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,
178 ;; so truncating is needed. 68 years on 32-bit platform should be enough
179 (sb!unix:nanosleep (min sec (1- (ash 1 (1- sb!vm:n-word-bits)))) nsec))
181 (sb!win32:millisleep (truncate (* seconds 1000)))
184 ;;;; the default toplevel function
188 "a list of all the values returned by the most recent top level EVAL")
189 (defvar // nil #!+sb-doc "the previous value of /")
190 (defvar /// nil #!+sb-doc "the previous value of //")
191 (defvar * nil #!+sb-doc "the value of the most recent top level EVAL")
192 (defvar ** nil #!+sb-doc "the previous value of *")
193 (defvar *** nil #!+sb-doc "the previous value of **")
194 (defvar + nil #!+sb-doc "the value of the most recent top level READ")
195 (defvar ++ nil #!+sb-doc "the previous value of +")
196 (defvar +++ nil #!+sb-doc "the previous value of ++")
197 (defvar - nil #!+sb-doc "the form currently being evaluated")
199 (defun interactive-eval (form &key (eval #'eval))
201 "Evaluate FORM, returning whatever it returns and adjusting ***, **, *,
202 +++, ++, +, ///, //, /, and -."
205 (let ((results (multiple-value-list (funcall eval form))))
216 ;; The bogon returned an unbound marker.
217 ;; FIXME: It would be safer to check every one of the values in RESULTS,
218 ;; instead of just the first one.
220 (cerror "Go on with * set to NIL."
221 "EVAL returned an unbound marker."))
224 ;;; Flush anything waiting on one of the ANSI Common Lisp standard
225 ;;; output streams before proceeding.
226 (defun flush-standard-output-streams ()
227 (dolist (name '(*debug-io*
233 ;; FINISH-OUTPUT may block more easily than FORCE-OUTPUT
234 (force-output (symbol-value name)))
237 (defun process-init-file (specified-pathname kind)
238 (multiple-value-bind (context default-function)
241 (values "sysinit" *sysinit-pathname-function*))
243 (values "userinit" *userinit-pathname-function*)))
244 (flet ((process-stream (stream pathname)
245 (with-simple-restart (abort "Skip rest of ~A file ~S."
246 context (native-namestring pathname))
249 (continue "Ignore error and continue processing ~A file ~S."
250 context (native-namestring pathname))
251 (let ((form (read stream nil stream)))
253 (return-from process-init-file nil)
255 (if specified-pathname
256 (with-open-file (stream (parse-native-namestring specified-pathname)
257 :if-does-not-exist nil)
259 (process-stream stream (pathname stream))
260 (cerror "Ignore missing init file"
261 "The specified ~A file ~A was not found."
262 context specified-pathname)))
263 (let ((default (funcall default-function)))
265 (with-open-file (stream (pathname default) :if-does-not-exist nil)
267 (process-stream stream (pathname stream))))))))))
269 (defun process-eval/load-options (options)
270 (/show0 "handling --eval and --load options")
271 (flet ((process-1 (cons)
272 (destructuring-bind (opt . value) cons
275 (with-simple-restart (continue "Ignore runtime option --eval ~S."
277 (multiple-value-bind (expr pos) (read-from-string value)
278 (if (eq value (read-from-string value nil value :start pos))
280 (error "Multiple expressions in --eval option: ~S"
283 (with-simple-restart (continue "Ignore runtime option --load ~S."
285 (load (native-pathname value))))))
286 (flush-standard-output-streams)))
287 (with-simple-restart (abort "Skip rest of --eval and --load options.")
288 (dolist (option options)
289 (process-1 option)))))
291 (defun process-script (script)
292 (let ((pathname (native-pathname script)))
293 (handling-end-of-the-world
294 (with-open-file (f pathname :element-type :default)
295 (sb!fasl::maybe-skip-shebang-line f)
296 (load f :verbose nil :print nil)
299 ;; Errors while processing the command line cause the system to QUIT,
300 ;; instead of trying to go into the Lisp debugger, because trying to
301 ;; go into the Lisp debugger would get into various annoying issues of
302 ;; where we should go after the user tries to return from the
304 (defun startup-error (control-string &rest args)
305 (format *error-output*
306 "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%"
309 (quit :unix-status 1))
311 ;;; the default system top level function
312 (defun toplevel-init ()
313 (/show0 "entering TOPLEVEL-INIT")
314 (let ( ;; value of --sysinit option
316 ;; t if --no-sysinit option given
318 ;; value of --userinit option
320 ;; t if --no-userinit option given
322 ;; t if --disable-debugger option given
323 (disable-debugger nil)
324 ;; list of (<kind> . <string>) conses representing --eval and --load
325 ;; options. options. --eval options are stored as strings, so that
326 ;; they can be passed to READ only after their predecessors have been
327 ;; EVALed, so that things work when e.g. REQUIRE in one EVAL form
328 ;; creates a package referred to in the next EVAL form. Storing the
329 ;; original string also makes for easier debugging.
