lisp/emacs-lisp/debug.el

   1 ;;; debug.el --- debuggers and related commands for Emacs
   2
   3 ;; Copyright (C) 1985, 1986, 1994 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: lisp, tools, maint
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; This is a major mode documented in the Emacs manual.
  28
  29 ;;; Code:
  30
  31 (defgroup debugger nil
  32   "Debuggers and related commands for Emacs."
  33   :prefix "debugger-"
  34   :group 'debug)
  35
  36 (defcustom debugger-mode-hook nil
  37   "*Hooks run when `debugger-mode' is turned on."
  38   :type 'hook
  39   :group 'debugger
  40   :version "20.3")
  41
  42 (defcustom debugger-batch-max-lines 40
  43   "*Maximum lines to show in debugger buffer in a noninteractive Emacs.
  44 When the debugger is entered and Emacs is running in batch mode,
  45 if the backtrace text has more than this many lines,
  46 the middle is discarded, and just the beginning and end are displayed."
  47   :type 'integer
  48   :group 'debugger
  49   :version "21.1")
  50
  51 (defcustom debug-function-list nil
  52   "List of functions currently set for debug on entry."
  53   :type '(repeat function)
  54   :group 'debugger)
  55
  56 (defcustom debugger-step-after-exit nil
  57   "Non-nil means \"single-step\" after the debugger exits."
  58   :type 'boolean
  59   :group 'debugger)
  60
  61 (defvar debugger-value nil
  62   "This is the value for the debugger to return, when it returns.")
  63
  64 (defvar debugger-old-buffer nil
  65   "This is the buffer that was current when the debugger was entered.")
  66
  67 (defvar debugger-outer-match-data)
  68 (defvar debugger-outer-load-read-function)
  69 (defvar debugger-outer-overriding-local-map)
  70 (defvar debugger-outer-overriding-terminal-local-map)
  71 (defvar debugger-outer-track-mouse)
  72 (defvar debugger-outer-last-command)
  73 (defvar debugger-outer-this-command)
  74 (defvar debugger-outer-unread-command-char)
  75 (defvar debugger-outer-unread-command-events)
  76 (defvar debugger-outer-unread-post-input-method-events)
  77 (defvar debugger-outer-last-input-event)
  78 (defvar debugger-outer-last-command-event)
  79 (defvar debugger-outer-last-nonmenu-event)
  80 (defvar debugger-outer-last-event-frame)
  81 (defvar debugger-outer-standard-input)
  82 (defvar debugger-outer-standard-output)
  83 (defvar debugger-outer-inhibit-redisplay)
  84 (defvar debugger-outer-cursor-in-echo-area)
  85
  86 ;;;###autoload
  87 (setq debugger 'debug)
  88 ;;;###autoload
  89 (defun debug (&rest debugger-args)
  90   "Enter debugger.  To return, type \\<debugger-mode-map>`\\[debugger-continue]'.
  91 Arguments are mainly for use when this is called from the internals
  92 of the evaluator.
  93
  94 You may call with no args, or you may pass nil as the first arg and
  95 any other args you like.  In that case, the list of args after the
  96 first will be printed into the backtrace buffer."
  97   (interactive)
  98   (unless noninteractive
  99     (message "Entering debugger..."))
 100   (let (debugger-value
 101         (debug-on-error nil)
 102         (debug-on-quit nil)
 103         (debugger-buffer (let ((default-major-mode 'fundamental-mode))
 104                            (get-buffer-create "*Backtrace*")))
 105         (debugger-old-buffer (current-buffer))
 106         (debugger-step-after-exit nil)
 107         ;; Don't keep reading from an executing kbd macro!
 108         (executing-kbd-macro nil)
 109         ;; Save the outer values of these vars for the `e' command
 110         ;; before we replace the values.
