262 lines
8.7 KiB
EmacsLisp
262 lines
8.7 KiB
EmacsLisp
;; Debuggers and related commands for Emacs
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;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 1, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to
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;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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(setq debugger 'debug)
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(defun debug (&rest debugger-args)
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"Enter debugger. Returns if user says \"continue\".
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Arguments are mainly for use when this is called
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from the internals of the evaluator.
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You may call with no args, or you may
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pass nil as the first arg and any other args you like.
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In that case, the list of args after the first will
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be printed into the backtrace buffer."
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(message "Entering debugger...")
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(let (debugger-value
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(debugger-match-data (match-data))
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(debug-on-error nil)
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(debug-on-quit nil)
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(debugger-buffer (let ((default-major-mode 'fundamental-mode))
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(generate-new-buffer "*Backtrace*")))
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(debugger-old-buffer (current-buffer))
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(debugger-step-after-exit nil)
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;; Don't keep reading from an executing kbd macro!
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(executing-macro nil)
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(cursor-in-echo-area nil))
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(unwind-protect
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(save-excursion
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(save-window-excursion
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(pop-to-buffer debugger-buffer)
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(erase-buffer)
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(let ((standard-output (current-buffer))
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(print-escape-newlines t)
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(print-length 50))
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(backtrace))
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(goto-char (point-min))
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(debugger-mode)
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(delete-region (point)
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(progn
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(forward-sexp 8)
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(forward-line 1)
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(point)))
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(cond ((memq (car debugger-args) '(lambda debug))
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(insert "Entering:\n")
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(if (eq (car debugger-args) 'debug)
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(progn
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(backtrace-debug 4 t)
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(delete-char 1)
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(insert ?*)
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(beginning-of-line))))
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((eq (car debugger-args) 'exit)
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(insert "Return value: ")
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(setq debugger-value (nth 1 debugger-args))
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(prin1 debugger-value (current-buffer))
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(insert ?\n)
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(delete-char 1)
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(insert ? )
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(beginning-of-line))
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((eq (car debugger-args) 'error)
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(insert "Signalling: ")
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(prin1 (nth 1 debugger-args) (current-buffer))
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(insert ?\n))
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((eq (car debugger-args) t)
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(insert "Beginning evaluation of function call form:\n"))
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(t
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(prin1 (if (eq (car debugger-args) 'nil)
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(cdr debugger-args) debugger-args)
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(current-buffer))
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(insert ?\n)))
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(message "")
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(let ((inhibit-trace t)
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(standard-output nil)
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(buffer-read-only t))
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(message "")
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(recursive-edit))))
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;; So that users do not try to execute debugger commands
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;; in an invalid context
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(kill-buffer debugger-buffer)
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(store-match-data debugger-match-data))
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(setq debug-on-next-call debugger-step-after-exit)
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debugger-value))
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(defun debugger-step-through ()
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"Proceed, stepping through subexpressions of this expression.
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Enter another debugger on next entry to eval, apply or funcall."
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(interactive)
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(setq debugger-step-after-exit t)
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(message "Proceding, will debug on next eval or call.")
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(exit-recursive-edit))
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(defun debugger-continue ()
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"Continue, evaluating this expression without stopping."
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(interactive)
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(message "Continuing.")
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(exit-recursive-edit))
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(defun debugger-return-value (val)
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"Continue, specifying value to return.
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This is only useful when the value returned from the debugger
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will be used, such as in a debug on exit from a frame."
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(interactive "XReturn value (evaluated): ")
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(setq debugger-value val)
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(princ "Returning " t)
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(prin1 debugger-value)
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(exit-recursive-edit))
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(defun debugger-frame-number ()
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"Return number of frames in backtrace before the one point points at."
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(save-excursion
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(beginning-of-line)
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(let ((opoint (point))
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(count 0))
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(goto-char (point-min))
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(if (or (equal (buffer-substring (point) (+ (point) 6))
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"Signal")
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(equal (buffer-substring (point) (+ (point) 6))
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"Return"))
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(progn
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(search-forward ":")
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(forward-sexp 1)))
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(forward-line 1)
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(while (progn
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(forward-char 2)
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(if (= (following-char) ?\()
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(forward-sexp 1)
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(forward-sexp 2))
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(forward-line 1)
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(<= (point) opoint))
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(setq count (1+ count)))
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count)))
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;; Chosen empirically to account for all the frames
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;; that will exist when debugger-frame is called
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;; within the first one that appears in the backtrace buffer.
