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 pathname
60 designator for the default sysinit file, or NIL. If the function returns NIL,
61 no sysinit file is used unless one has been specified on the command-line.")
63 (defvar *userinit-pathname-function* #'userinit-pathname
65 "Designator for a function of zero arguments called to obtain a pathname
66 designator or a stream for the default userinit file, or NIL. If the function
67 returns NIL, no userinit file is used unless one has been specified on the
71 ;;;; miscellaneous utilities for working with with TOPLEVEL
73 ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g.
74 ;;; by QUIT) is caught and any final processing and return codes are
75 ;;; handled appropriately.
76 (defmacro handling-end-of-the-world (&body body)
77 (with-unique-names (caught)
80 (catch '%end-of-the-world
82 (with-local-interrupts ,@body (quit))
84 (with-local-interrupts
85 (call-hooks "exit" *exit-hooks* :on-error :warn))
88 ;; If user called QUIT and exit hooks were OK, the status is what it
89 ;; is -- even eg. streams cannot be flushed anymore. Even if
90 ;; something goes wrong now, we still report what was asked. We still
91 ;; want to have %END-OF-THE-WORLD visible, though.
92 (catch '%end-of-the-world
96 (flush-standard-output-streams)
97 (sb!thread::terminate-session))
98 (sb!unix:unix-exit ,caught))
99 (serious-condition ())))))))
101 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
103 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
105 (defmacro infinite-error-protect (&rest forms)
106 `(unless (infinite-error-protector)
107 (/show0 "back from INFINITE-ERROR-PROTECTOR")
108 (let ((*current-error-depth* (1+ *current-error-depth*)))
109 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
110 ;; arbitrary truncation
111 #!+sb-show (sb!debug:backtrace 8)
114 ;;; a helper function for INFINITE-ERROR-PROTECT
115 (defun infinite-error-protector ()
116 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
117 (/hexstr *current-error-depth*)
118 (cond ((not *cold-init-complete-p*)
119 (%primitive print "Argh! error in cold init, halting")
120 (%primitive sb!c:halt))
121 ((or (not (boundp '*current-error-depth*))
122 (not (realp *current-error-depth*))
123 (not (boundp '*maximum-error-depth*))
124 (not (realp *maximum-error-depth*)))
125 (%primitive print "Argh! corrupted error depth, halting")
126 (%primitive sb!c:halt))
127 ((> *current-error-depth* *maximum-error-depth*)
128 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
129 (/hexstr *maximum-error-depth*)
130 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
131 (error-error "Help! "
132 *current-error-depth*
134 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
137 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
140 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
141 ;;; one point (shown below), and SBCL cross-compiled it without
142 ;;; warning about FORMS being undefined. Check whether that problem
143 ;;; (missing warning) is repeatable in the final system and if so, fix
146 (defun infinite-error-protector ()
147 `(cond ((not *cold-init-complete-p*)
148 (%primitive print "Argh! error in cold init, halting")
149 (%primitive sb!c:halt))
150 ((or (not (boundp '*current-error-depth*))
151 (not (realp *current-error-depth*))
152 (not (boundp '*maximum-error-depth*))
153 (not (realp *maximum-error-depth*)))
154 (%primitive print "Argh! corrupted error depth, halting")
155 (%primitive sb!c:halt))
156 ((> *current-error-depth* *maximum-error-depth*)
157 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
158 (error-error "Help! "
159 *current-error-depth*
161 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
165 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
169 ;;;; miscellaneous external functions
171 (defun sleep (seconds)
173 "This function causes execution to be suspended for SECONDS. SECONDS may be
174 any non-negative real number."
175 (when (or (not (realp seconds))
177 (error 'simple-type-error
178 :format-control "invalid argument to SLEEP: ~S"
179 :format-arguments (list seconds)
181 :expected-type '(real 0)))
183 (multiple-value-bind (sec nsec)
184 (if (integerp seconds)
186 (multiple-value-bind (sec frac)
188 (values sec (truncate frac 1e-9))))
189 ;; nanosleep() accepts time_t as the first argument, but on some platforms
190 ;; it is restricted to 100 million seconds. Maybe someone can actually
191 ;; have a reason to sleep for over 3 years?