 111         (debugger-outer-match-data (match-data))
 112         (debugger-outer-load-read-function load-read-function)
 113         (debugger-outer-overriding-local-map overriding-local-map)
 114         (debugger-outer-overriding-terminal-local-map
 115          overriding-terminal-local-map)
 116         (debugger-outer-track-mouse track-mouse)
 117         (debugger-outer-last-command last-command)
 118         (debugger-outer-this-command this-command)
 119         (debugger-outer-unread-command-char unread-command-char)
 120         (debugger-outer-unread-command-events unread-command-events)
 121         (debugger-outer-unread-post-input-method-events
 122          unread-post-input-method-events)
 123         (debugger-outer-last-input-event last-input-event)
 124         (debugger-outer-last-command-event last-command-event)
 125         (debugger-outer-last-nonmenu-event last-nonmenu-event)
 126         (debugger-outer-last-event-frame last-event-frame)
 127         (debugger-outer-standard-input standard-input)
 128         (debugger-outer-standard-output standard-output)
 129         (debugger-outer-inhibit-redisplay inhibit-redisplay)
 130         (debugger-outer-cursor-in-echo-area cursor-in-echo-area))
 131     ;; Set this instead of binding it, so that `q'
 132     ;; will not restore it.
 133     (setq overriding-terminal-local-map nil)
 134     ;; Don't let these magic variables affect the debugger itself.
 135     (let ((last-command nil) this-command track-mouse
 136           (unread-command-char -1) unread-command-events
 137           unread-post-input-method-events
 138           last-input-event last-command-event last-nonmenu-event
 139           last-event-frame
 140           overriding-local-map
 141           load-read-function
 142           ;; If we are inside a minibuffer, allow nesting
 143           ;; so that we don't get an error from the `e' command.
 144           (enable-recursive-minibuffers
 145            (or enable-recursive-minibuffers (> (minibuffer-depth) 0)))
 146           (standard-input t) (standard-output t)
 147           inhibit-redisplay
 148           (cursor-in-echo-area nil))
 149       (unwind-protect
 150           (save-excursion
 151             (save-window-excursion
 152               (pop-to-buffer debugger-buffer)
 153               (debugger-mode)
 154               (debugger-setup-buffer debugger-args)
 155               (when noninteractive
 156                 ;; If the backtrace is long, save the beginning
 157                 ;; and the end, but discard the middle.
 158                 (when (> (count-lines (point-min) (point-max))
 159                          debugger-batch-max-lines)
 160                   (goto-char (point-min))
 161                   (forward-line (/ 2 debugger-batch-max-lines))
 162                   (let ((middlestart (point)))
 163                     (goto-char (point-max))
 164                     (forward-line (- (/ 2 debugger-batch-max-lines)
 165                                      debugger-batch-max-lines))
 166                     (delete-region middlestart (point)))
 167                   (insert "...\n"))
 168                 (goto-char (point-min))
 169                 (message (buffer-string))
 170                 (kill-emacs))
 171               (if (eq (car debugger-args) 'debug)
 172                   ;; Skip the frames for backtrace-debug, byte-code, and debug.
 173                   (backtrace-debug 3 t))
 174               (debugger-reenable)
 175               (message "")
 176               (let ((inhibit-trace t)
 177                     (standard-output nil)
 178                     (buffer-read-only t))
 179                 (message "")
 180                 ;; Make sure we unbind buffer-read-only in the right buffer.
 181                 (save-excursion
 182                   (recursive-edit)))))
 183         ;; Kill or at least neuter the backtrace buffer, so that users
 184         ;; don't try to execute debugger commands in an invalid context.
 185         (if (get-buffer-window debugger-buffer 'visible)
 186             ;; Still visible despite the save-window-excursion?  Maybe it
 187             ;; it's in a pop-up frame.  It would be annoying to delete and
 188             ;; recreate it every time the debugger stops, so instead we'll
 189             ;; erase it but leave it visible.
