1;;; help-fns.el --- Complex help functions 2 3;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001, 4;; 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Maintainer: FSF 7;; Keywords: help, internal 8 9;; This file is part of GNU Emacs. 10 11;; GNU Emacs is free software; you can redistribute it and/or modify 12;; it under the terms of the GNU General Public License as published by 13;; the Free Software Foundation; either version 2, or (at your option) 14;; any later version. 15 16;; GNU Emacs is distributed in the hope that it will be useful, 17;; but WITHOUT ANY WARRANTY; without even the implied warranty of 18;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19;; GNU General Public License for more details. 20 21;; You should have received a copy of the GNU General Public License 22;; along with GNU Emacs; see the file COPYING. If not, write to the 23;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, 24;; Boston, MA 02110-1301, USA. 25 26;;; Commentary: 27 28;; This file contains those help commands which are complicated, and 29;; which may not be used in every session. For example 30;; `describe-function' will probably be heavily used when doing elisp 31;; programming, but not if just editing C files. Simpler help commands 32;; are in help.el 33 34;;; Code: 35 36(require 'help-mode) 37 38;; Functions 39 40;;;###autoload 41(defun describe-function (function) 42 "Display the full documentation of FUNCTION (a symbol)." 43 (interactive 44 (let ((fn (function-called-at-point)) 45 (enable-recursive-minibuffers t) 46 val) 47 (setq val (completing-read (if fn 48 (format "Describe function (default %s): " fn) 49 "Describe function: ") 50 obarray 'fboundp t nil nil 51 (and fn (symbol-name fn)))) 52 (list (if (equal val "") 53 fn (intern val))))) 54 (if (null function) 55 (message "You didn't specify a function") 56 (help-setup-xref (list #'describe-function function) (interactive-p)) 57 (save-excursion 58 (with-output-to-temp-buffer (help-buffer) 59 (prin1 function) 60 ;; Use " is " instead of a colon so that 61 ;; it is easier to get out the function name using forward-sexp. 62 (princ " is ") 63 (describe-function-1 function) 64 (print-help-return-message) 65 (with-current-buffer standard-output 66 ;; Return the text we displayed. 67 (buffer-string)))))) 68 69(defun help-split-fundoc (docstring def) 70 "Split a function DOCSTRING into the actual doc and the usage info. 71Return (USAGE . DOC) or nil if there's no usage info. 72DEF is the function whose usage we're looking for in DOCSTRING." 73 ;; Functions can get the calling sequence at the end of the doc string. 74 ;; In cases where `function' has been fset to a subr we can't search for 75 ;; function's name in the doc string so we use `fn' as the anonymous 76 ;; function name instead. 77 (when (and docstring (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring)) 78 (cons (format "(%s%s" 79 ;; Replace `fn' with the actual function name. 80 (if (consp def) "anonymous" def) 81 (match-string 1 docstring)) 82 (substring docstring 0 (match-beginning 0))))) 83 84(defun help-add-fundoc-usage (docstring arglist) 85 "Add the usage info to DOCSTRING. 86If DOCSTRING already has a usage info, then just return it unchanged. 87The usage info is built from ARGLIST. DOCSTRING can be nil. 88ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"." 89 (unless (stringp docstring) (setq docstring "Not documented")) 90 (if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring) (eq arglist t)) 91 docstring 92 (concat docstring 93 (if (string-match "\n?