code.delx.au - gnu-emacs/blob - lisp/emacs-lisp/find-func.el

   1 ;;; find-func.el --- find the definition of the Emacs Lisp function near point  -*- lexical-binding:t -*-
   2
   3 ;; Copyright (C) 1997, 1999, 2001-2015 Free Software Foundation, Inc.
   4
   5 ;; Author: Jens Petersen <petersen@kurims.kyoto-u.ac.jp>
   6 ;; Maintainer: petersen@kurims.kyoto-u.ac.jp
   7 ;; Keywords: emacs-lisp, functions, variables
   8 ;; Created: 97/07/25
   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 3 of the License, or
  15 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26 ;;
  27 ;; The funniest thing about this is that I can't imagine why a package
  28 ;; so obviously useful as this hasn't been written before!!
  29 ;; ;;; find-func
  30 ;; (find-function-setup-keys)
  31 ;;
  32 ;; or just:
  33 ;;
  34 ;; (load "find-func")
  35 ;;
  36 ;; if you don't like the given keybindings and away you go!  It does
  37 ;; pretty much what you would expect, putting the cursor at the
  38 ;; definition of the function or variable at point.
  39 ;;
  40 ;; The code started out from `describe-function', `describe-key'
  41 ;; ("help.el") and `fff-find-loaded-emacs-lisp-function' (Noah Friedman's
  42 ;; "fff.el").
  43
  44 ;;; Code:
  45
  46 ;;; User variables:
  47
  48 (defgroup find-function nil
  49   "Finds the definition of the Emacs Lisp symbol near point."
  50 ;;   :prefix "find-function"
  51   :group 'lisp)
  52
  53 (defconst find-function-space-re "\\(?:\\s-\\|\n\\|;.*\n\\)+")
  54
  55 (defcustom find-function-regexp
  56   ;; Match things like (defun foo ...), (defmacro foo ...),
  57   ;; (define-skeleton foo ...), (define-generic-mode 'foo ...),
  58   ;;  (define-derived-mode foo ...), (define-minor-mode foo)
  59   (concat
  60    "^\\s-*(\\(def\\(ine-skeleton\\|ine-generic-mode\\|ine-derived-mode\\|\
  61 ine\\(?:-global\\)?-minor-mode\\|ine-compilation-mode\\|un-cvs-mode\\|\
  62 foo\\|\\(?:[^icfgv]\\|g[^r]\\)\\(\\w\\|\\s_\\)+\\*?\\)\\|easy-mmode-define-[a-z-]+\\|easy-menu-define\\|\
  63 menu-bar-make-toggle\\)"
  64    find-function-space-re
  65    "\\('\\|\(quote \\)?%s\\(\\s-\\|$\\|\(\\|\)\\)")
  66   "The regexp used by `find-function' to search for a function definition.
  67 Note it must contain a `%s' at the place where `format'
  68 should insert the function name.  The default value avoids `defconst',
  69 `defgroup', `defvar', `defface'.
  70
  71 Please send improvements and fixes to the maintainer."
  72   :type 'regexp
  73   :group 'find-function
  74   :version "21.1")
  75
  76 (defcustom find-variable-regexp
  77   (concat
  78    "^\\s-*(\\(def[^fumag]\\(\\w\\|\\s_\\)+\\*?\\|\
  79 easy-mmode-def\\(map\\|syntax\\)\\|easy-menu-define\\)"
  80    find-function-space-re
  81    "%s\\(\\s-\\|$\\)")
  82   "The regexp used by `find-variable' to search for a variable definition.
  83 Note it must contain a `%s' at the place where `format'
  84 should insert the variable name.  The default value
  85 avoids `defun', `defmacro', `defalias', `defadvice', `defgroup', `defface'.
  86
  87 Please send improvements and fixes to the maintainer."
  88   :type 'regexp
  89   :group 'find-function
  90   :version "21.1")
  91
  92 (defcustom find-face-regexp
  93   (concat"^\\s-*(defface" find-function-space-re "%s\\(\\s-\\|$\\)")
  94   "The regexp used by `find-face' to search for a face definition.
