1 ;;;; stuff related to the toplevel read-eval-print loop, plus some
2 ;;;; other miscellaneous functions that we don't have any better place
5 ;;;; This software is part of the SBCL system. See the README file for
8 ;;;; This software is derived from the CMU CL system, which was
9 ;;;; written at Carnegie Mellon University and released into the
10 ;;;; public domain. The software is in the public domain and is
11 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
12 ;;;; files for more information.
14 (in-package "SB!IMPL")
16 ;;;; magic specials initialized by GENESIS
18 ;;; FIXME: The DEFVAR here is redundant with the (DECLAIM (SPECIAL ..))
19 ;;; of all static symbols in early-impl.lisp.
21 (defvar sb!vm::*current-catch-block*)
22 (defvar sb!vm::*current-unwind-protect-block*)
23 #!+hpux (defvar sb!vm::*c-lra*)
24 (defvar *free-interrupt-context-index*))
26 ;;; specials initialized by !COLD-INIT
28 ;;; FIXME: These could be converted to DEFVARs.
29 (declaim (special #!+(or x86 x86-64) *pseudo-atomic-bits*
30 *allow-with-interrupts*
33 *type-system-initialized*))
35 (defvar *cold-init-complete-p*)
37 ;;; counts of nested errors (with internal errors double-counted)
38 (defvar *maximum-error-depth*)
39 (defvar *current-error-depth*)
41 ;;;; default initfiles
43 (defun sysinit-pathname ()
44 (or (let ((sbcl-homedir (sbcl-homedir-pathname)))
46 (probe-file (merge-pathnames "sbclrc" sbcl-homedir))))
48 (merge-pathnames "sbcl\\sbclrc"
49 (sb!win32::get-folder-pathname
50 sb!win32::csidl_common_appdata))
54 (defun userinit-pathname ()
55 (merge-pathnames ".sbclrc" (user-homedir-pathname)))
57 (defvar *sysinit-pathname-function* #'sysinit-pathname
59 "Designator for a function of zero arguments called to obtain a
60 pathname designator for the default sysinit file, or NIL. If the
61 function returns NIL, no sysinit file is used unless one has been
62 specified on the command-line.")
64 (defvar *userinit-pathname-function* #'userinit-pathname
66 "Designator for a function of zero arguments called to obtain a
67 pathname designator or a stream for the default userinit file, or NIL.
68 If the function returns NIL, no userinit file is used unless one has
69 been specified on the command-line.")
72 ;;;; miscellaneous utilities for working with with TOPLEVEL
74 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
75 ;;; by QUIT) is caught and any final processing and return codes are
76 ;;; handled appropriately.
77 (defmacro handling-end-of-the-world (&body body)
78 (with-unique-names (caught)
81 (catch '%end-of-the-world
83 (with-local-interrupts ,@body (quit))
85 (with-local-interrupts
86 (call-hooks "exit" *exit-hooks* :on-error :warn))
89 ;; If user called QUIT and exit hooks were OK, the status is what it
90 ;; is -- even eg. streams cannot be flushed anymore. Even if
91 ;; something goes wrong now, we still report what was asked. We still
92 ;; want to have %END-OF-THE-WORLD visible, though.
