;;;; stuff related to the toplevel read-eval-print loop, plus some ;;;; other miscellaneous functions that we don't have any better place ;;;; for ;;;; This software is part of the SBCL system. See the README file for ;;;; more information. ;;;; ;;;; This software is derived from the CMU CL system, which was ;;;; written at Carnegie Mellon University and released into the ;;;; public domain. The software is in the public domain and is ;;;; provided with absolutely no warranty. See the COPYING and CREDITS ;;;; files for more information. (in-package "SB!IMPL") ;;;; magic specials initialized by GENESIS ;;; FIXME: The DEFVAR here is redundant with the (DECLAIM (SPECIAL ..)) ;;; of all static symbols in early-impl.lisp. (progn (defvar sb!vm::*current-catch-block*) (defvar sb!vm::*current-unwind-protect-block*) #!+hpux (defvar sb!vm::*c-lra*) (defvar *free-interrupt-context-index*)) ;;; specials initialized by !COLD-INIT ;;; FIXME: These could be converted to DEFVARs. (declaim (special #!+(or x86 x86-64) *pseudo-atomic-bits* *allow-with-interrupts* *interrupts-enabled* *interrupt-pending* #!+sb-thruption *thruption-pending* *type-system-initialized*)) (defvar *cold-init-complete-p*) ;;; counts of nested errors (with internal errors double-counted) (defvar *maximum-error-depth*) (defvar *current-error-depth*) ;;;; default initfiles (defun sysinit-pathname () (or (let ((sbcl-homedir (sbcl-homedir-pathname))) (when sbcl-homedir (probe-file (merge-pathnames "sbclrc" sbcl-homedir)))) #!+win32 (merge-pathnames "sbcl\\sbclrc" (sb!win32::get-folder-pathname sb!win32::csidl_common_appdata)) #!-win32 "/etc/sbclrc")) (defun userinit-pathname () (merge-pathnames ".sbclrc" (user-homedir-pathname))) (defvar *sysinit-pathname-function* #'sysinit-pathname #!+sb-doc "Designator for a function of zero arguments called to obtain a pathname designator for the default sysinit file, or NIL. If the function returns NIL, no sysinit file is used unless one has been specified on the command-line.") (defvar *userinit-pathname-function* #'userinit-pathname #!+sb-doc "Designator for a function of zero arguments called to obtain a pathname designator or a stream for the default userinit file, or NIL. If the function returns NIL, no userinit file is used unless one has been specified on the command-line.") ;;;; miscellaneous utilities for working with with TOPLEVEL ;;; Execute BODY in a context where any %END-OF-THE-WORLD (thrown e.g. ;;; by QUIT) is caught and any final processing and return codes are ;;; handled appropriately. (defmacro handling-end-of-the-world (&body body) `(without-interrupts (catch '%end-of-the-world (unwind-protect (with-local-interrupts (unwind-protect (progn ,@body) (call-exit-hooks))) (%exit))))) (defvar *exit-lock*) (defvar *exit-in-process* nil) (declaim (type (or null real) *exit-timeout*)) (defvar *exit-timeout* 60 "Default amount of seconds, if any, EXIT should wait for other threads to finish after terminating them. Default value is 60. NIL means to wait indefinitely.") (defun os-exit-handler (condition) (declare (ignore condition)) (os-exit *exit-in-process* :abort t)) (defvar *exit-error-handler* #'os-exit-handler) (defun call-exit-hooks () (unless *exit-in-process* (setf *exit-in-process* 0)) (handler-bind ((serious-condition *exit-error-handler*)) (call-hooks "exit" *exit-hooks* :on-error :warn))) (defun %exit () ;; If anything goes wrong, we will exit immediately and forcibly. (handler-bind ((serious-condition *exit-error-handler*)) (let ((ok nil) (code *exit-in-process*)) (if (consp code) ;; Another thread called EXIT, and passed the buck to us -- only ;; final call left to do. (os-exit (car code) :abort nil) (unwind-protect (progn (flush-standard-output-streams) (sb!thread::%exit-other-threads) (setf ok t)) (os-exit code :abort (not ok))))))) ;;;; working with *CURRENT-ERROR-DEPTH* and *MAXIMUM-ERROR-DEPTH* ;;; INFINITE-ERROR-PROTECT is used by ERROR and friends to keep us out ;;; of hyperspace. (defmacro infinite-error-protect (&rest forms) `(unless (infinite-error-protector) (/show0 "back from INFINITE-ERROR-PROTECTOR") (let ((*current-error-depth* (1+ *current-error-depth*))) (/show0 "in INFINITE-ERROR-PROTECT, incremented error depth") ;; arbitrary truncation #!