  95 Note it must contain a `%s' at the place where `format'
  96 should insert the face name.
  97
  98 Please send improvements and fixes to the maintainer."
  99   :type 'regexp
 100   :group 'find-function
 101   :version "22.1")
 102
 103 (defvar find-function-regexp-alist
 104   '((nil . find-function-regexp)
 105     (defvar . find-variable-regexp)
 106     (defface . find-face-regexp))
 107   "Alist mapping definition types into regexp variables.
 108 Each regexp variable's value should actually be a format string
 109 to be used to substitute the desired symbol name into the regexp.
 110 Instead of regexp variable, types can be mapped to functions as well,
 111 in which case the function is called with one argument (the object
 112 we're looking for) and it should search for it.")
 113 (put 'find-function-regexp-alist 'risky-local-variable t)
 114
 115 (defcustom find-function-source-path nil
 116   "The default list of directories where `find-function' searches.
 117
 118 If this variable is nil then `find-function' searches `load-path' by
 119 default."
 120   :type '(repeat directory)
 121   :group 'find-function)
 122
 123 (defcustom find-function-recenter-line 1
 124   "The window line-number from which to start displaying a symbol definition.
 125 A value of nil implies center the beginning of the definition.
 126 See `find-function' and `find-variable'."
 127   :type '(choice (const :tag "Center" nil)
 128                  integer)
 129   :group 'find-function
 130   :version "20.3")
 131
 132 (defcustom find-function-after-hook nil
 133   "Hook run after finding symbol definition.
 134
 135 See the functions `find-function' and `find-variable'."
 136   :type 'hook
 137   :group 'find-function
 138   :version "20.3")
 139
 140 ;;; Functions:
 141
 142 (defun find-library-suffixes ()
 143   (let ((suffixes nil))
 144     (dolist (suffix (get-load-suffixes) (nreverse suffixes))
 145       (unless (string-match "elc" suffix) (push suffix suffixes)))))
 146
 147 (defun find-library--load-name (library)
 148   (let ((name library))
 149     (dolist (dir load-path)
 150       (let ((rel (file-relative-name library dir)))
 151         (if (and (not (string-match "\\`\\.\\./" rel))
 152                  (< (length rel) (length name)))
 153             (setq name rel))))
 154     (unless (equal name library) name)))
 155
 156 (defun find-library-name (library)
 157   "Return the absolute file name of the Emacs Lisp source of LIBRARY.
 158 LIBRARY should be a string (the name of the library)."
 159   ;; If the library is byte-compiled, try to find a source library by
 160   ;; the same name.
 161   (if (string-match "\\.el\\(c\\(\\..*\\)?\\)\\'" library)
 162       (setq library (replace-match "" t t library)))
 163   (or
 164    (locate-file library
 165                 (or find-function-source-path load-path)
 166                 (find-library-suffixes))
 167    (locate-file library
 168                 (or find-function-source-path load-path)
 169                 load-file-rep-suffixes)
 170    (when (file-name-absolute-p library)
 171      (let ((rel (find-library--load-name library)))
 172        (when rel
 173          (or
 174           (locate-file rel
 175                        (or find-function-source-path load-path)
 176                        (find-library-suffixes))
 177           (locate-file rel
 178                        (or find-function-source-path load-path)
 179                        load-file-rep-suffixes)))))
 180    (error "Can't find library %s" library)))
 181
 182 (defvar find-function-C-source-directory
 183   (let ((dir (expand-file-name "src" source-directory)))
 184     (if (file-accessible-directory-p dir) dir))
 185   "Directory where the C source files of Emacs can be found.
 186 If nil, do not try to find the source code of functions and variables
 187 defined in C.")
 188
 189 (declare-function ad-get-advice-info "advice" (function))
 190
 191 (defun find-function-advised-original (func)
 192   "Return the original function definition of an advised function FUNC.
 193 If FUNC is not a symbol, return it.  Else, if it's not advised,
 194 return the symbol's function definition."