 190             (save-excursion
 191               (set-buffer debugger-buffer)
 192               (erase-buffer)
 193               (fundamental-mode))
 194           (kill-buffer debugger-buffer))
 195         (set-match-data debugger-outer-match-data)))
 196     ;; Put into effect the modified values of these variables
 197     ;; in case the user set them with the `e' command.
 198     (setq load-read-function debugger-outer-load-read-function)
 199     (setq overriding-local-map debugger-outer-overriding-local-map)
 200     (setq overriding-terminal-local-map
 201           debugger-outer-overriding-terminal-local-map)
 202     (setq track-mouse debugger-outer-track-mouse)
 203     (setq last-command debugger-outer-last-command)
 204     (setq this-command debugger-outer-this-command)
 205     (setq unread-command-char debugger-outer-unread-command-char)
 206     (setq unread-command-events debugger-outer-unread-command-events)
 207     (setq unread-post-input-method-events
 208           debugger-outer-unread-post-input-method-events)
 209     (setq last-input-event debugger-outer-last-input-event)
 210     (setq last-command-event debugger-outer-last-command-event)
 211     (setq last-nonmenu-event debugger-outer-last-nonmenu-event)
 212     (setq last-event-frame debugger-outer-last-event-frame)
 213     (setq standard-input debugger-outer-standard-input)
 214     (setq standard-output debugger-outer-standard-output)
 215     (setq inhibit-redisplay debugger-outer-inhibit-redisplay)
 216     (setq cursor-in-echo-area debugger-outer-cursor-in-echo-area)
 217     (setq debug-on-next-call debugger-step-after-exit)
 218     debugger-value))
 219 \f
 220 (defun debugger-setup-buffer (debugger-args)
 221   "Initialize the `*Backtrace*' buffer for entry to the debugger.
 222 That buffer should be current already."
 223   (setq buffer-read-only nil)
 224   (erase-buffer)
 225   (set-buffer-multibyte nil)
 226   (let ((standard-output (current-buffer))
 227         (print-escape-newlines t)
 228         (print-level 8)
 229         (print-length 50))
 230     (backtrace))
 231   (goto-char (point-min))
 232   (delete-region (point)
 233                  (progn
 234                    (search-forward "\n  debug(")
 235                    (forward-line 1)
 236                    (point)))
 237   (insert "Debugger entered")
 238   ;; lambda is for debug-on-call when a function call is next.
 239   ;; debug is for debug-on-entry function called.
 240   (cond ((memq (car debugger-args) '(lambda debug))
 241          (insert "--entering a function:\n")
 242          (if (eq (car debugger-args) 'debug)
 243              (progn
 244                (delete-char 1)
 245                (insert ?*)
 246                (beginning-of-line))))
 247         ;; Exiting a function.
 248         ((eq (car debugger-args) 'exit)
 249          (insert "--returning value: ")
 250          (setq debugger-value (nth 1 debugger-args))
 251          (prin1 debugger-value (current-buffer))
 252          (insert ?\n)
 253          (delete-char 1)
 254          (insert ? )
 255          (beginning-of-line))
 256         ;; Debugger entered for an error.
 257         ((eq (car debugger-args) 'error)
 258          (insert "--Lisp error: ")
 259          (prin1 (nth 1 debugger-args) (current-buffer))
 260          (insert ?\n))
 261         ;; debug-on-call, when the next thing is an eval.
 262         ((eq (car debugger-args) t)
 263          (insert "--beginning evaluation of function call form:\n"))
 264         ;; User calls debug directly.
 265         (t
 266          (insert ": ")
 267          (prin1 (if (eq (car debugger-args) 'nil)
 268                     (cdr debugger-args) debugger-args)
 269                 (current-buffer))
 270          (insert ?\n))))
 271 \f
 272 (defun debugger-step-through ()
 273   "Proceed, stepping through subexpressions of this expression.
