0.pre7.86.flaky7.21:

[sbcl.git] / src / code / toplevel.lisp

diff --git a/src/code/toplevel.lisp b/src/code/toplevel.lisp
index a2a141f..cd9463c 100644 (file)
--- a/src/code/toplevel.lisp
+++ b/src/code/toplevel.lisp
@@ -459,46 +459,52 @@
   (let ((* nil) (** nil) (*** nil)
        (- nil)
        (+ nil) (++ nil) (+++ nil)
-       (/// nil) (// nil) (/ nil)
-       (eof-marker (cons :eof nil)))
+       (/// nil) (// nil) (/ nil))
+    (/show0 "about to set up restarts in TOPLEVEL-REPL")
+    ;; There should only be one TOPLEVEL restart, and it's here, so
+    ;; restarting at TOPLEVEL always bounces you all the way out here.
+    (with-simple-restart (toplevel
+                         "Restart at toplevel READ/EVAL/PRINT loop.")
+      ;; We add a new ABORT restart for every debugger level, so 
+      ;; restarting at ABORT in a nested debugger gets you out to the
+      ;; innermost enclosing debugger, and only when you're in the
+      ;; outermost, unnested debugger level does restarting at ABORT 
+      ;; get you out to here.
+      (with-simple-restart (abort "Reduce debugger level (leaving debugger).")
+       (catch 'toplevel-catcher
+         (sb!unix:unix-sigsetmask 0)   ; FIXME: What is this for?
+         (repl noprint))))))
+
+(defun repl (noprint)
+  (/show0 "entering REPL")
+  (let ((eof-marker (cons :eof nil)))
     (loop
-      (/show0 "at head of outer LOOP in TOPLEVEL-REPL")
-      ;; There should only be one TOPLEVEL restart, and it's here, so
-      ;; restarting at TOPLEVEL always bounces you all the way out here.
-      (with-simple-restart (toplevel
-                           "Restart at toplevel READ/EVAL/PRINT loop.")
-       ;; We add a new ABORT restart for every debugger level, so 
-       ;; restarting at ABORT in a nested debugger gets you out to the
-        ;; innermost enclosing debugger, and only when you're in the
-        ;; outermost, unnested debugger level does restarting at ABORT 
-       ;; get you out to here.
-        (with-simple-restart (abort
-                             "Reduce debugger level (leaving debugger).")
-         (catch 'toplevel-catcher
-           (sb!unix:unix-sigsetmask 0) ; FIXME: What is this for?
-           (/show0 "about to enter inner LOOP in TOPLEVEL-REPL")
-           (loop ; FIXME: Do we need this inner LOOP?
-            ;; FIXME: It seems bad to have GC behavior depend on scrubbing
-            ;; the control stack before each interactive command. Isn't
-            ;; there some way we can convince the GC to just ignore
-            ;; dead areas of the control stack, so that we don't need to
-            ;; rely on this half-measure?
-            (scrub-control-stack)
+     ;; FIXME: It seems bad to have GC behavior depend on scrubbing the
+     ;; control stack before each interactive command. Isn't there some
+     ;; way we can convince the GC to just ignore dead areas of the
+     ;; control stack, so that we don't need to rely on this
+     ;; half-measure?
+     (/show0 "at head of LOOP")
+     (scrub-control-stack)
+     (/show0 "back from SCRUB-CONTROL-STACK")
+     (unless noprint
+       (fresh-line)
+       (/show0 "back from FRESH-LINE")
+       (princ (if (functionp *prompt*)
+                 (funcall *prompt*)
+                 *prompt*))
+       (/show0 "back from PRINC")
+       (flush-standard-output-streams)
+       (/show0 "back from FLUSH-STANDARD-OUTPUT-STREAMS"))
+     (let ((form (read *standard-input* nil eof-marker)))
+       (/show0 "back from READ")
+       (if (eq form eof-marker)
+          (quit)
+          (let ((results (multiple-value-list (interactive-eval form))))
             (unless noprint
-              (fresh-line)
-              (princ (if (functionp *prompt*)
-                         (funcall *prompt*)
-                         *prompt*))
-              (flush-standard-output-streams))
-            (let ((form (read *standard-input* nil eof-marker)))
-              (if (eq form eof-marker)
-                  (quit)
-                  (let ((results
-                         (multiple-value-list (interactive-eval form))))
-                    (unless noprint
-                      (dolist (result results)
-                        (fresh-line)
-                        (prin1 result)))))))))))))
+              (dolist (result results)
+                (fresh-line)
+                (prin1 result)))))))))
 
 (defun noprogrammer-debugger-hook-fun (condition old-debugger-hook)
   (declare (ignore old-debugger-hook))
@@ -512,12 +518,14 @@
     (handler-case
        (progn
          (format *error-output*
-                 "~@<unhandled condition (of type ~S): ~2I~_~A~:>~2%"
+                 "~&~@<unhandled condition (of type ~S): ~2I~_~A~:>~2%"
                  (type-of condition)
                  condition)
          ;; Flush *ERROR-OUTPUT* even before the BACKTRACE, so that
-         ;; even if we hit an error within BACKTRACE we'll at least
-         ;; have the CONDITION printed out before we die.
+         ;; even if we hit an error within BACKTRACE (e.g. a bug in
+         ;; the debugger's own frame-walking code, or a bug in a user
+         ;; PRINT-OBJECT method) we'll at least have the CONDITION
+         ;; printed out before we die.
          (finish-output *error-output*)
          ;; (Where to truncate the BACKTRACE is of course arbitrary, but
          ;; it seems as though we should at least truncate it somewhere.)