 195   (or (and (symbolp func)
 196            (featurep 'nadvice)
 197            (let ((ofunc (advice--symbol-function func)))
 198              (if (advice--p ofunc)
 199                  (advice--cd*r ofunc)
 200                ofunc)))
 201       func))
 202
 203 (defun find-function-C-source (fun-or-var file type)
 204   "Find the source location where FUN-OR-VAR is defined in FILE.
 205 TYPE should be nil to find a function, or `defvar' to find a variable."
 206   (let ((dir (or find-function-C-source-directory
 207                  (read-directory-name "Emacs C source dir: " nil nil t))))
 208     (setq file (expand-file-name file dir))
 209     (if (file-readable-p file)
 210         (if (null find-function-C-source-directory)
 211             (setq find-function-C-source-directory dir))
 212       (error "The C source file %s is not available"
 213              (file-name-nondirectory file))))
 214   (unless type
 215     ;; Either or both an alias and its target might be advised.
 216     (setq fun-or-var (find-function-advised-original
 217                       (indirect-function
 218                        (find-function-advised-original fun-or-var)))))
 219   (with-current-buffer (find-file-noselect file)
 220     (goto-char (point-min))
 221     (unless (re-search-forward
 222              (if type
 223                  (concat "DEFVAR[A-Z_]*[ \t\n]*([ \t\n]*\""
 224                          (regexp-quote (symbol-name fun-or-var))
 225                          "\"")
 226                (concat "DEFUN[ \t\n]*([ \t\n]*\""
 227                        (regexp-quote (subr-name (advice--cd*r fun-or-var)))
 228                        "\""))
 229              nil t)
 230       (error "Can't find source for %s" fun-or-var))
 231     (cons (current-buffer) (match-beginning 0))))
 232
 233 ;;;###autoload
 234 (defun find-library (library)
 235   "Find the Emacs Lisp source of LIBRARY.
 236 LIBRARY should be a string (the name of the library)."
 237   (interactive
 238    (let* ((dirs (or find-function-source-path load-path))
 239           (suffixes (find-library-suffixes))
 240           (table (apply-partially 'locate-file-completion-table
 241                                   dirs suffixes))
 242           (def (if (eq (function-called-at-point) 'require)
 243                    ;; `function-called-at-point' may return 'require
 244                    ;; with `point' anywhere on this line.  So wrap the
 245                    ;; `save-excursion' below in a `condition-case' to
 246                    ;; avoid reporting a scan-error here.
 247                    (condition-case nil
 248                        (save-excursion
 249                          (backward-up-list)
 250                          (forward-char)
 251                          (forward-sexp 2)
 252                          (thing-at-point 'symbol))
 253                      (error nil))
 254                  (thing-at-point 'symbol))))
 255      (when (and def (not (test-completion def table)))
 256        (setq def nil))
 257      (list
 258       (completing-read (if def (format "Library name (default %s): " def)
 259                          "Library name: ")
 260                        table nil nil nil nil def))))
 261   (let ((buf (find-file-noselect (find-library-name library))))
 262     (condition-case nil (switch-to-buffer buf) (error (pop-to-buffer buf)))))
 263
 264 ;;;###autoload
 265 (defun find-function-search-for-symbol (symbol type library)
 266   "Search for SYMBOL's definition of type TYPE in LIBRARY.
 267 Visit the library in a buffer, and return a cons cell (BUFFER . POSITION),
 268 or just (BUFFER . nil) if the definition can't be found in the file.
 269
 270 If TYPE is nil, look for a function definition.
 271 Otherwise, TYPE specifies the kind of definition,
 272 and it is interpreted via `find-function-regexp-alist'.
 273 The search is done in the source for library LIBRARY."
 274   (if (null library)
 275       (error "Don't know where `%s' is defined" symbol))
 276   ;; Some functions are defined as part of the construct
 277   ;; that defines something else.