93 (catch '%end-of-the-world
97 (flush-standard-output-streams)
98 (sb!thread::terminate-session))
99 (sb!unix:unix-exit ,caught))
100 (serious-condition ())))))))
102 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
104 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
106 (defmacro infinite-error-protect (&rest forms)
107 `(unless (infinite-error-protector)
108 (/show0 "back from INFINITE-ERROR-PROTECTOR")
109 (let ((*current-error-depth* (1+ *current-error-depth*)))
110 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
111 ;; arbitrary truncation
112 #!+sb-show (sb!debug:backtrace 8)
115 ;;; a helper function for INFINITE-ERROR-PROTECT
116 (defun infinite-error-protector ()
117 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
118 (/hexstr *current-error-depth*)
119 (cond ((not *cold-init-complete-p*)
120 (%primitive print "Argh! error in cold init, halting")
121 (%primitive sb!c:halt))
122 ((or (not (boundp '*current-error-depth*))
123 (not (realp *current-error-depth*))
124 (not (boundp '*maximum-error-depth*))
125 (not (realp *maximum-error-depth*)))
126 (%primitive print "Argh! corrupted error depth, halting")
127 (%primitive sb!c:halt))
128 ((> *current-error-depth* *maximum-error-depth*)
129 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
130 (/hexstr *maximum-error-depth*)
131 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
132 (error-error "Help! "
133 *current-error-depth*
135 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
138 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
141 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
142 ;;; one point (shown below), and SBCL cross-compiled it without
143 ;;; warning about FORMS being undefined. Check whether that problem
144 ;;; (missing warning) is repeatable in the final system and if so, fix
147 (defun infinite-error-protector ()
148 `(cond ((not *cold-init-complete-p*)
149 (%primitive print "Argh! error in cold init, halting")
150 (%primitive sb!c:halt))
151 ((or (not (boundp '*current-error-depth*))
152 (not (realp *current-error-depth*))
153 (not (boundp '*maximum-error-depth*))
154 (not (realp *maximum-error-depth*)))
155 (%primitive print "Argh! corrupted error depth, halting")
156 (%primitive sb!c:halt))
157 ((> *current-error-depth* *maximum-error-depth*)
158 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
159 (error-error "Help! "
160 *current-error-depth*
162 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
166 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
170 ;;;; miscellaneous external functions
172 (defun sleep (seconds)
174 "This function causes execution to be suspended for SECONDS. SECONDS may be
175 any non-negative real number."
176 (when (or (not (realp seconds))
178 (error 'simple-type-error
179 :format-control "invalid argument to SLEEP: ~S"
180 :format-arguments (list seconds)
182 :expected-type '(real 0)))
184 (multiple-value-bind (sec nsec)
185 (if (integerp seconds)
187 (multiple-value-bind (sec frac)
189 (values sec (truncate frac 1e-9))))
190 ;; nanosleep() accepts time_t as the first argument, but on some platforms
191 ;; it is restricted to 100 million seconds. Maybe someone can actually
192 ;; have a reason to sleep for over 3 years?
193 (loop while (> sec (expt 10 8))
194 do (decf sec (expt 10 8))
195 (sb!unix:nanosleep (expt 10 8) 0))
196 (sb!unix:nanosleep sec nsec))
198 (sb!win32:millisleep (truncate (* seconds 1000)))
201 ;;;; the default toplevel function
205 "a list of all the values returned by the most recent top level EVAL")
206 (defvar // nil #!+sb-doc "the previous value of /")
207 (defvar /// nil #!+sb-doc "the previous value of //")
208 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
209 (defvar ** nil #!+sb-doc "the previous value of *")
210 (defvar *** nil #!+sb-doc "the previous value of **")
211 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
212 (defvar ++ nil #!+sb-doc "the previous value of +")
213 (defvar +++ nil #!+sb-doc "the previous value of ++")
214 (defvar - nil #!+sb-doc "the form currently being evaluated")
216 (defun interactive-eval (form &key (eval #'eval))
218 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
219 +++, ++, +, ///, //, /, and -."
222 (let ((results (multiple-value-list (funcall eval form))))
233 ;; The bogon returned an unbound marker.
234 ;; FIXME: It would be safer to check every one of the values in RESULTS,
235 ;; instead of just the first one.
237 (cerror "Go on with * set to NIL."
238 "EVAL returned an unbound marker."))
241 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
242 ;;; output streams before proceeding.
243 (defun flush-standard-output-streams ()
244 (let ((null (make-broadcast-stream)))
245 (dolist (name '(*debug-io*
251 ;; 0. Pull out the underlying stream, so we know what it is.
252 ;; 1. Handle errors on it. We're doing this on entry to
253 ;; debugger, so we don't want recursive errors here.
254 ;; 2. Rebind the stream symbol in case some poor sod sees
255 ;; a broken stream here while running with *BREAK-ON-ERRORS*.
