lisp/gud.el

   1 ;;; gud.el --- Grand Unified Debugger mode for gdb, sdb, dbx, xdb or perldb
   2
   3 ;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
   4 ;; Maintainer: FSF
   5 ;; Keywords: unix, tools
   6
   7 ;; Copyright (C) 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; The ancestral gdb.el was by W. Schelter <wfs@rascal.ics.utexas.edu>
  29 ;; It was later rewritten by rms.  Some ideas were due to Masanobu.
  30 ;; Grand Unification (sdb/dbx support) by Eric S. Raymond <esr@thyrsus.com>
  31 ;; The overloading code was then rewritten by Barry Warsaw <bwarsaw@cen.com>,
  32 ;; who also hacked the mode to use comint.el.  Shane Hartman <shane@spr.com>
  33 ;; added support for xdb (HPUX debugger).  Rick Sladkey <jrs@world.std.com>
  34 ;; wrote the GDB command completion code.  Dave Love <d.love@dl.ac.uk>
  35 ;; added the IRIX kluge, re-implemented the Mips-ish variant and added
  36 ;; a menu. Brian D. Carlstrom <bdc@ai.mit.edu> combined the IRIX kluge with
  37 ;; the gud-xdb-directories hack producing gud-dbx-directories.
  38
  39 ;;; Code:
  40
  41 (require 'comint)
  42 (require 'etags)
  43
  44 ;; ======================================================================
  45 ;; GUD commands must be visible in C buffers visited by GUD
  46
  47 (defgroup gud nil
  48   "Grand Unified Debugger mode for gdb, sdb, dbx, xdb or perldb under Emacs."
  49   :group 'unix
  50   :group 'tools)
  51
  52
  53 (defcustom gud-key-prefix "\C-x\C-a"
  54   "Prefix of all GUD commands valid in C buffers."
  55   :type 'string
  56   :group 'gud)
  57
  58 (global-set-key (concat gud-key-prefix "\C-l") 'gud-refresh)
  59 (define-key ctl-x-map " " 'gud-break)   ;; backward compatibility hack
  60
  61 (defvar gud-marker-filter nil)
  62 (put 'gud-marker-filter 'permanent-local t)
  63 (defvar gud-find-file nil)
  64 (put 'gud-find-file 'permanent-local t)
  65
  66 (defun gud-marker-filter (&rest args)
  67   (apply gud-marker-filter args))
  68
  69 (defun gud-find-file (file)
  70   ;; Don't get confused by double slashes in the name that comes from GDB.
  71   (while (string-match "//+" file)
  72     (setq file (replace-match "/" t t file)))
  73   (funcall gud-find-file file))
  74
  75 ;; Keymap definitions for menu bar entries common to all debuggers and
  76 ;; slots for debugger-dependent ones in sensible places.  (Defined here
  77 ;; before use.)
  78 (defvar gud-menu-map (make-sparse-keymap "Gud") nil)
  79 (define-key gud-menu-map [refresh] '("Refresh" . gud-refresh))
  80 (define-key gud-menu-map [remove] '("Remove Breakpoint" . gud-remove))
  81 (define-key gud-menu-map [tbreak] nil)  ; gdb, sdb and xdb
  82 (define-key gud-menu-map [break] '("Set Breakpoint" . gud-break))
  83 (define-key gud-menu-map [up] nil)      ; gdb, dbx, and xdb
  84 (define-key gud-menu-map [down] nil)    ; gdb, dbx, and xdb
  85 (define-key gud-menu-map [print] '("Print Expression" . gud-print))
  86 (define-key gud-menu-map [finish] nil)  ; gdb or xdb
  87 (define-key gud-menu-map [stepi] '("Step Instruction" . gud-stepi))
  88 (define-key gud-menu-map [step] '("Step Line" . gud-step))
  89 (define-key gud-menu-map [next] '("Next Line" . gud-next))
  90 (define-key gud-menu-map [cont] '("Continue" . gud-cont))
  91 \f
  92 ;; ======================================================================
  93 ;; command definition
  94
  95 ;; This macro is used below to define some basic debugger interface commands.
  96 ;; Of course you may use `gud-def' with any other debugger command, including
  97 ;; user defined ones.
  98
  99 ;; A macro call like (gud-def FUNC NAME KEY DOC) expands to a form
 100 ;; which defines FUNC to send the command NAME to the debugger, gives
 101 ;; it the docstring DOC, and binds that function to KEY in the GUD
 102 ;; major mode.  The function is also bound in the global keymap with the
 103 ;; GUD prefix.
 104
 105 (defmacro gud-def (func cmd key &optional doc)
 106   "Define FUNC to be a command sending STR and bound to KEY, with
 107 optional doc string DOC.  Certain %-escapes in the string arguments
 108 are interpreted specially if present.  These are:
 109
 110   %f    name (without directory) of current source file.
 111   %d    directory of current source file.
 112   %l    number of current source line
 113   %e    text of the C lvalue or function-call expression surrounding point.
 114   %a    text of the hexadecimal address surrounding point
 115   %p    prefix argument to the command (if any) as a number
 116
 117   The `current' source file is the file of the current buffer (if
 118 we're in a C file) or the source file current at the last break or
 119 step (if we're in the GUD buffer).
 120   The `current' line is that of the current buffer (if we're in a
 121 source file) or the source line number at the last break or step (if
 122 we're in the GUD buffer)."
 123   (list 'progn
 124         (list 'defun func '(arg)
 125               (or doc "")
 126               '(interactive "p")
 127               (list 'gud-call cmd 'arg))
 128         (if key
 129             (list 'define-key
 130                   '(current-local-map)
 131                   (concat "\C-c" key)
 132                   (list 'quote func)))
 133         (if key
 134             (list 'global-set-key
 135                   (list 'concat 'gud-key-prefix key)
 136                   (list 'quote func)))))
 137
 138 ;; Where gud-display-frame should put the debugging arrow.  This is
 139 ;; set by the marker-filter, which scans the debugger's output for
 140 ;; indications of the current program counter.
 141 (defvar gud-last-frame nil)
 142
 143 ;; Used by gud-refresh, which should cause gud-display-frame to redisplay
 144 ;; the last frame, even if it's been called before and gud-last-frame has
 145 ;; been set to nil.
 146 (defvar gud-last-last-frame nil)
 147
 148 ;; All debugger-specific information is collected here.
 149 ;; Here's how it works, in case you ever need to add a debugger to the mode.
 150 ;;
 151 ;; Each entry must define the following at startup:
 152 ;;
 153 ;;<name>
 154 ;; comint-prompt-regexp
 155 ;; gud-<name>-massage-args
 156 ;; gud-<name>-marker-filter
 157 ;; gud-<name>-find-file
 158 ;;
 159 ;; The job of the massage-args method is to modify the given list of
 160 ;; debugger arguments before running the debugger.
 161 ;;
 162 ;; The job of the marker-filter method is to detect file/line markers in
 163 ;; strings and set the global gud-last-frame to indicate what display
 164 ;; action (if any) should be triggered by the marker.  Note that only
 165 ;; whatever the method *returns* is displayed in the buffer; thus, you
 166 ;; can filter the debugger's output, interpreting some and passing on
 167 ;; the rest.
 168 ;;
 169 ;; The job of the find-file method is to visit and return the buffer indicated
 170 ;; by the car of gud-tag-frame.  This may be a file name, a tag name, or
 171 ;; something else.  It would be good if it also copied the Gud menubar entry.
 172 \f
 173 ;; ======================================================================
 174 ;; gdb functions
 175
 176 ;;; History of argument lists passed to gdb.
 177 (defvar gud-gdb-history nil)
 178
 179 (defun gud-gdb-massage-args (file args)
 180   (cons "-fullname" args))
 181
 182 (defvar gud-gdb-marker-regexp
 183   ;; This used to use path-separator instead of ":";
 184   ;; however, we found that on both Windows 32 and MSDOS
 185   ;; a colon is correct here.
 186   (concat "\032\032\\(.:?[^" ":" "\n]*\\)" ":"
 187           "\\([0-9]*\\)" ":" ".*\n"))
 188
 189 ;; There's no guarantee that Emacs will hand the filter the entire
 190 ;; marker at once; it could be broken up across several strings.  We
 191 ;; might even receive a big chunk with several markers in it.  If we
 192 ;; receive a chunk of text which looks like it might contain the
 193 ;; beginning of a marker, we save it here between calls to the
 194 ;; filter.
 195 (defvar gud-marker-acc "")
 196 (make-variable-buffer-local 'gud-marker-acc)
 197
 198 (defun gud-gdb-marker-filter (string)
 199   (setq gud-marker-acc (concat gud-marker-acc string))
 200   (let ((output ""))
 201
 202     ;; Process all the complete markers in this chunk.
 203     (while (string-match gud-gdb-marker-regexp gud-marker-acc)
 204       (setq
 205
 206        ;; Extract the frame position from the marker.
 207        gud-last-frame
 208        (cons (substring gud-marker-acc (match-beginning 1) (match-end 1))
 209              (string-to-int (substring gud-marker-acc
 210                                        (match-beginning 2)
 211                                        (match-end 2))))
 212
 213        ;; Append any text before the marker to the output we're going
 214        ;; to return - we don't include the marker in this text.
 215        output (concat output
 216                       (substring gud-marker-acc 0 (match-beginning 0)))
 217
 218        ;; Set the accumulator to the remaining text.
 219        gud-marker-acc (substring gud-marker-acc (match-end 0))))
 220
 221     ;; Does the remaining text look like it might end with the
 222     ;; beginning of another marker?  If it does, then keep it in
 223     ;; gud-marker-acc until we receive the rest of it.  Since we
 224     ;; know the full marker regexp above failed, it's pretty simple to
 225     ;; test for marker starts.