 278   (while (and (symbolp symbol) (get symbol 'definition-name))
 279     (setq symbol (get symbol 'definition-name)))
 280   (if (string-match "\\`src/\\(.*\\.\\(c\\|m\\)\\)\\'" library)
 281       (find-function-C-source symbol (match-string 1 library) type)
 282     (when (string-match "\\.el\\(c\\)\\'" library)
 283       (setq library (substring library 0 (match-beginning 1))))
 284     ;; Strip extension from .emacs.el to make sure symbol is searched in
 285     ;; .emacs too.
 286     (when (string-match "\\.emacs\\(.el\\)" library)
 287       (setq library (substring library 0 (match-beginning 1))))
 288     (let* ((filename (find-library-name library))
 289            (regexp-symbol (cdr (assq type find-function-regexp-alist))))
 290       (with-current-buffer (find-file-noselect filename)
 291         (let ((regexp (if (functionp regexp-symbol) regexp-symbol
 292                         (format (symbol-value regexp-symbol)
 293                                 ;; Entry for ` (backquote) macro in loaddefs.el,
 294                                 ;; (defalias (quote \`)..., has a \ but
 295                                 ;; (symbol-name symbol) doesn't.  Add an
 296                                 ;; optional \ to catch this.
 297                                 (concat "\\\\?"
 298                                         (regexp-quote (symbol-name symbol))))))
 299               (case-fold-search))
 300           (with-syntax-table emacs-lisp-mode-syntax-table
 301             (goto-char (point-min))
 302             (if (if (functionp regexp)
 303                     (funcall regexp symbol)
 304                   (or (re-search-forward regexp nil t)
 305                       ;; `regexp' matches definitions using known forms like
 306                       ;; `defun', or `defvar'.  But some functions/variables
 307                       ;; are defined using special macros (or functions), so
 308                       ;; if `regexp' can't find the definition, we look for
 309                       ;; something of the form "(SOMETHING <symbol> ...)".
 310                       ;; This fails to distinguish function definitions from
 311                       ;; variable declarations (or even uses thereof), but is
 312                       ;; a good pragmatic fallback.
 313                       (re-search-forward
 314                        (concat "^([^ ]+" find-function-space-re "['(]?"
 315                                (regexp-quote (symbol-name symbol))
 316                                "\\_>")
 317                        nil t)))
 318                 (progn
 319                   (beginning-of-line)
 320                   (cons (current-buffer) (point)))
 321               (cons (current-buffer) nil))))))))
 322
 323 (defun find-function-library (function &optional lisp-only verbose)
 324   "Return the pair (ORIG-FUNCTION . LIBRARY) for FUNCTION.
 325
 326 ORIG-FUNCTION is the original name, after removing all advice and
 327 resolving aliases.  LIBRARY is an absolute file name, a relative
 328 file name inside the C sources directory, or a name of an
 329 autoloaded feature.
 330
 331 If ORIG-FUNCTION is a built-in function and LISP-ONLY is non-nil,
 332 signal an error.
 333
 334 If VERBOSE is non-nil, and FUNCTION is an alias, display a
 335 message about the whole chain of aliases."
 336   (let ((def (if (symbolp function)
 337                  (find-function-advised-original function)))
 338         aliases)
 339     ;; FIXME for completeness, it might be nice to print something like:
 340     ;; foo (which is advised), which is an alias for bar (which is advised).
 341     (while (and def (symbolp def))
 342       (or (eq def function)
 343           (not verbose)
 344           (setq aliases (if aliases
 345                             (concat aliases
 346                                     (format ", which is an alias for `%s'"
 347                                             (symbol-name def)))
 348                           (format "`%s' is an alias for `%s'"
 349                                   function (symbol-name def)))))
 350       (setq function (find-function-advised-original function)
 351             def (find-function-advised-original function)))
 352     (if aliases
 353         (message "%s" aliases))
 354     (cons function
 355           (cond
 356            ((autoloadp def) (nth 1 def))
 357            ((subrp def)
 358             (if lisp-only
 359                 (error "%s is a built-in function" function))
 360             (help-C-file-name def 'subr))
 361            ((symbol-file function 'defun))))))
 362
 363 ;;;###autoload
 364 (defun find-function-noselect (function &optional lisp-only)
 365   "Return a pair (BUFFER . POINT) pointing to the definition of FUNCTION.