330 (reversed-options nil)
331 ;; Has a --noprint option been seen?
333 ;; Has a --script option been seen?
335 ;; everything in *POSIX-ARGV* except for argv[0]=programname
336 (options (rest *posix-argv*)))
338 (declare (type list options))
340 (/show0 "done with outer LET in TOPLEVEL-INIT")
342 ;; FIXME: There are lots of ways for errors to happen around here
343 ;; (e.g. bad command line syntax, or READ-ERROR while trying to
344 ;; READ an --eval string). Make sure that they're handled
347 ;; Process command line options.
348 (loop while options do
349 (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
350 (let ((option (first options)))
351 (flet ((pop-option ()
355 "unexpected end of command line options"))))
356 (cond ((string= option "--script")
358 (setf disable-debugger t
363 ((string= option "--sysinit")
366 (startup-error "multiple --sysinit options")
367 (setf sysinit (pop-option))))
368 ((string= option "--no-sysinit")
371 ((string= option "--userinit")
374 (startup-error "multiple --userinit options")
375 (setf userinit (pop-option))))
376 ((string= option "--no-userinit")
378 (setf no-userinit t))
379 ((string= option "--eval")
381 (push (cons :eval (pop-option)) reversed-options))
382 ((string= option "--load")
384 (push (cons :load (pop-option)) reversed-options))
385 ((string= option "--noprint")
388 ((string= option "--disable-debugger")
390 (setf disable-debugger t))
391 ((string= option "--end-toplevel-options")
395 ;; Anything we don't recognize as a toplevel
396 ;; option must be the start of user-level
397 ;; options.. except that if we encounter
398 ;; "--end-toplevel-options" after we gave up
399 ;; because we didn't recognize an option as a
400 ;; toplevel option, then the option we gave up on
401 ;; must have been an error. (E.g. in
402 ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options"
403 ;; this test will let us detect that the string
404 ;; "--eval(b)" is an error.)
405 (if (find "--end-toplevel-options" options
407 (startup-error "bad toplevel option: ~S"
410 (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT")
412 ;; Delete all the options that we processed, so that only
413 ;; user-level options are left visible to user code.
414 (setf (rest *posix-argv*) options)
416 ;; Disable debugger before processing initialization files & co.
417 (when disable-debugger
418 (sb!ext:disable-debugger))
420 ;; Handle initialization files.
421 (/show0 "handling initialization files in TOPLEVEL-INIT")
422 ;; This CATCH is needed for the debugger command TOPLEVEL to
424 (catch 'toplevel-catcher
425 ;; We wrap all the pre-REPL user/system customized startup
426 ;; code in a restart.
428 ;; (Why not wrap everything, even the stuff above, in this
429 ;; restart? Errors above here are basically command line
430 ;; or Unix environment errors, e.g. a missing file or a
431 ;; typo on the Unix command line, and you don't need to
432 ;; get into Lisp to debug them, you should just start over
433 ;; and do it right at the Unix level. Errors below here
434 ;; are generally errors in user Lisp code, and it might be
435 ;; helpful to let the user reach the REPL in order to help
436 ;; figure out what's going on.)
440 (process-init-file sysinit :system))
442 (process-init-file userinit :user))
443 (process-eval/load-options (nreverse reversed-options))
445 (process-script script)
446 (bug "PROCESS-SCRIPT returned")))
451 ;; In case script calls (enable-debugger)!
452 "Abort script, exiting lisp."
453 "Skip to toplevel READ/EVAL/PRINT loop.")
455 (/show0 "CONTINUEing from pre-REPL RESTART-CASE")
456 (values)) ; (no-op, just fall through)
458 :report "Quit SBCL (calling #'QUIT, killing the process)."