 226     (if (string-match "\032.*\\'" gud-marker-acc)
 227         (progn
 228           ;; Everything before the potential marker start can be output.
 229           (setq output (concat output (substring gud-marker-acc
 230                                                  0 (match-beginning 0))))
 231
 232           ;; Everything after, we save, to combine with later input.
 233           (setq gud-marker-acc
 234                 (substring gud-marker-acc (match-beginning 0))))
 235
 236       (setq output (concat output gud-marker-acc)
 237             gud-marker-acc ""))
 238
 239     output))
 240
 241 (defun gud-gdb-find-file (f)
 242   (save-excursion
 243     (let ((buf (find-file-noselect f)))
 244       (set-buffer buf)
 245       (gud-make-debug-menu)
 246       (local-set-key [menu-bar debug tbreak]
 247                      '("Temporary Breakpoint" . gud-tbreak))
 248       (local-set-key [menu-bar debug finish] '("Finish Function" . gud-finish))
 249       (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
 250       (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
 251       buf)))
 252
 253 (defvar gdb-minibuffer-local-map nil
 254   "Keymap for minibuffer prompting of gdb startup command.")
 255 (if gdb-minibuffer-local-map
 256     ()
 257   (setq gdb-minibuffer-local-map (copy-keymap minibuffer-local-map))
 258   (define-key
 259     gdb-minibuffer-local-map "\C-i" 'comint-dynamic-complete-filename))
 260
 261 ;;;###autoload
 262 (defun gdb (command-line)
 263   "Run gdb on program FILE in buffer *gud-FILE*.
 264 The directory containing FILE becomes the initial working directory
 265 and source-file directory for your debugger."
 266   (interactive
 267    (list (read-from-minibuffer "Run gdb (like this): "
 268                                (if (consp gud-gdb-history)
 269                                    (car gud-gdb-history)
 270                                  "gdb ")
 271                                gdb-minibuffer-local-map nil
 272                                '(gud-gdb-history . 1))))
 273
 274   (gud-common-init command-line 'gud-gdb-massage-args
 275                    'gud-gdb-marker-filter 'gud-gdb-find-file)
 276
 277   (gud-def gud-break  "break %f:%l"  "\C-b" "Set breakpoint at current line.")
 278   (gud-def gud-tbreak "tbreak %f:%l" "\C-t" "Set temporary breakpoint at current line.")
 279   (gud-def gud-remove "clear %f:%l"  "\C-d" "Remove breakpoint at current line")
 280   (gud-def gud-step   "step %p"      "\C-s" "Step one source line with display.")
 281   (gud-def gud-stepi  "stepi %p"     "\C-i" "Step one instruction with display.")
 282   (gud-def gud-next   "next %p"      "\C-n" "Step one line (skip functions).")
 283   (gud-def gud-cont   "cont"         "\C-r" "Continue with display.")
 284   (gud-def gud-finish "finish"       "\C-f" "Finish executing current function.")
 285   (gud-def gud-up     "up %p"        "<" "Up N stack frames (numeric arg).")
 286   (gud-def gud-down   "down %p"      ">" "Down N stack frames (numeric arg).")
 287   (gud-def gud-print  "print %e"     "\C-p" "Evaluate C expression at point.")
 288
 289   (local-set-key "\C-i" 'gud-gdb-complete-command)
 290   (local-set-key [menu-bar debug tbreak] '("Temporary Breakpoint" . gud-tbreak))
 291   (local-set-key [menu-bar debug finish] '("Finish Function" . gud-finish))
 292   (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
 293   (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
 294   (setq comint-prompt-regexp "^(.*gdb[+]?) *")
 295   (setq paragraph-start comint-prompt-regexp)
 296   (run-hooks 'gdb-mode-hook)
 297   )
 298
 299 ;; One of the nice features of GDB is its impressive support for
 300 ;; context-sensitive command completion.  We preserve that feature
 301 ;; in the GUD buffer by using a GDB command designed just for Emacs.
 302
 303 ;; The completion process filter indicates when it is finished.
 304 (defvar gud-gdb-complete-in-progress)
 305
 306 ;; Since output may arrive in fragments we accumulate partials strings here.
 307 (defvar gud-gdb-complete-string)
 308
 309 ;; We need to know how much of the completion to chop off.
 310 (defvar gud-gdb-complete-break)
 311
 312 ;; The completion list is constructed by the process filter.
 313 (defvar gud-gdb-complete-list)
 314
 315 (defvar gud-comint-buffer nil)
 316
 317 (defun gud-gdb-complete-command ()
 318   "Perform completion on the GDB command preceding point.
 319 This is implemented using the GDB `complete' command which isn't
 320 available with older versions of GDB."
 321   (interactive)
 322   (let* ((end (point))
 323          (command (save-excursion
 324                     (beginning-of-line)
 325                     (and (looking-at comint-prompt-regexp)
 326                          (goto-char (match-end 0)))
 327                     (buffer-substring (point) end)))
 328          command-word)
 329     ;; Find the word break.  This match will always succeed.
 330     (string-match "\\(\\`\\| \\)\\([^ ]*\\)\\'" command)
 331     (setq gud-gdb-complete-break (match-beginning 2)
 332           command-word (substring command gud-gdb-complete-break))
 333     ;; Temporarily install our filter function.
 334     (let ((gud-marker-filter 'gud-gdb-complete-filter))
 335       ;; Issue the command to GDB.
 336       (gud-basic-call (concat "complete " command))
 337       (setq gud-gdb-complete-in-progress t
 338             gud-gdb-complete-string nil
 339             gud-gdb-complete-list nil)
 340       ;; Slurp the output.
 341       (while gud-gdb-complete-in-progress
 342         (accept-process-output (get-buffer-process gud-comint-buffer))))
 343     ;; Protect against old versions of GDB.
 344     (and gud-gdb-complete-list
 345          (string-match "^Undefined command: \"complete\""
 346                        (car gud-gdb-complete-list))
 347          (error "This version of GDB doesn't support the `complete' command."))
 348     ;; Sort the list like readline.
 349     (setq gud-gdb-complete-list
 350           (sort gud-gdb-complete-list (function string-lessp)))
 351     ;; Remove duplicates.
 352     (let ((first gud-gdb-complete-list)
 353           (second (cdr gud-gdb-complete-list)))
 354       (while second
 355         (if (string-equal (car first) (car second))
 356             (setcdr first (setq second (cdr second)))
 357           (setq first second
 358                 second (cdr second)))))
 359     ;; Add a trailing single quote if there is a unique completion
 360     ;; and it contains an odd number of unquoted single quotes.
 361     (and (= (length gud-gdb-complete-list) 1)
 362          (let ((str (car gud-gdb-complete-list))
 363                (pos 0)
 364                (count 0))
 365            (while (string-match "\\([^'\\]\\|\\\\'\\)*'" str pos)
 366              (setq count (1+ count)
 367                    pos (match-end 0)))
 368            (and (= (mod count 2) 1)
 369                 (setq gud-gdb-complete-list (list (concat str "'"))))))
 370     ;; Let comint handle the rest.
 371     (comint-dynamic-simple-complete command-word gud-gdb-complete-list)))
 372
 373 ;; The completion process filter is installed temporarily to slurp the
 374 ;; output of GDB up to the next prompt and build the completion list.
 375 (defun gud-gdb-complete-filter (string)
 376   (setq string (concat gud-gdb-complete-string string))
 377   (while (string-match "\n" string)
 378     (setq gud-gdb-complete-list
 379           (cons (substring string gud-gdb-complete-break (match-beginning 0))
 380                 gud-gdb-complete-list))
 381     (setq string (substring string (match-end 0))))
 382   (if (string-match comint-prompt-regexp string)
 383       (progn
 384         (setq gud-gdb-complete-in-progress nil)
 385         string)
 386     (progn
 387       (setq gud-gdb-complete-string string)
 388       "")))
 389
 390 \f
 391 ;; ======================================================================
 392 ;; sdb functions
 393
 394 ;;; History of argument lists passed to sdb.
 395 (defvar gud-sdb-history nil)
 396
 397 (defvar gud-sdb-needs-tags (not (file-exists-p "/var"))
 398   "If nil, we're on a System V Release 4 and don't need the tags hack.")
 399
 400 (defvar gud-sdb-lastfile nil)
 401
 402 (defun gud-sdb-massage-args (file args) args)
 403
 404 (defun gud-sdb-marker-filter (string)
 405   (setq gud-marker-acc
 406         (if gud-marker-acc (concat gud-marker-acc string) string))
 407   (let (start)
 408     ;; Process all complete markers in this chunk
 409     (while
 410         (cond
 411          ;; System V Release 3.2 uses this format
 412          ((string-match "\\(^\\|\n\\)\\*?\\(0x\\w* in \\)?\\([^:\n]*\\):\\([0-9]*\\):.*\n"
 413                         gud-marker-acc start)
 414           (setq gud-last-frame
 415                 (cons
 416                  (substring gud-marker-acc (match-beginning 3) (match-end 3))
 417                  (string-to-int
 418                   (substring gud-marker-acc (match-beginning 4) (match-end 4))))))
 419          ;; System V Release 4.0 quite often clumps two lines together
 420          ((string-match "^\\(BREAKPOINT\\|STEPPED\\) process [0-9]+ function [^ ]+ in \\(.+\\)\n\\([0-9]+\\):"
 421                         gud-marker-acc start)
 422           (setq gud-sdb-lastfile
 423                 (substring gud-marker-acc (match-beginning 2) (match-end 2)))
 424           (setq gud-last-frame
 425                 (cons
 426                  gud-sdb-lastfile
 427                  (string-to-int
 428                   (substring gud-marker-acc (match-beginning 3) (match-end 3))))))
 429          ;; System V Release 4.0
 430          ((string-match "^\\(BREAKPOINT\\|STEPPED\\) process [0-9]+ function [^ ]+ in \\(.+\\)\n"
 431                         gud-marker-acc start)
 432           (setq gud-sdb-lastfile
 433                 (substring gud-marker-acc (match-beginning 2) (match-end 2))))
 434          ((and gud-sdb-lastfile (string-match "^\\([0-9]+\\):"
 435                                               gud-marker-acc start))
 436                (setq gud-last-frame
 437                      (cons
 438                       gud-sdb-lastfile
 439                       (string-to-int
 440                        (substring gud-marker-acc (match-beginning 1) (match-end 1))))))
 441          (t
 442           (setq gud-sdb-lastfile nil)))
 443       (setq start (match-end 0)))
 444
 445     ;; Search for the last incomplete line in this chunk
 446     (while (string-match "\n" gud-marker-acc start)
 447       (setq start (match-end 0)))
 448
 449     ;; If we have an incomplete line, store it in gud-marker-acc.
