code.delx.au - gnu-emacs/blob - lisp/info-look.el

   1 ;;; info-look.el --- major-mode-sensitive Info index lookup facility.
   2 ;; An older version of this was known as libc.el.
   3
   4 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
   5
   6 ;; Author: Ralph Schleicher <rs@purple.UL.BaWue.DE>
   7 ;; Maintainers: FSF (unless Schleicher can be found)
   8 ;; Keywords: help languages
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  24 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  25 ;; Boston, MA 02111-1307, USA.
  26
  27 ;;; Code:
  28
  29 (require 'info)
  30
  31 (defgroup info-lookup nil
  32   "Major mode sensitive help agent."
  33   :group 'help :group 'languages)
  34
  35 (defvar info-lookup-mode nil
  36   "Symbol of the current buffer's help mode.
  37 Help is provided according to the buffer's major mode if value is nil.
  38 Automatically becomes buffer local when set in any fashion.")
  39 (make-variable-buffer-local 'info-lookup-mode)
  40
  41 (defcustom info-lookup-other-window-flag t
  42   "Non-nil means pop up the Info buffer in another window."
  43   :group 'info-lookup :type 'boolean)
  44
  45 (defcustom info-lookup-highlight-face 'highlight
  46   "Face for highlighting looked up help items.
  47 Setting this variable to nil disables highlighting."
  48   :group 'info-lookup :type 'face)
  49
  50 (defvar info-lookup-highlight-overlay nil
  51   "Overlay object used for highlighting.")
  52
  53 (defcustom info-lookup-file-name-alist
  54   '(("\\`configure\\.in\\'" . autoconf-mode)
  55     ("\\`aclocal\\.m4\\'" . autoconf-mode)
  56     ("\\`acsite\\.m4\\'" . autoconf-mode)
  57     ("\\`acinclude\\.m4\\'" . autoconf-mode))
  58   "Alist of file names handled specially.
  59 List elements are cons cells of the form
  60
  61     (REGEXP . MODE)
  62
  63 If a file name matches REGEXP, then use help mode MODE instead of the
  64 buffer's major mode."
  65   :group 'info-lookup :type '(repeat (cons (string :tag "Regexp")
  66                                            (symbol :tag "Mode"))))
  67
  68 (defvar info-lookup-history nil
  69   "History of previous input lines.")
  70
  71 (defvar info-lookup-alist nil
  72   "Alist of known help topics.
  73 Cons cells are of the form
  74
  75     (HELP-TOPIC . HELP-DATA)
  76
  77 HELP-TOPIC is the symbol of a help topic.
  78 HELP-DATA is a HELP-TOPIC's public data set.
  79  Value is an alist with elements of the form
  80
  81     (HELP-MODE REGEXP IGNORE-CASE DOC-SPEC PARSE-RULE OTHER-MODES)
  82
  83 HELP-MODE is a mode's symbol.
  84 REGEXP is a regular expression matching those help items whose
  85  documentation can be looked up via DOC-SPEC.
  86 IGNORE-CASE is non-nil if help items are case insensitive.
  87 DOC-SPEC is a list of documentation specifications of the form
  88
  89     (INFO-NODE TRANS-FUNC PREFIX SUFFIX)
  90
  91 INFO-NODE is the name (including file name part) of an Info index.
  92 TRANS-FUNC is a function translating index entries into help items;
  93  nil means add only those index entries matching REGEXP, a string
  94  means prepend string to the first word of all index entries.
  95 PREFIX and SUFFIX are parts of a regular expression.  If one of
  96  them is non-nil then search the help item's Info node for the
  97  first occurrence of the regular expression `PREFIX ITEM SUFFIX'.
  98  ITEM will be highlighted with `info-lookup-highlight-face' if this
  99  variable is not nil.
 100 PARSE-RULE is either the symbol name of a function or a regular
 101  expression for guessing the default help item at point.  Fuzzy
 102  regular expressions like \"[_a-zA-Z0-9]+\" do a better job if
 103  there are no clear delimiters; do not try to write too complex
 104  expressions.  PARSE-RULE defaults to REGEXP.