256 (let ((stream (stream-output-stream (symbol-value name))))
257 (progv (list name) (list null)
258 (handler-bind ((stream-error
260 (when (eq stream (stream-error-stream c))
262 (force-output stream))))
266 (defun stream-output-stream (stream)
271 (stream-output-stream
272 (symbol-value (synonym-stream-symbol stream))))
274 (stream-output-stream
275 (two-way-stream-output-stream stream)))
279 (defun process-init-file (specified-pathname kind)
280 (multiple-value-bind (context default-function)
283 (values "sysinit" *sysinit-pathname-function*))
285 (values "userinit" *userinit-pathname-function*)))
286 (if specified-pathname
287 (with-open-file (stream (parse-native-namestring specified-pathname)
288 :if-does-not-exist nil)
290 (load-as-source stream :context context)
291 (cerror "Ignore missing init file"
292 "The specified ~A file ~A was not found."
293 context specified-pathname)))
294 (let ((default (funcall default-function)))
296 (with-open-file (stream (pathname default) :if-does-not-exist nil)
298 (load-as-source stream :context context))))))))
300 (defun process-eval/load-options (options)
301 (/show0 "handling --eval and --load options")
302 (flet ((process-1 (cons)
303 (destructuring-bind (opt . value) cons
306 (with-simple-restart (continue "Ignore runtime option --eval ~S."
308 (multiple-value-bind (expr pos) (read-from-string value)
309 (if (eq value (read-from-string value nil value :start pos))
311 (error "Multiple expressions in --eval option: ~S"
314 (with-simple-restart (continue "Ignore runtime option --load ~S."
316 (load (native-pathname value))))
319 (flush-standard-output-streams)))
320 (with-simple-restart (abort "Skip rest of --eval and --load options.")
321 (dolist (option options)
322 (process-1 option)))))
324 (defun process-script (script)
325 (flet ((load-script (stream)
326 ;; Scripts don't need to be stylish or fast, but silence is usually a
327 ;; desirable quality...
328 (handler-bind (((or style-warning compiler-note) #'muffle-warning)
329 (stream-error (lambda (e)
331 (when (member (stream-error-stream e)
332 (list *stdout* *stdin* *stderr*))
334 ;; Let's not use the *TTY* for scripts, ok? Also, normally we use
335 ;; synonym streams, but in order to have the broken pipe/eof error
336 ;; handling right we want to bind them for scripts.
337 (let ((*terminal-io* (make-two-way-stream *stdin* *stdout*))
338 (*debug-io* (make-two-way-stream *stdin* *stderr*))
339 (*standard-input* *stdin*)
340 (*standard-output* *stdout*)
341 (*error-output* *stderr*))
342 (load stream :verbose nil :print nil)))))
343 (handling-end-of-the-world
345 (load-script *stdin*)
346 (with-open-file (f (native-pathname script) :element-type :default)
347 (sb!fasl::maybe-skip-shebang-line f)
350 ;; Errors while processing the command line cause the system to QUIT,
351 ;; instead of trying to go into the Lisp debugger, because trying to
352 ;; go into the Lisp debugger would get into various annoying issues of
353 ;; where we should go after the user tries to return from the
355 (defun startup-error (control-string &rest args)
356 (format *error-output*
357 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
360 (quit :unix-status 1))
362 ;;; the default system top level function
363 (defun toplevel-init ()
364 (/show0 "entering TOPLEVEL-INIT")
365 (let ( ;; value of --sysinit option
367 ;; t if --no-sysinit option given
369 ;; value of --userinit option
371 ;; t if --no-userinit option given
373 ;; t if --disable-debugger option given
374 (disable-debugger nil)
375 ;; list of (<kind> . <string>) conses representing --eval and --load
376 ;; options. options. --eval options are stored as strings, so that
377 ;; they can be passed to READ only after their predecessors have been
378 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL form
379 ;; creates a package referred to in the next EVAL form. Storing the
380 ;; original string also makes for easier debugging.
381 (reversed-options nil)
382 ;; Has a --noprint option been seen?
384 ;; Has a --script option been seen?