 274 Enter another debugger on next entry to eval, apply or funcall."
 275   (interactive)
 276   (setq debugger-step-after-exit t)
 277   (message "Proceeding, will debug on next eval or call.")
 278   (exit-recursive-edit))
 279
 280 (defun debugger-continue ()
 281   "Continue, evaluating this expression without stopping."
 282   (interactive)
 283   (unless debugger-may-continue
 284     (error "Cannot continue"))
 285   (message "Continuing.")
 286   (exit-recursive-edit))
 287
 288 (defun debugger-return-value (val)
 289   "Continue, specifying value to return.
 290 This is only useful when the value returned from the debugger
 291 will be used, such as in a debug on exit from a frame."
 292   (interactive "XReturn value (evaluated): ")
 293   (setq debugger-value val)
 294   (princ "Returning " t)
 295   (prin1 debugger-value)
 296   (exit-recursive-edit))
 297
 298 ;; Chosen empirically to account for all the frames
 299 ;; that will exist when debugger-frame is called
 300 ;; within the first one that appears in the backtrace buffer.
 301 ;; Assumes debugger-frame is called from a key;
 302 ;; will be wrong if it is called with Meta-x.
 303 (defconst debugger-frame-offset 8 "")
 304
 305 (defun debugger-jump ()
 306   "Continue to exit from this frame, with all debug-on-entry suspended."
 307   (interactive)
 308   ;; Compensate for the two extra stack frames for debugger-jump.
 309   (let ((debugger-frame-offset (+ debugger-frame-offset 2)))
 310     (debugger-frame))
 311   ;; Turn off all debug-on-entry functions
 312   ;; but leave them in the list.
 313   (let ((list debug-function-list))
 314     (while list
 315       (fset (car list)
 316             (debug-on-entry-1 (car list) (symbol-function (car list)) nil))
 317       (setq list (cdr list))))
 318   (message "Continuing through this frame")
 319   (exit-recursive-edit))
 320
 321 (defun debugger-reenable ()
 322   "Turn all debug-on-entry functions back on."
 323   (let ((list debug-function-list))
 324     (while list
 325       (or (consp (symbol-function (car list)))
 326           (debug-convert-byte-code (car list)))
 327       (fset (car list)
 328             (debug-on-entry-1 (car list) (symbol-function (car list)) t))
 329       (setq list (cdr list)))))
 330
 331 (defun debugger-frame-number ()
 332   "Return number of frames in backtrace before the one point points at."
 333   (save-excursion
 334     (beginning-of-line)
 335     (let ((opoint (point))
 336           (count 0))
 337       (goto-char (point-min))
 338       (if (or (equal (buffer-substring (point) (+ (point) 6))
 339                      "Signal")
 340               (equal (buffer-substring (point) (+ (point) 6))
 341                      "Return"))
 342           (progn
 343             (search-forward ":")
 344             (forward-sexp 1)))
 345       (forward-line 1)
 346       (while (progn
 347                (forward-char 2)
 348                (if (= (following-char) ?\()
 349                    (forward-sexp 1)
 350                  (forward-sexp 2))
 351                (forward-line 1)
 352                (<= (point) opoint))
 353         (setq count (1+ count)))
 354       count)))
 355
 356 (defun debugger-frame ()
 357   "Request entry to debugger when this frame exits.
 358 Applies to the frame whose line point is on in the backtrace."
 359   (interactive)
 360   (beginning-of-line)
 361   (let ((level (debugger-frame-number)))
 362     (backtrace-debug (+ level debugger-frame-offset) t))
 363   (if (= (following-char) ? )
 364       (let ((buffer-read-only nil))
 365         (delete-char 1)
 366         (insert ?*)))
 367   (beginning-of-line))
 368
 369 (defun debugger-frame-clear ()
 370   "Do not enter debugger when this frame exits.