 366
 367 Finds the source file containing the definition of FUNCTION
 368 in a buffer and the point of the definition.  The buffer is
 369 not selected.  If the function definition can't be found in
 370 the buffer, returns (BUFFER).
 371
 372 If FUNCTION is a built-in function, this function normally
 373 attempts to find it in the Emacs C sources; however, if LISP-ONLY
 374 is non-nil, signal an error instead.
 375
 376 If the file where FUNCTION is defined is not known, then it is
 377 searched for in `find-function-source-path' if non-nil, otherwise
 378 in `load-path'."
 379   (if (not function)
 380     (error "You didn't specify a function"))
 381   (let ((func-lib (find-function-library function lisp-only t)))
 382     (find-function-search-for-symbol (car func-lib) nil (cdr func-lib))))
 383
 384 (defun find-function-read (&optional type)
 385   "Read and return an interned symbol, defaulting to the one near point.
 386
 387 If TYPE is nil, insist on a symbol with a function definition.
 388 Otherwise TYPE should be `defvar' or `defface'.
 389 If TYPE is nil, defaults using `function-called-at-point',
 390 otherwise uses `variable-at-point'."
 391   (let* ((symb1 (cond ((null type) (function-called-at-point))
 392                       ((eq type 'defvar) (variable-at-point))
 393                       (t (variable-at-point t))))
 394          (symb  (unless (eq symb1 0) symb1))
 395          (predicate (cdr (assq type '((nil . fboundp)
 396                                       (defvar . boundp)
 397                                       (defface . facep)))))
 398          (prompt-type (cdr (assq type '((nil . "function")
 399                                         (defvar . "variable")
 400                                         (defface . "face")))))
 401          (prompt (concat "Find " prompt-type
 402                          (and symb (format " (default %s)" symb))
 403                          ": "))
 404          (enable-recursive-minibuffers t))
 405     (list (intern (completing-read
 406                    prompt obarray predicate
 407                    t nil nil (and symb (symbol-name symb)))))))
 408
 409 (defun find-function-do-it (symbol type switch-fn)
 410   "Find Emacs Lisp SYMBOL in a buffer and display it.
 411 TYPE is nil to search for a function definition,
 412 or else `defvar' or `defface'.
 413
 414 The variable `find-function-recenter-line' controls how
 415 to recenter the display.  SWITCH-FN is the function to call
 416 to display and select the buffer.
 417 See also `find-function-after-hook'.
 418
 419 Set mark before moving, if the buffer already existed."
 420   (let* ((orig-point (point))
 421         (orig-buffers (buffer-list))
 422         (buffer-point (save-excursion
 423                         (find-definition-noselect symbol type)))
 424         (new-buf (car buffer-point))
 425         (new-point (cdr buffer-point)))
 426     (when buffer-point
 427       (when (memq new-buf orig-buffers)
 428         (push-mark orig-point))
 429       (funcall switch-fn new-buf)
 430       (when new-point (goto-char new-point))
 431       (recenter find-function-recenter-line)
 432       (run-hooks 'find-function-after-hook))))
 433
 434 ;;;###autoload
 435 (defun find-function (function)
 436   "Find the definition of the FUNCTION near point.
 437
 438 Finds the source file containing the definition of the function
 439 near point (selected by `function-called-at-point') in a buffer and
 440 places point before the definition.
 441 Set mark before moving, if the buffer already existed.
 442
 443 The library where FUNCTION is defined is searched for in
 444 `find-function-source-path', if non-nil, otherwise in `load-path'.
 445 See also `find-function-recenter-line' and `find-function-after-hook'."
 446   (interactive (find-function-read))
 447   (find-function-do-it function nil 'switch-to-buffer))
 448
 449 ;;;###autoload
 450 (defun find-function-other-window (function)
 451   "Find, in another window, the definition of FUNCTION near point.