+sb-show (sb!debug:print-backtrace :count 8) ,@forms))) ;;; a helper function for INFINITE-ERROR-PROTECT (defun infinite-error-protector () (/show0 "entering INFINITE-ERROR-PROTECTOR, *CURRENT-ERROR-DEPTH*=..") (/hexstr *current-error-depth*) (cond ((not *cold-init-complete-p*) (%primitive print "Argh! error in cold init, halting") (%primitive sb!c:halt)) ((or (not (boundp '*current-error-depth*)) (not (realp *current-error-depth*)) (not (boundp '*maximum-error-depth*)) (not (realp *maximum-error-depth*))) (%primitive print "Argh! corrupted error depth, halting") (%primitive sb!c:halt)) ((> *current-error-depth* *maximum-error-depth*) (/show0 "*MAXIMUM-ERROR-DEPTH*=..") (/hexstr *maximum-error-depth*) (/show0 "in INFINITE-ERROR-PROTECTOR, calling ERROR-ERROR") (error-error "Help! " *current-error-depth* " nested errors. " "SB-KERNEL:*MAXIMUM-ERROR-DEPTH* exceeded.") t) (t (/show0 "returning normally from INFINITE-ERROR-PROTECTOR") nil))) ;;;; miscellaneous external functions (defun split-seconds-for-sleep (seconds) (declare (optimize speed)) (flet ((split-float () ;; KLUDGE: This whole thing to avoid consing floats (let ((whole-seconds (truly-the fixnum (%unary-truncate seconds)))) (values whole-seconds (truly-the fixnum (%unary-truncate (* (- seconds whole-seconds) (load-time-value 1s9 t)))))))) (declare (inline split-float)) (typecase seconds ((single-float 0s0 #.(float most-positive-fixnum 1s0)) (split-float)) ((double-float 0d0 #.(float most-positive-fixnum 1d0)) (split-float)) (ratio (multiple-value-bind (quot rem) (truncate (numerator seconds) (denominator seconds)) (values quot (truncate (* rem (/ 1000000000 (denominator seconds))))))) (t (multiple-value-bind (sec frac) (truncate seconds) (values sec (truncate frac (load-time-value 1s-9 t)))))))) (defun sleep (seconds) #!+sb-doc "This function causes execution to be suspended for SECONDS. SECONDS may be any non-negative real number." (when (or (not (realp seconds)) (minusp seconds)) (error 'simple-type-error :format-control "Invalid argument to SLEEP: ~S, ~ should be a non-negative real." :format-arguments (list seconds) :datum seconds :expected-type '(real 0))) #!-(and win32 (not sb-thread)) (multiple-value-bind (sec nsec) (if (integerp seconds) (values seconds 0) (split-seconds-for-sleep seconds)) ;; nanosleep() accepts time_t as the first argument, but on some platforms ;; it is restricted to 100 million seconds. Maybe someone can actually ;; have a reason to sleep for over 3 years? (loop while (> sec (expt 10 8)) do (decf sec (expt 10 8)) (sb!unix:nanosleep (expt 10 8) 0)) (sb!unix:nanosleep sec nsec)) #!+(and win32 (not sb-thread)) (sb!win32:millisleep (truncate (* seconds 1000))) nil) ;;;; the default toplevel function (defvar / nil #!+sb-doc "a list of all the values returned by the most recent top level EVAL") (defvar // nil #!+sb-doc "the previous value of /") (defvar /// nil #!+sb-doc "the previous value of //") (defvar * nil #!+sb-doc "the value of the most recent top level EVAL") (defvar ** nil #!+sb-doc "the previous value of *") (defvar *** nil #!+sb-doc "the previous value of **") (defvar + nil #!+sb-doc "the value of the most recent top level READ") (defvar ++ nil #!+sb-doc "the previous value of +") (defvar +++ nil #!+sb-doc "the previous value of ++") (defvar - nil #!+sb-doc "the form currently being evaluated") (defun interactive-eval (form &key (eval #'eval)) #!+sb-doc "Evaluate FORM, returning whatever it returns and adjusting ***, **, *, +++, ++, +, ///, //, /, and -." (setf - form) (unwind-protect (let ((results (multiple-value-list (funcall eval form)))) (setf /// // // / / results *** ** ** * * (car results))) (setf +++ ++ ++ + + -)) (unless (boundp '*) ;; The bogon returned an unbound marker. ;; FIXME: It would be safer to check every one of the values in RESULTS, ;; instead of just the first one. (setf * nil) (cerror "Go on with * set to NIL." "EVAL returned an unbound marker.")) (values-list /)) ;;; Flush anything waiting on one of the ANSI Common Lisp standard ;;; output streams before proceeding. (defun flush-standard-output-streams () (let ((null (make-broadcast-stream))) (dolist (name '(*debug-io* *error-output* *query-io* *standard-output* *trace-output* *terminal-io*)) ;; 0. Pull out the underlying stream, so we know what it is. ;; 