 105 OTHER-MODES is a list of cross references to other help modes.")
 106
 107 (defsubst info-lookup->topic-value (topic)
 108   (cdr (assoc topic info-lookup-alist)))
 109
 110 (defsubst info-lookup->mode-value (topic mode)
 111   (assoc mode (info-lookup->topic-value topic)))
 112
 113 (defsubst info-lookup->regexp (topic mode)
 114   (nth 1 (info-lookup->mode-value topic mode)))
 115
 116 (defsubst info-lookup->ignore-case (topic mode)
 117   (nth 2 (info-lookup->mode-value topic mode)))
 118
 119 (defsubst info-lookup->doc-spec (topic mode)
 120   (nth 3 (info-lookup->mode-value topic mode)))
 121
 122 (defsubst info-lookup->parse-rule (topic mode)
 123   (nth 4 (info-lookup->mode-value topic mode)))
 124
 125 (defsubst info-lookup->other-modes (topic mode)
 126   (nth 5 (info-lookup->mode-value topic mode)))
 127
 128 (eval-and-compile
 129   (mapcar (lambda (keyword)
 130             (or (boundp keyword)
 131                 (set keyword keyword)))
 132           '(:topic :mode :regexp :ignore-case
 133             :doc-spec :parse-rule :other-modes)))
 134
 135 (defun info-lookup-add-help (&rest arg)
 136   "Add or update a help specification.
 137 Function arguments are one or more options of the form
 138
 139     KEYWORD ARGUMENT
 140
 141 KEYWORD is either `:topic', `:mode', `:regexp', `:ignore-case',
 142  `:doc-spec', `:parse-rule', or `:other-modes'.
 143 ARGUMENT has a value as explained in the documentation of the
 144  variable `info-lookup-alist'.
 145
 146 If no topic or mode option has been specified, then the help topic defaults
 147 to `symbol', and the help mode defaults to the current major mode."
 148   (apply 'info-lookup-add-help* nil arg))
 149
 150 (defun info-lookup-maybe-add-help (&rest arg)
 151   "Add a help specification iff no one is defined.
 152 See the documentation of the function `info-lookup-add-help'
 153 for more details."
 154   (apply 'info-lookup-add-help* t arg))
 155
 156 (defun info-lookup-add-help* (maybe &rest arg)
 157   (let (topic mode regexp ignore-case doc-spec
 158               parse-rule other-modes keyword value)
 159     (setq topic 'symbol
 160           mode major-mode
 161           regexp "\\w+")
 162     (while arg
 163       (setq keyword (car arg))
 164       (or (symbolp keyword)
 165           (error "Junk in argument list \"%S\"" arg))
 166       (setq arg (cdr arg))
 167       (and (null arg)
 168            (error "Keyword \"%S\" is missing an argument" keyword))
 169       (setq value (car arg)
 170             arg (cdr arg))
 171       (cond ((eq keyword :topic)
 172              (setq topic value))
 173             ((eq keyword :mode)
 174              (setq mode value))
 175             ((eq keyword :regexp)
 176              (setq regexp value))
 177             ((eq keyword :ignore-case)
 178              (setq ignore-case value))
 179             ((eq keyword :doc-spec)
 180              (setq doc-spec value))
 181             ((eq keyword :parse-rule)
 182              (setq parse-rule value))
 183             ((eq keyword :other-modes)
 184              (setq other-modes value))
 185             (t
 186              (error "Unknown keyword \"%S\"" keyword))))
 187     (or (and maybe (info-lookup->mode-value topic mode))
 188         (let* ((data (list regexp ignore-case doc-spec parse-rule other-modes))
 189                (topic-cell (or (assoc topic info-lookup-alist)
 190                                (car (setq info-lookup-alist
 191                                           (cons (cons topic nil)
 192                                                 info-lookup-alist)))))
 193                (mode-cell (assoc mode topic-cell)))
 194           (if (null mode-cell)
 195               (setcdr topic-cell (cons (cons mode data) (cdr topic-cell)))
 196             (setcdr mode-cell data))))
 197     nil))
 198
 199 (defvar info-lookup-cache nil
 200   "Cache storing data maintained automatically by the program.
 201 Value is an alist with cons cell of the form
 202
 203     (HELP-TOPIC . ((HELP-MODE INITIALIZED COMPLETIONS REFER-MODES) ...))
 204
 205 HELP-TOPIC is the symbol of a help topic.
 206 HELP-MODE is a mode's symbol.
 207 INITIALIZED is nil if HELP-MODE is uninitialized, t if
 208  HELP-MODE is initialized, and `0' means HELP-MODE is
 209  initialized but void.
