;;; apropos.el --- apropos commands for users and programmers

;; Copyright (C) 1989, 1994, 1995, 2001, 2002, 2003, 2004,
;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.

;; Author: Joe Wells <jbw@bigbird.bu.edu>
;; Rewritten: Daniel Pfeiffer <occitan@esperanto.org>
;; Keywords: help

;; 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, 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; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; The ideas for this package were derived from the C code in
;; src/keymap.c and elsewhere.  The functions in this file should
;; always be byte-compiled for speed.  Someone should rewrite this in
;; C (as part of src/keymap.c) for speed.

;; The idea for super-apropos is based on the original implementation
;; by Lynn Slater <lrs@esl.com>.

;; History:
;; Fixed bug, current-local-map can return nil.
;; Change, doesn't calculate key-bindings unless needed.
;; Added super-apropos capability, changed print functions.
;;; Made fast-apropos and super-apropos share code.
;;; Sped up fast-apropos again.
;; Added apropos-do-all option.
;;; Added fast-command-apropos.
;; Changed doc strings to comments for helping functions.
;;; Made doc file buffer read-only, buried it.
;; Only call substitute-command-keys if do-all set.

;; Optionally use configurable faces to make the output more legible.
;; Differentiate between command, function and macro.
;; Apropos-command (ex command-apropos) does cmd and optionally user var.
;; Apropos shows all 3 aspects of symbols (fn, var and plist)
;; Apropos-documentation (ex super-apropos) now finds all it should.
;; New apropos-value snoops through all values and optionally plists.
;; Reading DOC file doesn't load nroff.
;; Added hypertext following of documentation, mouse-2 on variable gives value
;;   from buffer in active window.

;;; Code:

(require 'button)
(eval-when-compile (require 'cl))

(defgroup apropos nil
  "Apropos commands for users and programmers."
  :group 'help
  :prefix "apropos")

;; I see a degradation of maybe 10-20% only.
(defcustom apropos-do-all nil
  "*Whether the apropos commands should do more.

Slows them down more or less.  Set this non-nil if you have a fast machine."
  :group 'apropos
  :type 'boolean)


(defcustom apropos-symbol-face 'bold
  "*Face for symbol name in Apropos output, or nil for none."
  :group 'apropos
  :type 'face)

(defcustom apropos-keybinding-face 'underline
  "*Face for lists of keybinding in Apropos output, or nil for none."
  :group 'apropos
  :type 'face)

(defcustom apropos-label-face 'italic
  "*Face for label (`Command', `Variable' ...) in Apropos output.
A value of nil means don't use any special font for them, and also
turns off mouse highlighting."
  :group 'apropos
  :type 'face)

(defcustom apropos-property-face 'bold-italic
  "*Face for property name in apropos output, or nil for none."
  :group 'apropos
  :type 'face)

(defcustom apropos-match-face 'match
  "*Face for matching text in Apropos documentation/value, or nil for none.
This applies when you look for matches in the documentation or variable value
for the pattern; the part that matches gets displayed in this font."
  :group 'apropos
  :type 'face)

(defcustom apropos-sort-by-scores nil
  "*Non-nil means sort matches by scores; best match is shown first.
This applies to all `apropos' commands except `apropos-documentation'.
If value is `verbose', the computed score is shown for each match."
  :group 'apropos
  :type '(choice (const :tag "off" nil)
		 (const :tag "on" t)
		 (const :tag "show scores" verbose)))

(defcustom apropos-documentation-sort-by-scores t
  "*Non-nil means sort matches by scores; best match is shown first.
This applies to `apropos-documentation' only.
If value is `verbose', the computed score is shown for each match."
  :group 'apropos
  :type '(choice (const :tag "off" nil)
		 (const :tag "on" t)
		 (const :tag "show scores" verbose)))

(defvar apropos-mode-map
  (let ((map (make-sparse-keymap)))
    (set-keymap-parent map button-buffer-map)
    ;; Use `apropos-follow' instead of just using the button
    ;; definition of RET, so that users can use it anywhere in an
    ;; apropos item, not just on top of a button.
    (define-key map "\C-m" 'apropos-follow)
    (define-key map " "    'scroll-up)
    (define-key map "\177" 'scroll-down)
    (define-key map "q"    'quit-window)
    map)
  "Keymap used in Apropos mode.")

(defvar apropos-mode-hook nil
  "*Hook run when mode is turned on.")

(defvar apropos-pattern nil
  "Apropos pattern as entered by user.")

(defvar apropos-pattern-quoted nil
  "Apropos pattern passed through `regexp-quote'.")

(defvar apropos-words ()
  "Current list of apropos words extracted from `apropos-pattern'.")