 371 Applies to the frame whose line point is on in the backtrace."
 372   (interactive)
 373   (beginning-of-line)
 374   (let ((level (debugger-frame-number)))
 375     (backtrace-debug (+ level debugger-frame-offset) nil))
 376   (if (= (following-char) ?*)
 377       (let ((buffer-read-only nil))
 378         (delete-char 1)
 379         (insert ? )))
 380   (beginning-of-line))
 381
 382
 383
 384 (put 'debugger-env-macro 'lisp-indent-function 0)
 385 (defmacro debugger-env-macro (&rest body)
 386   "Run BODY in original environment."
 387   `(save-excursion
 388     (if (null (buffer-name debugger-old-buffer))
 389         ;; old buffer deleted
 390         (setq debugger-old-buffer (current-buffer)))
 391     (set-buffer debugger-old-buffer)
 392     (let ((load-read-function debugger-outer-load-read-function)
 393           (overriding-terminal-local-map
 394            debugger-outer-overriding-terminal-local-map)
 395           (overriding-local-map debugger-outer-overriding-local-map)
 396           (track-mouse debugger-outer-track-mouse)
 397           (last-command debugger-outer-last-command)
 398           (this-command debugger-outer-this-command)
 399           (unread-command-char debugger-outer-unread-command-char)
 400           (unread-command-events debugger-outer-unread-command-events)
 401           (unread-post-input-method-events
 402            debugger-outer-unread-post-input-method-events)
 403           (last-input-event debugger-outer-last-input-event)
 404           (last-command-event debugger-outer-last-command-event)
 405           (last-nonmenu-event debugger-outer-last-nonmenu-event)
 406           (last-event-frame debugger-outer-last-event-frame)
 407           (standard-input debugger-outer-standard-input)
 408           (standard-output debugger-outer-standard-output)
 409           (inhibit-redisplay debugger-outer-inhibit-redisplay)
 410           (cursor-in-echo-area debugger-outer-cursor-in-echo-area))
 411       (set-match-data debugger-outer-match-data)
 412       (prog1 (progn ,@body)
 413         (setq debugger-outer-match-data (match-data))
 414         (setq debugger-outer-load-read-function load-read-function)
 415         (setq debugger-outer-overriding-terminal-local-map
 416               overriding-terminal-local-map)
 417         (setq debugger-outer-overriding-local-map overriding-local-map)
 418         (setq debugger-outer-track-mouse track-mouse)
 419         (setq debugger-outer-last-command last-command)
 420         (setq debugger-outer-this-command this-command)
 421         (setq debugger-outer-unread-command-char unread-command-char)
 422         (setq debugger-outer-unread-command-events unread-command-events)
 423         (setq debugger-outer-unread-post-input-method-events
 424               unread-post-input-method-events)
 425         (setq debugger-outer-last-input-event last-input-event)
 426         (setq debugger-outer-last-command-event last-command-event)
 427         (setq debugger-outer-last-nonmenu-event last-nonmenu-event)
 428         (setq debugger-outer-last-event-frame last-event-frame)
 429         (setq debugger-outer-standard-input standard-input)
 430         (setq debugger-outer-standard-output standard-output)
 431         (setq debugger-outer-inhibit-redisplay inhibit-redisplay)
 432         (setq debugger-outer-cursor-in-echo-area cursor-in-echo-area)
 433         ))))
 434
 435 (defun debugger-eval-expression (exp)
 436   "Eval an expression, in an environment like that outside the debugger."