 210 COMPLETIONS is an alist of documented help items.
 211 REFER-MODES is a list of other help modes to use.")
 212
 213 (defsubst info-lookup->cache (topic)
 214   (or (assoc topic info-lookup-cache)
 215       (car (setq info-lookup-cache
 216                  (cons (cons topic nil)
 217                        info-lookup-cache)))))
 218
 219 (defun info-lookup->topic-cache (topic)
 220   (cdr (info-lookup->cache topic)))
 221
 222 (defun info-lookup->mode-cache (topic mode)
 223   (assoc mode (info-lookup->topic-cache topic)))
 224
 225 (defun info-lookup->initialized (topic mode)
 226   (nth 1 (info-lookup->mode-cache topic mode)))
 227
 228 (defun info-lookup->completions (topic mode)
 229   (or (info-lookup->initialized topic mode)
 230       (info-lookup-setup-mode topic mode))
 231   (nth 2 (info-lookup->mode-cache topic mode)))
 232
 233 (defun info-lookup->refer-modes (topic mode)
 234   (or (info-lookup->initialized topic mode)
 235       (info-lookup-setup-mode topic mode))
 236   (nth 3 (info-lookup->mode-cache topic mode)))
 237
 238 (defun info-lookup->all-modes (topic mode)
 239   (cons mode (info-lookup->refer-modes topic mode)))
 240
 241 (defun info-lookup-quick-all-modes (topic mode)
 242   (cons mode (info-lookup->other-modes topic mode)))
 243
 244 ;;;###autoload
 245 (defun info-lookup-reset ()
 246   "Throw away all cached data.
 247 This command is useful if the user wants to start at the beginning without
 248 quitting Emacs, for example, after some Info documents were updated on the
 249 system."
 250   (interactive)
 251   (setq info-lookup-cache nil))
 252
 253 ;;;###autoload
 254 (defun info-lookup-symbol (symbol &optional mode)
 255   "Display the definition of SYMBOL, as found in the relevant manual.
 256 When this command is called interactively, it reads SYMBOL from the minibuffer.
 257 In the minibuffer, use M-n to yank the default argument value
 258 into the minibuffer so you can edit it.
 259 The default symbol is the one found at point.
 260
 261 With prefix arg a query for the symbol help mode is offered."
 262   (interactive
 263    (info-lookup-interactive-arguments 'symbol current-prefix-arg))
 264   (info-lookup 'symbol symbol mode))
 265
 266 ;;;###autoload
 267 (defun info-lookup-file (file &optional mode)
 268   "Display the documentation of a file.
 269 When this command is called interactively, it reads FILE from the minibuffer.
 270 In the minibuffer, use M-n to yank the default file name
 271 into the minibuffer so you can edit it.
 272 The default file name is the one found at point.
 273
 274 With prefix arg a query for the file help mode is offered."
 275   (interactive
 276    (info-lookup-interactive-arguments 'file current-prefix-arg))
 277   (info-lookup 'file file mode))
 278
 279 (defun info-lookup-interactive-arguments (topic &optional query)
 280   "Read and return argument value (and help mode) for help topic TOPIC.
 281 If optional argument QUERY is non-nil, query for the help mode."
 282   (let* ((mode (cond (query
 283                       (info-lookup-change-mode topic))
 284                      ((info-lookup->mode-value topic (info-lookup-select-mode))
 285                       info-lookup-mode)
 286                      ((info-lookup-change-mode topic))))
 287          (completions (info-lookup->completions topic mode))
 288          (default (info-lookup-guess-default topic mode))
 289          (completion-ignore-case (info-lookup->ignore-case topic mode))
 290          (enable-recursive-minibuffers t)
 291          (value (completing-read
 292                  (if default
 293                      (format "Describe %s (default %s): " topic default)
 294                    (format "Describe %s: " topic))
 295                  completions nil nil nil 'info-lookup-history default)))
 296     (list (if (equal value "") default value) mode)))
 297
 298 (defun info-lookup-select-mode ()
 299   (when (and (not info-lookup-mode) (buffer-file-name))
 300     (let ((file-name (file-name-nondirectory (buffer-file-name)))
 301           (file-name-alist info-lookup-file-name-alist))
 302       (while (and (not info-lookup-mode) file-name-alist)
 303         (when (string-match (caar file-name-alist) file-name)
 304           (setq info-lookup-mode (cdar file-name-alist)))
 305         (setq file-name-alist (cdr file-name-alist)))))
 306   (or info-lookup-mode (setq info-lookup-mode major-mode)))
 307
 308 (defun info-lookup-change-mode (topic)
 309   (let* ((completions (mapcar (lambda (arg)
 310                                 (cons (symbol-name (car arg)) (car arg)))
 311                               (info-lookup->topic-value topic)))
 312          (mode (completing-read
 313                 (format "Use %s help mode: " topic)
 314                 completions nil t nil 'info-lookup-history)))
 315     (or (setq mode (cdr (assoc mode completions)))
 316         (error "No %s help available" topic))
 317     (or (info-lookup->mode-value topic mode)
 318         (error "No %s help available for `%s'" topic mode))
 319     (setq info-lookup-mode mode)))
 320
 321 (defun info-lookup (topic item mode)
 322   "Display the documentation of a help item."