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;; Assumes debugger-frame is called from a key;
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;; will be wrong if it is called with Meta-x.
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(defconst debugger-frame-offset 8 "")
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(defun debugger-frame ()
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"Request entry to debugger when this frame exits.
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Applies to the frame whose line point is on in the backtrace."
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(interactive)
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(beginning-of-line)
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(let ((level (debugger-frame-number)))
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(backtrace-debug (+ level debugger-frame-offset) t))
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(if (= (following-char) ? )
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(let ((buffer-read-only nil))
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(delete-char 1)
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(insert ?*)))
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(beginning-of-line))
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(defun debugger-frame-clear ()
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"Do not enter to debugger when this frame exits.
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Applies to the frame whose line point is on in the backtrace."
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(interactive)
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(beginning-of-line)
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(let ((level (debugger-frame-number)))
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(backtrace-debug (+ level debugger-frame-offset) nil))
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(if (= (following-char) ?*)
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(let ((buffer-read-only nil))
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(delete-char 1)
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(insert ? )))
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(beginning-of-line))
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(defun debugger-eval-expression (exp)
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(interactive "xEval: ")
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(save-excursion
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(if (null (buffer-name debugger-old-buffer))
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;; old buffer deleted
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(setq debugger-old-buffer (current-buffer)))
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(set-buffer debugger-old-buffer)
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(eval-expression exp)))
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(defvar debugger-mode-map nil)
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(if debugger-mode-map
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nil
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(let ((loop ? ))
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(setq debugger-mode-map (make-keymap))
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(suppress-keymap debugger-mode-map)
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(define-key debugger-mode-map "-" 'negative-argument)
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(define-key debugger-mode-map "b" 'debugger-frame)
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(define-key debugger-mode-map "c" 'debugger-continue)
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(define-key debugger-mode-map "r" 'debugger-return-value)
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(define-key debugger-mode-map "u" 'debugger-frame-clear)
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(define-key debugger-mode-map "d" 'debugger-step-through)
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(define-key debugger-mode-map "h" 'describe-mode)
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(define-key debugger-mode-map "q" 'top-level)
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(define-key debugger-mode-map "e" 'debugger-eval-expression)
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(define-key debugger-mode-map " " 'next-line)))
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(put 'debugger-mode 'mode-class 'special)
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(defun debugger-mode ()
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"Mode for backtrace buffers, selected in debugger.
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\\{debugger-mode-map}
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For the r command, when in debugger due to frame being exited,
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the value specified here will be used as the value of that frame.
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Note lines starting with * are frames that will
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enter debugger when exited."
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(kill-all-local-variables)
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(setq major-mode 'debugger-mode)
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(setq mode-name "Debugger")
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(setq truncate-lines t)
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(set-syntax-table emacs-lisp-mode-syntax-table)
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(use-local-map debugger-mode-map))
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(defun debug-on-entry (function)
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"Request FUNCTION to invoke debugger each time it is called.
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If the user continues, FUNCTION's execution proceeds.
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Works by modifying the definition of FUNCTION,
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which must be written in Lisp, not predefined.
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Use `cancel-debug-on-entry' to cancel the effect of this command.
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Redefining FUNCTION also does that."
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(interactive "aDebug on entry (to function): ")
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(let ((defn (symbol-function function)))
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(if (eq (car defn) 'macro)
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(fset function (cons 'macro (debug-on-entry-1 function (cdr defn) t)))
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(fset function (debug-on-entry-1 function defn t))))
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function)
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(defun cancel-debug-on-entry (function)
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"Undoes effect of debug-on-entry on FUNCTION."
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(interactive "aCancel debug on entry (to function): ")
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(let ((defn (symbol-function function)))
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(if (eq (car defn) 'macro)
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(fset function
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(cons 'macro (debug-on-entry-1 function (cdr defn) nil)))
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(fset function (debug-on-entry-1 function defn nil))))
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function)
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(defun debug-on-entry-1 (function defn flag)
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(or (eq (car defn) 'lambda)
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(error "%s not user-defined Lisp function." function))
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(let (tail prec)
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(if (stringp (car (nthcdr 2 defn)))
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(setq tail (nthcdr 3 defn)
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prec (list (car defn) (car (cdr defn)) (car (cdr (cdr defn)))))
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(setq tail (nthcdr 2 defn)
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prec (list (car defn) (car (cdr defn)))))
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(if (eq flag (equal (car tail) '(debug 'debug)))
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nil
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(if flag
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(nconc prec (cons '(debug 'debug) tail))
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(nconc prec (cdr tail))))))
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