\n\\'" docstring) 94 (if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "") 95 "\n\n") 96 (if (and (stringp arglist) 97 (string-match "\\`([^ ]+\\(.*\\))\\'" arglist)) 98 (concat "(fn" (match-string 1 arglist) ")") 99 (format "%S" (help-make-usage 'fn arglist)))))) 100 101(defun help-function-arglist (def) 102 ;; Handle symbols aliased to other symbols. 103 (if (and (symbolp def) (fboundp def)) (setq def (indirect-function def))) 104 ;; If definition is a macro, find the function inside it. 105 (if (eq (car-safe def) 'macro) (setq def (cdr def))) 106 (cond 107 ((byte-code-function-p def) (aref def 0)) 108 ((eq (car-safe def) 'lambda) (nth 1 def)) 109 ((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap))) 110 "[Arg list not available until function definition is loaded.]") 111 (t t))) 112 113(defun help-make-usage (function arglist) 114 (cons (if (symbolp function) function 'anonymous) 115 (mapcar (lambda (arg) 116 (if (not (symbolp arg)) 117 (if (and (consp arg) (symbolp (car arg))) 118 ;; CL style default values for optional args. 119 (cons (intern (upcase (symbol-name (car arg)))) 120 (cdr arg)) 121 arg) 122 (let ((name (symbol-name arg))) 123 (if (string-match "\\`&" name) arg 124 (intern (upcase name)))))) 125 arglist))) 126 127;; Could be this, if we make symbol-file do the work below. 128;; (defun help-C-file-name (subr-or-var kind) 129;; "Return the name of the C file where SUBR-OR-VAR is defined. 130;; KIND should be `var' for a variable or `subr' for a subroutine." 131;; (symbol-file (if (symbolp subr-or-var) subr-or-var 132;; (subr-name subr-or-var)) 133;; (if (eq kind 'var) 'defvar 'defun))) 134;;;###autoload 135(defun help-C-file-name (subr-or-var kind) 136 "Return the name of the C file where SUBR-OR-VAR is defined. 137KIND should be `var' for a variable or `subr' for a subroutine." 138 (let ((docbuf (get-buffer-create " *DOC*")) 139 (name (if (eq 'var kind) 140 (concat "V" (symbol-name subr-or-var)) 141 (concat "F" (subr-name subr-or-var))))) 142 (with-current-buffer docbuf 143 (goto-char (point-min)) 144 (if (eobp) 145 (insert-file-contents-literally 146 (expand-file-name internal-doc-file-name doc-directory))) 147 (let ((file (catch 'loop 148 (while t 149 (let ((pnt (search-forward (concat "" name "\n")))) 150 (re-search-backward "S\\(.*\\)") 151 (let ((file (match-string 1))) 152 (if (member file build-files) 153 (throw 'loop file) 154 (goto-char pnt)))))))) 155 (if (string-match "\\.\\(o\\|obj\\)\\'" file) 156 (setq file (replace-match ".c" t t file))) 157 (if (string-match "\\.c\\'" file) 158 (concat "src/" file) 159 file))))) 160 161(defface help-argument-name '((((supports :slant italic)) :inherit italic)) 162 "Face to highlight argument names in *Help* buffers." 163 :group 'help) 164 165(defun help-default-arg-highlight (arg) 166 "Default function to highlight arguments in *Help* buffers. 167It returns ARG in face `help-argument-name'; ARG is also 168downcased if it displays differently than the default 169face (according to `face-differs-from-default-p')." 170 (propertize (if (face-differs-from-default-p 'help-argument-name) 171 (downcase arg) 172 arg) 173 'face 'help-argument-name)) 174 175(defun help-do-arg-highlight (doc args) 176 (with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table) 177 (modify-syntax-entry ?