)

(defun shortdoc--display-function (data)
  (let ((function (pop data))
        (start-section (point))
        arglist-start)
    ;; Function calling convention.
    (insert (propertize "(" 'shortdoc-function function))
    (if (plist-get data :no-manual)
        (insert-text-button
         (symbol-name function)
         'face 'button
         'action (lambda (_)
                   (describe-function function))
         'follow-link t
         'help-echo "mouse-1, RET: describe function")
      (insert-text-button
       (symbol-name function)
       'face 'button
       'action (lambda (_)
                 (info-lookup-symbol function 'emacs-lisp-mode))
       'follow-link t
       'help-echo "mouse-1, RET: show \
function's documentation in the Info manual"))
    (setq arglist-start (point))
    (insert ")\n")
    ;; Doc string.
    (insert "  "
            (or (plist-get data :doc)
                (car (split-string (documentation function) "\n"))))
    (insert "\n")
    (add-face-text-property start-section (point) 'shortdoc-section t)
    (let ((print-escape-newlines t)
          (double-arrow (if (char-displayable-p ?⇒)
                            "⇒"
                          "=>"))
          (single-arrow (if (char-displayable-p ?→)
                            "→"
                          "->")))
      (cl-loop for (type value) on data by #'cddr
               do
               (cl-case type
                 (:eval
                  (if (stringp value)
                      (insert "  " value "\n")
                    (insert "  ")
                    (prin1 value (current-buffer))
                    (insert "\n")
                    (insert "    " double-arrow " ")
                    (prin1 (eval value) (current-buffer))
                    (insert "\n")))
                 (:no-eval*
                  (if (stringp value)
                      (insert "  " value "\n")
                    (insert "  ")
                    (prin1 value (current-buffer)))
                  (insert "\n    " single-arrow " "
                          (propertize "[it depends]"
                                      'face 'shortdoc-section)
                          "\n"))
                 (:no-value
                  (if (stringp value)
                      (insert "  " value)
                    (insert "  ")
                    (prin1 value (current-buffer)))
                  (insert "\n"))
                 (:no-eval
                  (if (stringp value)
                      (insert "  " value)
                    (insert "  ")
                    (prin1 value (current-buffer)))
                  (insert "\n"))
                 (:result
                  (insert "    " double-arrow " ")
                  (prin1 value (current-buffer))
                  (insert "\n"))
                 (:result-string
                  (insert "    " double-arrow " ")
                  (princ value (current-buffer))
                  (insert "\n"))
                 (:eg-result
                  (insert "    e.g. " double-arrow " ")
                  (prin1 value (current-buffer))
                  (insert "\n"))
                 (:eg-result-string
                  (insert "    e.g. " double-arrow " ")
                  (princ value (current-buffer))
                  (insert "\n")))))
    ;; Insert the arglist after doing the evals, in case that's pulled
    ;; in the function definition.
    (save-excursion
      (goto-char arglist-start)
      (dolist (param (or (plist-get data :args)
                         (help-function-arglist function t)))
        (insert " " (symbol-name param)))
      (add-face-text-property arglist-start (point) 'shortdoc-section t))))

(defun shortdoc-function-groups (function)
  "Return all shortdoc groups FUNCTION appears in."
  (cl-loop for group in shortdoc--groups
           when (assq function (cdr group))
           collect (car group)))

(defun shortdoc-add-function (group section elem)
  "Add ELEM to shortdoc GROUP in SECTION.
If GROUP doesn't exist, it will be created.
If SECTION doesn't exist, it will be added.

ELEM is a Lisp form.  See `define-short-documentation-group' for
details.

Example:

  (shortdoc-add-function
    \\='file \"Predicates\"
    \\='(file-locked-p :no-eval (file-locked-p \"/tmp\")))"
  (let ((glist (assq group shortdoc--groups)))
    (unless glist
      (setq glist (list group))
      (push glist shortdoc--groups))
    (let ((slist (member section glist)))
      (unless slist
        (setq slist (list section))
        (nconc glist slist))
      (while (and (cdr slist)
                  (not (stringp (cadr slist))))
        (setq slist (cdr slist)))
      (setcdr slist (cons elem (cdr slist))))))

(defvar-keymap shortdoc-mode-map
  :doc "Keymap for `shortdoc-mode'."
  "n"       #'shortdoc-next
  "p"       #'shortdoc-previous
  "N"       #'shortdoc-next-section
  "P"       #'shortdoc-previous-section
  "C-c C-n" #'shortdoc-next-section
  "C-c C-p" #'shortdoc-previous-section
  "w"       #'shortdoc-copy-function-as-kill)

(define-derived-mode shortdoc-mode special-mode "shortdoc"
  "Mode for shortdoc."
  :interactive nil)

(defun shortdoc--goto-section (arg sym &optional reverse)
  (unless (natnump arg)
    (setq arg 1))
  (while (> arg 0)
    (funcall
     (if reverse 'text-property-search-backward
       'text-property-search-forward)
     sym nil t)
    (setq arg (1- arg))))

(defun shortdoc-next (&optional arg)
  "Move point to the next function.
With prefix numeric argument ARG, do it that many times."
  (interactive "p" shortdoc-mode)
  (shortdoc--goto-section arg 'shortdoc-function))

(defun shortdoc-previous (&optional arg)
  "Move point to the previous function.
With prefix numeric argument ARG, do it that many times."
  (interactive "p" shortdoc-mode)
  (shortdoc--goto-section arg 'shortdoc-function t)
  (backward-char 1))

(defun shortdoc-next-section (&optional arg)
  "Move point to the next section.
With prefix numeric argument ARG, do it that many times."
  (interactive "p" shortdoc-mode)
  (shortdoc--goto-section arg 'shortdoc-section))

(defun shortdoc-previous-section (&optional arg)
  "Move point to the previous section.
With prefix numeric argument ARG, do it that many times."
  (interactive "p" shortdoc-mode)
  (shortdoc--goto-section arg 'shortdoc-section t)
  (forward-line -2))

(defun shortdoc-copy-function-as-kill ()
  "Copy name of the function near point into the kill ring."
  (interactive)
  (save-excursion
    (goto-char (pos-bol))
    (when-let* ((re (rx bol "(" (group (+ (not (in " "))))))
                (string
                 (and (or (looking-at re)
                          (re-search-backward re nil t))
                      (match-string 1))))
      (set-text-properties 0 (length string) nil string)
      (kill-new string)
      (message string))))

(provide 'shortdoc)

;;; shortdoc.el ends here