 323   (or mode (setq mode (info-lookup-select-mode)))
 324   (or (info-lookup->mode-value topic mode)
 325       (error "No %s help available for `%s'" topic mode))
 326   (let ((entry (or (assoc (if (info-lookup->ignore-case topic mode)
 327                               (downcase item) item)
 328                           (info-lookup->completions topic mode))
 329                    (error "Not documented as a %s: %s" topic (or item ""))))
 330         (modes (info-lookup->all-modes topic mode))
 331         (window (selected-window))
 332         found doc-spec node prefix suffix doc-found)
 333     (if (or (not info-lookup-other-window-flag)
 334             (eq (current-buffer) (get-buffer "*info*")))
 335         (info)
 336       (save-window-excursion (info))
 337       (switch-to-buffer-other-window "*info*"))
 338     (while (and (not found) modes)
 339       (setq doc-spec (info-lookup->doc-spec topic (car modes)))
 340       (while (and (not found) doc-spec)
 341         (setq node (nth 0 (car doc-spec))
 342               prefix (nth 2 (car doc-spec))
 343               suffix (nth 3 (car doc-spec)))
 344         (when (condition-case error-data
 345                   (progn
 346                     (Info-goto-node node)
 347                     (setq doc-found t))
 348                 (error
 349                  (message "Cannot access Info node %s" node)
 350                  (sit-for 1)
 351                  nil))
 352           (condition-case nil
 353               (progn
 354                 (Info-menu (or (cdr entry) item))
 355                 (setq found t)
 356                 (if (or prefix suffix)
 357                     (let ((case-fold-search
 358                            (info-lookup->ignore-case topic (car modes)))
 359                           (buffer-read-only nil))
 360                       (goto-char (point-min))
 361                       (re-search-forward
 362                        (concat prefix (regexp-quote item) suffix))
 363                       (goto-char (match-beginning 0))
 364                       (and window-system info-lookup-highlight-face
 365                            ;; Search again for ITEM so that the first
 366                            ;; occurence of ITEM will be highlighted.
 367                            (re-search-forward (regexp-quote item))
 368                            (let ((start (match-beginning 0))
 369                                  (end (match-end 0)))
 370                              (if (overlayp info-lookup-highlight-overlay)
 371                                  (move-overlay info-lookup-highlight-overlay
 372                                                start end (current-buffer))
 373                                (setq info-lookup-highlight-overlay
 374                                      (make-overlay start end))))
 375                            (overlay-put info-lookup-highlight-overlay
 376                                         'face info-lookup-highlight-face)))))
 377             (error nil)))
 378         (setq doc-spec (cdr doc-spec)))
 379       (setq modes (cdr modes)))
 380     (or doc-found
 381         (error "Info documentation for lookup was not found"))
 382     ;; Don't leave the Info buffer if the help item couldn't be looked up.
 383     (if (and info-lookup-other-window-flag found)
 384         (select-window window))))
 385
 386 (defun info-lookup-setup-mode (topic mode)
 387   "Initialize the internal data structure."
 388   (or (info-lookup->initialized topic mode)
 389       (let (cell data (initialized 0) completions refer-modes)
 390         (if (not (info-lookup->mode-value topic mode))
 391             (message "No %s help available for `%s'" topic mode)
 392           ;; Recursively setup cross references.
 393           ;; But refer only to non-void modes.
 394           (mapcar (lambda (arg)
 395                     (or (info-lookup->initialized topic arg)
 396                         (info-lookup-setup-mode topic arg))
 397                     (and (eq (info-lookup->initialized topic arg) t)
 398                          (setq refer-modes (cons arg refer-modes))))
 399                   (info-lookup->other-modes topic mode))
 400           (setq refer-modes (nreverse refer-modes))
 401           ;; Build the full completion alist.
