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)
78 `(let ((,caught (catch '%end-of-the-world
79 (/show0 "inside CATCH '%END-OF-THE-WORLD")
82 (call-hooks "exit" *exit-hooks*)))))
83 (/show0 "back from CATCH '%END-OF-THE-WORLD, flushing output")
84 (flush-standard-output-streams)
85 (sb!thread::terminate-session)
86 (/show0 "calling UNIX-EXIT")
87 (sb!unix:unix-exit ,caught))))
89 ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH*
91 ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out
93 (defmacro infinite-error-protect (&rest forms)
94 `(unless (infinite-error-protector)
95 (/show0 "back from INFINITE-ERROR-PROTECTOR")
96 (let ((*current-error-depth* (1+ *current-error-depth*)))
97 (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth")
98 ;; arbitrary truncation
99 #!+sb-show (sb!debug:backtrace 8)
102 ;;; a helper function for INFINITE-ERROR-PROTECT
103 (defun infinite-error-protector ()
104 (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..")
105 (/hexstr *current-error-depth*)
106 (cond ((not *cold-init-complete-p*)
107 (%primitive print "Argh! error in cold init, halting")
108 (%primitive sb!c:halt))
109 ((or (not (boundp '*current-error-depth*))
110 (not (realp *current-error-depth*))
111 (not (boundp '*maximum-error-depth*))
112 (not (realp *maximum-error-depth*)))
113 (%primitive print "Argh! corrupted error depth, halting")
114 (%primitive sb!c:halt))
115 ((> *current-error-depth* *maximum-error-depth*)
116 (/show0 "*MAXIMUM-ERROR-DEPTH*=..")
117 (/hexstr *maximum-error-depth*)
118 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
119 (error-error "Help! "
120 *current-error-depth*
122 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
125 (/show0 "returning normally from INFINITE-ERROR-PROTECTOR")
128 ;;; FIXME: I had a badly broken version of INFINITE-ERROR-PROTECTOR at
129 ;;; one point (shown below), and SBCL cross-compiled it without
130 ;;; warning about FORMS being undefined. Check whether that problem
131 ;;; (missing warning) is repeatable in the final system and if so, fix
134 (defun infinite-error-protector ()
135 `(cond ((not *cold-init-complete-p*)
136 (%primitive print "Argh! error in cold init, halting")
137 (%primitive sb!c:halt))
138 ((or (not (boundp '*current-error-depth*))
139 (not (realp *current-error-depth*))
140 (not (boundp '*maximum-error-depth*))
141 (not (realp *maximum-error-depth*)))
142 (%primitive print "Argh! corrupted error depth, halting")
143 (%primitive sb!c:halt))
144 ((> *current-error-depth* *maximum-error-depth*)
145 (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR")
146 (error-error "Help! "
147 *current-error-depth*
149 "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.")
153 (/show0 "in INFINITE-ERROR-PROTECTOR, returning normally")
157 ;;;; miscellaneous external functions
159 (defun sleep (seconds)
161 "This function causes execution to be suspended for SECONDS. SECONDS may be
162 any non-negative real number."
163 (when (or (not (realp seconds))
165 (error 'simple-type-error
166 :format-control "invalid argument to SLEEP: ~S"
167 :format-arguments (list seconds)
169 :expected-type '(real 0)))
171 (multiple-value-bind (sec nsec)
172 (if (integerp seconds)
174 (multiple-value-bind (sec frac)
176 (values sec (truncate frac 1e-9))))
177 ;; nanosleep() accepts time_t as the first argument, but on some platforms
178 ;; it is restricted to 100 million seconds. Maybe someone can actually
179 ;; have a reason to sleep for over 3 years?