 450     (setq gud-marker-acc (substring gud-marker-acc (or start 0))))
 451   string)
 452
 453 (defun gud-sdb-find-file (f)
 454   (save-excursion
 455     (let ((buf (if gud-sdb-needs-tags
 456                    (find-tag-noselect f)
 457                  (find-file-noselect f))))
 458       (set-buffer buf)
 459       (gud-make-debug-menu)
 460       (local-set-key [menu-bar debug tbreak] '("Temporary Breakpoint" . gud-tbreak))
 461       buf)))
 462
 463 ;;;###autoload
 464 (defun sdb (command-line)
 465   "Run sdb on program FILE in buffer *gud-FILE*.
 466 The directory containing FILE becomes the initial working directory
 467 and source-file directory for your debugger."
 468   (interactive
 469    (list (read-from-minibuffer "Run sdb (like this): "
 470                                (if (consp gud-sdb-history)
 471                                    (car gud-sdb-history)
 472                                  "sdb ")
 473                                nil nil
 474                                '(gud-sdb-history . 1))))
 475   (if (and gud-sdb-needs-tags
 476            (not (and (boundp 'tags-file-name)
 477                      (stringp tags-file-name)
 478                      (file-exists-p tags-file-name))))
 479       (error "The sdb support requires a valid tags table to work."))
 480
 481   (gud-common-init command-line 'gud-sdb-massage-args
 482                    'gud-sdb-marker-filter 'gud-sdb-find-file)
 483
 484   (gud-def gud-break  "%l b" "\C-b"   "Set breakpoint at current line.")
 485   (gud-def gud-tbreak "%l c" "\C-t"   "Set temporary breakpoint at current line.")
 486   (gud-def gud-remove "%l d" "\C-d"   "Remove breakpoint at current line")
 487   (gud-def gud-step   "s %p" "\C-s"   "Step one source line with display.")
 488   (gud-def gud-stepi  "i %p" "\C-i"   "Step one instruction with display.")
 489   (gud-def gud-next   "S %p" "\C-n"   "Step one line (skip functions).")
 490   (gud-def gud-cont   "c"    "\C-r"   "Continue with display.")
 491   (gud-def gud-print  "%e/"  "\C-p"   "Evaluate C expression at point.")
 492
 493   (setq comint-prompt-regexp  "\\(^\\|\n\\)\\*")
 494   (setq paragraph-start comint-prompt-regexp)
 495   (local-set-key [menu-bar debug tbreak]
 496     '("Temporary Breakpoint" . gud-tbreak))
 497   (run-hooks 'sdb-mode-hook)
 498   )
 499 \f
 500 ;; ======================================================================
 501 ;; dbx functions
 502
 503 ;;; History of argument lists passed to dbx.
 504 (defvar gud-dbx-history nil)
 505
 506 (defcustom gud-dbx-directories nil
 507   "*A list of directories that dbx should search for source code.
 508 If nil, only source files in the program directory
 509 will be known to dbx.
 510
 511 The file names should be absolute, or relative to the directory
 512 containing the executable being debugged."
 513   :type '(choice (const :tag "Current Directory" nil)
 514                  (repeat :value ("")
 515                          directory))
 516   :group 'gud)
 517
 518 (defun gud-dbx-massage-args (file args)
 519   (nconc (let ((directories gud-dbx-directories)
 520                (result nil))
 521            (while directories
 522              (setq result (cons (car directories) (cons "-I" result)))
 523              (setq directories (cdr directories)))
 524            (nreverse result))
 525          args))
 526
 527 (defun gud-dbx-file-name (f)
 528   "Transform a relative file name to an absolute file name, for dbx."
 529   (let ((result nil))
 530     (if (file-exists-p f)
 531         (setq result (expand-file-name f))
 532       (let ((directories gud-dbx-directories))
 533         (while directories
 534           (let ((path (concat (car directories) "/" f)))
 535             (if (file-exists-p path)
 536                 (setq result (expand-file-name path)
 537                       directories nil)))
 538           (setq directories (cdr directories)))))
 539     result))
 540
 541 (defun gud-dbx-marker-filter (string)
 542   (setq gud-marker-acc (if gud-marker-acc (concat gud-marker-acc string) string))
 543
 544   (let (start)
 545     ;; Process all complete markers in this chunk.
 546     (while (or (string-match
 547                 "stopped in .* at line \\([0-9]*\\) in file \"\\([^\"]*\\)\""
 548                 gud-marker-acc start)
 549                (string-match
 550                 "signal .* in .* at line \\([0-9]*\\) in file \"\\([^\"]*\\)\""
 551                 gud-marker-acc start))
 552       (setq gud-last-frame
 553             (cons
 554              (substring gud-marker-acc (match-beginning 2) (match-end 2))
 555              (string-to-int
 556               (substring gud-marker-acc (match-beginning 1) (match-end 1))))
 557             start (match-end 0)))
 558
 559     ;; Search for the last incomplete line in this chunk
 560     (while (string-match "\n" gud-marker-acc start)
 561       (setq start (match-end 0)))
 562
 563     ;; If the incomplete line APPEARS to begin with another marker, keep it
 564     ;; in the accumulator.  Otherwise, clear the accumulator to avoid an
 565     ;; unnecessary concat during the next call.
 566     (setq gud-marker-acc
 567           (if (string-match "\\(stopped\\|signal\\)" gud-marker-acc start)
 568               (substring gud-marker-acc (match-beginning 0))
 569             nil)))
 570   string)
 571
 572 ;; Functions for Mips-style dbx.  Given the option `-emacs', documented in
 573 ;; OSF1, not necessarily elsewhere, it produces markers similar to gdb's.
 574 (defvar gud-mips-p
 575   (or (string-match "^mips-[^-]*-ultrix" system-configuration)
 576       ;; We haven't tested gud on this system:
 577       (string-match "^mips-[^-]*-riscos" system-configuration)
 578       ;; It's documented on OSF/1.3
 579       (string-match "^mips-[^-]*-osf1" system-configuration)
 580       (string-match "^alpha-[^-]*-osf" system-configuration))
 581   "Non-nil to assume the MIPS/OSF dbx conventions (argument `-emacs').")
 582
 583 (defun gud-mipsdbx-massage-args (file args)
 584   (cons "-emacs" args))
 585
 586 ;; This is just like the gdb one except for the regexps since we need to cope
 587 ;; with an optional breakpoint number in [] before the ^Z^Z
 588 (defun gud-mipsdbx-marker-filter (string)
 589   (setq gud-marker-acc (concat gud-marker-acc string))
 590   (let ((output ""))
 591
 592     ;; Process all the complete markers in this chunk.
 593     (while (string-match
 594             ;; This is like th gdb marker but with an optional
 595             ;; leading break point number like `[1] '
 596             "[][ 0-9]*\032\032\\([^:\n]*\\):\\([0-9]*\\):.*\n"
 597             gud-marker-acc)
 598       (setq
 599
 600        ;; Extract the frame position from the marker.
 601        gud-last-frame
 602        (cons (substring gud-marker-acc (match-beginning 1) (match-end 1))
 603              (string-to-int (substring gud-marker-acc
 604                                        (match-beginning 2)
 605                                        (match-end 2))))
 606
 607        ;; Append any text before the marker to the output we're going
 608        ;; to return - we don't include the marker in this text.
 609        output (concat output
 610                       (substring gud-marker-acc 0 (match-beginning 0)))
 611
 612        ;; Set the accumulator to the remaining text.
 613        gud-marker-acc (substring gud-marker-acc (match-end 0))))
 614
 615     ;; Does the remaining text look like it might end with the
 616     ;; beginning of another marker?  If it does, then keep it in
 617     ;; gud-marker-acc until we receive the rest of it.  Since we
 618     ;; know the full marker regexp above failed, it's pretty simple to
 619     ;; test for marker starts.
 620     (if (string-match "[][ 0-9]*\032.*\\'" gud-marker-acc)
 621         (progn
 622           ;; Everything before the potential marker start can be output.
 623           (setq output (concat output (substring gud-marker-acc
 624                                                  0 (match-beginning 0))))
 625
 626           ;; Everything after, we save, to combine with later input.
 627           (setq gud-marker-acc
 628                 (substring gud-marker-acc (match-beginning 0))))
 629
 630       (setq output (concat output gud-marker-acc)
 631             gud-marker-acc ""))
 632
 633     output))
 634
 635 ;; The dbx in IRIX is a pain.  It doesn't print the file name when
 636 ;; stopping at a breakpoint (but you do get it from the `up' and
 637 ;; `down' commands...).  The only way to extract the information seems
 638 ;; to be with a `file' command, although the current line number is
 639 ;; available in $curline.  Thus we have to look for output which
 640 ;; appears to indicate a breakpoint.  Then we prod the dbx sub-process
 641 ;; to output the information we want with a combination of the
 642 ;; `printf' and `file' commands as a pseudo marker which we can
 643 ;; recognise next time through the marker-filter.  This would be like
 644 ;; the gdb marker but you can't get the file name without a newline...