(defvar apropos-all-words ()
  "Current list of words and synonyms.")

(defvar apropos-regexp nil
  "Regexp used in current apropos run.")

(defvar apropos-all-words-regexp nil
  "Regexp matching apropos-all-words.")

(defvar apropos-files-scanned ()
  "List of elc files already scanned in current run of `apropos-documentation'.")

(defvar apropos-accumulator ()
  "Alist of symbols already found in current apropos run.")

(defvar apropos-item ()
  "Current item in or for `apropos-accumulator'.")

(defvar apropos-synonyms '(
  ("find" "open" "edit")
  ("kill" "cut")
  ("yank" "paste")
  ("region" "selection"))
  "List of synonyms known by apropos.
Each element is a list of words where the first word is the standard Emacs
term, and the rest of the words are alternative terms.")


;;; Button types used by apropos

(define-button-type 'apropos-symbol
  'face apropos-symbol-face
  'help-echo "mouse-2, RET: Display more help on this symbol"
  'follow-link t
  'action #'apropos-symbol-button-display-help
  'skip t)

(defun apropos-symbol-button-display-help (button)
  "Display further help for the `apropos-symbol' button BUTTON."
  (button-activate
   (or (apropos-next-label-button (button-start button))
       (error "There is nothing to follow for `%s'" (button-label button)))))

(define-button-type 'apropos-function
  'apropos-label "Function"
  'help-echo "mouse-2, RET: Display more help on this function"
  'follow-link t
  'action (lambda (button)
	    (describe-function (button-get button 'apropos-symbol))))

(define-button-type 'apropos-macro
  'apropos-label "Macro"
  'help-echo "mouse-2, RET: Display more help on this macro"
  'follow-link t
  'action (lambda (button)
	    (describe-function (button-get button 'apropos-symbol))))

(define-button-type 'apropos-command
  'apropos-label "Command"
  'help-echo "mouse-2, RET: Display more help on this command"
  'follow-link t
  'action (lambda (button)
	    (describe-function (button-get button 'apropos-symbol))))

;; We used to use `customize-variable-other-window' instead for a
;; customizable variable, but that is slow.  It is better to show an
;; ordinary help buffer and let the user click on the customization
;; button in that buffer, if he wants to.
;; Likewise for `customize-face-other-window'.
(define-button-type 'apropos-variable
  'apropos-label "Variable"
  'help-echo "mouse-2, RET: Display more help on this variable"
  'follow-link t
  'action (lambda (button)
	    (describe-variable (button-get button 'apropos-symbol))))

(define-button-type 'apropos-face
  'apropos-label "Face"
  'help-echo "mouse-2, RET: Display more help on this face"
  'follow-link t
  'action (lambda (button)
	    (describe-face (button-get button 'apropos-symbol))))

(define-button-type 'apropos-group
  'apropos-label "Group"
  'help-echo "mouse-2, RET: Display more help on this group"
  'follow-link t
  'action (lambda (button)
	    (customize-group-other-window
	     (button-get button 'apropos-symbol))))

(define-button-type 'apropos-widget
  'apropos-label "Widget"
  'help-echo "mouse-2, RET: Display more help on this widget"
  'follow-link t
  'action (lambda (button)
	    (widget-browse-other-window (button-get button 'apropos-symbol))))

(define-button-type 'apropos-plist
  'apropos-label "Plist"
  'help-echo "mouse-2, RET: Display more help on this plist"
  'follow-link t
  'action (lambda (button)
	    (apropos-describe-plist (button-get button 'apropos-symbol))))

(defun apropos-next-label-button (pos)
  "Return the next apropos label button after POS, or nil if there's none.
Will also return nil if more than one `apropos-symbol' button is encountered
before finding a label."
  (let* ((button (next-button pos t))
	 (already-hit-symbol nil)
	 (label (and button (button-get button 'apropos-label)))
	 (type (and button (button-get button 'type))))
    (while (and button
		(not label)
		(or (not (eq type 'apropos-symbol))
		    (not already-hit-symbol)))
      (when (eq type 'apropos-symbol)
	(setq already-hit-symbol t))
      (setq button (next-button (button-start button)))
      (when button
	(setq label (button-get button 'apropos-label))
	(setq type (button-get button 'type))))
    (and label button)))


(defun apropos-words-to-regexp (words wild)
  "Make regexp matching any two of the words in WORDS."
  (concat "\\("
	  (mapconcat 'identity words "\\|")
	  "\\)"
	  (if (cdr words)
	      (concat wild
		      "\\("
		      (mapconcat 'identity words "\\|")
		      "\\)")
	    "")))

;;;###autoload
(defun apropos-read-pattern (subject)
  "Read an apropos pattern, either a word list or a regexp.
Returns the user pattern, either a list of words which are matched
literally, or a string which is used as a regexp to search for.