 402           (setq completions
 403                 (nconc (condition-case nil
 404                            (info-lookup-make-completions topic mode)
 405                          (error nil))
 406                        (apply 'append
 407                               (mapcar (lambda (arg)
 408                                         (info-lookup->completions topic arg))
 409                                       refer-modes))))
 410           (setq initialized t))
 411         ;; Update `info-lookup-cache'.
 412         (setq cell (info-lookup->mode-cache topic mode)
 413               data (list initialized completions refer-modes))
 414         (if (not cell)
 415             (setcdr (info-lookup->cache topic)
 416                     (cons (cons mode data) (info-lookup->topic-cache topic)))
 417           (setcdr cell data))
 418         initialized)))
 419
 420 (defun info-lookup-make-completions (topic mode)
 421   "Create a unique alist from all index entries."
 422   (let ((doc-spec (info-lookup->doc-spec topic mode))
 423         (regexp (concat "^\\(" (info-lookup->regexp topic mode)
 424                         "\\)\\([ \t].*\\)?$"))
 425         node trans entry item prefix result doc-found
 426         (buffer (get-buffer-create " temp-info-look")))
 427     (with-current-buffer buffer
 428       (Info-mode))
 429     (while doc-spec
 430       (setq node (nth 0 (car doc-spec))
 431             trans (cond ((eq (nth 1 (car doc-spec)) nil)
 432                          (lambda (arg)
 433                            (if (string-match regexp arg)
 434                                (match-string 1 arg))))
 435                         ((stringp (nth 1 (car doc-spec)))
 436                          (setq prefix (nth 1 (car doc-spec)))
 437                          (lambda (arg)
 438                            (if (string-match "^\\([^: \t\n]+\\)" arg)
 439                                (concat prefix (match-string 1 arg)))))
 440                         (t (nth 1 (car doc-spec)))))
 441       (with-current-buffer buffer
 442         (message "Processing Info node `%s'..." node)
 443         (when (condition-case error-data
 444                   (progn
 445                     (Info-goto-node node)
 446                     (setq doc-found t))
 447                 (error
 448                  (message "Cannot access Info node `%s'" node)
 449                  (sit-for 1)
 450                  nil))
 451           (condition-case nil
 452               (progn
 453                 (goto-char (point-min))
 454                 (and (search-forward "\n* Menu:" nil t)
 455                      (while (re-search-forward "\n\\* \\([^:\t\n]*\\):" nil t)
 456                        (setq entry (match-string 1)
 457                              item (funcall trans entry))
 458                        ;; `trans' can return nil if the regexp doesn't match.
 459                        (when (and item
 460                                   ;; Sometimes there's more than one Menu:
 461                                   (not (string= entry "Menu")))
 462                          (and (info-lookup->ignore-case topic mode)
 463                               (setq item (downcase item)))
 464                          (and (string-equal entry item)
 465                               (setq entry nil))
 466                          (and (or (assoc item result)
 467                                   (setq result (cons (cons item entry)
 468                                                      result))))))))
 469             (error nil))))
 470       (message "Processing Info node `%s'...done" node)
 471       (setq doc-spec (cdr doc-spec)))
 472     (or doc-found
 473         (error "Info documentation for lookup was not found"))
 474     result))
 475
 476 (defun info-lookup-guess-default (topic mode)
 477   "Return a guess for a symbol to look up, based on text around point.
 478 Try all related modes applicable to TOPIC and MODE.
 479 Return nil if there is nothing appropriate in the buffer near point."
 480   (let ((modes (info-lookup->all-modes topic mode))
 481         guess)
 482     (while (and (not guess) modes)
 483       (setq guess (info-lookup-guess-default* topic (car modes))
 484             modes (cdr modes)))
 485     ;; Collapse whitespace characters.
 486     (when guess
 487       (let ((pos 0))
 488         (while (string-match "[ \t\n]+" guess pos)
 489           (setq pos (1+ (match-beginning 0)))
 490           (setq guess (replace-match " " t t guess)))))
 491     guess))
 492
 493 (defun info-lookup-guess-default* (topic mode)
 494   (let ((case-fold-search (info-lookup->ignore-case topic mode))
 495         (rule (or (info-lookup->parse-rule topic mode)
 496                   (info-lookup->regexp topic mode)))
 497         (start (point)) end regexp subexp result)
 498     (save-excursion
 499       (if (symbolp rule)
 500           (setq result (funcall rule))
 501         (if (consp rule)
 502             (setq regexp (car rule)
 503                   subexp (cdr rule))
 504           (setq regexp rule
 505                 subexp 0))
 506         ;; If at start of symbol, don't go back to end of previous one.
