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;;; apropos.el --- faster apropos commands.

;; Copyright (C) 1989 Free Software Foundation, Inc.

;; Author: Joe Wells <jbw@bigbird.bu.edu>
;; Keyword: 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 2, 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, 675 Mass Ave, Cambridge, MA 02139, 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.

;;; Code:

(defvar apropos-do-all nil
  "*Whether `apropos' and `super-apropos' should do everything that they can.
Makes them run 2 or 3 times slower.  Set this non-nil if you have a fast
machine.")

;; If there isn't already a lisp variable named internal-doc-file-name, create
;; it and document it.  This is so the code will work right after RMS adds
;; internal-doc-file-name.
;(or (boundp 'internal-doc-file-name)
;    (setq internal-doc-file-name (concat data-directory "DOC")))
;(or (documentation-property 'internal-doc-file-name 'variable-documentation)
;    (put 'internal-doc-file-name 'variable-documentation
;	 "The complete pathname of the documentation file that contains all
;documentation for functions and variables defined before Emacs is dumped."))

;;;###autoload
(defun apropos (regexp &optional do-all pred)
  "Show all symbols whose names contain matches for REGEXP.
If optional argument DO-ALL is non-nil, does more (time-consuming) work such as
showing key bindings.  Optional argument PRED is called with each symbol, and
if it returns nil, the symbol is not shown.

Returns list of symbols and documentation found."
  (interactive "sApropos (regexp): \nP")
  (setq do-all (or apropos-do-all do-all))
  (let ((apropos-accumulate (apropos-internal regexp pred)))
    (if (null apropos-accumulate)
	(message "No apropos matches for `%s'" regexp)
      (apropos-get-doc apropos-accumulate)
      (with-output-to-temp-buffer "*Help*"
	(apropos-print-matches apropos-accumulate regexp nil do-all)))
    apropos-accumulate))

;; If "C-h a" still has its original binding of command-apropos, change it to
;; use fast-command-apropos.  I don't use substitute-key-definition because
;; it's slow.
;(if (eq 'command-apropos (lookup-key help-map "a"))
;    (define-key help-map "a" 'fast-command-apropos))

;; Takes LIST of symbols and adds documentation.  Modifies LIST in place.
;; Resulting alist is of form ((symbol fn-doc var-doc) ...).  Should only be
;; called by apropos.  Returns LIST.

(defun apropos-get-doc (list)
  (let ((p list)
	fn-doc var-doc symbol)
    (while (consp p)
      (setq symbol (car p)
	    fn-doc (and (fboundp symbol)
			(documentation symbol))
	    var-doc (documentation-property symbol 'variable-documentation)
	    fn-doc (and fn-doc
			(substring fn-doc 0 (string-match "\n" fn-doc)))
	    var-doc (and var-doc
			 (substring var-doc 0 (string-match "\n" var-doc))))
      (setcar p (list symbol fn-doc var-doc))
      (setq p (cdr p)))
    list))

;;;###autoload
(defun super-apropos (regexp &optional do-all)
  "Show symbols whose names/documentation contain matches for REGEXP.
If optional argument DO-ALL is non-nil, does more (time-consuming) work such as
showing key bindings and documentation that is not stored in the documentation
file.

Returns list of symbols and documentation found."
  (interactive "sSuper Apropos: \nP")
  (setq do-all (or apropos-do-all do-all))
  (let (apropos-accumulate fn-doc var-doc item)
    (setq apropos-accumulate (super-apropos-check-doc-file regexp))
    (if (null apropos-accumulate)
	(message "No apropos matches for `%s'" regexp)
      (if do-all (mapatoms 'super-apropos-accumulate))
      (with-output-to-temp-buffer "*Help*"
	(apropos-print-matches apropos-accumulate nil t do-all)))
    apropos-accumulate))

;; Finds all documentation related to REGEXP in internal-doc-file-name.
;; Returns an alist of form ((symbol fn-doc var-doc) ...).