192 (loop while (> sec (expt 10 8))
193 do (decf sec (expt 10 8))
194 (sb!unix:nanosleep (expt 10 8) 0))
195 (sb!unix:nanosleep sec nsec))
197 (sb!win32:millisleep (truncate (* seconds 1000)))
200 ;;;; the default toplevel function
204 "a list of all the values returned by the most recent top level EVAL")
205 (defvar // nil #!+sb-doc "the previous value of /")
206 (defvar /// nil #!+sb-doc "the previous value of //")
207 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
208 (defvar ** nil #!+sb-doc "the previous value of *")
209 (defvar *** nil #!+sb-doc "the previous value of **")
210 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
211 (defvar ++ nil #!+sb-doc "the previous value of +")
212 (defvar +++ nil #!+sb-doc "the previous value of ++")
213 (defvar - nil #!+sb-doc "the form currently being evaluated")
215 (defun interactive-eval (form &key (eval #'eval))
217 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
218 +++, ++, +, ///, //, /, and -."
221 (let ((results (multiple-value-list (funcall eval form))))
232 ;; The bogon returned an unbound marker.
233 ;; FIXME: It would be safer to check every one of the values in RESULTS,
234 ;; instead of just the first one.
236 (cerror "Go on with * set to NIL."
237 "EVAL returned an unbound marker."))
240 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
241 ;;; output streams before proceeding.
242 (defun flush-standard-output-streams ()
243 (dolist (name '(*debug-io*
249 ;; FINISH-OUTPUT may block more easily than FORCE-OUTPUT
250 (force-output (symbol-value name)))
253 (defun process-init-file (specified-pathname kind)
254 (multiple-value-bind (context default-function)
257 (values "sysinit" *sysinit-pathname-function*))
259 (values "userinit" *userinit-pathname-function*)))
260 (if specified-pathname
261 (with-open-file (stream (parse-native-namestring specified-pathname)
262 :if-does-not-exist nil)
264 (load-as-source stream :context context)
265 (cerror "Ignore missing init file"
266 "The specified ~A file ~A was not found."
267 context specified-pathname)))
268 (let ((default (funcall default-function)))
270 (with-open-file (stream (pathname default) :if-does-not-exist nil)
272 (load-as-source stream :context context))))))))
274 (defun process-eval/load-options (options)
275 (/show0 "handling --eval and --load options")
276 (flet ((process-1 (cons)
277 (destructuring-bind (opt . value) cons
280 (with-simple-restart (continue "Ignore runtime option --eval ~S."
282 (multiple-value-bind (expr pos) (read-from-string value)
283 (if (eq value (read-from-string value nil value :start pos))
285 (error "Multiple expressions in --eval option: ~S"
288 (with-simple-restart (continue "Ignore runtime option --load ~S."
290 (load (native-pathname value))))))
291 (flush-standard-output-streams)))
292 (with-simple-restart (abort "Skip rest of --eval and --load options.")
293 (dolist (option options)
294 (process-1 option)))))
296 (defun process-script (script)
297 (flet ((load-script (stream)
298 ;; Scripts don't need to be stylish or fast, but silence is usually a
299 ;; desirable quality...
300 (handler-bind (((or style-warning compiler-note) #'muffle-warning)
301 (stream-error (lambda (e)
303 (when (member (stream-error-stream e)
304 (list *stdout* *stdin* *stderr*))
306 ;; Let's not use the *TTY* for scripts, ok? Also, normally we use
307 ;; synonym streams, but in order to have the broken pipe/eof error
308 ;; handling right we want to bind them for scripts.
309 (let ((*terminal-io* (make-two-way-stream *stdin* *stdout*))
310 (*debug-io* (make-two-way-stream *stdin* *stderr*))
311 (*standard-input* *stdin*)
312 (*standard-output* *stdout*)
313 (*error-output* *stderr*))
314 (load stream :verbose nil :print nil)))))
315 (handling-end-of-the-world
317 (load-script *stdin*)
318 (with-open-file (f (native-pathname script) :element-type :default)
319 (sb!fasl::maybe-skip-shebang-line f)
322 ;; Errors while processing the command line cause the system to QUIT,
323 ;; instead of trying to go into the Lisp debugger, because trying to
324 ;; go into the Lisp debugger would get into various annoying issues of
325 ;; where we should go after the user tries to return from the
327 (defun startup-error (control-string &rest args)
328 (format *error-output*
329 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
332 (quit :unix-status 1))
334 ;;; the default system top level function
335 (defun toplevel-init ()
336 (/show0 "entering TOPLEVEL-INIT")
337 (let ( ;; value of --sysinit option
339 ;; t if --no-sysinit option given
341 ;; value of --userinit option
343 ;; t if --no-userinit option given
345 ;; t if --disable-debugger option given
346 (disable-debugger nil)
347 ;; list of (<kind> . <string>) conses representing --eval and --load
348 ;; options. options. --eval options are stored as strings, so that
349 ;; they can be passed to READ only after their predecessors have been
350 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL form
351 ;; creates a package referred to in the next EVAL form. Storing the
352 ;; original string also makes for easier debugging.