180 (loop while (> sec (expt 10 8))
181 do (decf sec (expt 10 8))
182 (sb!unix:nanosleep (expt 10 8) 0))
183 (sb!unix:nanosleep sec nsec))
185 (sb!win32:millisleep (truncate (* seconds 1000)))
188 ;;;; the default toplevel function
192 "a list of all the values returned by the most recent top level EVAL")
193 (defvar // nil #!+sb-doc "the previous value of /")
194 (defvar /// nil #!+sb-doc "the previous value of //")
195 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
196 (defvar ** nil #!+sb-doc "the previous value of *")
197 (defvar *** nil #!+sb-doc "the previous value of **")
198 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
199 (defvar ++ nil #!+sb-doc "the previous value of +")
200 (defvar +++ nil #!+sb-doc "the previous value of ++")
201 (defvar - nil #!+sb-doc "the form currently being evaluated")
203 (defun interactive-eval (form &key (eval #'eval))
205 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
206 +++, ++, +, ///, //, /, and -."
209 (let ((results (multiple-value-list (funcall eval form))))
220 ;; The bogon returned an unbound marker.
221 ;; FIXME: It would be safer to check every one of the values in RESULTS,
222 ;; instead of just the first one.
224 (cerror "Go on with * set to NIL."
225 "EVAL returned an unbound marker."))
228 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
229 ;;; output streams before proceeding.
230 (defun flush-standard-output-streams ()
231 (dolist (name '(*debug-io*
237 ;; FINISH-OUTPUT may block more easily than FORCE-OUTPUT
238 (force-output (symbol-value name)))
241 (defun process-init-file (specified-pathname kind)
242 (multiple-value-bind (context default-function)
245 (values "sysinit" *sysinit-pathname-function*))
247 (values "userinit" *userinit-pathname-function*)))
248 (flet ((process-stream (stream pathname)
249 (with-simple-restart (abort "Skip rest of ~A file ~S."
250 context (native-namestring pathname))
253 (continue "Ignore error and continue processing ~A file ~S."
254 context (native-namestring pathname))
255 (let ((form (read stream nil stream)))
257 (return-from process-init-file nil)
259 (if specified-pathname
260 (with-open-file (stream (parse-native-namestring specified-pathname)
261 :if-does-not-exist nil)
263 (process-stream stream (pathname stream))
264 (cerror "Ignore missing init file"
265 "The specified ~A file ~A was not found."
266 context specified-pathname)))
267 (let ((default (funcall default-function)))
269 (with-open-file (stream (pathname default) :if-does-not-exist nil)
271 (process-stream stream (pathname stream))))))))))
273 (defun process-eval/load-options (options)
274 (/show0 "handling --eval and --load options")
275 (flet ((process-1 (cons)
276 (destructuring-bind (opt . value) cons
279 (with-simple-restart (continue "Ignore runtime option --eval ~S."
281 (multiple-value-bind (expr pos) (read-from-string value)
282 (if (eq value (read-from-string value nil value :start pos))
284 (error "Multiple expressions in --eval option: ~S"
287 (with-simple-restart (continue "Ignore runtime option --load ~S."
289 (load (native-pathname value))))))
290 (flush-standard-output-streams)))
291 (with-simple-restart (abort "Skip rest of --eval and --load options.")
292 (dolist (option options)
293 (process-1 option)))))
295 (defun process-script (script)
296 (let ((pathname (native-pathname script)))
297 (handling-end-of-the-world
298 (with-open-file (f pathname :element-type :default)
299 (sb!fasl::maybe-skip-shebang-line f)
300 ;; Scripts don't need to be stylish or fast, but silence is usually a
301 ;; desirable quality...
302 (handler-bind (((or style-warning compiler-note) #'muffle-warning))
303 (load f :verbose nil :print nil))
306 ;; Errors while processing the command line cause the system to QUIT,
307 ;; instead of trying to go into the Lisp debugger, because trying to
308 ;; go into the Lisp debugger would get into various annoying issues of
309 ;; where we should go after the user tries to return from the
311 (defun startup-error (control-string &rest args)
312 (format *error-output*
313 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
316 (quit :unix-status 1))
318 ;;; the default system top level function
319 (defun toplevel-init ()
320 (/show0 "entering TOPLEVEL-INIT")
321 (let ( ;; value of --sysinit option
323 ;; t if --no-sysinit option given
325 ;; value of --userinit option
327 ;; t if --no-userinit option given
329 ;; t if --disable-debugger option given
330 (disable-debugger nil)
331 ;; list of (<kind> . <string>) conses representing --eval and --load
332 ;; options. options. --eval options are stored as strings, so that
333 ;; they can be passed to READ only after their predecessors have been
334 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL form
335 ;; creates a package referred to in the next EVAL form. Storing the
336 ;; original string also makes for easier debugging.