(defun super-apropos-check-doc-file (regexp)
  (let ((doc-buffer (find-file-noselect internal-doc-file-name t))
	;;	(doc-buffer (or (get-file-buffer internal-doc-file-name)
	;;			(find-file-noselect internal-doc-file-name)))
	type symbol doc sym-list)
    (save-excursion
      (set-buffer doc-buffer)
      ;; a user said he might accidentally edit the doc file
      (setq buffer-read-only t)
      (bury-buffer doc-buffer)
      (goto-char (point-min))
      (while (re-search-forward regexp nil t)
	(search-backward "\C-_")
	(setq type (if (eq ?F (char-after (1+ (point))))
		       1		;function documentation
		     2)			;variable documentation
	      symbol (progn
		       (forward-char 2)
		       (read doc-buffer))
	      doc (buffer-substring
		   (point)
		   (progn
		     (if (search-forward "\C-_" nil 'move)
			 (1- (point))
		       (point))))
	      item (assq symbol sym-list))
	(or item
	    (setq item (list symbol nil nil)
		  sym-list (cons item sym-list)))
	(setcar (nthcdr type item) doc)))
    sym-list))

;; This is passed as the argument to map-atoms, so it is called once for every
;; symbol in obarray.  Takes one argument SYMBOL, and finds any memory-resident
;; documentation on that symbol if it matches a variable regexp.  WARNING: this
;; function depends on the symbols fn-doc var-doc regexp and item being bound
;; correctly when it is called!"

(defun super-apropos-accumulate (symbol)
  (cond ((string-match regexp (symbol-name symbol))
	 (setq item (apropos-get-accum-item symbol))
	 (setcar (cdr item) (or (safe-documentation symbol)
				(nth 1 item)))
	 (setcar (nthcdr 2 item) (or (safe-documentation-property symbol)
				     (nth 2 item))))
	(t
	 (and (setq fn-doc (safe-documentation symbol))
	      (string-match regexp fn-doc)
	      (setcar (cdr (apropos-get-accum-item symbol)) fn-doc))
	 (and (setq var-doc (safe-documentation-property symbol))
	      (string-match regexp var-doc)
	      (setcar (nthcdr 2 (apropos-get-accum-item symbol)) var-doc))))
  nil)

;; Prints the symbols and documentation in alist MATCHES of form ((symbol
;; fn-doc var-doc) ...).  Uses optional argument REGEXP to speed up searching
;; for keybindings.  The names of all symbols in MATCHES must match REGEXP.
;; Displays in the buffer pointed to by standard-output.  Optional argument
;; SPACING means put blank lines in between each symbol's documentation.
;; Optional argument DO-ALL means do more time-consuming work, specifically,
;; consulting key bindings.  Should only be called within a
;; with-output-to-temp-buffer.

(defun apropos-print-matches (matches &optional regexp spacing do-all)
  (setq matches (sort matches (function
			       (lambda (a b)
				 (string-lessp (car a) (car b))))))
  (let ((p matches)
	(old-buffer (current-buffer))
	item keys-done symbol)
    (save-excursion
      (set-buffer standard-output)
      (or matches (princ "No matches found."))
      (while (consp p)
	(setq item (car p)
	      symbol (car item)
	      p (cdr p))
	(or (not spacing) (bobp) (terpri))
	(princ symbol)		        ;print symbol name
	;; don't calculate key-bindings unless needed
	(cond ((and do-all (commandp symbol) (not keys-done))
	       (save-excursion
		 (set-buffer old-buffer)
		 (apropos-match-keys matches regexp))
	       (setq keys-done t)))
	(cond ((and do-all
		    (or (setq tem (nthcdr 3 item))
			(commandp symbol)))
	       (indent-to 30 1)
	       (if tem
		   (princ (mapconcat 'key-description tem ", "))
		 (princ "(not bound to any keys)"))))
	(terpri)
	(cond ((setq tem (nth 1 item))
	       (princ "  Function: ")
	       (princ (if do-all (substitute-command-keys tem) tem))))
	(or (bolp) (terpri))
	(cond ((setq tem (nth 2 item))
	       (princ "  Variable: ")
	       (princ (if do-all (substitute-command-keys tem) tem))))
	(or (bolp) (terpri)))))
  t)