\- "w") 178 (dolist (arg args doc) 179 (setq doc (replace-regexp-in-string 180 ;; This is heuristic, but covers all common cases 181 ;; except ARG1-ARG2 182 (concat "\\<" ; beginning of word 183 "\\(?:[a-z-]*-\\)?" ; for xxx-ARG 184 "\\(" 185 (regexp-quote arg) 186 "\\)" 187 "\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs 188 "\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n 189 "\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), <x>, [x], `x' 190 "\\>") ; end of word 191 (help-default-arg-highlight arg) 192 doc t t 1))))) 193 194(defun help-highlight-arguments (usage doc &rest args) 195 (when usage 196 (with-temp-buffer 197 (insert usage) 198 (goto-char (point-min)) 199 (let ((case-fold-search nil) 200 (next (not (or args (looking-at "\\[")))) 201 (opt nil)) 202 ;; Make a list of all arguments 203 (skip-chars-forward "^ ") 204 (while next 205 (or opt (not (looking-at " &")) (setq opt t)) 206 (if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t)) 207 (setq next nil) 208 (setq args (cons (match-string 2) args)) 209 (when (and opt (string= (match-string 1) "(")) 210 ;; A pesky CL-style optional argument with default value, 211 ;; so let's skip over it 212 (search-backward "(") 213 (goto-char (scan-sexps (point) 1))))) 214 ;; Highlight aguments in the USAGE string 215 (setq usage (help-do-arg-highlight (buffer-string) args)) 216 ;; Highlight arguments in the DOC string 217 (setq doc (and doc (help-do-arg-highlight doc args)))))) 218 ;; Return value is like the one from help-split-fundoc, but highlighted 219 (cons usage doc)) 220 221;;;###autoload 222(defun describe-simplify-lib-file-name (file) 223 "Simplify a library name FILE to a relative name, and make it a source file." 224 (if file 225 ;; Try converting the absolute file name to a library name. 226 (let ((libname (file-name-nondirectory file))) 227 ;; Now convert that back to a file name and see if we get 228 ;; the original one. If so, they are equivalent. 229 (if (equal file (locate-file libname load-path '(""))) 230 (if (string-match "[.]elc\\'" libname) 231 (substring libname 0 -1) 232 libname) 233 file)))) 234 235;;;###autoload 236(defun describe-function-1 (function) 237 (let* ((def (if (symbolp function) 238 (symbol-function function) 239 function)) 240 file-name string 241 (beg (if (commandp def) "an interactive " "a "))) 242 (setq string 243 (cond ((or (stringp def) 244 (vectorp def)) 245 "a keyboard macro") 246 ((subrp def) 247 (if (eq 'unevalled (cdr (subr-arity def))) 248 (concat beg "special form") 249 (concat beg "built-in function"))) 250 ((byte-code-function-p def) 251 (concat beg "compiled Lisp function")) 252 ((symbolp def) 253 (while (symbolp (symbol-function def)) 254 (setq def (symbol-function def))) 255 (format "an alias for `%s'" def)) 256 ((eq (car-safe def) 'lambda) 257 (concat beg "Lisp function")) 258 ((eq (car-safe def) 'macro) 259 "a Lisp macro") 260 ((eq (car-safe def) 'autoload) 261 (setq file-name (nth 1 def)) 262 (format "%s autoloaded %s" 263 (if (commandp def) "an interactive" "an") 264 (if (eq (nth 4 def) 'keymap) "keymap" 265 (if (nth 4 def) "Lisp macro" "Lisp function")) 266 )) 267 ((keymapp def) 268 (let ((is-full nil) 269 (elts (cdr-safe def))) 270 (while elts 271 (if (char-table-p (car-safe elts)) 272 (setq is-full t 273 elts nil)) 274 (setq elts (cdr-safe elts))) 275 (if is-full 276 "a full keymap" 277 "a sparse keymap"))) 278 (t ""))) 279 (princ string) 280 (with-current-buffer standard-output 281 (save-excursion 282 (save-match-data 283 (if (re-search-backward "alias for `\\([^`']+\\)'" nil t) 284 (help-xref-button 1 'help-function def))))) 285 (or file-name 286 (setq file-name (symbol-file function 'defun))) 287 (setq file-name (describe-simplify-lib-file-name file-name)) 288 (when (equal file-name "loaddefs.el") 289 ;; Find the real def site of the preloaded function. 