1. Handle errors on it. We're doing this on entry to ;; debugger, so we don't want recursive errors here. ;; 2. Rebind the stream symbol in case some poor sod sees ;; a broken stream here while running with *BREAK-ON-ERRORS*. (let ((stream (stream-output-stream (symbol-value name)))) (progv (list name) (list null) (handler-bind ((stream-error (lambda (c) (when (eq stream (stream-error-stream c)) (go :next))))) (force-output stream)))) :next)) (values)) (defun stream-output-stream (stream) (typecase stream (fd-stream stream) (synonym-stream (stream-output-stream (symbol-value (synonym-stream-symbol stream)))) (two-way-stream (stream-output-stream (two-way-stream-output-stream stream))) (t stream))) (defun process-init-file (specified-pathname kind) (multiple-value-bind (context default-function) (ecase kind (:system (values "sysinit" *sysinit-pathname-function*)) (:user (values "userinit" *userinit-pathname-function*))) (if specified-pathname (with-open-file (stream (parse-native-namestring specified-pathname) :if-does-not-exist nil) (if stream (load-as-source stream :context context) (cerror "Ignore missing init file" "The specified ~A file ~A was not found." context specified-pathname))) (let ((default (funcall default-function))) (when default (with-open-file (stream (pathname default) :if-does-not-exist nil) (when stream (load-as-source stream :context context)))))))) (defun process-eval/load-options (options) (/show0 "handling --eval and --load options") (flet ((process-1 (cons) (destructuring-bind (opt . value) cons (ecase opt (:eval (with-simple-restart (continue "Ignore runtime option --eval ~S." value) (multiple-value-bind (expr pos) (read-from-string value) (if (eq value (read-from-string value nil value :start pos)) (eval expr) (error "Multiple expressions in --eval option: ~S" value))))) (:load (with-simple-restart (continue "Ignore runtime option --load ~S." value) (load (native-pathname value)))) (:quit (exit)))) (flush-standard-output-streams))) (with-simple-restart (abort "Skip rest of --eval and --load options.") (dolist (option options) (process-1 option))))) (defun process-script (script) (flet ((load-script (stream) ;; Scripts don't need to be stylish or fast, but silence is usually a ;; desirable quality... (handler-bind (((or style-warning compiler-note) #'muffle-warning) (stream-error (lambda (e) ;; Shell-style. (when (member (stream-error-stream e) (list *stdout* *stdin* *stderr*)) (exit))))) ;; Let's not use the *TTY* for scripts, ok? Also, normally we use ;; synonym streams, but in order to have the broken pipe/eof error ;; handling right we want to bind them for scripts. (let ((*terminal-io* (make-two-way-stream *stdin* *stdout*)) (*debug-io* (make-two-way-stream *stdin* *stderr*)) (*standard-input* *stdin*) (*standard-output* *stdout*) (*error-output* *stderr*)) (load stream :verbose nil :print nil))))) (handling-end-of-the-world (if (eq t script) (load-script *stdin*) (with-open-file (f (native-pathname script) :element-type :default) (sb!fasl::maybe-skip-shebang-line f) (load-script f)))))) ;; Errors while processing the command line cause the system to EXIT, ;; instead of trying to go into the Lisp debugger, because trying to ;; go into the Lisp debugger would get into various annoying issues of ;; where we should go after the user tries to return from the ;; debugger. (defun startup-error (control-string &rest args) (format *error-output* "fatal error before reaching READ-EVAL-PRINT loop: ~% ~?~%" control-string args) (exit :code 1)) ;;; the default system top level function (defun toplevel-init () (/show0 "entering TOPLEVEL-INIT") (let ( ;; value of --sysinit option (sysinit nil) ;; t if --no-sysinit option given (no-sysinit nil) ;; value of --userinit option (userinit nil) ;; t if --no-userinit option given (no-userinit nil) ;; t if --disable-debugger option given (disable-debugger nil) ;; list of ( . ) conses representing --eval and --load ;; options. options. --eval options are stored as strings, so that ;; they can be passed to READ only after their predecessors have been ;; EVALed, so that things work when e.g. REQUIRE in one EVAL form ;; creates a package referred to in the next EVAL form. Storing the ;; original string also makes for easier debugging. (reversed-options