353 (reversed-options nil)
354 ;; Has a --noprint option been seen?
356 ;; Has a --script option been seen?
358 ;; everything in *POSIX-ARGV* except for argv[0]=programname
359 (options (rest *posix-argv*)))
361 (declare (type list options))
363 (/show0 "done with outer LET in TOPLEVEL-INIT")
365 ;; FIXME: There are lots of ways for errors to happen around here
366 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
367 ;; READ an --eval string). Make sure that they're handled
370 ;; Process command line options.
371 (loop while options do
372 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
373 (let ((option (first options)))
374 (flet ((pop-option ()
378 "unexpected end of command line options"))))
379 (cond ((string= option "--script")
381 (setf disable-debugger t
384 script (if options (pop-option) t))
386 ((string= option "--sysinit")
389 (startup-error "multiple --sysinit options")
390 (setf sysinit (pop-option))))
391 ((string= option "--no-sysinit")
394 ((string= option "--userinit")
397 (startup-error "multiple --userinit options")
398 (setf userinit (pop-option))))
399 ((string= option "--no-userinit")
401 (setf no-userinit t))
402 ((string= option "--eval")
404 (push (cons :eval (pop-option)) reversed-options))
405 ((string= option "--load")
407 (push (cons :load (pop-option)) reversed-options))
408 ((string= option "--noprint")
411 ((string= option "--disable-debugger")
413 (setf disable-debugger t))
414 ((string= option "--end-toplevel-options")
418 ;; Anything we don't recognize as a toplevel
419 ;; option must be the start of user-level
420 ;; options.. except that if we encounter
421 ;; "--end-toplevel-options" after we gave up
422 ;; because we didn't recognize an option as a
423 ;; toplevel option, then the option we gave up on
424 ;; must have been an error. (E.g. in
425 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
426 ;; this test will let us detect that the string
427 ;; "--eval(b)" is an error.)
428 (if (find "--end-toplevel-options" options
430 (startup-error "bad toplevel option: ~S"
433 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
435 ;; Delete all the options that we processed, so that only
436 ;; user-level options are left visible to user code.
437 (setf (rest *posix-argv*) options)
439 ;; Disable debugger before processing initialization files & co.
440 (when disable-debugger
441 (sb!ext:disable-debugger))
443 ;; Handle initialization files.
444 (/show0 "handling initialization files in TOPLEVEL-INIT")
445 ;; This CATCH is needed for the debugger command TOPLEVEL to
447 (catch 'toplevel-catcher
448 ;; We wrap all the pre-REPL user/system customized startup
449 ;; code in a restart.
451 ;; (Why not wrap everything, even the stuff above, in this
452 ;; restart? Errors above here are basically command line
453 ;; or Unix environment errors, e.g. a missing file or a
454 ;; typo on the Unix command line, and you don't need to
455 ;; get into Lisp to debug them, you should just start over
456 ;; and do it right at the Unix level. Errors below here
457 ;; are generally errors in user Lisp code, and it might be
458 ;; helpful to let the user reach the REPL in order to help
459 ;; figure out what's going on.)
463 (process-init-file sysinit :system))
465 (process-init-file userinit :user))
466 (process-eval/load-options (nreverse reversed-options))
468 (process-script script)
469 (bug "PROCESS-SCRIPT returned")))
474 ;; In case script calls (enable-debugger)!
475 "Abort script, exiting lisp."
476 "Skip to toplevel READ/EVAL/PRINT loop.")
478 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
479 (values)) ; (no-op, just fall through)
481 :report "Quit SBCL (calling #'QUIT, killing the process)."