290 ;; This is necessary only for defaliases. 291 (let ((location 292 (condition-case nil 293 (find-function-search-for-symbol function nil "loaddefs.el") 294 (error nil)))) 295 (when location 296 (with-current-buffer (car location) 297 (goto-char (cdr location)) 298 (when (re-search-backward 299 "^;;; Generated autoloads from \\(.*\\)" nil t) 300 (setq file-name (match-string 1))))))) 301 (when (and (null file-name) (subrp def)) 302 ;; Find the C source file name. 303 (setq file-name (if (get-buffer " *DOC*") 304 (help-C-file-name def 'subr) 305 'C-source))) 306 (when file-name 307 (princ " in `") 308 ;; We used to add .el to the file name, 309 ;; but that's completely wrong when the user used load-file. 310 (princ (if (eq file-name 'C-source) "C source code" file-name)) 311 (princ "'") 312 ;; Make a hyperlink to the library. 313 (with-current-buffer standard-output 314 (save-excursion 315 (re-search-backward "`\\([^`']+\\)'" nil t) 316 (help-xref-button 1 'help-function-def function file-name)))) 317 (princ ".") 318 (terpri) 319 (when (commandp function) 320 (if (and (eq function 'self-insert-command) 321 (eq (key-binding "a") 'self-insert-command) 322 (eq (key-binding "b") 'self-insert-command) 323 (eq (key-binding "c") 'self-insert-command)) 324 (princ "It is bound to many ordinary text characters.\n") 325 (let* ((remapped (command-remapping function)) 326 (keys (where-is-internal 327 (or remapped function) overriding-local-map nil nil)) 328 non-modified-keys) 329 ;; Which non-control non-meta keys run this command? 330 (dolist (key keys) 331 (if (member (event-modifiers (aref key 0)) '(nil (shift))) 332 (push key non-modified-keys))) 333 (when remapped 334 (princ "It is remapped to `") 335 (princ (symbol-name remapped)) 336 (princ "'")) 337 338 (when keys 339 (princ (if remapped " which is bound to " "It is bound to ")) 340 ;; If lots of ordinary text characters run this command, 341 ;; don't mention them one by one. 342 (if (< (length non-modified-keys) 10) 343 (princ (mapconcat 'key-description keys ", ")) 344 (dolist (key non-modified-keys) 345 (setq keys (delq key keys))) 346 (if keys 347 (progn 348 (princ (mapconcat 'key-description keys ", ")) 349 (princ ", and many ordinary text characters")) 350 (princ "many ordinary text characters")))) 351 (when (or remapped keys non-modified-keys) 352 (princ ".") 353 (terpri))))) 354 (let* ((arglist (help-function-arglist def)) 355 (doc (documentation function)) 356 (usage (help-split-fundoc doc function))) 357 (with-current-buffer standard-output 358 ;; If definition is a keymap, skip arglist note. 359 (unless (keymapp def) 360 (let* ((use (cond 361 (usage (setq doc (cdr usage)) (car usage)) 362 ((listp arglist) 363 (format "%S" (help-make-usage function arglist))) 364 ((stringp arglist) arglist) 365 ;; Maybe the arglist is in the docstring of the alias. 366 ((let ((fun function)) 367 (while (and (symbolp fun) 368 (setq fun (symbol-function fun)) 369 (not (setq usage (help-split-fundoc 370 (documentation fun) 371 function))))) 372 usage) 373 (car usage)) 374 ((or (stringp def) 375 (vectorp def)) 376 (format "\nMacro: %s" (format-kbd-macro def))) 377 (t "[Missing arglist. Please make a bug report.]"))) 378 (high (help-highlight-arguments use doc))) 379 (let ((fill-begin (point))) 380 (insert (car high) "\n") 381 (fill-region fill-begin (point))) 382 (setq doc (cdr high)))) 383 (let ((obsolete (and 384 ;; function might be a lambda construct. 