SUBJECT is a string that is included in the prompt to identify what
kind of objects to search."
  (let ((pattern
	 (read-string (concat "Apropos " subject " (word list or regexp): "))))
    (if (string-equal (regexp-quote pattern) pattern)
	;; Split into words
	(split-string pattern "[ \t]+")
      pattern)))

(defun apropos-parse-pattern (pattern)
  "Rewrite a list of words to a regexp matching all permutations.
If PATTERN is a string, that means it is already a regexp.
This updates variables `apropos-pattern', `apropos-pattern-quoted',
`apropos-regexp', `apropos-words', and `apropos-all-words-regexp'."
  (setq apropos-words nil
	apropos-all-words nil)
  (if (consp pattern)
      ;; We don't actually make a regexp matching all permutations.
      ;; Instead, for e.g. "a b c", we make a regexp matching
      ;; any combination of two or more words like this:
      ;; (a|b|c).*(a|b|c) which may give some false matches,
      ;; but as long as it also gives the right ones, that's ok.
      (let ((words pattern))
	(setq apropos-pattern (mapconcat 'identity pattern " ")
	      apropos-pattern-quoted (regexp-quote apropos-pattern))
	(dolist (word words)
	  (let ((syn apropos-synonyms) (s word) (a word))
	    (while syn
	      (if (member word (car syn))
		  (progn
		    (setq a (mapconcat 'identity (car syn) "\\|"))
		    (if (member word (cdr (car syn)))
			(setq s a))
		    (setq syn nil))
		(setq syn (cdr syn))))
	    (setq apropos-words (cons s apropos-words)
		  apropos-all-words (cons a apropos-all-words))))
	(setq apropos-all-words-regexp
	      (apropos-words-to-regexp apropos-all-words ".+"))
	(setq apropos-regexp
	      (apropos-words-to-regexp apropos-words ".*?")))
    (setq apropos-pattern-quoted (regexp-quote pattern)
	  apropos-all-words-regexp pattern
	  apropos-pattern pattern
	  apropos-regexp pattern)))


(defun apropos-calc-scores (str words)
  "Return apropos scores for string STR matching WORDS.
Value is a list of offsets of the words into the string."
  (let (scores i)
    (if words
	(dolist (word words scores)
	  (if (setq i (string-match word str))
	      (setq scores (cons i scores))))
      ;; Return list of start and end position of regexp
      (and (string-match apropos-pattern str)
	   (list (match-beginning 0) (match-end 0))))))

(defun apropos-score-str (str)
  "Return apropos score for string STR."
  (if str
      (let* ((l (length str))
	     (score (- (/ l 10))))
	(dolist (s (apropos-calc-scores str apropos-all-words) score)
	  (setq score (+ score 1000 (/ (* (- l s) 1000) l)))))
      0))

(defun apropos-score-doc (doc)
  "Return apropos score for documentation string DOC."
  (let ((l (length doc)))
    (if (> l 0)
	(let ((score 0) i)
	  (when (setq i (string-match apropos-pattern-quoted doc))
	    (setq score 10000))
	  (dolist (s (apropos-calc-scores doc apropos-all-words) score)
	    (setq score (+ score 50 (/ (* (- l s) 50) l)))))
      0)))

(defun apropos-score-symbol (symbol &optional weight)
  "Return apropos score for SYMBOL."
  (setq symbol (symbol-name symbol))
  (let ((score 0)
	(l (length symbol)))
    (dolist (s (apropos-calc-scores symbol apropos-words) (* score (or weight 3)))
      (setq score (+ score (- 60 l) (/ (* (- l s) 60) l))))))

(defun apropos-true-hit (str words)
  "Return t if STR is a genuine hit.
This may fail if only one of the keywords is matched more than once.
This requires that at least 2 keywords (unless only one was given)."
  (or (not str)
      (not words)
      (not (cdr words))
      (> (length (apropos-calc-scores str words)) 1)))

(defun apropos-false-hit-symbol (symbol)
  "Return t if SYMBOL is not really matched by the current keywords."
  (not (apropos-true-hit (symbol-name symbol) apropos-words)))

(defun apropos-false-hit-str (str)
  "Return t if STR is not really matched by the current keywords."
  (not (apropos-true-hit str apropos-words)))

(defun apropos-true-hit-doc (doc)
  "Return t if DOC is really matched by the current keywords."
  (apropos-true-hit doc apropos-all-words))

(define-derived-mode apropos-mode fundamental-mode "Apropos"
  "Major mode for following hyperlinks in output of apropos commands.