nil) ;; Has a --noprint option been seen? (noprint nil) ;; Has a --script option been seen? (script nil) ;; Quit after processing other options? (finally-quit nil) ;; everything in *POSIX-ARGV* except for argv[0]=programname (options (rest *posix-argv*))) (declare (type list options)) (/show0 "done with outer LET in TOPLEVEL-INIT") ;; FIXME: There are lots of ways for errors to happen around here ;; (e.g. bad command line syntax, or READ-ERROR while trying to ;; READ an --eval string). Make sure that they're handled ;; reasonably. ;; Process command line options. (loop while options do (/show0 "at head of LOOP WHILE OPTIONS DO in TOPLEVEL-INIT") (let ((option (first options))) (flet ((pop-option () (if options (pop options) (startup-error "unexpected end of command line options")))) (cond ((string= option "--script") (pop-option) (setf disable-debugger t no-userinit t no-sysinit t script (if options (pop-option) t)) (return)) ((string= option "--sysinit") (pop-option) (if sysinit (startup-error "multiple --sysinit options") (setf sysinit (pop-option)))) ((string= option "--no-sysinit") (pop-option) (setf no-sysinit t)) ((string= option "--userinit") (pop-option) (if userinit (startup-error "multiple --userinit options") (setf userinit (pop-option)))) ((string= option "--no-userinit") (pop-option) (setf no-userinit t)) ((string= option "--eval") (pop-option) (push (cons :eval (pop-option)) reversed-options)) ((string= option "--load") (pop-option) (push (cons :load (pop-option)) reversed-options)) ((string= option "--noprint") (pop-option) (setf noprint t)) ((string= option "--disable-debugger") (pop-option) (setf disable-debugger t)) ((string= option "--quit") (pop-option) (setf finally-quit t)) ((string= option "--non-interactive") ;; This option is short for --quit and --disable-debugger, ;; which are needed in combination for reliable non- ;; interactive startup. (pop-option) (setf finally-quit t) (setf disable-debugger t)) ((string= option "--end-toplevel-options") (pop-option) (return)) (t ;; Anything we don't recognize as a toplevel ;; option must be the start of user-level ;; options.. except that if we encounter ;; "--end-toplevel-options" after we gave up ;; because we didn't recognize an option as a ;; toplevel option, then the option we gave up on ;; must have been an error. (E.g. in ;; "sbcl --eval '(a)' --eval'(b)' --end-toplevel-options" ;; this test will let us detect that the string ;; "--eval(b)" is an error.) (if (find "--end-toplevel-options" options :test #'string=) (startup-error "bad toplevel option: ~S" (first options)) (return))))))) (/show0 "done with LOOP WHILE OPTIONS DO in TOPLEVEL-INIT") ;; Delete all the options that we processed, so that only ;; user-level options are left visible to user code. (when *posix-argv* (setf (rest *posix-argv*) options)) ;; Disable debugger before processing initialization files & co. (when disable-debugger (sb!ext:disable-debugger)) ;; Handle initialization files. (/show0 "handling initialization files in TOPLEVEL-INIT") ;; This CATCH is needed for the debugger command TOPLEVEL to ;; work. (catch 'toplevel-catcher ;; We wrap all the pre-REPL user/system customized startup ;; code in a restart. ;; ;; (Why not wrap everything, even the stuff above, in this ;; restart? Errors above here are basically command line ;; or Unix environment errors, e.g. a missing file or a ;; typo on the Unix command line, and you don't need to ;; get into Lisp to debug them, you should just start over ;; and do it right at the Unix level. Errors below here ;; are generally errors in user Lisp code, and it might be ;; helpful to let the user reach the REPL in order to help ;; figure out what's going on.) (restart-case (progn (unless no-sysinit (process-init-file sysinit :system)) (unless no-userinit (process-init-file userinit :user)) (when finally-quit (push (list :quit) reversed-options)) (process-eval/load-options (nreverse reversed-options)) (when script (process-script script) (bug "PROCESS-SCRIPT returned"))) (abort () :report (lambda (s) (write-string (if script ;; In case script calls (enable-debugger)! "Abort script, exiting lisp." "Skip to toplevel READ/EVAL/PRINT loop.") s)) (/show0 "CONTINUEing from pre-REPL RESTART-CASE") (values)) ; (no-op, just