 437   (interactive
 438    (list (read-from-minibuffer "Eval: "
 439                                nil read-expression-map t
 440                                'read-expression-history)))
 441   (debugger-env-macro (eval-expression exp)))
 442 \f
 443 (defvar debugger-mode-map nil)
 444 (if debugger-mode-map
 445     nil
 446   (let ((loop ? ))
 447     (setq debugger-mode-map (make-keymap))
 448     (suppress-keymap debugger-mode-map)
 449     (define-key debugger-mode-map "-" 'negative-argument)
 450     (define-key debugger-mode-map "b" 'debugger-frame)
 451     (define-key debugger-mode-map "c" 'debugger-continue)
 452     (define-key debugger-mode-map "j" 'debugger-jump)
 453     (define-key debugger-mode-map "r" 'debugger-return-value)
 454     (define-key debugger-mode-map "u" 'debugger-frame-clear)
 455     (define-key debugger-mode-map "d" 'debugger-step-through)
 456     (define-key debugger-mode-map "l" 'debugger-list-functions)
 457     (define-key debugger-mode-map "h" 'describe-mode)
 458     (define-key debugger-mode-map "q" 'top-level)
 459     (define-key debugger-mode-map "e" 'debugger-eval-expression)
 460     (define-key debugger-mode-map " " 'next-line)
 461     (define-key debugger-mode-map "R" 'debugger-record-expression)
 462     ))
 463
 464
 465 (defcustom debugger-record-buffer "*Debugger-record*"
 466   "*Buffer name for expression values, for \\[debugger-record-expression]."
 467   :type 'string
 468   :group 'debugger
 469   :version "20.3")
 470
 471 (defun debugger-record-expression  (exp)
 472   "Display a variable's value and record it in `*Backtrace-record*' buffer."
 473   (interactive
 474    (list (read-from-minibuffer
 475           "Record Eval: "
 476           nil
 477           read-expression-map t
 478           'read-expression-history)))
 479   (let* ((buffer (get-buffer-create debugger-record-buffer))
 480          (standard-output buffer))
 481     (princ (format "Debugger Eval (%s): " exp))
 482     (princ (debugger-eval-expression exp))
 483     (terpri))
 484
 485   (with-current-buffer (get-buffer debugger-record-buffer)
 486     (save-excursion
 487       (forward-line -1)
 488       (message
 489        (buffer-substring (point) (progn (end-of-line) (point)))))))
 490
 491 (put 'debugger-mode 'mode-class 'special)
 492
 493 (defun debugger-mode ()
 494   "Mode for backtrace buffers, selected in debugger.
 495 \\<debugger-mode-map>
 496 A line starts with `*' if exiting that frame will call the debugger.
 497 Type \\[debugger-frame] or \\[debugger-frame-clear] to set or remove the `*'.
 498
 499 When in debugger due to frame being exited,
 500 use the \\[debugger-return-value] command to override the value
 501 being returned from that frame.
 502
 503 Use \\[debug-on-entry] and \\[cancel-debug-on-entry] to control
 504 which functions will enter the debugger when called.
 505
 506 Complete list of commands:
 507 \\{debugger-mode-map}"
 508   (kill-all-local-variables)
 509   (setq major-mode 'debugger-mode)
 510   (setq mode-name "Debugger")
 511   (setq truncate-lines t)
 512   (set-syntax-table emacs-lisp-mode-syntax-table)
 513   (use-local-map debugger-mode-map)
 514   (run-hooks 'debugger-mode-hook))
 515 \f
 516 ;;;###autoload
 517 (defun debug-on-entry (function)
 518   "Request FUNCTION to invoke debugger each time it is called.
 519 If you tell the debugger to continue, FUNCTION's execution proceeds.
 520 This works by modifying the definition of FUNCTION,
 521 which must be written in Lisp, not predefined.
 522 Use \\[cancel-debug-on-entry] to cancel the effect of this command.
 523 Redefining FUNCTION also cancels it."
 524   (interactive "aDebug on entry (to function): ")
 525   (debugger-reenable)
 526   ;; Handle a function that has been aliased to some other function.