\\{apropos-mode-map}")

;;;###autoload
(defun apropos-variable (pattern &optional do-all)
  "Show user variables that match PATTERN.
PATTERN can be a word, a list of words (separated by spaces),
or a regexp (using some regexp special characters).  If it is a word,
search for matches for that word as a substring.  If it is a list of words,
search for matches for any two (or more) of those words.

With \\[universal-argument] prefix, or if `apropos-do-all' is non-nil, also show
normal variables."
  (interactive (list (apropos-read-pattern
		      (if (or current-prefix-arg apropos-do-all)
			  "variable" "user option"))
                     current-prefix-arg))
  (apropos-command pattern nil
		   (if (or do-all apropos-do-all)
		       #'(lambda (symbol)
			   (and (boundp symbol)
				(get symbol 'variable-documentation)))
		     'user-variable-p)))

;; For auld lang syne:
;;;###autoload
(defalias 'command-apropos 'apropos-command)
;;;###autoload
(defun apropos-command (pattern &optional do-all var-predicate)
  "Show commands (interactively callable functions) that match PATTERN.
PATTERN can be a word, a list of words (separated by spaces),
or a regexp (using some regexp special characters).  If it is a word,
search for matches for that word as a substring.  If it is a list of words,
search for matches for any two (or more) of those words.

With \\[universal-argument] prefix, or if `apropos-do-all' is non-nil, also show
noninteractive functions.

If VAR-PREDICATE is non-nil, show only variables, and only those that
satisfy the predicate VAR-PREDICATE.

When called from a Lisp program, a string PATTERN is used as a regexp,
while a list of strings is used as a word list."
  (interactive (list (apropos-read-pattern
		      (if (or current-prefix-arg apropos-do-all)
			  "command or function" "command"))
		     current-prefix-arg))
  (apropos-parse-pattern pattern)
  (let ((message
	 (let ((standard-output (get-buffer-create "*Apropos*")))
	   (print-help-return-message 'identity))))
    (or do-all (setq do-all apropos-do-all))
    (setq apropos-accumulator
	  (apropos-internal apropos-regexp
			    (or var-predicate
				(if do-all 'functionp 'commandp))))
    (let ((tem apropos-accumulator))
      (while tem
	(if (or (get (car tem) 'apropos-inhibit)
		(apropos-false-hit-symbol (car tem)))
	    (setq apropos-accumulator (delq (car tem) apropos-accumulator)))
	(setq tem (cdr tem))))
    (let ((p apropos-accumulator)
	  doc symbol score)
      (while p
	(setcar p (list
		   (setq symbol (car p))
		   (setq score (apropos-score-symbol symbol))
		   (unless var-predicate
		     (if (functionp symbol)
			 (if (setq doc (documentation symbol t))
			     (progn
			       (setq score (+ score (apropos-score-doc doc)))
			       (substring doc 0 (string-match "\n" doc)))
			   "(not documented)")))
		   (and var-predicate
			(funcall var-predicate symbol)
			(if (setq doc (documentation-property
				       symbol 'variable-documentation t))
			     (progn
			       (setq score (+ score (apropos-score-doc doc)))
			       (substring doc 0
					  (string-match "\n" doc)))))))
	(setcar (cdr (car p)) score)
	(setq p (cdr p))))
    (and (apropos-print t nil nil t)
	 message
	 (message "%s" message))))


;;;###autoload
(defun apropos-documentation-property (symbol property raw)
  "Like (documentation-property SYMBOL PROPERTY RAW) but handle errors."
  (condition-case ()
      (let ((doc (documentation-property symbol property raw)))
	(if doc (substring doc 0 (string-match "\n" doc))
	  "(not documented)"))
    (error "(error retrieving documentation)")))


;;;###autoload
(defun apropos (pattern &optional do-all)
  "Show all meaningful Lisp symbols whose names match PATTERN.
Symbols are shown if they are defined as functions, variables, or
faces, or if they have nonempty property lists.

PATTERN can be a word, a list of words (separated by spaces),
or a regexp (using some regexp special characters).  If it is a word,
search for matches for that word as a substring.  If it is a list of words,
search for matches for any two (or more) of those words.

With \\[universal-argument] prefix, or if `apropos-do-all' is non-nil,
consider all symbols (if they match PATTERN).