 507         (if (save-match-data
 508               (looking-at "[ \t\n]"))
 509             (skip-chars-backward " \t\n"))
 510         (setq end (point))
 511         (while (and (re-search-backward regexp nil t)
 512                     (looking-at regexp)
 513                     (>= (match-end 0) end))
 514           (setq result (match-string subexp)))
 515         (if (not result)
 516             (progn
 517               (goto-char start)
 518               (skip-chars-forward " \t\n")
 519               (and (looking-at regexp)
 520                    (setq result (match-string subexp)))))))
 521     result))
 522
 523 (defun info-lookup-guess-c-symbol ()
 524   "Get the C symbol at point."
 525   (condition-case nil
 526       (progn
 527         (skip-syntax-backward "w_")
 528         (let ((start (point)) prefix name)
 529           ;; Test for a leading `struct', `union', or `enum' keyword
 530           ;; but ignore names like `foo_struct'.
 531           (setq prefix (and (< (skip-chars-backward " \t\n") 0)
 532                             (< (skip-chars-backward "_a-zA-Z0-9") 0)
 533                             (looking-at "\\(struct\\|union\\|enum\\)\\s ")
 534                             (concat (match-string 1) " ")))
 535           (goto-char start)
 536           (and (looking-at "[_a-zA-Z][_a-zA-Z0-9]*")
 537                (setq name (match-string 0)))
 538           ;; Caveat!  Look forward if point is at `struct' etc.
 539           (and (not prefix)
 540                (or (string-equal name "struct")
 541                    (string-equal name "union")
 542                    (string-equal name "enum"))
 543                (looking-at "[a-z]+\\s +\\([_a-zA-Z][_a-zA-Z0-9]*\\)")
 544                (setq prefix (concat name " ")
 545                      name (match-string 1)))
 546           (and (or prefix name)
 547                (concat prefix name))))
 548     (error nil)))
 549
 550 ;;;###autoload
 551 (defun info-complete-symbol (&optional mode)
 552   "Perform completion on symbol preceding point."
 553   (interactive)
 554   (info-complete 'symbol
 555                  (or mode
 556                      (if (info-lookup->mode-value
 557                           'symbol (info-lookup-select-mode))
 558                          info-lookup-mode
 559                        (info-lookup-change-mode 'symbol)))))
 560
 561 ;;;###autoload
 562 (defun info-complete-file (&optional mode)
 563   "Perform completion on file preceding point."
 564   (interactive)
 565   (info-complete 'file
 566                  (or mode
 567                      (if (info-lookup->mode-value
 568                           'file (info-lookup-select-mode))
 569                          info-lookup-mode
 570                        (info-lookup-change-mode 'file)))))
 571
 572 (defun info-complete (topic mode)
 573   "Try to complete a help item."
 574   (barf-if-buffer-read-only)
 575   (or mode (setq mode (info-lookup-select-mode)))
 576   (or (info-lookup->mode-value topic mode)
 577       (error "No %s completion available for `%s'" topic mode))
 578   (let ((modes (info-lookup-quick-all-modes topic mode))
 579         (start (point))
 580         try)
 581     (while (and (not try) modes)
 582       (setq mode (car modes)
 583             modes (cdr modes)
 584             try (info-lookup-guess-default* topic mode))
 585       (goto-char start))
 586     (and (not try)
 587          (error "Found no %S to complete" topic))
 588     (let ((completions (info-lookup->completions topic mode))
 589           (completion-ignore-case (info-lookup->ignore-case topic mode))
 590           completion)
 591       (setq completion (try-completion try completions))
 592       (cond ((not completion)
 593              (ding)
 594              (message "No match"))
 595             ((stringp completion)
 596              (or (assoc completion completions)
 597                  (setq completion (completing-read
 598                                    (format "Complete %S: " topic)
 599                                    completions nil t completion
 600                                    info-lookup-history)))
 601              ;; Find the original symbol and zap it.