 452
 453 See `find-function' for more details."
 454   (interactive (find-function-read))
 455   (find-function-do-it function nil 'switch-to-buffer-other-window))
 456
 457 ;;;###autoload
 458 (defun find-function-other-frame (function)
 459   "Find, in another frame, the definition of FUNCTION near point.
 460
 461 See `find-function' for more details."
 462   (interactive (find-function-read))
 463   (find-function-do-it function nil 'switch-to-buffer-other-frame))
 464
 465 ;;;###autoload
 466 (defun find-variable-noselect (variable &optional file)
 467   "Return a pair `(BUFFER . POINT)' pointing to the definition of VARIABLE.
 468
 469 Finds the library containing the definition of VARIABLE in a buffer and
 470 the point of the definition.  The buffer is not selected.
 471 If the variable's definition can't be found in the buffer, return (BUFFER).
 472
 473 The library where VARIABLE is defined is searched for in FILE or
 474 `find-function-source-path', if non-nil, otherwise in `load-path'."
 475   (if (not variable)
 476       (error "You didn't specify a variable")
 477     (let ((library (or file
 478                        (symbol-file variable 'defvar)
 479                        (help-C-file-name variable 'var))))
 480       (find-function-search-for-symbol variable 'defvar library))))
 481
 482 ;;;###autoload
 483 (defun find-variable (variable)
 484   "Find the definition of the VARIABLE at or before point.
 485
 486 Finds the library containing the definition of the variable
 487 near point (selected by `variable-at-point') in a buffer and
 488 places point before the definition.
 489
 490 Set mark before moving, if the buffer already existed.
 491
 492 The library where VARIABLE is defined is searched for in
 493 `find-function-source-path', if non-nil, otherwise in `load-path'.
 494 See also `find-function-recenter-line' and `find-function-after-hook'."
 495   (interactive (find-function-read 'defvar))
 496   (find-function-do-it variable 'defvar 'switch-to-buffer))
 497
 498 ;;;###autoload
 499 (defun find-variable-other-window (variable)
 500   "Find, in another window, the definition of VARIABLE near point.
 501
 502 See `find-variable' for more details."
 503   (interactive (find-function-read 'defvar))
 504   (find-function-do-it variable 'defvar 'switch-to-buffer-other-window))
 505
 506 ;;;###autoload
 507 (defun find-variable-other-frame (variable)
 508   "Find, in another frame, the definition of VARIABLE near point.
 509
 510 See `find-variable' for more details."
 511   (interactive (find-function-read 'defvar))
 512   (find-function-do-it variable 'defvar 'switch-to-buffer-other-frame))
 513
 514 ;;;###autoload
 515 (defun find-definition-noselect (symbol type &optional file)
 516   "Return a pair `(BUFFER . POINT)' pointing to the definition of SYMBOL.
 517 If the definition can't be found in the buffer, return (BUFFER).
 518 TYPE says what type of definition: nil for a function, `defvar' for a
 519 variable, `defface' for a face.  This function does not switch to the
 520 buffer nor display it.
 521
 522 The library where SYMBOL is defined is searched for in FILE or
 523 `find-function-source-path', if non-nil, otherwise in `load-path'."
 524   (cond
 525    ((not symbol)
 526     (error "You didn't specify a symbol"))
 527    ((null type)
 528     (find-function-noselect symbol))
 529    ((eq type 'defvar)
 530     (find-variable-noselect symbol file))
 531    (t
 532     (let ((library (or file (symbol-file symbol type))))
 533       (find-function-search-for-symbol symbol type library)))))
 534
 535 ;; For symmetry, this should be called find-face; but some programs
 536 ;; assume that, if that name is defined, it means something else.
 537 ;;;###autoload
 538 (defun find-face-definition (face)
 539   "Find the definition of FACE.  FACE defaults to the name near point.
 540
 541 Finds the Emacs Lisp library containing the definition of the face
 542 near point (selected by `variable-at-point') in a buffer and
 543 places point before the definition.