 645 ;; Note that gud-remove won't work since Irix dbx expects a breakpoint
 646 ;; number rather than a line number etc.  Maybe this could be made to
 647 ;; work by listing all the breakpoints and picking the one(s) with the
 648 ;; correct line number, but life's too short.
 649 ;;   d.love@dl.ac.uk (Dave Love) can be blamed for this
 650
 651 (defvar gud-irix-p
 652   (and (string-match "^mips-[^-]*-irix" system-configuration)
 653        (not (string-match "irix[6-9]\\.[1-9]" system-configuration)))
 654   "Non-nil to assume the interface appropriate for IRIX dbx.
 655 This works in IRIX 4, 5 and 6, but `gud-dbx-use-stopformat-p' provides
 656 a better solution in 6.1 upwards.")
 657 (defvar gud-dbx-use-stopformat-p
 658   (string-match "irix[6-9]\\.[1-9]" system-configuration)
 659   "Non-nil to use the dbx feature present at least from Irix 6.1
 660   whereby $stopformat=1 produces an output format compatiable with
 661   `gud-dbx-marker-filter'.")
 662 ;; [Irix dbx seems to be a moving target.  The dbx output changed
 663 ;; subtly sometime between OS v4.0.5 and v5.2 so that, for instance,
 664 ;; the output from `up' is no longer spotted by gud (and it's probably
 665 ;; not distinctive enough to try to match it -- use C-<, C->
 666 ;; exclusively) .  For 5.3 and 6.0, the $curline variable changed to
 667 ;; `long long'(why?!), so the printf stuff needed changing.  The line
 668 ;; number was cast to `long' as a compromise between the new `long
 669 ;; long' and the original `int'.  This is reported not to work in 6.2,
 670 ;; so it's changed back to int -- don't make your sources too long.
 671 ;; From Irix6.1 (but not 6.0?) dbx supports an undocumented feature
 672 ;; whereby `set $stopformat=1' reportedly produces output compatible
 673 ;; with `gud-dbx-marker-filter', which we prefer.
 674
 675 ;; The process filter is also somewhat
 676 ;; unreliable, sometimes not spotting the markers; I don't know
 677 ;; whether there's anything that can be done about that.  It would be
 678 ;; much better if SGI could be persuaded to (re?)instate the MIPS
 679 ;; -emacs flag for gdb-like output (which ought to be possible as most
 680 ;; of the communication I've had over it has been from sgi.com).]
 681
 682 ;; this filter is influenced by the xdb one rather than the gdb one
 683 (defun gud-irixdbx-marker-filter (string)
 684   (let (result (case-fold-search nil))
 685     (if (or (string-match comint-prompt-regexp string)
 686             (string-match ".*\012" string))
 687         (setq result (concat gud-marker-acc string)
 688               gud-marker-acc "")
 689       (setq gud-marker-acc (concat gud-marker-acc string)))
 690     (if result
 691         (cond
 692          ;; look for breakpoint or signal indication e.g.:
 693          ;; [2] Process  1267 (pplot) stopped at [params:338 ,0x400ec0]
 694          ;; Process  1281 (pplot) stopped at [params:339 ,0x400ec8]
 695          ;; Process  1270 (pplot) Floating point exception [._read._read:16 ,0x452188]
 696          ((string-match
 697            "^\\(\\[[0-9]+] \\)?Process +[0-9]+ ([^)]*) [^[]+\\[[^]\n]*]\n"
 698            result)
 699           ;; prod dbx into printing out the line number and file
 700           ;; name in a form we can grok as below
 701           (process-send-string (get-buffer-process gud-comint-buffer)
 702                                "printf \"\032\032%1d:\",(int)$curline;file\n"))
 703          ;; look for result of, say, "up" e.g.:
 704          ;; .pplot.pplot(0x800) ["src/pplot.f":261, 0x400c7c]
 705          ;; (this will also catch one of the lines printed by "where")
 706          ((string-match
 707            "^[^ ][^[]*\\[\"\\([^\"]+\\)\":\\([0-9]+\\), [^]]+]\n"
 708            result)
 709           (let ((file (substring result (match-beginning 1)
 710                                  (match-end 1))))
 711             (if (file-exists-p file)
 712                 (setq gud-last-frame
 713                       (cons
 714                        (substring
 715                         result (match-beginning 1) (match-end 1))
 716                        (string-to-int
 717                         (substring
 718                          result (match-beginning 2) (match-end 2)))))))
 719           result)
 720          ((string-match                 ; kluged-up marker as above
 721            "\032\032\\([0-9]*\\):\\(.*\\)\n" result)
 722           (let ((file (gud-dbx-file-name
 723                        (substring result (match-beginning 2) (match-end 2)))))
 724             (if (and file (file-exists-p file))
 725                 (setq gud-last-frame
 726                       (cons
 727                        file
 728                        (string-to-int
 729                         (substring
 730                          result (match-beginning 1) (match-end 1)))))))
 731           (setq result (substring result 0 (match-beginning 0))))))
 732     (or result "")))
 733
 734 (defvar gud-dgux-p (string-match "-dgux" system-configuration)
 735   "Non-nil means to assume the interface approriate for DG/UX dbx.
 736 This was tested using R4.11.")
 737
 738 ;; There are a couple of differences between DG's dbx output and normal
 739 ;; dbx output which make it nontrivial to integrate this into the
 740 ;; standard dbx-marker-filter (mainly, there are a different number of
 741 ;; backreferences).  The markers look like:
 742 ;;
 743 ;;     (0) Stopped at line 10, routine main(argc=1, argv=0xeffff0e0), file t.c
 744 ;;
 745 ;; from breakpoints (the `(0)' there isn't constant, it's the breakpoint
 746 ;; number), and
 747 ;;
 748 ;;     Stopped at line 13, routine main(argc=1, argv=0xeffff0e0), file t.c
 749 ;;
 750 ;; from signals and
 751 ;;
 752 ;;     Frame 21, line 974, routine command_loop(), file keyboard.c
 753 ;;
 754 ;; from up/down/where.
 755
 756 (defun gud-dguxdbx-marker-filter (string)
 757   (setq gud-marker-acc (if gud-marker-acc
 758                            (concat gud-marker-acc string)
 759                          string))
 760   (let ((re (concat "^\\(\\(([0-9]+) \\)?Stopped at\\|Frame [0-9]+,\\)"
 761                     " line \\([0-9]+\\), routine .*, file \\([^ \t\n]+\\)"))
 762         start)
 763     ;; Process all complete markers in this chunk.
 764     (while (string-match re gud-marker-acc start)
 765       (setq gud-last-frame
 766             (cons
 767              (substring gud-marker-acc (match-beginning 4) (match-end 4))
 768              (string-to-int (substring gud-marker-acc
 769                                        (match-beginning 3) (match-end 3))))
 770             start (match-end 0)))
 771
 772     ;; Search for the last incomplete line in this chunk
 773     (while (string-match "\n" gud-marker-acc start)
 774       (setq start (match-end 0)))
 775
 776     ;; If the incomplete line APPEARS to begin with another marker, keep it
 777     ;; in the accumulator.  Otherwise, clear the accumulator to avoid an
 778     ;; unnecessary concat during the next call.
 779     (setq gud-marker-acc
 780           (if (string-match "Stopped\\|Frame" gud-marker-acc start)
 781               (substring gud-marker-acc (match-beginning 0))
 782             nil)))
 783   string)
 784
 785 (defun gud-dbx-find-file (f)
 786   (save-excursion
 787     (let ((realf (gud-dbx-file-name f)))
 788       (if realf
 789           (let ((buf (find-file-noselect realf)))
 790             (set-buffer buf)
 791             (gud-make-debug-menu)
 792             (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
 793             (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
 794             buf)
 795         nil))))
 796
 797 ;;;###autoload
 798 (defun dbx (command-line)
 799   "Run dbx on program FILE in buffer *gud-FILE*.
 800 The directory containing FILE becomes the initial working directory
 801 and source-file directory for your debugger."
 802   (interactive
 803    (list (read-from-minibuffer "Run dbx (like this): "
 804                                (if (consp gud-dbx-history)
 805                                    (car gud-dbx-history)
 806                                  "dbx ")
 807                                nil nil
 808                                '(gud-dbx-history . 1))))
 809
 810   (cond
 811    (gud-mips-p
 812     (gud-common-init command-line 'gud-mipsdbx-massage-args
 813                      'gud-mipsdbx-marker-filter 'gud-dbx-find-file))
 814    (gud-irix-p
 815     (gud-common-init command-line 'gud-dbx-massage-args
 816                      'gud-irixdbx-marker-filter 'gud-dbx-find-file))
 817    (gud-dgux-p
 818     (gud-common-init command-line 'gud-dbx-massage-args
 819                      'gud-dguxdbx-marker-filter 'gud-dbx-find-file))
 820    (t
 821     (gud-common-init command-line 'gud-dbx-massage-args
 822                      'gud-dbx-marker-filter 'gud-dbx-find-file)))
 823
 824   (cond
 825    (gud-mips-p
 826     (gud-def gud-up     "up %p"         "<" "Up (numeric arg) stack frames.")
 827     (gud-def gud-down   "down %p" ">" "Down (numeric arg) stack frames.")
 828     (gud-def gud-break "stop at \"%f\":%l"
 829                                   "\C-b" "Set breakpoint at current line.")