482 :test (lambda (c) (declare (ignore c)) (not script))
483 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
484 (quit :unix-status 1))))
486 ;; one more time for good measure, in case we fell out of the
487 ;; RESTART-CASE above before one of the flushes in the ordinary
488 ;; flow of control had a chance to operate
489 (flush-standard-output-streams)
491 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
492 (toplevel-repl noprint)
493 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
494 (critically-unreachable "after TOPLEVEL-REPL")))
496 ;;; hooks to support customized toplevels like ACL-style toplevel from
497 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
498 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
499 (defvar *repl-read-form-fun* #'repl-read-form-fun
501 "A function of two stream arguments IN and OUT for the toplevel REPL to
502 call: Return the next Lisp form to evaluate (possibly handling other magic --
503 like ACL-style keyword commands -- which precede the next Lisp form). The OUT
504 stream is there to support magic which requires issuing new prompts.")
505 (defvar *repl-prompt-fun* #'repl-prompt-fun
507 "A function of one argument STREAM for the toplevel REPL to call: Prompt
508 the user for input.")
509 (defvar *repl-fun-generator* (constantly #'repl-fun)
511 "A function of no arguments returning a function of one argument NOPRINT
512 that provides the REPL for the system. Assumes that *STANDARD-INPUT* and
513 *STANDARD-OUTPUT* are set up.")
515 ;;; read-eval-print loop for the default system toplevel
516 (defun toplevel-repl (noprint)
517 (/show0 "entering TOPLEVEL-REPL")
518 (let ((* nil) (** nil) (*** nil)
520 (+ nil) (++ nil) (+++ nil)
521 (/// nil) (// nil) (/ nil))
522 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
523 (let ((repl-fun (funcall *repl-fun-generator*)))
524 ;; Each REPL in a multithreaded world should have bindings of
525 ;; most CL specials (most critically *PACKAGE*).
526 (with-rebound-io-syntax
527 (handler-bind ((step-condition 'invoke-stepper))
529 (/show0 "about to set up restarts in TOPLEVEL-REPL")
530 ;; CLHS recommends that there should always be an
531 ;; ABORT restart; we have this one here, and one per
534 (abort "~@<Exit debugger, returning to top level.~@:>")
535 (catch 'toplevel-catcher
536 ;; In the event of a control-stack-exhausted-error, we
537 ;; should have unwound enough stack by the time we get
538 ;; here that this is now possible.
540 (sb!kernel::reset-control-stack-guard-page)
541 (funcall repl-fun noprint)
542 (critically-unreachable "after REPL")))))))))
544 ;;; Our default REPL prompt is the minimal traditional one.
545 (defun repl-prompt-fun (stream)
547 (write-string "* " stream)) ; arbitrary but customary REPL prompt
549 ;;; Our default form reader does relatively little magic, but does
550 ;;; handle the Unix-style EOF-is-end-of-process convention.
551 (defun repl-read-form-fun (in out)
552 (declare (type stream in out) (ignore out))
553 ;; KLUDGE: *READ-SUPPRESS* makes the REPL useless, and cannot be
554 ;; recovered from -- flip it here.
555 (when *read-suppress*
556 (warn "Setting *READ-SUPPRESS* to NIL to restore toplevel usability.")
557 (setf *read-suppress* nil))
558 (let* ((eof-marker (cons nil nil))
559 (form (read in nil eof-marker)))
560 (if (eq form eof-marker)
564 (defun repl-fun (noprint)
565 (/show0 "entering REPL")
569 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
570 (scrub-control-stack)
571 (sb!thread::get-foreground)
573 (flush-standard-output-streams)
574 (funcall *repl-prompt-fun* *standard-output*)
575 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
576 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
577 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
578 ;; odd. But maybe there *is* a valid reason in some
579 ;; circumstances? perhaps some deadlock issue when being driven
580 ;; by another process or something...)
581 (force-output *standard-output*))
582 (let* ((form (funcall *repl-read-form-fun*
585 (results (multiple-value-list (interactive-eval form))))
587 (dolist (result results)
590 ;; If we started stepping in the debugger we want to stop now.
591 (disable-stepping))))
593 ;;; a convenient way to get into the assembly-level debugger
595 (%primitive sb!c:halt))