 527   (if (symbolp (symbol-function function))
 528       (fset function `(lambda (&rest debug-on-entry-args)
 529                         (apply ',(symbol-function function)
 530                                debug-on-entry-args))))
 531   (if (subrp (symbol-function function))
 532       (error "Function %s is a primitive" function))
 533   (or (consp (symbol-function function))
 534       (debug-convert-byte-code function))
 535   (or (consp (symbol-function function))
 536       (error "Definition of %s is not a list" function))
 537   (fset function (debug-on-entry-1 function (symbol-function function) t))
 538   (or (memq function debug-function-list)
 539       (setq debug-function-list (cons function debug-function-list)))
 540   function)
 541
 542 ;;;###autoload
 543 (defun cancel-debug-on-entry (&optional function)
 544   "Undo effect of \\[debug-on-entry] on FUNCTION.
 545 If argument is nil or an empty string, cancel for all functions."
 546   (interactive
 547    (list (let ((name
 548                 (completing-read "Cancel debug on entry (to function): "
 549                                  ;; Make an "alist" of the functions
 550                                  ;; that now have debug on entry.
 551                                  (mapcar 'list
 552                                          (mapcar 'symbol-name
 553                                                  debug-function-list))
 554                                  nil t nil)))
 555            (if name (intern name)))))
 556   (debugger-reenable)
 557   (if (and function (not (string= function "")))
 558       (progn
 559         (fset function
 560               (debug-on-entry-1 function (symbol-function function) nil))
 561         (setq debug-function-list (delq function debug-function-list))
 562         function)
 563     (message "Cancelling debug-on-entry for all functions")
 564     (mapcar 'cancel-debug-on-entry debug-function-list)))
 565
 566 (defun debug-convert-byte-code (function)
 567   (let ((defn (symbol-function function)))
 568     (if (not (consp defn))
 569         ;; Assume a compiled code object.
 570         (let* ((contents (append defn nil))
 571                (body
 572                 (list (list 'byte-code (nth 1 contents)
 573                             (nth 2 contents) (nth 3 contents)))))
 574           (if (nthcdr 5 contents)
 575               (setq body (cons (list 'interactive (nth 5 contents)) body)))
 576           (if (nth 4 contents)
 577               ;; Use `documentation' here, to get the actual string,
 578               ;; in case the compiled function has a reference
 579               ;; to the .elc file.
 580               (setq body (cons (documentation function) body)))
 581           (fset function (cons 'lambda (cons (car contents) body)))))))
 582
 583 (defun debug-on-entry-1 (function defn flag)
 584   (if (subrp defn)
 585       (error "%s is a built-in function" function)
 586     (if (eq (car defn) 'macro)
 587         (debug-on-entry-1 function (cdr defn) flag)
 588       (or (eq (car defn) 'lambda)
 589           (error "%s not user-defined Lisp function" function))
 590       (let (tail prec)
 591         (if (stringp (car (nthcdr 2 defn)))
 592             (setq tail (nthcdr 3 defn)
 593                   prec (list (car defn) (car (cdr defn))
 594                              (car (cdr (cdr defn)))))
 595           (setq tail (nthcdr 2 defn)
 596                 prec (list (car defn) (car (cdr defn)))))
 597         (if (eq flag (equal (car tail) '(debug 'debug)))
 598             defn
 599           (if flag
 600               (nconc prec (cons '(debug 'debug) tail))
 601             (nconc prec (cdr tail))))))))
 602
 603 (defun debugger-list-functions ()
 604   "Display a list of all the functions now set to debug on entry."
 605   (interactive)
 606   (with-output-to-temp-buffer "*Help*"
 607     (if (null debug-function-list)
 608         (princ "No debug-on-entry functions now\n")
 609       (princ "Functions set to debug on entry:\n\n")
 610       (let ((list debug-function-list))
 611         (while list
 612           (prin1 (car list))
 613           (terpri)
 614           (setq list (cdr list))))
 615       (princ "Note: if you have redefined a function, then it may no longer\n")
 616       (princ "be set to debug on entry, even if it is in the list."))
 617     (save-excursion
 618       (set-buffer standard-output)
 619       (help-mode))))
 620
 621 (provide 'debug)
 622
 623 ;;; debug.el ends here