 830     (gud-def gud-finish "return"  "\C-f" "Finish executing current function."))
 831    (gud-irix-p
 832     (gud-def gud-break "stop at \"%d%f\":%l"
 833                                   "\C-b" "Set breakpoint at current line.")
 834     (gud-def gud-finish "return"  "\C-f" "Finish executing current function.")
 835     (gud-def gud-up     "up %p; printf \"\032\032%1d:\",(int)$curline;file\n"
 836              "<" "Up (numeric arg) stack frames.")
 837     (gud-def gud-down "down %p; printf \"\032\032%1d:\",(int)$curline;file\n"
 838              ">" "Down (numeric arg) stack frames.")
 839     ;; Make dbx give out the source location info that we need.
 840     (process-send-string (get-buffer-process gud-comint-buffer)
 841                          "printf \"\032\032%1d:\",(int)$curline;file\n"))
 842    (gud-dbx-use-stopformat-p
 843     (process-send-string (get-buffer-process gud-comint-buffer)
 844                          "set $stopformat=1\n"))
 845    (t
 846     (gud-def gud-up     "up %p"         "<" "Up (numeric arg) stack frames.")
 847     (gud-def gud-down   "down %p" ">" "Down (numeric arg) stack frames.")
 848     (gud-def gud-break "file \"%d%f\"\nstop at %l"
 849                                   "\C-b" "Set breakpoint at current line.")))
 850
 851   (gud-def gud-remove "clear %l"  "\C-d" "Remove breakpoint at current line")
 852   (gud-def gud-step   "step %p"   "\C-s" "Step one line with display.")
 853   (gud-def gud-stepi  "stepi %p"  "\C-i" "Step one instruction with display.")
 854   (gud-def gud-next   "next %p"   "\C-n" "Step one line (skip functions).")
 855   (gud-def gud-cont   "cont"      "\C-r" "Continue with display.")
 856   (gud-def gud-print  "print %e"  "\C-p" "Evaluate C expression at point.")
 857
 858   (setq comint-prompt-regexp  "^[^)\n]*dbx) *")
 859   (setq paragraph-start comint-prompt-regexp)
 860   (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
 861   (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
 862   (run-hooks 'dbx-mode-hook)
 863   )
 864 \f
 865 ;; ======================================================================
 866 ;; xdb (HP PARISC debugger) functions
 867
 868 ;;; History of argument lists passed to xdb.
 869 (defvar gud-xdb-history nil)
 870
 871 (defcustom gud-xdb-directories nil
 872   "*A list of directories that xdb should search for source code.
 873 If nil, only source files in the program directory
 874 will be known to xdb.
 875
 876 The file names should be absolute, or relative to the directory
 877 containing the executable being debugged."
 878   :type '(choice (const :tag "Current Directory" nil)
 879                  (repeat :value ("")
 880                          directory))
 881   :group 'gud)
 882
 883 (defun gud-xdb-massage-args (file args)
 884   (nconc (let ((directories gud-xdb-directories)
 885                (result nil))
 886            (while directories
 887              (setq result (cons (car directories) (cons "-d" result)))
 888              (setq directories (cdr directories)))
 889            (nreverse result))
 890          args))
 891
 892 (defun gud-xdb-file-name (f)
 893   "Transform a relative pathname to a full pathname in xdb mode"
 894   (let ((result nil))
 895     (if (file-exists-p f)
 896         (setq result (expand-file-name f))
 897       (let ((directories gud-xdb-directories))
 898         (while directories
 899           (let ((path (concat (car directories) "/" f)))
 900             (if (file-exists-p path)
 901                 (setq result (expand-file-name path)
 902                       directories nil)))
 903           (setq directories (cdr directories)))))
 904     result))
 905
 906 ;; xdb does not print the lines all at once, so we have to accumulate them
 907 (defun gud-xdb-marker-filter (string)
 908   (let (result)
 909     (if (or (string-match comint-prompt-regexp string)
 910             (string-match ".*\012" string))
 911         (setq result (concat gud-marker-acc string)
 912               gud-marker-acc "")
 913       (setq gud-marker-acc (concat gud-marker-acc string)))
 914     (if result
 915         (if (or (string-match "\\([^\n \t:]+\\): [^:]+: \\([0-9]+\\)[: ]"
 916                               result)
 917                 (string-match "[^: \t]+:[ \t]+\\([^:]+\\): [^:]+: \\([0-9]+\\):"
 918                               result))
 919             (let ((line (string-to-int
 920                          (substring result (match-beginning 2) (match-end 2))))
 921                   (file (gud-xdb-file-name
 922                          (substring result (match-beginning 1) (match-end 1)))))
 923               (if file
 924                   (setq gud-last-frame (cons file line))))))
 925     (or result "")))
 926
 927 (defun gud-xdb-find-file (f)
 928   (save-excursion
 929     (let ((realf (gud-xdb-file-name f)))
 930       (if realf
 931           (let ((buf (find-file-noselect realf)))
 932             (set-buffer buf)
 933             (gud-make-debug-menu)
 934             (local-set-key [menu-bar debug tbreak]
 935                            '("Temporary Breakpoint" . gud-tbreak))
 936             (local-set-key [menu-bar debug finish]
 937                            '("Finish Function" . gud-finish))
 938             (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
 939             (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
 940             buf)
 941         nil))))
 942
 943 ;;;###autoload
 944 (defun xdb (command-line)
 945   "Run xdb on program FILE in buffer *gud-FILE*.
 946 The directory containing FILE becomes the initial working directory
 947 and source-file directory for your debugger.
 948
 949 You can set the variable 'gud-xdb-directories' to a list of program source
 950 directories if your program contains sources from more than one directory."
 951   (interactive
 952    (list (read-from-minibuffer "Run xdb (like this): "
 953                                (if (consp gud-xdb-history)
 954                                    (car gud-xdb-history)
 955                                  "xdb ")
 956                                nil nil
 957                                '(gud-xdb-history . 1))))
 958
 959   (gud-common-init command-line 'gud-xdb-massage-args
 960                    'gud-xdb-marker-filter 'gud-xdb-find-file)
 961
 962   (gud-def gud-break  "b %f:%l"    "\C-b" "Set breakpoint at current line.")
 963   (gud-def gud-tbreak "b %f:%l\\t" "\C-t"
 964            "Set temporary breakpoint at current line.")
 965   (gud-def gud-remove "db"         "\C-d" "Remove breakpoint at current line")
 966   (gud-def gud-step   "s %p"       "\C-s" "Step one line with display.")
 967   (gud-def gud-next   "S %p"       "\C-n" "Step one line (skip functions).")
 968   (gud-def gud-cont   "c"          "\C-r" "Continue with display.")
 969   (gud-def gud-up     "up %p"      "<"    "Up (numeric arg) stack frames.")
 970   (gud-def gud-down   "down %p"    ">"    "Down (numeric arg) stack frames.")
 971   (gud-def gud-finish "bu\\t"      "\C-f" "Finish executing current function.")
 972   (gud-def gud-print  "p %e"       "\C-p" "Evaluate C expression at point.")
 973
 974   (setq comint-prompt-regexp  "^>")
 975   (setq paragraph-start comint-prompt-regexp)
 976   (local-set-key [menu-bar debug tbreak] '("Temporary Breakpoint" . gud-tbreak))
 977   (local-set-key [menu-bar debug finish] '("Finish Function" . gud-finish))
 978   (local-set-key [menu-bar debug up] '("Up Stack" . gud-up))
 979   (local-set-key [menu-bar debug down] '("Down Stack" . gud-down))
 980   (run-hooks 'xdb-mode-hook))
 981 \f
 982 ;; ======================================================================
 983 ;; perldb functions
 984
 985 ;;; History of argument lists passed to perldb.
 986 (defvar gud-perldb-history nil)
 987
 988 (defun gud-perldb-massage-args (file args)
 989   (cond ((equal (car args) "-e")
 990          (cons "-d"
 991                (cons (car args)
 992                      (cons (nth 1 args)
 993                            (cons "--" (cons "-emacs" (cdr (cdr args))))))))
 994         (t
 995          (cons "-d" (cons (car args) (cons "-emacs" (cdr args)))))))
 996
 997 ;; There's no guarantee that Emacs will hand the filter the entire
 998 ;; marker at once; it could be broken up across several strings.  We
 999 ;; might even receive a big chunk with several markers in it.  If we
1000 ;; receive a chunk of text which looks like it might contain the
1001 ;; beginning of a marker, we save it here between calls to the
1002 ;; filter.
1003 (defvar gud-perldb-marker-acc "")
1004
1005 (defun gud-perldb-marker-filter (string)
1006   (setq gud-marker-acc (concat gud-marker-acc string))
1007   (let ((output ""))
1008
1009     ;; Process all the complete markers in this chunk.
1010     (while (string-match "\032\032\\(\\([a-zA-Z]:\\)?[^:\n]*\\):\\([0-9]*\\):.*\n"
1011                          gud-marker-acc)
1012       (setq
1013
1014        ;; Extract the frame position from the marker.
1015        gud-last-frame
1016        (cons (substring gud-marker-acc (match-beginning 1) (match-end 1))
1017              (string-to-int (substring gud-marker-acc
1018                                        (match-beginning 3)
1019                                        (match-end 3))))
1020
1021        ;; Append any text before the marker to the output we're going
1022        ;; to return - we don't include the marker in this text.
1023        output (concat output
1024                       (substring gud-marker-acc 0 (match-beginning 0)))
1025
1026        ;; Set the accumulator to the remaining text.
1027        gud-marker-acc (substring gud-marker-acc (match-end 0))))
1028
1029     ;; Does the remaining text look like it might end with the
1030     ;; beginning of another marker?  If it does, then keep it in
1031     ;; gud-marker-acc until we receive the rest of it.  Since we
1032     ;; know the full marker regexp above failed, it's pretty simple to
1033     ;; test for marker starts.