337 (reversed-options nil)
338 ;; Has a --noprint option been seen?
340 ;; Has a --script option been seen?
342 ;; everything in *POSIX-ARGV* except for argv[0]=programname
343 (options (rest *posix-argv*)))
345 (declare (type list options))
347 (/show0 "done with outer LET in TOPLEVEL-INIT")
349 ;; FIXME: There are lots of ways for errors to happen around here
350 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
351 ;; READ an --eval string). Make sure that they're handled
354 ;; Process command line options.
355 (loop while options do
356 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
357 (let ((option (first options)))
358 (flet ((pop-option ()
362 "unexpected end of command line options"))))
363 (cond ((string= option "--script")
365 (setf disable-debugger t
370 ((string= option "--sysinit")
373 (startup-error "multiple --sysinit options")
374 (setf sysinit (pop-option))))
375 ((string= option "--no-sysinit")
378 ((string= option "--userinit")
381 (startup-error "multiple --userinit options")
382 (setf userinit (pop-option))))
383 ((string= option "--no-userinit")
385 (setf no-userinit t))
386 ((string= option "--eval")
388 (push (cons :eval (pop-option)) reversed-options))
389 ((string= option "--load")
391 (push (cons :load (pop-option)) reversed-options))
392 ((string= option "--noprint")
395 ((string= option "--disable-debugger")
397 (setf disable-debugger t))
398 ((string= option "--end-toplevel-options")
402 ;; Anything we don't recognize as a toplevel
403 ;; option must be the start of user-level
404 ;; options.. except that if we encounter
405 ;; "--end-toplevel-options" after we gave up
406 ;; because we didn't recognize an option as a
407 ;; toplevel option, then the option we gave up on
408 ;; must have been an error. (E.g. in
409 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
410 ;; this test will let us detect that the string
411 ;; "--eval(b)" is an error.)
412 (if (find "--end-toplevel-options" options
414 (startup-error "bad toplevel option: ~S"
417 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
419 ;; Delete all the options that we processed, so that only
420 ;; user-level options are left visible to user code.
421 (setf (rest *posix-argv*) options)
423 ;; Disable debugger before processing initialization files & co.
424 (when disable-debugger
425 (sb!ext:disable-debugger))
427 ;; Handle initialization files.
428 (/show0 "handling initialization files in TOPLEVEL-INIT")
429 ;; This CATCH is needed for the debugger command TOPLEVEL to
431 (catch 'toplevel-catcher
432 ;; We wrap all the pre-REPL user/system customized startup
433 ;; code in a restart.
435 ;; (Why not wrap everything, even the stuff above, in this
436 ;; restart? Errors above here are basically command line
437 ;; or Unix environment errors, e.g. a missing file or a
438 ;; typo on the Unix command line, and you don't need to
439 ;; get into Lisp to debug them, you should just start over
440 ;; and do it right at the Unix level. Errors below here
441 ;; are generally errors in user Lisp code, and it might be
442 ;; helpful to let the user reach the REPL in order to help
443 ;; figure out what's going on.)
447 (process-init-file sysinit :system))
449 (process-init-file userinit :user))
450 (process-eval/load-options (nreverse reversed-options))
452 (process-script script)
453 (bug "PROCESS-SCRIPT returned")))
458 ;; In case script calls (enable-debugger)!
459 "Abort script, exiting lisp."
460 "Skip to toplevel READ/EVAL/PRINT loop.")
462 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
463 (values)) ; (no-op, just fall through)
465 :report "Quit SBCL (calling #'QUIT, killing the process)."