 602              (end-of-line)
 603              (while (and (search-backward try nil t)
 604                          (< start (point))))
 605              (replace-match "")
 606              (insert completion))
 607             (t
 608              (message "%s is complete"
 609                       (capitalize (prin1-to-string topic))))))))
 610
 611 \f
 612 ;;; Initialize some common modes.
 613
 614 (info-lookup-maybe-add-help
 615  :mode 'c-mode :topic 'symbol
 616  :regexp "\\(struct \\|union \\|enum \\)?[_a-zA-Z][_a-zA-Z0-9]*"
 617  :doc-spec '(("(libc)Function Index" nil
 618               "^[ \t]+- \\(Function\\|Macro\\): .*\\<" "\\>")
 619              ("(libc)Variable Index" nil
 620               "^[ \t]+- \\(Variable\\|Macro\\): .*\\<" "\\>")
 621              ("(libc)Type Index" nil
 622               "^[ \t]+- Data Type: \\<" "\\>")
 623              ("(termcap)Var Index" nil
 624               "^[ \t]*`" "'"))
 625  :parse-rule 'info-lookup-guess-c-symbol)
 626
 627 (info-lookup-maybe-add-help
 628  :mode 'c-mode :topic 'file
 629  :regexp "[_a-zA-Z0-9./+-]+"
 630  :doc-spec '(("(libc)File Index")))
 631
 632 (info-lookup-maybe-add-help
 633  :mode 'bison-mode
 634  :regexp "[:;|]\\|%\\([%{}]\\|[_a-z]+\\)\\|YY[_A-Z]+\\|yy[_a-z]+"
 635  :doc-spec '(("(bison)Index" nil
 636               "`" "'"))
 637  :parse-rule "[:;|]\\|%\\([%{}]\\|[_a-zA-Z][_a-zA-Z0-9]*\\)"
 638  :other-modes '(c-mode))
 639
 640 (info-lookup-maybe-add-help
 641  :mode 'makefile-mode
 642  :regexp "\\$[^({]\\|\\.[_A-Z]*\\|[_a-zA-Z][_a-zA-Z0-9-]*"
 643  :doc-spec '(("(make)Name Index" nil
 644               "^[ \t]*`" "'"))
 645  :parse-rule "\\$[^({]\\|\\.[_A-Z]*\\|[_a-zA-Z0-9-]+")
 646
 647 (info-lookup-maybe-add-help
 648  :mode 'texinfo-mode
 649  :regexp "@\\([a-zA-Z]+\\|[^a-zA-Z]\\)"
 650  :doc-spec '(("(texinfo)Command and Variable Index"
 651               ;; Ignore Emacs commands and prepend a `@'.
 652               (lambda (item)
 653                 (if (string-match "^\\([a-zA-Z]+\\|[^a-zA-Z]\\)\\( .*\\)?$" item)
 654                     (concat "@" (match-string 1 item))))
 655               "`" "'")))
 656
 657 (info-lookup-maybe-add-help
 658  :mode 'm4-mode
 659  :regexp "[_a-zA-Z][_a-zA-Z0-9]*"
 660  :doc-spec '(("(m4)Macro index"))
 661  :parse-rule "[_a-zA-Z0-9]+")
 662
 663 (info-lookup-maybe-add-help
 664  :mode 'autoconf-mode
 665  :regexp "A[CM]_[_A-Z0-9]+"
 666  :doc-spec '(("(autoconf)Macro Index" "AC_"
 667               "^[ \t]+- \\(Macro\\|Variable\\): .*\\<" "\\>")
 668              ("(automake)Index" nil
 669               "^[ \t]*`" "'"))
 670  ;; Autoconf symbols are M4 macros.  Thus use M4's parser.
 671  :parse-rule 'ignore
 672  :other-modes '(m4-mode))
 673
 674 (info-lookup-maybe-add-help
 675  :mode 'awk-mode
 676  :regexp "[_a-zA-Z]+"
 677  :doc-spec '(("(gawk)Index"
 678               (lambda (item)
 679                 (let ((case-fold-search nil))
 680                   (cond
 681                    ;; `BEGIN' and `END'.
 682                    ((string-match "^\\([A-Z]+\\) special pattern\\b" item)
 683                     (match-string 1 item))
 684                    ;; `if', `while', `do', ...
 685                    ((string-match "^\\([a-z]+\\) statement\\b" item)
 686                     (if (not (string-equal (match-string 1 item) "control"))
 687                         (match-string 1 item)))
 688                    ;; `NR', `NF', ...