Returns list of symbols and documentation found."
  (interactive (list (apropos-read-pattern "symbol")
		     current-prefix-arg))
  (apropos-parse-pattern pattern)
  (apropos-symbols-internal
   (apropos-internal apropos-regexp
		     (and (not do-all)
			  (not apropos-do-all)
			  (lambda (symbol)
			    (or (fboundp symbol)
				(boundp symbol)
				(facep symbol)
				(symbol-plist symbol)))))
   (or do-all apropos-do-all)))

(defun apropos-symbols-internal (symbols keys &optional text)
  ;; Filter out entries that are marked as apropos-inhibit.
  (let ((all nil))
    (dolist (symbol symbols)
      (unless (get symbol 'apropos-inhibit)
	(push symbol all)))
    (setq symbols all))
  (let ((apropos-accumulator
	 (mapcar
	  (lambda (symbol)
	    (let (doc properties)
	      (list
	       symbol
	       (apropos-score-symbol symbol)
	       (when (fboundp symbol)
		 (if (setq doc (condition-case nil
				   (documentation symbol t)
				 (void-function
				  "(alias for undefined function)")
				 (error
				  "(can't retrieve function documentation)")))
		     (substring doc 0 (string-match "\n" doc))
		   "(not documented)"))
	       (when (boundp symbol)
		 (apropos-documentation-property
		    symbol 'variable-documentation t))
		 (when (setq properties (symbol-plist symbol))
		   (setq doc (list (car properties)))
		   (while (setq properties (cdr (cdr properties)))
		     (setq doc (cons (car properties) doc)))
		   (mapconcat #'symbol-name (nreverse doc) " "))
		 (when (get symbol 'widget-type)
		   (apropos-documentation-property
		    symbol 'widget-documentation t))
	       (when (facep symbol)
		 (apropos-documentation-property
		  symbol 'face-documentation t))
	       (when (get symbol 'custom-group)
		   (apropos-documentation-property
		    symbol 'group-documentation t)))))
	  symbols)))
    (apropos-print keys nil text)))


;;;###autoload
(defun apropos-value (pattern &optional do-all)
  "Show all symbols whose value's printed representation matches PATTERN.
PATTERN can be a word, a list of words (separated by spaces),
or a regexp (using some regexp special characters).  If it is a word,
search for matches for that word as a substring.  If it is a list of words,
search for matches for any two (or more) of those words.

With \\[universal-argument] prefix, or if `apropos-do-all' is non-nil, also looks
at the function and at the names and values of properties.
Returns list of symbols and values found."
  (interactive (list (apropos-read-pattern "value")
		     current-prefix-arg))
  (apropos-parse-pattern pattern)
  (or do-all (setq do-all apropos-do-all))
  (setq apropos-accumulator ())
   (let (f v p)
     (mapatoms
      (lambda (symbol)
	(setq f nil v nil p nil)
	(or (memq symbol '(apropos-regexp
			   apropos-pattern apropos-all-words-regexp
			   apropos-words apropos-all-words
			   do-all apropos-accumulator
			   symbol f v p))
	    (setq v (apropos-value-internal 'boundp symbol 'symbol-value)))
	(if do-all
	    (setq f (apropos-value-internal 'fboundp symbol 'symbol-function)
		  p (apropos-format-plist symbol "\n    " t)))
	(if (apropos-false-hit-str v)
	    (setq v nil))
	(if (apropos-false-hit-str f)
	    (setq f nil))
	(if (apropos-false-hit-str p)
	    (setq p nil))
	(if (or f v p)
	    (setq apropos-accumulator (cons (list symbol
						  (+ (apropos-score-str f)
						     (apropos-score-str v)
						     (apropos-score-str p))
						  f v p)
					    apropos-accumulator))))))
  (apropos-print nil "\n----------------\n"))


;;;###autoload
(defun apropos-documentation (pattern &optional do-all)
  "Show symbols whose documentation contains matches for PATTERN.
PATTERN can be a word, a list of words (separated by spaces),
or a regexp (using some regexp special characters).  If it is a word,
search for matches for that word as a substring.  If it is a list of words,
search for matches for any two (or more) of those words.