466 :test (lambda (c) (declare (ignore c)) (not script))
467 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
468 (quit :unix-status 1))))
470 ;; one more time for good measure, in case we fell out of the
471 ;; RESTART-CASE above before one of the flushes in the ordinary
472 ;; flow of control had a chance to operate
473 (flush-standard-output-streams)
475 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
476 (toplevel-repl noprint)
477 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
478 (critically-unreachable "after TOPLEVEL-REPL")))
480 ;;; hooks to support customized toplevels like ACL-style toplevel from
481 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
482 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
483 (defvar *repl-read-form-fun* #'repl-read-form-fun
485 "A function of two stream arguments IN and OUT for the toplevel REPL to
486 call: Return the next Lisp form to evaluate (possibly handling other magic --
487 like ACL-style keyword commands -- which precede the next Lisp form). The OUT
488 stream is there to support magic which requires issuing new prompts.")
489 (defvar *repl-prompt-fun* #'repl-prompt-fun
491 "A function of one argument STREAM for the toplevel REPL to call: Prompt
492 the user for input.")
493 (defvar *repl-fun-generator* (constantly #'repl-fun)
495 "A function of no arguments returning a function of one argument NOPRINT
496 that provides the REPL for the system. Assumes that *STANDARD-INPUT* and
497 *STANDARD-OUTPUT* are set up.")
499 ;;; read-eval-print loop for the default system toplevel
500 (defun toplevel-repl (noprint)
501 (/show0 "entering TOPLEVEL-REPL")
502 (let ((* nil) (** nil) (*** nil)
504 (+ nil) (++ nil) (+++ nil)
505 (/// nil) (// nil) (/ nil))
506 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
507 (let ((repl-fun (funcall *repl-fun-generator*)))
508 ;; Each REPL in a multithreaded world should have bindings of
509 ;; most CL specials (most critically *PACKAGE*).
510 (with-rebound-io-syntax
511 (handler-bind ((step-condition 'invoke-stepper))
513 (/show0 "about to set up restarts in TOPLEVEL-REPL")
514 ;; CLHS recommends that there should always be an
515 ;; ABORT restart; we have this one here, and one per
518 (abort "~@<Exit debugger, returning to top level.~@:>")
519 (catch 'toplevel-catcher
520 ;; In the event of a control-stack-exhausted-error, we
521 ;; should have unwound enough stack by the time we get
522 ;; here that this is now possible.
524 (sb!kernel::reset-control-stack-guard-page)
525 (funcall repl-fun noprint)
526 (critically-unreachable "after REPL")))))))))
528 ;;; Our default REPL prompt is the minimal traditional one.
529 (defun repl-prompt-fun (stream)
531 (write-string "* " stream)) ; arbitrary but customary REPL prompt
533 ;;; Our default form reader does relatively little magic, but does
534 ;;; handle the Unix-style EOF-is-end-of-process convention.
535 (defun repl-read-form-fun (in out)
536 (declare (type stream in out) (ignore out))
537 ;; KLUDGE: *READ-SUPPRESS* makes the REPL useless, and cannot be
538 ;; recovered from -- flip it here.
539 (when *read-suppress*
540 (warn "Setting *READ-SUPPRESS* to NIL to restore toplevel usability.")
541 (setf *read-suppress* nil))
542 (let* ((eof-marker (cons nil nil))
543 (form (read in nil eof-marker)))
544 (if (eq form eof-marker)
548 (defun repl-fun (noprint)
549 (/show0 "entering REPL")
553 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
554 (scrub-control-stack)
555 (sb!thread::get-foreground)
557 (flush-standard-output-streams)
558 (funcall *repl-prompt-fun* *standard-output*)
559 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
560 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
561 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
562 ;; odd. But maybe there *is* a valid reason in some
563 ;; circumstances? perhaps some deadlock issue when being driven
564 ;; by another process or something...)
565 (force-output *standard-output*))
566 (let* ((form (funcall *repl-read-form-fun*
569 (results (multiple-value-list (interactive-eval form))))
571 (dolist (result results)
574 ;; If we started stepping in the debugger we want to stop now.
575 (disable-stepping))))
577 ;;; a convenient way to get into the assembly-level debugger
579 (%primitive sb!c:halt))