 689                    ((string-match "^[A-Z]+$" item)
 690                     item)
 691                    ;; Built-in functions (matches to many entries).
 692                    ((string-match "^[a-z]+$" item)
 693                     item))))
 694               "`" "\\([ \t]*([^)]*)\\)?'")))
 695
 696 (info-lookup-maybe-add-help
 697  :mode 'perl-mode
 698  :regexp "[$@%][^a-zA-Z]\\|\\$\\^[A-Z]\\|[$@%]?[a-zA-Z][_a-zA-Z0-9]*"
 699  :doc-spec '(("(perl5)Function Index"
 700               (lambda (item)
 701                 (if (string-match "^\\([a-zA-Z0-9]+\\)" item)
 702                     (match-string 1 item)))
 703               "^" "\\b")
 704              ("(perl5)Variable Index"
 705               (lambda (item)
 706                 ;; Work around bad formatted array variables.
 707                 (let ((sym (cond ((or (string-match "^\\$\\(.\\|@@\\)$" item)
 708                                       (string-match "^\\$\\^[A-Z]$" item))
 709                                   item)
 710                                  ((string-match
 711                                    "^\\([$%@]\\|@@\\)?[_a-zA-Z0-9]+" item)
 712                                   (match-string 0 item))
 713                                  (t ""))))
 714                   (if (string-match "@@" sym)
 715                       (setq sym (concat (substring sym 0 (match-beginning 0))
 716                                         (substring sym (1- (match-end 0))))))
 717                   (if (string-equal sym "") nil sym)))
 718               "^" "\\b"))
 719  :parse-rule "[$@%]?\\([_a-zA-Z0-9]+\\|[^a-zA-Z]\\)")
 720
 721 (info-lookup-maybe-add-help
 722  :mode 'latex-mode
 723  :regexp "\\\\\\([a-zA-Z]+\\|[^a-zA-Z]\\)"
 724  :doc-spec '(("(latex)Command Index" nil
 725               "`" "\\({[^}]*}\\)?'")))
 726
 727 (info-lookup-maybe-add-help
 728  :mode 'emacs-lisp-mode
 729  :regexp "[^()' \t\n]+"
 730  :doc-spec '(("(emacs)Command Index")
 731              ("(emacs)Variable Index")
 732              ("(elisp)Index"
 733               (lambda (item)
 734                 (let ((sym (intern-soft item)))
 735                   (cond ((null sym)
 736                          (if (string-equal item "nil") item))
 737                         ((or (boundp sym) (fboundp sym))
 738                          item))))
 739               "^[ \t]+- [^:]+:[ \t]*" "\\b")))
 740
 741 (info-lookup-maybe-add-help
 742  :mode 'lisp-interaction-mode
 743  :regexp "[^()' \t\n]+"
 744  :parse-rule 'ignore
 745  :other-modes '(emacs-lisp-mode))
 746
 747 (info-lookup-maybe-add-help
 748  :mode 'lisp-mode
 749  :regexp "[^()' \t\n]+"
 750  :parse-rule 'ignore
 751  :other-modes '(emacs-lisp-mode))
 752
 753 (info-lookup-maybe-add-help
 754  :mode 'scheme-mode
 755  :regexp "[^()' \t\n]+"
 756  :ignore-case t
 757  ;; Aubrey Jaffer's rendition from <URL:ftp://ftp-swiss.ai.mit.edu/pub/scm>
 758  :doc-spec '(("(r5rs)Index" nil
 759               "^[ \t]+- [^:]+:[ \t]*" "\\b")))
 760
 761 (info-lookup-maybe-add-help
 762  :mode 'octave-mode
 763  :regexp "[_a-zA-Z0-9]+"
 764  :doc-spec '(("(octave)Function Index" nil
 765               "^ - [^:]+:[ ]+\\(\\[[^=]*=[ ]+\\)?" nil)
 766              ("(octave)Variable Index" nil "^ - [^:]+:[ ]+" nil)
 767              ;; Catch lines of the form "xyz statement"
 768              ("(octave)Concept Index"
 769               (lambda (item)
 770                 (cond
 771                  ((string-match "^\\([A-Z]+\\) statement\\b" item)
 772                     (match-string 1 item))
 773                  (t nil)))
 774               nil; "^ - [^:]+:[ ]+" don't think this prefix is useful here.
 775               nil)))
 776 \f
 777 (provide 'info-look)
 778
 779 ;;; info-look.el ends here