459 :test (lambda (c) (declare (ignore c)) (not script))
460 (/show0 "falling through to QUIT from pre-REPL RESTART-CASE")
461 (quit :unix-status 1))))
463 ;; one more time for good measure, in case we fell out of the
464 ;; RESTART-CASE above before one of the flushes in the ordinary
465 ;; flow of control had a chance to operate
466 (flush-standard-output-streams)
468 (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT")
469 (toplevel-repl noprint)
470 ;; (classic CMU CL error message: "You're certainly a clever child.":-)
471 (critically-unreachable "after TOPLEVEL-REPL")))
473 ;;; hooks to support customized toplevels like ACL-style toplevel from
474 ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for
475 ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*.
476 (defvar *repl-read-form-fun* #'repl-read-form-fun
478 "A function of two stream arguments IN and OUT for the toplevel REPL to
479 call: Return the next Lisp form to evaluate (possibly handling other magic --
480 like ACL-style keyword commands -- which precede the next Lisp form). The OUT
481 stream is there to support magic which requires issuing new prompts.")
482 (defvar *repl-prompt-fun* #'repl-prompt-fun
484 "A function of one argument STREAM for the toplevel REPL to call: Prompt
485 the user for input.")
486 (defvar *repl-fun-generator* (constantly #'repl-fun)
488 "A function of no arguments returning a function of one argument NOPRINT
489 that provides the REPL for the system. Assumes that *STANDARD-INPUT* and
490 *STANDARD-OUTPUT* are set up.")
492 ;;; read-eval-print loop for the default system toplevel
493 (defun toplevel-repl (noprint)
494 (/show0 "entering TOPLEVEL-REPL")
495 (let ((* nil) (** nil) (*** nil)
497 (+ nil) (++ nil) (+++ nil)
498 (/// nil) (// nil) (/ nil))
499 (/show0 "about to funcall *REPL-FUN-GENERATOR*")
500 (let ((repl-fun (funcall *repl-fun-generator*)))
501 ;; Each REPL in a multithreaded world should have bindings of
502 ;; most CL specials (most critically *PACKAGE*).
503 (with-rebound-io-syntax
504 (handler-bind ((step-condition 'invoke-stepper))
506 (/show0 "about to set up restarts in TOPLEVEL-REPL")
507 ;; CLHS recommends that there should always be an
508 ;; ABORT restart; we have this one here, and one per
511 (abort "~@<Exit debugger, returning to top level.~@:>")
512 (catch 'toplevel-catcher
513 ;; In the event of a control-stack-exhausted-error, we
514 ;; should have unwound enough stack by the time we get
515 ;; here that this is now possible.
517 (sb!kernel::reset-control-stack-guard-page)
518 (funcall repl-fun noprint)
519 (critically-unreachable "after REPL")))))))))
521 ;;; Our default REPL prompt is the minimal traditional one.
522 (defun repl-prompt-fun (stream)
524 (write-string "* " stream)) ; arbitrary but customary REPL prompt
526 ;;; Our default form reader does relatively little magic, but does
527 ;;; handle the Unix-style EOF-is-end-of-process convention.
528 (defun repl-read-form-fun (in out)
529 (declare (type stream in out) (ignore out))
530 ;; KLUDGE: *READ-SUPPRESS* makes the REPL useless, and cannot be
531 ;; recovered from -- flip it here.
532 (when *read-suppress*
533 (warn "Setting *READ-SUPPRESS* to NIL to restore toplevel usability.")
534 (setf *read-suppress* nil))
535 (let* ((eof-marker (cons nil nil))
536 (form (read in nil eof-marker)))
537 (if (eq form eof-marker)
541 (defun repl-fun (noprint)
542 (/show0 "entering REPL")
546 ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.)
547 (scrub-control-stack)
548 (sb!thread::get-foreground)
550 (flush-standard-output-streams)
551 (funcall *repl-prompt-fun* *standard-output*)
552 ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own
553 ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to
554 ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems
555 ;; odd. But maybe there *is* a valid reason in some
556 ;; circumstances? perhaps some deadlock issue when being driven
557 ;; by another process or something...)
558 (force-output *standard-output*))
559 (let* ((form (funcall *repl-read-form-fun*
562 (results (multiple-value-list (interactive-eval form))))
564 (dolist (result results)
567 ;; If we started stepping in the debugger we want to stop now.
568 (disable-stepping))))
570 ;;; a convenient way to get into the assembly-level debugger
572 (%primitive sb!c:halt))