385 (symbolp function) 386 (get function 'byte-obsolete-info)))) 387 (when obsolete 388 (princ "\nThis function is obsolete") 389 (when (nth 2 obsolete) 390 (insert (format " since %s" (nth 2 obsolete)))) 391 (insert ";\n" 392 (if (stringp (car obsolete)) (car obsolete) 393 (format "use `%s' instead." (car obsolete))) 394 "\n")) 395 (insert "\n" 396 (or doc "Not documented."))))))) 397 398 399;; Variables 400 401;;;###autoload 402(defun variable-at-point (&optional any-symbol) 403 "Return the bound variable symbol found at or before point. 404Return 0 if there is no such symbol. 405If ANY-SYMBOL is non-nil, don't insist the symbol be bound." 406 (or (condition-case () 407 (with-syntax-table emacs-lisp-mode-syntax-table 408 (save-excursion 409 (or (not (zerop (skip-syntax-backward "_w"))) 410 (eq (char-syntax (following-char)) ?w) 411 (eq (char-syntax (following-char)) ?_) 412 (forward-sexp -1)) 413 (skip-chars-forward "'") 414 (let ((obj (read (current-buffer)))) 415 (and (symbolp obj) (boundp obj) obj)))) 416 (error nil)) 417 (let* ((str (find-tag-default)) 418 (sym (if str (intern-soft str)))) 419 (if (and sym (or any-symbol (boundp sym))) 420 sym 421 (save-match-data 422 (when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str)) 423 (setq sym (intern-soft (match-string 1 str))) 424 (and (or any-symbol (boundp sym)) sym))))) 425 0)) 426 427;;;###autoload 428(defun describe-variable (variable &optional buffer) 429 "Display the full documentation of VARIABLE (a symbol). 430Returns the documentation as a string, also. 431If VARIABLE has a buffer-local value in BUFFER (default to the current buffer), 432it is displayed along with the global value." 433 (interactive 434 (let ((v (variable-at-point)) 435 (enable-recursive-minibuffers t) 436 val) 437 (setq val (completing-read (if (symbolp v) 438 (format 439 "Describe variable (default %s): " v) 440 "Describe variable: ") 441 obarray 442 '(lambda (vv) 443 (or (boundp vv) 444 (get vv 'variable-documentation))) 445 t nil nil 446 (if (symbolp v) (symbol-name v)))) 447 (list (if (equal val "") 448 v (intern val))))) 449 (unless (buffer-live-p buffer) (setq buffer (current-buffer))) 450 (if (not (symbolp variable)) 451 (message "You did not specify a variable") 452 (save-excursion 453 (let* ((valvoid (not (with-current-buffer buffer (boundp variable)))) 454 ;; Extract the value before setting up the output buffer, 455 ;; in case `buffer' *is* the output buffer. 456 (val (unless valvoid (buffer-local-value variable buffer))) 457 val-start-pos) 458 (help-setup-xref (list #'describe-variable variable buffer) 459 (interactive-p)) 460 (with-output-to-temp-buffer (help-buffer) 461 (with-current-buffer buffer 462 (prin1 variable) 463 ;; Make a hyperlink to the library if appropriate. (Don't 464 ;; change the format of the buffer's initial line in case 465 ;; anything expects the current format.) 466 (let ((file-name (symbol-file variable 'defvar))) 467 (setq file-name (describe-simplify-lib-file-name file-name)) 468 (when (equal file-name "loaddefs.el") 469 ;; Find the real def site of the preloaded variable. 470 (let ((location 471 (condition-case nil 472 (find-variable-noselect variable file-name) 473 (error nil)))) 474 (when location 475 (with-current-buffer (car location) 476 (when (cdr location) 477 (goto-char (cdr location))) 478 (when (re-search-backward 479 "^;;; Generated autoloads from \\(.