- ;; FIXME: This seems to be the source of one of the basic debugger
- ;; choices in
- ;; Restarts:
- ;; 0: [CONTINUE] Return from BREAK.
- ;; 1: [ABORT ] Return to toplevel.
- ;; (The "Return from BREAK" choice is defined in BREAK.) I'd like to add
- ;; another choice,
- ;; 2: [TERMINATE] Terminate the current Lisp.
- ;; That way, a user hitting ^C could get out of Lisp without knowing
- ;; enough about the system to run (SB-EXT:QUIT).
- ;;
- ;; If I understand the documentation of WITH-SIMPLE-RESTART correctly,
- ;; it shows how to replace this WITH-SIMPLE-RESTART with a RESTART-CASE
- ;; with two choices (ABORT and QUIT). Or perhaps ABORT should be renamed
- ;; TOPLEVEL?
- ;; Restarts:
- ;; 0: [CONTINUE ] Return from BREAK, continuing calculation
- ;; as though nothing happened.
- ;; 1: [TOPLEVEL ] Transfer control to toplevel read/eval/print
- ;; loop, aborting current calculation.
- ;; 2: [TERMINATE] Terminate the current Lisp (equivalent to
- ;; executing (SB-EXT:QUIT)).
- (/show0 "at head of outer LOOP in TOPLEVEL-REPL")
- (with-simple-restart (abort "Return to toplevel.")
- (catch 'top-level-catcher
- (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
- (let ((*in-top-level-catcher* t))
- (/show0 "about to enter inner LOOP in TOPLEVEL-REPL")
- (loop ; FIXME: Do we need this inner LOOP?
- ;; FIXME: It seems bad to have GC behavior depend on scrubbing
- ;; the control stack before each interactive command. Isn't
- ;; there some way we can convince the GC to just ignore
- ;; dead areas of the control stack, so that we don't need to
- ;; rely on this half-measure?
- (scrub-control-stack)
- (unless noprint
- (fresh-line)
- (princ (if (functionp *prompt*)
- (funcall *prompt*)
- *prompt*))
- (flush-standard-output-streams))
- (let ((form (read *standard-input* nil eof-marker)))
- (if (eq form eof-marker)
- (quit)
- (let ((results
- (multiple-value-list (interactive-eval form))))
- (unless noprint
- (dolist (result results)
- (fresh-line)
- (prin1 result)))))))))))))
+ (/show0 "about to set up restarts in TOPLEVEL-REPL")
+ ;; There should only be one TOPLEVEL restart, and it's here, so
+ ;; restarting at TOPLEVEL always bounces you all the way out here.
+ (with-simple-restart (toplevel
+ "Restart at toplevel READ/EVAL/PRINT loop.")
+ ;; We add a new ABORT restart for every debugger level, so
+ ;; restarting at ABORT in a nested debugger gets you out to the
+ ;; innermost enclosing debugger, and only when you're in the
+ ;; outermost, unnested debugger level does restarting at ABORT
+ ;; get you out to here.
+ (with-simple-restart
+ (abort
+ "~@<Reduce debugger level (leaving debugger, returning to toplevel).~@:>")
+ (catch 'toplevel-catcher
+ #!-sunos (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
+ ;; in the event of a control-stack-exhausted-error, we should
+ ;; have unwound enough stack by the time we get here that this
+ ;; is now possible
+ (sb!kernel::protect-control-stack-guard-page 1)
+ (repl noprint)
+ (critically-unreachable "after REPL")))))))
+
+(defun repl (noprint)
+ (/show0 "entering REPL")
+ (let ((eof-marker (cons :eof nil)))
+ (loop
+ ;; see comment preceding definition of SCRUB-CONTROL-STACK
+ (scrub-control-stack)
+ (unless noprint
+ (fresh-line)
+ (write-string "* ") ; arbitrary but customary REPL prompt
+ (flush-standard-output-streams))
+ (let ((form (read *standard-input* nil eof-marker)))
+ (cond ((eq form eof-marker)
+ (/show0 "doing QUIT for EOF in REPL")
+ (quit))
+ (t
+ (let ((results (multiple-value-list (interactive-eval form))))
+ (unless noprint
+ (dolist (result results)
+ (fresh-line)
+ (prin1 result))))))))))
+
+;;; suitable value for *DEBUGGER-HOOK* for a noninteractive Unix-y program
+(defun noprogrammer-debugger-hook-fun (condition old-debugger-hook)
+ (declare (ignore old-debugger-hook))
+ (flet ((failure-quit (&key recklessly-p)
+ (/show0 "in FAILURE-QUIT (in --disable-debugger debugger hook)")
+ (quit :unix-status 1 :recklessly-p recklessly-p)))
+ ;; This HANDLER-CASE is here mostly to stop output immediately
+ ;; (and fall through to QUIT) when there's an I/O error. Thus,
+ ;; when we're run under a shell script or something, we can die
+ ;; cleanly when the script dies (and our pipes are cut), instead
+ ;; of falling into ldb or something messy like that.
+ (handler-case
+ (progn
+ (format *error-output*
+ "~&~@<unhandled condition (of type ~S): ~2I~_~A~:>~2%"
+ (type-of condition)
+ condition)
+ ;; Flush *ERROR-OUTPUT* even before the BACKTRACE, so that
+ ;; even if we hit an error within BACKTRACE (e.g. a bug in
+ ;; the debugger's own frame-walking code, or a bug in a user
+ ;; PRINT-OBJECT method) we'll at least have the CONDITION
+ ;; printed out before we die.
+ (finish-output *error-output*)
+ ;; (Where to truncate the BACKTRACE is of course arbitrary, but
+ ;; it seems as though we should at least truncate it somewhere.)
+ (sb!debug:backtrace 128 *error-output*)
+ (format
+ *error-output*
+ "~%unhandled condition in --disable-debugger mode, quitting~%")
+ (finish-output *error-output*)
+ (failure-quit))
+ (condition ()
+ ;; We IGNORE-ERRORS here because even %PRIMITIVE PRINT can
+ ;; fail when our output streams are blown away, as e.g. when
+ ;; we're running under a Unix shell script and it dies somehow
+ ;; (e.g. because of a SIGINT). In that case, we might as well
+ ;; just give it up for a bad job, and stop trying to notify
+ ;; the user of anything.
+ ;;
+ ;; Actually, the only way I've run across to exercise the
+ ;; problem is to have more than one layer of shell script.
+ ;; I have a shell script which does
+ ;; time nice -10 sh make.sh "$1" 2>&1 | tee make.tmp
+ ;; and the problem occurs when I interrupt this with Ctrl-C
+ ;; under Linux 2.2.14-5.0 and GNU bash, version 1.14.7(1).
+ ;; I haven't figured out whether it's bash, time, tee, Linux, or
+ ;; what that is responsible, but that it's possible at all
+ ;; means that we should IGNORE-ERRORS here. -- WHN 2001-04-24
+ (ignore-errors
+ (%primitive print
+ "Argh! error within --disable-debugger error handling"))
+ (failure-quit :recklessly-p t)))))