1034     (if (string-match "\032.*\\'" gud-marker-acc)
1035         (progn
1036           ;; Everything before the potential marker start can be output.
1037           (setq output (concat output (substring gud-marker-acc
1038                                                  0 (match-beginning 0))))
1039
1040           ;; Everything after, we save, to combine with later input.
1041           (setq gud-marker-acc
1042                 (substring gud-marker-acc (match-beginning 0))))
1043
1044       (setq output (concat output gud-marker-acc)
1045             gud-marker-acc ""))
1046
1047     output))
1048
1049 (defun gud-perldb-find-file (f)
1050   (save-excursion
1051     (let ((buf (find-file-noselect f)))
1052       (set-buffer buf)
1053       (gud-make-debug-menu)
1054       buf)))
1055
1056 (defcustom perldb-command-name "perl"
1057   "File name for executing Perl."
1058   :type 'string
1059   :group 'gud)
1060
1061 ;;;###autoload
1062 (defun perldb (command-line)
1063   "Run perldb on program FILE in buffer *gud-FILE*.
1064 The directory containing FILE becomes the initial working directory
1065 and source-file directory for your debugger."
1066   (interactive
1067    (list (read-from-minibuffer "Run perldb (like this): "
1068                                (if (consp gud-perldb-history)
1069                                    (car gud-perldb-history)
1070                                  (concat perldb-command-name
1071                                          " "
1072                                          (or (buffer-file-name)
1073                                              "-e 0")
1074                                          " "))
1075                                nil nil
1076                                '(gud-perldb-history . 1))))
1077
1078   (gud-common-init command-line 'gud-perldb-massage-args
1079                    'gud-perldb-marker-filter 'gud-perldb-find-file)
1080
1081   (gud-def gud-break  "b %l"         "\C-b" "Set breakpoint at current line.")
1082   (gud-def gud-remove "d %l"         "\C-d" "Remove breakpoint at current line")
1083   (gud-def gud-step   "s"            "\C-s" "Step one source line with display.")
1084   (gud-def gud-next   "n"            "\C-n" "Step one line (skip functions).")
1085   (gud-def gud-cont   "c"            "\C-r" "Continue with display.")
1086 ;  (gud-def gud-finish "finish"       "\C-f" "Finish executing current function.")
1087 ;  (gud-def gud-up     "up %p"        "<" "Up N stack frames (numeric arg).")
1088 ;  (gud-def gud-down   "down %p"      ">" "Down N stack frames (numeric arg).")
1089   (gud-def gud-print  "%e"           "\C-p" "Evaluate perl expression at point.")
1090
1091   (setq comint-prompt-regexp "^  DB<+[0-9]+>+ ")
1092   (setq paragraph-start comint-prompt-regexp)
1093   (run-hooks 'perldb-mode-hook)
1094   )
1095
1096 ;;
1097 ;; End of debugger-specific information
1098 ;;
1099
1100 \f
1101 ;;; When we send a command to the debugger via gud-call, it's annoying
1102 ;;; to see the command and the new prompt inserted into the debugger's
1103 ;;; buffer; we have other ways of knowing the command has completed.
1104 ;;;
1105 ;;; If the buffer looks like this:
1106 ;;; --------------------
1107 ;;; (gdb) set args foo bar
1108 ;;; (gdb) -!-
1109 ;;; --------------------
1110 ;;; (the -!- marks the location of point), and we type `C-x SPC' in a
1111 ;;; source file to set a breakpoint, we want the buffer to end up like
1112 ;;; this:
1113 ;;; --------------------
1114 ;;; (gdb) set args foo bar
1115 ;;; Breakpoint 1 at 0x92: file make-docfile.c, line 49.
1116 ;;; (gdb) -!-
1117 ;;; --------------------
1118 ;;; Essentially, the old prompt is deleted, and the command's output
1119 ;;; and the new prompt take its place.
1120 ;;;
1121 ;;; Not echoing the command is easy enough; you send it directly using
1122 ;;; process-send-string, and it never enters the buffer.  However,
1123 ;;; getting rid of the old prompt is trickier; you don't want to do it
1124 ;;; when you send the command, since that will result in an annoying
1125 ;;; flicker as the prompt is deleted, redisplay occurs while Emacs
1126 ;;; waits for a response from the debugger, and the new prompt is
1127 ;;; inserted.  Instead, we'll wait until we actually get some output
1128 ;;; from the subprocess before we delete the prompt.  If the command
1129 ;;; produced no output other than a new prompt, that prompt will most
1130 ;;; likely be in the first chunk of output received, so we will delete
1131 ;;; the prompt and then replace it with an identical one.  If the
1132 ;;; command produces output, the prompt is moving anyway, so the
1133 ;;; flicker won't be annoying.
1134 ;;;
1135 ;;; So - when we want to delete the prompt upon receipt of the next
1136 ;;; chunk of debugger output, we position gud-delete-prompt-marker at
1137 ;;; the start of the prompt; the process filter will notice this, and
1138 ;;; delete all text between it and the process output marker.  If
1139 ;;; gud-delete-prompt-marker points nowhere, we leave the current
1140 ;;; prompt alone.
1141 (defvar gud-delete-prompt-marker nil)
1142
1143 \f
1144 (put 'gud-mode 'mode-class 'special)
1145
1146 (defun gud-mode ()
1147   "Major mode for interacting with an inferior debugger process.
1148
1149    You start it up with one of the commands M-x gdb, M-x sdb, M-x dbx,
1150 M-x perldb, or M-x xdb.  Each entry point finishes by executing a
1151 hook; `gdb-mode-hook', `sdb-mode-hook', `dbx-mode-hook',
1152 `perldb-mode-hook', or `xdb-mode-hook' respectively.
1153
1154 After startup, the following commands are available in both the GUD
1155 interaction buffer and any source buffer GUD visits due to a breakpoint stop
1156 or step operation:
1157
1158 \\[gud-break] sets a breakpoint at the current file and line.  In the
1159 GUD buffer, the current file and line are those of the last breakpoint or
1160 step.  In a source buffer, they are the buffer's file and current line.
1161
1162 \\[gud-remove] removes breakpoints on the current file and line.
1163
1164 \\[gud-refresh] displays in the source window the last line referred to
1165 in the gud buffer.
1166
1167 \\[gud-step], \\[gud-next], and \\[gud-stepi] do a step-one-line,
1168 step-one-line (not entering function calls), and step-one-instruction
1169 and then update the source window with the current file and position.
1170 \\[gud-cont] continues execution.
1171
1172 \\[gud-print] tries to find the largest C lvalue or function-call expression
1173 around point, and sends it to the debugger for value display.
1174
1175 The above commands are common to all supported debuggers except xdb which
1176 does not support stepping instructions.
1177
1178 Under gdb, sdb and xdb, \\[gud-tbreak] behaves exactly like \\[gud-break],
1179 except that the breakpoint is temporary; that is, it is removed when
1180 execution stops on it.
1181
1182 Under gdb, dbx, and xdb, \\[gud-up] pops up through an enclosing stack
1183 frame.  \\[gud-down] drops back down through one.
1184
1185 If you are using gdb or xdb, \\[gud-finish] runs execution to the return from
1186 the current function and stops.
1187
1188 All the keystrokes above are accessible in the GUD buffer
1189 with the prefix C-c, and in all buffers through the prefix C-x C-a.
1190
1191 All pre-defined functions for which the concept make sense repeat
1192 themselves the appropriate number of times if you give a prefix
1193 argument.
1194
1195 You may use the `gud-def' macro in the initialization hook to define other
1196 commands.
1197
1198 Other commands for interacting with the debugger process are inherited from
1199 comint mode, which see."
1200   (interactive)
1201   (comint-mode)
1202   (setq major-mode 'gud-mode)
1203   (setq mode-name "Debugger")
1204   (setq mode-line-process '(":%s"))
1205   (use-local-map comint-mode-map)
1206   (gud-make-debug-menu)
1207   (define-key (current-local-map) "\C-c\C-l" 'gud-refresh)
1208   (make-local-variable 'gud-last-frame)
1209   (setq gud-last-frame nil)
1210   (make-local-variable 'comint-prompt-regexp)
1211   ;; Don't put repeated commands in command history many times.
1212   (make-local-variable 'comint-input-ignoredups)
1213   (setq comint-input-ignoredups t)
1214   (make-local-variable 'paragraph-start)
1215   (make-local-variable 'gud-delete-prompt-marker)
1216   (setq gud-delete-prompt-marker (make-marker))
1217   (run-hooks 'gud-mode-hook))
1218
1219 ;; Chop STRING into words separated by SPC or TAB and return a list of them.
1220 (defun gud-chop-words (string)
1221   (let ((i 0) (beg 0)
1222         (len (length string))
1223         (words nil))
1224     (while (< i len)
1225       (if (memq (aref string i) '(?\t ? ))
1226           (progn
1227             (setq words (cons (substring string beg i) words)
1228                   beg (1+ i))
1229             (while (and (< beg len) (memq (aref string beg) '(?\t ? )))
1230               (setq beg (1+ beg)))
1231             (setq i (1+ beg)))
1232         (setq i (1+ i))))
1233     (if (< beg len)
1234         (setq words (cons (substring string beg) words)))
1235     (nreverse words)))
1236
1237 ;; Perform initializations common to all debuggers.
1238 ;; The first arg is the specified command line,
1239 ;; which starts with the program to debug.
1240 ;; The other three args specify the values to use
1241 ;; for local variables in the debugger buffer.