*\\)" nil t) 480 (setq file-name (match-string 1))))))) 481 (when (and (null file-name) 482 (integerp (get variable 'variable-documentation))) 483 ;; It's a variable not defined in Elisp but in C. 484 (setq file-name 485 (if (get-buffer " *DOC*") 486 (help-C-file-name variable 'var) 487 'C-source))) 488 (if file-name 489 (progn 490 (princ " is a variable defined in `") 491 (princ (if (eq file-name 'C-source) "C source code" file-name)) 492 (princ "'.\n") 493 (with-current-buffer standard-output 494 (save-excursion 495 (re-search-backward "`\\([^`']+\\)'" nil t) 496 (help-xref-button 1 'help-variable-def 497 variable file-name))) 498 (if valvoid 499 (princ "It is void as a variable.") 500 (princ "Its "))) 501 (if valvoid 502 (princ " is void as a variable.") 503 (princ "'s ")))) 504 (if valvoid 505 nil 506 (with-current-buffer standard-output 507 (setq val-start-pos (point)) 508 (princ "value is ") 509 (terpri) 510 (let ((from (point))) 511 (pp val) 512 ;; Hyperlinks in variable's value are quite frequently 513 ;; inappropriate e.g C-h v <RET> features <RET> 514 ;; (help-xref-on-pp from (point)) 515 (if (< (point) (+ from 20)) 516 (delete-region (1- from) from))))) 517 (terpri) 518 519 (when (local-variable-p variable) 520 (princ (format "%socal in buffer %s; " 521 (if (get variable 'permanent-local) 522 "Permanently l" "L") 523 (buffer-name))) 524 (if (not (default-boundp variable)) 525 (princ "globally void") 526 (let ((val (default-value variable))) 527 (with-current-buffer standard-output 528 (princ "global value is ") 529 (terpri) 530 ;; Fixme: pp can take an age if you happen to 531 ;; ask for a very large expression. We should 532 ;; probably print it raw once and check it's a 533 ;; sensible size before prettyprinting. -- fx 534 (let ((from (point))) 535 (pp val) 536 ;; See previous comment for this function. 537 ;; (help-xref-on-pp from (point)) 538 (if (< (point) (+ from 20)) 539 (delete-region (1- from) from))))))) 540 ;; Add a note for variables that have been make-var-buffer-local. 541 (when (and (local-variable-if-set-p variable) 542 (or (not (local-variable-p variable)) 543 (with-temp-buffer 544 (local-variable-if-set-p variable)))) 545 (princ "\nAutomatically becomes buffer-local when set in any fashion.\n")) 546 (terpri) 547 548 ;; If the value is large, move it to the end. 549 (with-current-buffer standard-output 550 (when (> (count-lines (point-min) (point-max)) 10) 551 ;; Note that setting the syntax table like below 552 ;; makes forward-sexp move over a `'s' at the end 553 ;; of a symbol. 554 (set-syntax-table emacs-lisp-mode-syntax-table) 555 (goto-char val-start-pos) 556 ;; The line below previously read as 557 ;; (delete-region (point) (progn (end-of-line) (point))) 558 ;; which suppressed display of the buffer local value for 559 ;; large values. 560 (when (looking-at "value is") (replace-match "")) 561 (save-excursion 562 (insert "\n\nValue:") 563 (set (make-local-variable 'help-button-cache) 564 (point-marker))) 565 (insert "value is shown ") 566 (insert-button "below" 567 'action help-button-cache 568 'follow-link t 569 'help-echo "mouse-2, RET: show value") 570 (insert ".\n"))) 571 572 ;; Mention if it's an alias 573 (let* ((alias (condition-case nil 574 (indirect-variable variable) 575 (error variable))) 576 (obsolete (get variable 'byte-obsolete-variable)) 577 (safe-var (get variable 'safe-local-variable)) 578 (doc (or (documentation-property variable 'variable-documentation) 579 (documentation-property alias 'variable-documentation)))) 580 (unless (eq alias variable) 581 (princ (format "\nThis variable is an alias for `%s'.