 544
 545 Set mark before moving, if the buffer already existed.
 546
 547 The library where FACE is defined is searched for in
 548 `find-function-source-path', if non-nil, otherwise in `load-path'.
 549 See also `find-function-recenter-line' and `find-function-after-hook'."
 550   (interactive (find-function-read 'defface))
 551   (find-function-do-it face 'defface 'switch-to-buffer))
 552
 553 (defun find-function-on-key-do-it (key find-fn)
 554   "Find the function that KEY invokes.  KEY is a string.
 555 Set mark before moving, if the buffer already existed.
 556
 557 FIND-FN is the function to call to navigate to the function."
 558   (let (defn)
 559     (save-excursion
 560       (let* ((event (and (eventp key) (aref key 0))) ; Null event OK below.
 561              (start (event-start event))
 562              (modifiers (event-modifiers event))
 563              (window (and (or (memq 'click modifiers) (memq 'down modifiers)
 564                               (memq 'drag modifiers))
 565                           (posn-window start))))
 566         ;; For a mouse button event, go to the button it applies to
 567         ;; to get the right key bindings.  And go to the right place
 568         ;; in case the keymap depends on where you clicked.
 569         (when (windowp window)
 570           (set-buffer (window-buffer window))
 571           (goto-char (posn-point start)))
 572         (setq defn (key-binding key))))
 573     (let ((key-desc (key-description key)))
 574       (if (or (null defn) (integerp defn))
 575           (message "%s is unbound" key-desc)
 576         (if (consp defn)
 577             (message "%s runs %s" key-desc (prin1-to-string defn))
 578           (funcall find-fn defn))))))
 579
 580 ;;;###autoload
 581 (defun find-function-on-key (key)
 582   "Find the function that KEY invokes.  KEY is a string.
 583 Set mark before moving, if the buffer already existed."
 584   (interactive "kFind function on key: ")
 585   (find-function-on-key-do-it key #'find-function))
 586
 587 ;;;###autoload
 588 (defun find-function-on-key-other-window (key)
 589   "Find, in the other window, the function that KEY invokes.
 590 See `find-function-on-key'."
 591   (interactive "kFind function on key: ")
 592   (find-function-on-key-do-it key #'find-function-other-window))
 593
 594 ;;;###autoload
 595 (defun find-function-on-key-other-frame (key)
 596   "Find, in the other frame, the function that KEY invokes.
 597 See `find-function-on-key'."
 598   (interactive "kFind function on key: ")
 599   (find-function-on-key-do-it key #'find-function-other-frame))
 600
 601 ;;;###autoload
 602 (defun find-function-at-point ()
 603   "Find directly the function at point in the other window."
 604   (interactive)
 605   (let ((symb (function-called-at-point)))
 606     (when symb
 607       (find-function-other-window symb))))
 608
 609 ;;;###autoload
 610 (defun find-variable-at-point ()
 611   "Find directly the variable at point in the other window."
 612   (interactive)
 613   (let ((symb (variable-at-point)))
 614     (when (and symb (not (equal symb 0)))
 615       (find-variable-other-window symb))))
 616
 617 ;;;###autoload
 618 (defun find-function-setup-keys ()
 619   "Define some key bindings for the find-function family of functions."
 620   (define-key ctl-x-map "F" 'find-function)
 621   (define-key ctl-x-4-map "F" 'find-function-other-window)
 622   (define-key ctl-x-5-map "F" 'find-function-other-frame)
 623   (define-key ctl-x-map "K" 'find-function-on-key)
 624   (define-key ctl-x-4-map "K" 'find-function-on-key-other-window)
 625   (define-key ctl-x-5-map "K" 'find-function-on-key-other-frame)
 626   (define-key ctl-x-map "V" 'find-variable)
 627   (define-key ctl-x-4-map "V" 'find-variable-other-window)
 628   (define-key ctl-x-5-map "V" 'find-variable-other-frame))
 629
 630 (provide 'find-func)
 631
 632 ;;; find-func.el ends here