386 ;; Quit after processing other options?
388 ;; everything in *POSIX-ARGV* except for argv[0]=programname
389 (options (rest *posix-argv*)))
391 (declare (type list options))
393 (/show0 "done with outer LET in TOPLEVEL-INIT")
395 ;; FIXME: There are lots of ways for errors to happen around here
396 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
397 ;; READ an --eval string). Make sure that they're handled
400 ;; Process command line options.
401 (loop while options do
402 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
403 (let ((option (first options)))
404 (flet ((pop-option ()
408 "unexpected end of command line options"))))
409 (cond ((string= option "--script")
411 (setf disable-debugger t
414 script (if options (pop-option) t))
416 ((string= option "--sysinit")
419 (startup-error "multiple --sysinit options")
420 (setf sysinit (pop-option))))
421 ((string= option "--no-sysinit")
424 ((string= option "--userinit")
427 (startup-error "multiple --userinit options")
428 (setf userinit (pop-option))))
429 ((string= option "--no-userinit")
431 (setf no-userinit t))
432 ((string= option "--eval")
434 (push (cons :eval (pop-option)) reversed-options))
435 ((string= option "--load")
437 (push (cons :load (pop-option)) reversed-options))
438 ((string= option "--noprint")
441 ((string= option "--disable-debugger")
443 (setf disable-debugger t))
444 ((string= option "--quit")
446 (setf finally-quit t))
447 ((string= option "--non-interactive")
448 ;; This option is short for --quit and --disable-debugger,
449 ;; which are needed in combination for reliable non-
450 ;; interactive startup.
452 (setf finally-quit t)
453 (setf disable-debugger t))
454 ((string= option "--end-toplevel-options")
458 ;; Anything we don't recognize as a toplevel
459 ;; option must be the start of user-level
460 ;; options.. except that if we encounter
461 ;; "--end-toplevel-options" after we gave up
462 ;; because we didn't recognize an option as a
463 ;; toplevel option, then the option we gave up on
464 ;; must have been an error. (E.g. in
465 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
466 ;; this test will let us detect that the string
467 ;; "--eval(b)" is an error.)
468 (if (find "--end-toplevel-options" options
470 (startup-error "bad toplevel option: ~S"
473 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
475 ;; Delete all the options that we processed, so that only
476 ;; user-level options are left visible to user code.
477 (setf (rest *posix-argv*) options)
479 ;; Disable debugger before processing initialization files & co.
480 (when disable-debugger
481 (sb!ext:disable-debugger))
483 ;; Handle initialization files.
484 (/show0 "handling initialization files in TOPLEVEL-INIT")
485 ;; This CATCH is needed for the debugger command TOPLEVEL to
487 (catch 'toplevel-catcher
488 ;; We wrap all the pre-REPL user/system customized startup
489 ;; code in a restart.
491 ;; (Why not wrap everything, even the stuff above, in this
492 ;; restart? Errors above here are basically command line
493 ;; or Unix environment errors, e.g. a missing file or a
494 ;; typo on the Unix command line, and you don't need to
495 ;; get into Lisp to debug them, you should just start over
496 ;; and do it right at the Unix level. Errors below here
497 ;; are generally errors in user Lisp code, and it might be
498 ;; helpful to let the user reach the REPL in order to help
499 ;; figure out what's going on.)
503 (process-init-file sysinit :system))
505 (process-init-file userinit :user))
507 (push (list :quit) reversed-options))
508 (process-eval/load-options (nreverse reversed-options))
510 (process-script script)
511 (bug "PROCESS-SCRIPT returned")))
516 ;; In case script calls (enable-debugger)!
517 "Abort script, exiting lisp."
518 "Skip to toplevel READ/EVAL/PRINT loop.")
520 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
521 (values)) ; (no-op, just fall through)
523 :report "Quit SBCL (calling #'QUIT, killing the process)."