With \\[universal-argument] prefix, or if `apropos-do-all' is non-nil, also use
documentation that is not stored in the documentation file and show key
bindings.
Returns list of symbols and documentation found."
  (interactive (list (apropos-read-pattern "documentation")
		     current-prefix-arg))
  (apropos-parse-pattern pattern)
  (or do-all (setq do-all apropos-do-all))
  (setq apropos-accumulator () apropos-files-scanned ())
  (let ((standard-input (get-buffer-create " apropos-temp"))
	(apropos-sort-by-scores apropos-documentation-sort-by-scores)
	f v sf sv)
    (unwind-protect
	(save-excursion
	  (set-buffer standard-input)
	  (apropos-documentation-check-doc-file)
	  (if do-all
	      (mapatoms
	       (lambda (symbol)
		 (setq f (apropos-safe-documentation symbol)
		       v (get symbol 'variable-documentation))
		 (if (integerp v) (setq v))
		 (setq f (apropos-documentation-internal f)
		       v (apropos-documentation-internal v))
		 (setq sf (apropos-score-doc f)
		       sv (apropos-score-doc v))
		 (if (or f v)
		     (if (setq apropos-item
			       (cdr (assq symbol apropos-accumulator)))
			 (progn
			   (if f
			       (progn
				 (setcar (nthcdr 1 apropos-item) f)
				 (setcar apropos-item (+ (car apropos-item) sf))))
			   (if v
			       (progn
				 (setcar (nthcdr 2 apropos-item) v)
				 (setcar apropos-item (+ (car apropos-item) sv)))))
		       (setq apropos-accumulator
			     (cons (list symbol
					 (+ (apropos-score-symbol symbol 2) sf sv)
					 f v)
				   apropos-accumulator)))))))
	  (apropos-print nil "\n----------------\n" nil t))
      (kill-buffer standard-input))))


(defun apropos-value-internal (predicate symbol function)
  (if (funcall predicate symbol)
      (progn
	(setq symbol (prin1-to-string (funcall function symbol)))
	(if (string-match apropos-regexp symbol)
	    (progn
	      (if apropos-match-face
		  (put-text-property (match-beginning 0) (match-end 0)
				     'face apropos-match-face
				     symbol))
	      symbol)))))

(defun apropos-documentation-internal (doc)
  (if (consp doc)
      (apropos-documentation-check-elc-file (car doc))
    (if (and doc
	     (string-match apropos-all-words-regexp doc)
	     (apropos-true-hit-doc doc))
	(when apropos-match-face
	  (setq doc (substitute-command-keys (copy-sequence doc)))
	  (if (or (string-match apropos-pattern-quoted doc)
		  (string-match apropos-all-words-regexp doc))
	      (put-text-property (match-beginning 0)
				 (match-end 0)
				 'face apropos-match-face doc))
	  doc))))

(defun apropos-format-plist (pl sep &optional compare)
  (setq pl (symbol-plist pl))
  (let (p p-out)
    (while pl
      (setq p (format "%s %S" (car pl) (nth 1 pl)))
      (if (or (not compare) (string-match apropos-regexp p))
	  (if apropos-property-face
	      (put-text-property 0 (length (symbol-name (car pl)))
				 'face apropos-property-face p))
	(setq p nil))
      (if p
	  (progn
	    (and compare apropos-match-face
		 (put-text-property (match-beginning 0) (match-end 0)
				    'face apropos-match-face
				    p))
	    (setq p-out (concat p-out (if p-out sep) p))))
      (setq pl (nthcdr 2 pl)))
    p-out))


;; Finds all documentation related to APROPOS-REGEXP in internal-doc-file-name.

(defun apropos-documentation-check-doc-file ()
  (let (type symbol (sepa 2) sepb)
    (insert ?\^_)
    (backward-char)
    (insert-file-contents (concat doc-directory internal-doc-file-name))
    (forward-char)
    (while (save-excursion
	     (setq sepb (search-forward "\^_"))
	     (not (eobp)))
      (beginning-of-line 2)
      (if (save-restriction
	    (narrow-to-region (point) (1- sepb))
	    (re-search-forward apropos-all-words-regexp nil t))
	  (progn
	    (goto-char (1+ sepa))
	    (setq type (if (eq ?F (preceding-char))
			   2	; function documentation
			 3)		; variable documentation
		  symbol (read)
		  doc (buffer-substring (1+ (point)) (1- sepb)))
	    (when (apropos-true-hit-doc doc)
	      (or (and (setq apropos-item (assq symbol apropos-accumulator))
		       (setcar (cdr apropos-item)
			       (apropos-score-doc doc)))
		  (setq apropos-item (list symbol
					   (+ (apropos-score-symbol symbol 2)
					      (apropos-score-doc doc))
					   nil nil)
			apropos-accumulator (cons apropos-item
						  apropos-accumulator)))
	      (when apropos-match-face
		(setq doc (substitute-command-keys doc))
		(if (or (string-match apropos-pattern-quoted doc)
			(string-match apropos-all-words-regexp doc))
		    (put-text-property (match-beginning 0)
				       (match-end 0)
				       'face apropos-match-face doc)))
	      (setcar (nthcdr type apropos-item) doc))))
      (setq sepa (goto-char sepb)))))