1242 (defun gud-common-init (command-line massage-args marker-filter find-file)
1243   (let* ((words (gud-chop-words command-line))
1244          (program (car words))
1245          ;; Extract the file name from WORDS
1246          ;; and put t in its place.
1247          ;; Later on we will put the modified file name arg back there.
1248          (file-word (let ((w (cdr words)))
1249                       (while (and w (= ?- (aref (car w) 0)))
1250                         (setq w (cdr w)))
1251                       (and w
1252                            (prog1 (car w)
1253                              (setcar w t)))))
1254          (file-subst
1255           (and file-word (substitute-in-file-name file-word)))
1256          (args (cdr words))
1257          ;; If a directory was specified, expand the file name.
1258          ;; Otherwise, don't expand it, so GDB can use the PATH.
1259          ;; A file name without directory is literally valid
1260          ;; only if the file exists in ., and in that case,
1261          ;; omitting the expansion here has no visible effect.
1262          (file (and file-word
1263                     (if (file-name-directory file-subst)
1264                         (expand-file-name file-subst)
1265                       file-subst)))
1266          (filepart (and file-word (concat "-" (file-name-nondirectory file)))))
1267     (switch-to-buffer (concat "*gud" filepart "*"))
1268     ;; Set default-directory to the file's directory.
1269     (and file-word
1270          ;; Don't set default-directory if no directory was specified.
1271          ;; In that case, either the file is found in the current directory,
1272          ;; in which case this setq is a no-op,
1273          ;; or it is found by searching PATH,
1274          ;; in which case we don't know what directory it was found in.
1275          (file-name-directory file)
1276          (setq default-directory (file-name-directory file)))
1277     (or (bolp) (newline))
1278     (insert "Current directory is " default-directory "\n")
1279     ;; Put the substituted and expanded file name back in its place.
1280     (let ((w args))
1281       (while (and w (not (eq (car w) t)))
1282         (setq w (cdr w)))
1283       (if w
1284           (setcar w file)))
1285     (apply 'make-comint (concat "gud" filepart) program nil
1286            (funcall massage-args file args)))
1287   ;; Since comint clobbered the mode, we don't set it until now.
1288   (gud-mode)
1289   (make-local-variable 'gud-marker-filter)
1290   (setq gud-marker-filter marker-filter)
1291   (make-local-variable 'gud-find-file)
1292   (setq gud-find-file find-file)
1293
1294   (set-process-filter (get-buffer-process (current-buffer)) 'gud-filter)
1295   (set-process-sentinel (get-buffer-process (current-buffer)) 'gud-sentinel)
1296   (gud-set-buffer)
1297   )
1298
1299 (defun gud-set-buffer ()
1300   (cond ((eq major-mode 'gud-mode)
1301         (setq gud-comint-buffer (current-buffer)))))
1302
1303 (defvar gud-filter-defer-flag nil
1304   "Non-nil means don't process anything from the debugger right now.
1305 It is saved for when this flag is not set.")
1306
1307 (defvar gud-filter-pending-text nil
1308   "Non-nil means this is text that has been saved for later in `gud-filter'.")
1309
1310 ;; These functions are responsible for inserting output from your debugger
1311 ;; into the buffer.  The hard work is done by the method that is
1312 ;; the value of gud-marker-filter.
1313
1314 (defun gud-filter (proc string)
1315   ;; Here's where the actual buffer insertion is done
1316   (let (output process-window)
1317     (if (buffer-name (process-buffer proc))
1318         (if gud-filter-defer-flag
1319             ;; If we can't process any text now,
1320             ;; save it for later.
1321             (setq gud-filter-pending-text
1322                   (concat (or gud-filter-pending-text "") string))
1323
1324           ;; If we have to ask a question during the processing,
1325           ;; defer any additional text that comes from the debugger
1326           ;; during that time.
1327           (let ((gud-filter-defer-flag t))
1328             ;; Process now any text we previously saved up.
1329             (if gud-filter-pending-text
1330                 (setq string (concat gud-filter-pending-text string)
1331                       gud-filter-pending-text nil))
1332             (save-excursion
1333               (set-buffer (process-buffer proc))
1334               ;; If we have been so requested, delete the debugger prompt.
1335               (if (marker-buffer gud-delete-prompt-marker)
1336                   (progn
1337                     (delete-region (process-mark proc) gud-delete-prompt-marker)
1338                     (set-marker gud-delete-prompt-marker nil)))
1339               ;; Save the process output, checking for source file markers.
1340               (setq output (gud-marker-filter string))
1341               ;; Check for a filename-and-line number.
1342               ;; Don't display the specified file
1343               ;; unless (1) point is at or after the position where output appears
1344               ;; and (2) this buffer is on the screen.
1345               (setq process-window
1346                     (and gud-last-frame
1347                          (>= (point) (process-mark proc))
1348                          (get-buffer-window (current-buffer))))
1349
1350               ;; Let the comint filter do the actual insertion.
1351               ;; That lets us inherit various comint features.
1352               (comint-output-filter proc output)))
1353
1354           ;; Put the arrow on the source line.
1355           ;; This must be outside of the save-excursion
1356           ;; in case the source file is our current buffer.
1357           (if process-window
1358               (save-selected-window
1359                 (select-window process-window)
1360                 (gud-display-frame))
1361             ;; We have to be in the proper buffer, (process-buffer proc),
1362             ;; but not in a save-excursion, because that would restore point.
1363             (let ((old-buf (current-buffer)))
1364               (set-buffer (process-buffer proc))
1365               (unwind-protect
1366                   (gud-display-frame)
1367                 (set-buffer old-buf))))
1368
1369           ;; If we deferred text that arrived during this processing,
1370           ;; handle it now.
1371           (if gud-filter-pending-text
1372               (gud-filter proc ""))))))
1373
1374 (defun gud-sentinel (proc msg)
1375   (cond ((null (buffer-name (process-buffer proc)))
1376          ;; buffer killed
1377          ;; Stop displaying an arrow in a source file.
1378          (setq overlay-arrow-position nil)
1379          (set-process-buffer proc nil))
1380         ((memq (process-status proc) '(signal exit))
1381          ;; Stop displaying an arrow in a source file.
1382          (setq overlay-arrow-position nil)
1383          ;; Fix the mode line.
1384          (setq mode-line-process
1385                (concat ":"
1386                        (symbol-name (process-status proc))))
1387          (let* ((obuf (current-buffer)))
1388            ;; save-excursion isn't the right thing if
1389            ;;  process-buffer is current-buffer
1390            (unwind-protect
1391                (progn
1392                  ;; Write something in *compilation* and hack its mode line,
1393                  (set-buffer (process-buffer proc))
1394                  (force-mode-line-update)
1395                  (if (eobp)
1396                      (insert ?\n mode-name " " msg)
1397                    (save-excursion
1398                      (goto-char (point-max))
1399                      (insert ?\n mode-name " " msg)))
1400                  ;; If buffer and mode line will show that the process
1401                  ;; is dead, we can delete it now.  Otherwise it
1402                  ;; will stay around until M-x list-processes.
1403                  (delete-process proc))
1404              ;; Restore old buffer, but don't restore old point
1405              ;; if obuf is the gud buffer.
1406              (set-buffer obuf))))))
1407
1408 (defun gud-display-frame ()
1409   "Find and obey the last filename-and-line marker from the debugger.
1410 Obeying it means displaying in another window the specified file and line."
1411   (interactive)
1412   (if gud-last-frame
1413    (progn
1414      (gud-set-buffer)
1415      (gud-display-line (car gud-last-frame) (cdr gud-last-frame))
1416      (setq gud-last-last-frame gud-last-frame
1417            gud-last-frame nil))))
1418
1419 ;; Make sure the file named TRUE-FILE is in a buffer that appears on the screen
1420 ;; and that its line LINE is visible.
1421 ;; Put the overlay-arrow on the line LINE in that buffer.
1422 ;; Most of the trickiness in here comes from wanting to preserve the current
1423 ;; region-restriction if that's possible.  We use an explicit display-buffer
1424 ;; to get around the fact that this is called inside a save-excursion.
1425
1426 (defun gud-display-line (true-file line)
1427   (let* ((last-nonmenu-event t)  ; Prevent use of dialog box for questions.
1428          (buffer
1429           (save-excursion
1430             (or (eq (current-buffer) gud-comint-buffer)
1431                 (set-buffer gud-comint-buffer))
1432             (gud-find-file true-file)))
1433          (window (and buffer (or (get-buffer-window buffer)
1434                                  (display-buffer buffer))))
1435          (pos))
1436     (if buffer
1437         (progn
1438           (save-excursion
1439             (set-buffer buffer)
1440             (save-restriction
1441               (widen)
1442               (goto-line line)
1443               (setq pos (point))
1444               (setq overlay-arrow-string "=>")
1445               (or overlay-arrow-position
1446                   (setq overlay-arrow-position (make-marker)))
1447               (set-marker overlay-arrow-position (point) (current-buffer)))
1448             (cond ((or (< pos (point-min)) (> pos (point-max)))
1449                    (widen)
1450                    (goto-char pos))))
1451           (set-window-point window overlay-arrow-position)))))
1452
1453 ;;; The gud-call function must do the right thing whether its invoking
1454 ;;; keystroke is from the GUD buffer itself (via major-mode binding)
1455 ;;; or a C buffer.  In the former case, we want to supply data from
1456 ;;; gud-last-frame.  Here's how we do it:
1457
1458 (defun gud-format-command (str arg)
1459   (let ((insource (not (eq (current-buffer) gud-comint-buffer)))
1460         (frame (or gud-last-frame gud-last-last-frame))
1461         result)
1462     (while (and str (string-match "\\([^%]*\\)%\\([adeflp]\\)" str))
1463       (let ((key (string-to-char (substring str (match-beginning 2))))
1464             subst)
1465         (cond
1466          ((eq key ?f)
1467           (setq subst (file-name-nondirectory (if insource
1468                                                   (buffer-file-name)
1469                                                 (car frame)))))
1470          ((eq key ?d)
1471           (setq subst (file-name-directory (if insource
1472                                                (buffer-file-name)
1473                                              (car frame)))))
1474          ((eq key ?l)
1475           (setq subst (if insource
1476                           (save-excursion
1477                             (beginning-of-line)
1478                             (save-restriction (widen)
1479                                               (1+ (count-lines 1 (point)))))
1480                         (cdr frame))))
1481          ((eq key ?e)
1482           (setq subst (gud-find-c-expr)))
1483          ((eq key ?a)
1484           (setq subst (gud-read-address)))
1485          ((eq key ?p)
1486           (setq subst (if arg (int-to-string arg) ""))))
1487         (setq result (concat result
1488                              (substring str (match-beginning 1) (match-end 1))
1489                              subst)))
1490       (setq str (substring str (match-end 2))))
1491     ;; There might be text left in STR when the loop ends.