fall through) (exit () :report "Exit SBCL (calling #'EXIT, killing the process)." :test (lambda (c) (declare (ignore c)) (not script)) (/show0 "falling through to EXIT from pre-REPL RESTART-CASE") (exit :code 1)))) ;; one more time for good measure, in case we fell out of the ;; RESTART-CASE above before one of the flushes in the ordinary ;; flow of control had a chance to operate (flush-standard-output-streams) (/show0 "falling into TOPLEVEL-REPL from TOPLEVEL-INIT") (toplevel-repl noprint) ;; (classic CMU CL error message: "You're certainly a clever child.":-) (critically-unreachable "after TOPLEVEL-REPL"))) ;;; hooks to support customized toplevels like ACL-style toplevel from ;;; KMR on sbcl-devel 2002-12-21. Altered by CSR 2003-11-16 for ;;; threaded operation: altered *REPL-FUN* to *REPL-FUN-GENERATOR*. (defvar *repl-read-form-fun* #'repl-read-form-fun #!+sb-doc "A function of two stream arguments IN and OUT for the toplevel REPL to call: Return the next Lisp form to evaluate (possibly handling other magic -- like ACL-style keyword commands -- which precede the next Lisp form). The OUT stream is there to support magic which requires issuing new prompts.") (defvar *repl-prompt-fun* #'repl-prompt-fun #!+sb-doc "A function of one argument STREAM for the toplevel REPL to call: Prompt the user for input.") (defvar *repl-fun-generator* (constantly #'repl-fun) #!+sb-doc "A function of no arguments returning a function of one argument NOPRINT that provides the REPL for the system. Assumes that *STANDARD-INPUT* and *STANDARD-OUTPUT* are set up.") ;;; read-eval-print loop for the default system toplevel (defun toplevel-repl (noprint) (/show0 "entering TOPLEVEL-REPL") (let ((* nil) (** nil) (*** nil) (- nil) (+ nil) (++ nil) (+++ nil) (/// nil) (// nil) (/ nil)) (/show0 "about to funcall *REPL-FUN-GENERATOR*") (let ((repl-fun (funcall *repl-fun-generator*))) ;; Each REPL in a multithreaded world should have bindings of ;; most CL specials (most critically *PACKAGE*). (with-rebound-io-syntax (handler-bind ((step-condition 'invoke-stepper)) (loop (/show0 "about to set up restarts in TOPLEVEL-REPL") ;; CLHS recommends that there should always be an ;; ABORT restart; we have this one here, and one per ;; debugger level. (with-simple-restart (abort "~@") (catch 'toplevel-catcher ;; 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. #!-win32 (sb!kernel::reset-control-stack-guard-page) (funcall repl-fun noprint) (critically-unreachable "after REPL"))))))))) ;;; Our default REPL prompt is the minimal traditional one. (defun repl-prompt-fun (stream) (fresh-line stream) (write-string "* " stream)) ; arbitrary but customary REPL prompt ;;; Our default form reader does relatively little magic, but does ;;; handle the Unix-style EOF-is-end-of-process convention. (defun repl-read-form-fun (in out) (declare (type stream in out) (ignore out)) ;; KLUDGE: *READ-SUPPRESS* makes the REPL useless, and cannot be ;; recovered from -- flip it here. (when *read-suppress* (warn "Setting *READ-SUPPRESS* to NIL to restore toplevel usability.") (setf *read-suppress* nil)) (let* ((eof-marker (cons nil nil)) (form (read in nil eof-marker))) (if (eq form eof-marker) (exit) form))) (defun repl-fun (noprint) (/show0 "entering REPL") (loop (unwind-protect (progn ;; (See comment preceding the definition of SCRUB-CONTROL-STACK.) (scrub-control-stack) (sb!thread::get-foreground) (unless noprint (flush-standard-output-streams) (funcall *repl-prompt-fun* *standard-output*) ;; (Should *REPL-PROMPT-FUN* be responsible for doing its own ;; FORCE-OUTPUT? I can't imagine a valid reason for it not to ;; be done here, so leaving it up to *REPL-PROMPT-FUN* seems ;; odd. But maybe there *is* a valid reason in some ;; circumstances? perhaps some deadlock issue when being driven ;; by another process or something...) (force-output *standard-output*)) (let* ((form (funcall *repl-read-form-fun* *standard-input* *standard-output*)) (results (multiple-value-list (interactive-eval form)))) (unless noprint (dolist (result results) (fresh-line) (prin1 result))))) ;; If we started stepping in the debugger we want to stop now. (disable-stepping)))) ;;; a convenient way to get into the assembly-level debugger (defun %halt () (%primitive sb!c:halt))