(defun apropos-documentation-check-elc-file (file)
  (if (member file apropos-files-scanned)
      nil
    (let (symbol doc beg end this-is-a-variable)
      (setq apropos-files-scanned (cons file apropos-files-scanned))
      (erase-buffer)
      (insert-file-contents file)
      (while (search-forward "\n#@" nil t)
	;; Read the comment length, and advance over it.
	(setq end (read)
	      beg (1+ (point))
	      end (+ (point) end -1))
	(forward-char)
	(if (save-restriction
	      ;; match ^ and $ relative to doc string
	      (narrow-to-region beg end)
	      (re-search-forward apropos-all-words-regexp nil t))
	    (progn
	      (goto-char (+ end 2))
	      (setq doc (buffer-substring beg end)
		    end (- (match-end 0) beg)
		    beg (- (match-beginning 0) beg))
	      (when (apropos-true-hit-doc doc)
		(setq this-is-a-variable (looking-at "(def\\(var\\|const\\) ")
		      symbol (progn
			       (skip-chars-forward "(a-z")
			       (forward-char)
			       (read))
		      symbol (if (consp symbol)
				 (nth 1 symbol)
			       symbol))
		(if (if this-is-a-variable
			(get symbol 'variable-documentation)
		      (and (fboundp symbol) (apropos-safe-documentation symbol)))
		    (progn
		      (or (and (setq apropos-item (assq symbol apropos-accumulator))
			       (setcar (cdr apropos-item)
				       (+ (cadr apropos-item) (apropos-score-doc doc))))
			  (setq apropos-item (list symbol
						   (+ (apropos-score-symbol symbol 2)
						      (apropos-score-doc doc))
						   nil nil)
				apropos-accumulator (cons apropos-item
							  apropos-accumulator)))
		      (when apropos-match-face
			(setq doc (substitute-command-keys doc))
			(if (or (string-match apropos-pattern-quoted doc)
				(string-match apropos-all-words-regexp doc))
			    (put-text-property (match-beginning 0)
					       (match-end 0)
					       'face apropos-match-face doc)))
		      (setcar (nthcdr (if this-is-a-variable 3 2)
				      apropos-item)
			      doc))))))))))



(defun apropos-safe-documentation (function)
  "Like `documentation', except it avoids calling `get_doc_string'.
Will return nil instead."
  (while (and function (symbolp function))
    (setq function (if (fboundp function)
		       (symbol-function function))))
  (if (eq (car-safe function) 'macro)
      (setq function (cdr function)))
  (setq function (if (byte-code-function-p function)
		     (if (> (length function) 4)
			 (aref function 4))
		   (if (eq (car-safe function) 'autoload)
		       (nth 2 function)
		     (if (eq (car-safe function) 'lambda)
			 (if (stringp (nth 2 function))
			     (nth 2 function)
			   (if (stringp (nth 3 function))
			       (nth 3 function)))))))
  (if (integerp function)
      nil
    function))


(defun apropos-print (do-keys spacing &optional text nosubst)
  "Output result of apropos searching into buffer `*Apropos*'.
The value of `apropos-accumulator' is the list of items to output.
Each element should have the format
 (SYMBOL SCORE FN-DOC VAR-DOC [PLIST-DOC WIDGET-DOC FACE-DOC GROUP-DOC]).
The return value is the list that was in `apropos-accumulator', sorted
alphabetically by symbol name; but this function also sets
`apropos-accumulator' to nil before returning.