1492     (concat result str)))
1493
1494 (defun gud-read-address ()
1495   "Return a string containing the core-address found in the buffer at point."
1496   (save-excursion
1497     (let ((pt (point)) found begin)
1498       (setq found (if (search-backward "0x" (- pt 7) t) (point)))
1499       (cond
1500        (found (forward-char 2)
1501               (buffer-substring found
1502                                 (progn (re-search-forward "[^0-9a-f]")
1503                                        (forward-char -1)
1504                                        (point))))
1505        (t (setq begin (progn (re-search-backward "[^0-9]")
1506                              (forward-char 1)
1507                              (point)))
1508           (forward-char 1)
1509           (re-search-forward "[^0-9]")
1510           (forward-char -1)
1511           (buffer-substring begin (point)))))))
1512
1513 (defun gud-call (fmt &optional arg)
1514   (let ((msg (gud-format-command fmt arg)))
1515     (message "Command: %s" msg)
1516     (sit-for 0)
1517     (gud-basic-call msg)))
1518
1519 (defun gud-basic-call (command)
1520   "Invoke the debugger COMMAND displaying source in other window."
1521   (interactive)
1522   (gud-set-buffer)
1523   (let ((command (concat command "\n"))
1524         (proc (get-buffer-process gud-comint-buffer)))
1525     (or proc (error "Current buffer has no process"))
1526     ;; Arrange for the current prompt to get deleted.
1527     (save-excursion
1528       (set-buffer gud-comint-buffer)
1529       (goto-char (process-mark proc))
1530       (beginning-of-line)
1531       (if (looking-at comint-prompt-regexp)
1532           (set-marker gud-delete-prompt-marker (point))))
1533     (process-send-string proc command)))
1534
1535 (defun gud-refresh (&optional arg)
1536   "Fix up a possibly garbled display, and redraw the arrow."
1537   (interactive "P")
1538   (recenter arg)
1539   (or gud-last-frame (setq gud-last-frame gud-last-last-frame))
1540   (gud-display-frame))
1541 \f
1542
1543 (defun gud-new-keymap (map)
1544   "Return a new keymap which inherits from MAP and has name `Gud'."
1545   (nconc (make-sparse-keymap "Gud") map))
1546
1547 (defun gud-make-debug-menu ()
1548   "Make sure the current local map has a [menu-bar debug] submap.
1549 If it doesn't, replace it with a new map that inherits it,
1550 and create such a submap in that new map."
1551   (if (and (current-local-map)
1552            (lookup-key (current-local-map) [menu-bar debug]))
1553       nil
1554     (use-local-map (gud-new-keymap (current-local-map)))
1555     (define-key (current-local-map) [menu-bar debug]
1556       (cons "Gud" (gud-new-keymap gud-menu-map)))))
1557 \f
1558 ;;; Code for parsing expressions out of C code.  The single entry point is
1559 ;;; find-c-expr, which tries to return an lvalue expression from around point.
1560 ;;;
1561 ;;; The rest of this file is a hacked version of gdbsrc.el by
1562 ;;; Debby Ayers <ayers@asc.slb.com>,
1563 ;;; Rich Schaefer <schaefer@asc.slb.com> Schlumberger, Austin, Tx.
1564
1565 (defun gud-find-c-expr ()
1566   "Returns the C expr that surrounds point."
1567   (interactive)
1568   (save-excursion
1569     (let (p expr test-expr)
1570       (setq p (point))
1571       (setq expr (gud-innermost-expr))
1572       (setq test-expr (gud-prev-expr))
1573       (while (and test-expr (gud-expr-compound test-expr expr))
1574         (let ((prev-expr expr))
1575           (setq expr (cons (car test-expr) (cdr expr)))
1576           (goto-char (car expr))
1577           (setq test-expr (gud-prev-expr))
1578           ;; If we just pasted on the condition of an if or while,
1579           ;; throw it away again.
1580           (if (member (buffer-substring (car test-expr) (cdr test-expr))
1581                       '("if" "while" "for"))
1582               (setq test-expr nil
1583                     expr prev-expr))))
1584       (goto-char p)
1585       (setq test-expr (gud-next-expr))
1586       (while (gud-expr-compound expr test-expr)
1587         (setq expr (cons (car expr) (cdr test-expr)))
1588         (setq test-expr (gud-next-expr))
1589         )
1590       (buffer-substring (car expr) (cdr expr)))))
1591
1592 (defun gud-innermost-expr ()
1593   "Returns the smallest expr that point is in; move point to beginning of it.
1594 The expr is represented as a cons cell, where the car specifies the point in
1595 the current buffer that marks the beginning of the expr and the cdr specifies
1596 the character after the end of the expr."
1597   (let ((p (point)) begin end)
1598     (gud-backward-sexp)
1599     (setq begin (point))
1600     (gud-forward-sexp)
1601     (setq end (point))
1602     (if (>= p end)
1603         (progn
1604          (setq begin p)
1605          (goto-char p)
1606          (gud-forward-sexp)
1607          (setq end (point)))
1608       )
1609     (goto-char begin)
1610     (cons begin end)))
1611
1612 (defun gud-backward-sexp ()
1613   "Version of `backward-sexp' that catches errors."
1614   (condition-case nil
1615       (backward-sexp)
1616     (error t)))
1617
1618 (defun gud-forward-sexp ()
1619   "Version of `forward-sexp' that catches errors."
1620   (condition-case nil
1621      (forward-sexp)
1622     (error t)))
1623
1624 (defun gud-prev-expr ()
1625   "Returns the previous expr, point is set to beginning of that expr.
1626 The expr is represented as a cons cell, where the car specifies the point in
1627 the current buffer that marks the beginning of the expr and the cdr specifies
1628 the character after the end of the expr"
1629   (let ((begin) (end))
1630     (gud-backward-sexp)
1631     (setq begin (point))
1632     (gud-forward-sexp)
1633     (setq end (point))
1634     (goto-char begin)
1635     (cons begin end)))
1636
1637 (defun gud-next-expr ()
1638   "Returns the following expr, point is set to beginning of that expr.
1639 The expr is represented as a cons cell, where the car specifies the point in
1640 the current buffer that marks the beginning of the expr and the cdr specifies
1641 the character after the end of the expr."
1642   (let ((begin) (end))
1643     (gud-forward-sexp)
1644     (gud-forward-sexp)
1645     (setq end (point))
1646     (gud-backward-sexp)
1647     (setq begin (point))
1648     (cons begin end)))
1649
1650 (defun gud-expr-compound-sep (span-start span-end)
1651   "Scan from SPAN-START to SPAN-END for punctuation characters.
1652 If `->' is found, return `?.'.  If `.' is found, return `?.'.
1653 If any other punctuation is found, return `??'.
1654 If no punctuation is found, return `? '."
1655   (let ((result ?\ )
1656         (syntax))
1657     (while (< span-start span-end)
1658       (setq syntax (char-syntax (char-after span-start)))
1659       (cond
1660        ((= syntax ?\ ) t)
1661        ((= syntax ?.) (setq syntax (char-after span-start))
1662         (cond
1663          ((= syntax ?.) (setq result ?.))
1664          ((and (= syntax ?-) (= (char-after (+ span-start 1)) ?>))
1665           (setq result ?.)
1666           (setq span-start (+ span-start 1)))
1667          (t (setq span-start span-end)
1668             (setq result ??)))))
1669       (setq span-start (+ span-start 1)))
1670     result))
1671
1672 (defun gud-expr-compound (first second)
1673   "Non-nil if concatenating FIRST and SECOND makes a single C expression.
1674 The two exprs are represented as a cons cells, where the car
1675 specifies the point in the current buffer that marks the beginning of the
1676 expr and the cdr specifies the character after the end of the expr.
1677 Link exprs of the form:
1678       Expr -> Expr
1679       Expr . Expr
1680       Expr (Expr)
1681       Expr [Expr]
1682       (Expr) Expr
1683       [Expr] Expr"
1684   (let ((span-start (cdr first))
1685         (span-end (car second))
1686         (syntax))
1687     (setq syntax (gud-expr-compound-sep span-start span-end))
1688     (cond
1689      ((= (car first) (car second)) nil)
1690      ((= (cdr first) (cdr second)) nil)
1691      ((= syntax ?.) t)
1692      ((= syntax ?\ )
1693          (setq span-start (char-after (- span-start 1)))
1694          (setq span-end (char-after span-end))
1695          (cond
1696           ((= span-start ?)) t)
1697           ((= span-start ?]) t)
1698           ((= span-end ?() t)
1699           ((= span-end ?[) t)
1700           (t nil)))
1701      (t nil))))
1702
1703 (provide 'gud)
1704
1705 ;;; gud.el ends here