\n" alias))) 582 (if (or obsolete safe-var) 583 (terpri)) 584 585 (when obsolete 586 (princ "This variable is obsolete") 587 (if (cdr obsolete) (princ (format " since %s" (cdr obsolete)))) 588 (princ ";") (terpri) 589 (princ (if (stringp (car obsolete)) (car obsolete) 590 (format "use `%s' instead." (car obsolete)))) 591 (terpri)) 592 (when safe-var 593 (princ "This variable is safe as a file local variable ") 594 (princ "if its value\nsatisfies the predicate ") 595 (princ (if (byte-code-function-p safe-var) 596 "which is byte-compiled expression.\n" 597 (format "`%s'.\n" safe-var)))) 598 (princ "\nDocumentation:\n") 599 (princ (or doc "Not documented as a variable."))) 600 ;; Make a link to customize if this variable can be customized. 601 (if (custom-variable-p variable) 602 (let ((customize-label "customize")) 603 (terpri) 604 (terpri) 605 (princ (concat "You can " customize-label " this variable.")) 606 (with-current-buffer standard-output 607 (save-excursion 608 (re-search-backward 609 (concat "\\(" customize-label "\\)") nil t) 610 (help-xref-button 1 'help-customize-variable variable))))) 611 (print-help-return-message) 612 (save-excursion 613 (set-buffer standard-output) 614 ;; Return the text we displayed. 615 (buffer-string)))))))) 616 617 618;;;###autoload 619(defun describe-syntax (&optional buffer) 620 "Describe the syntax specifications in the syntax table of BUFFER. 621The descriptions are inserted in a help buffer, which is then displayed. 622BUFFER defaults to the current buffer." 623 (interactive) 624 (setq buffer (or buffer (current-buffer))) 625 (help-setup-xref (list #'describe-syntax buffer) (interactive-p)) 626 (with-output-to-temp-buffer (help-buffer) 627 (let ((table (with-current-buffer buffer (syntax-table)))) 628 (with-current-buffer standard-output 629 (describe-vector table 'internal-describe-syntax-value) 630 (while (setq table (char-table-parent table)) 631 (insert "\nThe parent syntax table is:") 632 (describe-vector table 'internal-describe-syntax-value)))))) 633 634(defun help-describe-category-set (value) 635 (insert (cond 636 ((null value) "default") 637 ((char-table-p value) "deeper char-table ...") 638 (t (condition-case err 639 (category-set-mnemonics value) 640 (error "invalid")))))) 641 642;;;###autoload 643(defun describe-categories (&optional buffer) 644 "Describe the category specifications in the current category table. 645The descriptions are inserted in a buffer, which is then displayed. 646If BUFFER is non-nil, then describe BUFFER's category table instead. 647BUFFER should be a buffer or a buffer name." 648 (interactive) 649 (setq buffer (or buffer (current-buffer))) 650 (help-setup-xref (list #'describe-categories buffer) (interactive-p)) 651 (with-output-to-temp-buffer (help-buffer) 652 (let ((table (with-current-buffer buffer (category-table)))) 653 (with-current-buffer standard-output 654 (describe-vector table 'help-describe-category-set) 655 (let ((docs (char-table-extra-slot table 0))) 656 (if (or (not (vectorp docs)) (/= (length docs) 95)) 657 (insert "Invalid first extra slot in this char table\n") 658 (insert "Meanings of mnemonic characters are:\n") 659 (dotimes (i 95) 660 (let ((elt (aref docs i))) 661 (when elt 662 (insert (+ i ?\s) ": " elt "\n")))) 663 (while (setq table (char-table-parent table)) 664 (insert "\nThe parent category table is:") 665 (describe-vector table 'help-describe-category-set)))))))) 666 667(provide 'help-fns) 668 669;; arch-tag: 9e10331c-ae81-4d13-965d-c4819aaab0b3 670;;; help-fns.el ends here 671