If SPACING is non-nil, it should be a string; separate items with that string.
If non-nil TEXT is a string that will be printed as a heading."
  (if (null apropos-accumulator)
      (message "No apropos matches for `%s'" apropos-pattern)
    (setq apropos-accumulator
	  (sort apropos-accumulator
		(lambda (a b)
		  ;; Don't sort by score if user can't see the score.
		  ;; It would be confusing.  -- rms.
		  (if apropos-sort-by-scores
		      (or (> (cadr a) (cadr b))
			  (and (= (cadr a) (cadr b))
			       (string-lessp (car a) (car b))))
		    (string-lessp (car a) (car b))))))
    (with-output-to-temp-buffer "*Apropos*"
      (let ((p apropos-accumulator)
	    (old-buffer (current-buffer))
	    symbol item)
	(set-buffer standard-output)
	(apropos-mode)
	(if (display-mouse-p)
	    (insert
	     "If moving the mouse over text changes the text's color, "
	     "you can click\n"
	     "mouse-2 (second button from right) on that text to "
	     "get more information.\n"))
	(insert "In this buffer, go to the name of the command, or function,"
		" or variable,\n"
		(substitute-command-keys
		 "and type \\[apropos-follow] to get full documentation.\n\n"))
	(if text (insert text "\n\n"))
	(while (consp p)
	  (when (and spacing (not (bobp)))
	    (princ spacing))
	  (setq apropos-item (car p)
		symbol (car apropos-item)
		p (cdr p))
	  ;; Insert dummy score element for backwards compatibility with 21.x
	  ;; apropos-item format.
	  (if (not (numberp (cadr apropos-item)))
	      (setq apropos-item
		    (cons (car apropos-item)
			  (cons nil (cdr apropos-item)))))
	  (insert-text-button (symbol-name symbol)
			      'type 'apropos-symbol
			      ;; Can't use default, since user may have
			      ;; changed the variable!
			      ;; Just say `no' to variables containing faces!
			      'face apropos-symbol-face)
	  (if (and (eq apropos-sort-by-scores 'verbose)
		   (cadr apropos-item))
	      (insert " (" (number-to-string (cadr apropos-item)) ") "))
	  ;; Calculate key-bindings if we want them.
	  (and do-keys
	       (commandp symbol)
	       (not (eq symbol 'self-insert-command))
	       (indent-to 30 1)
	       (if (let ((keys
			  (save-excursion
			    (set-buffer old-buffer)
			    (where-is-internal symbol)))
			 filtered)
		     ;; Copy over the list of key sequences,
		     ;; omitting any that contain a buffer or a frame.
		     (while keys
		       (let ((key (car keys))
			     (i 0)
			     loser)
			 (while (< i (length key))
			   (if (or (framep (aref key i))
				   (bufferp (aref key i)))
			       (setq loser t))
			   (setq i (1+ i)))
			 (or loser
			     (setq filtered (cons key filtered))))
		       (setq keys (cdr keys)))
		     (setq item filtered))
		   ;; Convert the remaining keys to a string and insert.
		   (insert
		    (mapconcat
		     (lambda (key)
		       (setq key (condition-case ()
				     (key-description key)
				   (error)))
		       (if apropos-keybinding-face
			   (put-text-property 0 (length key)
					      'face apropos-keybinding-face
					      key))
		       key)
		     item ", "))
		 (insert "M-x ... RET")
		 (when apropos-keybinding-face
		   (put-text-property (- (point) 11) (- (point) 8)
				      'face apropos-keybinding-face)
		   (put-text-property (- (point) 3) (point)
				      'face apropos-keybinding-face))))
	  (terpri)
	  (apropos-print-doc 2
			     (if (commandp symbol)
				 'apropos-command
			       (if (apropos-macrop symbol)
				   'apropos-macro
				 'apropos-function))
			     (not nosubst))
	  (apropos-print-doc 3 'apropos-variable (not nosubst))
	  (apropos-print-doc 7 'apropos-group t)
	  (apropos-print-doc 6 'apropos-face t)
	  (apropos-print-doc 5 'apropos-widget t)
	  (apropos-print-doc 4 'apropos-plist nil))
	(setq buffer-read-only t))))
  (prog1 apropos-accumulator
    (setq apropos-accumulator ())))	; permit gc


(defun apropos-macrop (symbol)
  "Return t if SYMBOL is a Lisp macro."
  (and (fboundp symbol)
       (consp (setq symbol
		    (symbol-function symbol)))
       (or (eq (car symbol) 'macro)
	   (if (eq (car symbol) 'autoload)
	       (memq (nth 4 symbol)
		     '(macro t))))))


(defun apropos-print-doc (i type do-keys)
  (if (stringp (setq i (nth i apropos-item)))
      (progn
	(insert "  ")
	(insert-text-button (button-type-get type 'apropos-label)
			    'type type
			    ;; Can't use the default button face, since
			    ;; user may have changed the variable!
			    ;; Just say `no' to variables containing faces!
			    'face apropos-label-face
			    'apropos-symbol (car apropos-item))
	(insert ": ")
	(insert (if do-keys (substitute-command-keys i) i))
	(or (bolp) (terpri)))))


(defun apropos-follow ()
  "Invokes any button at point, otherwise invokes the nearest label button."
  (interactive)
  (button-activate
   (or (apropos-next-label-button (line-beginning-position))
       (error "There is nothing to follow here"))))


(defun apropos-describe-plist (symbol)
  "Display a pretty listing of SYMBOL's plist."
  (help-setup-xref (list 'apropos-describe-plist symbol) (interactive-p))
  (with-output-to-temp-buffer (help-buffer)
    (set-buffer standard-output)
    (princ "Symbol ")
    (prin1 symbol)
    (princ "'s plist is\n (")
    (if apropos-symbol-face
	(put-text-property (+ (point-min) 7) (- (point) 14)
			   'face apropos-symbol-face))
    (insert (apropos-format-plist symbol "\n  "))
    (princ ")")
    (print-help-return-message)))


(provide 'apropos)

;;; arch-tag: d56fa2ac-e56b-4ce3-84ff-852f9c0dc66e
;;; apropos.el ends here