524 :test (lambda (c) (declare (ignore c)) (not script))
525 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
526 (quit :unix-status 1))))
528 ;; one more time for good measure, in case we fell out of the
529 ;; RESTART-CASE above before one of the flushes in the ordinary
530 ;; flow of control had a chance to operate
531 (flush-standard-output-streams)
533 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
534 (toplevel-repl noprint)
535 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
536 (critically-unreachable "after TOPLEVEL-REPL")))
538 ;;; hooks to support customized toplevels like ACL-style toplevel from
539 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
540 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
541 (defvar *repl-read-form-fun* #'repl-read-form-fun
543 "A function of two stream arguments IN and OUT for the toplevel REPL to
544 call: Return the next Lisp form to evaluate (possibly handling other magic --
545 like ACL-style keyword commands -- which precede the next Lisp form). The OUT
546 stream is there to support magic which requires issuing new prompts.")
547 (defvar *repl-prompt-fun* #'repl-prompt-fun
549 "A function of one argument STREAM for the toplevel REPL to call: Prompt
550 the user for input.")
551 (defvar *repl-fun-generator* (constantly #'repl-fun)
553 "A function of no arguments returning a function of one argument NOPRINT
554 that provides the REPL for the system. Assumes that *STANDARD-INPUT* and
555 *STANDARD-OUTPUT* are set up.")
557 ;;; read-eval-print loop for the default system toplevel
558 (defun toplevel-repl (noprint)
559 (/show0 "entering TOPLEVEL-REPL")
560 (let ((* nil) (** nil) (*** nil)
562 (+ nil) (++ nil) (+++ nil)
563 (/// nil) (// nil) (/ nil))
564 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
565 (let ((repl-fun (funcall *repl-fun-generator*)))
566 ;; Each REPL in a multithreaded world should have bindings of
567 ;; most CL specials (most critically *PACKAGE*).
568 (with-rebound-io-syntax
569 (handler-bind ((step-condition 'invoke-stepper))
571 (/show0 "about to set up restarts in TOPLEVEL-REPL")
572 ;; CLHS recommends that there should always be an
573 ;; ABORT restart; we have this one here, and one per
576 (abort "~@<Exit debugger, returning to top level.~@:>")
577 (catch 'toplevel-catcher
578 ;; In the event of a control-stack-exhausted-error, we
579 ;; should have unwound enough stack by the time we get
580 ;; here that this is now possible.
582 (sb!kernel::reset-control-stack-guard-page)
583 (funcall repl-fun noprint)
584 (critically-unreachable "after REPL")))))))))
586 ;;; Our default REPL prompt is the minimal traditional one.
587 (defun repl-prompt-fun (stream)
589 (write-string "* " stream)) ; arbitrary but customary REPL prompt
591 ;;; Our default form reader does relatively little magic, but does
592 ;;; handle the Unix-style EOF-is-end-of-process convention.
593 (defun repl-read-form-fun (in out)
594 (declare (type stream in out) (ignore out))
595 ;; KLUDGE: *READ-SUPPRESS* makes the REPL useless, and cannot be
596 ;; recovered from -- flip it here.
597 (when *read-suppress*
598 (warn "Setting *READ-SUPPRESS* to NIL to restore toplevel usability.")
599 (setf *read-suppress* nil))
600 (let* ((eof-marker (cons nil nil))
601 (form (read in nil eof-marker)))
602 (if (eq form eof-marker)
606 (defun repl-fun (noprint)
607 (/show0 "entering REPL")
611 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
612 (scrub-control-stack)
613 (sb!thread::get-foreground)
615 (flush-standard-output-streams)
616 (funcall *repl-prompt-fun* *standard-output*)
617 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
618 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
619 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
620 ;; odd. But maybe there *is* a valid reason in some
621 ;; circumstances? perhaps some deadlock issue when being driven
622 ;; by another process or something...)
623 (force-output *standard-output*))
624 (let* ((form (funcall *repl-read-form-fun*
627 (results (multiple-value-list (interactive-eval form))))
629 (dolist (result results)
632 ;; If we started stepping in the debugger we want to stop now.
633 (disable-stepping))))
635 ;;; a convenient way to get into the assembly-level debugger
637 (%primitive sb!c:halt))