;; Find key bindings for symbols that are cars in ALIST.  Optionally, first
;; match the symbol name against REGEXP.  Modifies ALIST in place.  Each key
;; binding is added as a string to the end of the list in ALIST whose car is
;; the corresponding symbol.  The pointer to ALIST is returned.

(defun apropos-match-keys (alist &optional regexp)
  (let* ((current-local-map (current-local-map))
	 (maps (append (and current-local-map
			    (accessible-keymaps current-local-map))
		       (accessible-keymaps (current-global-map))))
	 map				;map we are now inspecting
	 sequence			;key sequence to reach map
	 i				;index into vector map
	 command			;what is bound to current keys
	 key				;last key to reach command
	 local				;local binding for sequence + key
	 item)				;symbol data item in alist
    ;; examine all reachable keymaps
    (while (consp maps)
      (setq map (cdr (car maps))
	    sequence (car (car maps))	;keys to reach this map
	    maps (cdr maps))
      (setq i 0)
      ;; In an alist keymap, skip the leading `keymap', doc string, etc.
      (while (and (consp map) (not (consp (car map))))
	(setq map (cdr map)))
      (while (and map (< i 128))	;vector keymaps have 128 entries
	(cond ((consp map)
	       (setq command (cdr (car map))
		     key (car (car map))
		     map (cdr map))
	       ;; Skip any atoms in the keymap.
	       (while (and (consp map) (not (consp (car map))))
		 (setq map (cdr map))))
	      ((vectorp map)
	       (setq command (aref map i)
		     key i
		     i (1+ i))))
	;; Skip any menu prompt in this key binding.
	(and (consp command) (symbolp (cdr command))
	     (setq command (cdr command)))
	;; if is a symbol, and matches optional regexp, and is a car
	;; in alist, and is not shadowed by a different local binding,
	;; record it
	(and (symbolp command)
	     (if regexp (string-match regexp (symbol-name command)))
	     (setq item (assq command alist))
	     (setq key (concat sequence (char-to-string key)))
	     ;; checking if shadowed by local binding.
	     ;; either no local map, no local binding, or runs off the
	     ;; binding tree (number), or is the same binding
	     (or (not current-local-map)
		 (not (setq local (lookup-key current-local-map key)))
		 (numberp local)
		 (eq command local))
	     ;; add this key binding to the item in alist
	     (nconc item (cons key nil))))))
  alist)

;; Get an alist item in alist apropos-accumulate whose car is SYMBOL.  Creates
;; the item if not already present.  Modifies apropos-accumulate in place.

(defun apropos-get-accum-item (symbol)
  (or (assq symbol apropos-accumulate)
      (progn
	(setq apropos-accumulate
	      (cons (list symbol nil nil) apropos-accumulate))
	(assq symbol apropos-accumulate))))

(defun safe-documentation (function)
  "Like documentation, except it avoids calling `get_doc_string'.
Will return nil instead."
  (while (symbolp function)
    (setq function (if (fboundp function)
		       (symbol-function function)
		     0)))
  (if (not (consp function))
      nil
    (if (eq (car function) 'macro)
	(setq function (cdr function)))
    (if (not (memq (car function) '(lambda autoload)))
	nil
      (setq function (nth 2 function))
      (if (stringp function)
	  function
	nil))))

(defun safe-documentation-property (symbol)
  "Like documentation-property, except it avoids calling `get_doc_string'.
Will return nil instead."
  (setq symbol (get symbol 'variable-documentation))
  (if (numberp symbol)
      nil
    symbol))

;;; apropos.el ends here