X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Flate-extensions.lisp;h=4d0e08bbb715ef145092b12d735dd6753164b591;hb=71766d9db05e93567cb7e829abfc675c3cb895c9;hp=4b71114f62ce670d525de01e87fdf35d6be16efe;hpb=c41d75f1d2defd6234e644ef2b40440a5d1526c5;p=sbcl.git

diff --git a/src/code/late-extensions.lisp b/src/code/late-extensions.lisp
index 4b71114..4d0e08b 100644
--- a/src/code/late-extensions.lisp
+++ b/src/code/late-extensions.lisp
@@ -20,12 +20,12 @@
 (defun list-with-length-p (x)
   (values (ignore-errors (list-length x))))
 
-;;; not used in 0.7.8, but possibly useful for defensive programming 
+;;; not used in 0.7.8, but possibly useful for defensive programming
 ;;; in e.g. (COERCE ... 'VECTOR)
 ;;;(defun list-length-or-die (x)
 ;;;  (or (list-length x)
 ;;;      ;; not clear how to do this best:
-;;;      ;;   * Should this be a TYPE-ERROR? Colloquially that'd make 
+;;;      ;;   * Should this be a TYPE-ERROR? Colloquially that'd make
 ;;;      ;;     lots of sense, but since I'm not sure how to express
 ;;;      ;;     "noncircular list" as a Lisp type expression, coding
 ;;;      ;;     it seems awkward.
@@ -35,3 +35,13 @@
 ;;;      ;;     be doing him a favor by printing the object here.
 ;;;      ;; -- WHN 2002-10-19
 ;;;      (error "can't calculate length of cyclic list")))
+
+;;; This is used in constructing arg lists for debugger printing,
+;;; and when needing to print unbound slots in PCL.
+(defstruct (unprintable-object
+            (:constructor make-unprintable-object (string))
+            (:print-object (lambda (x s)
+                             (print-unreadable-object (x s)
+                               (write-string (unprintable-object-string x) s))))
+            (:copier nil))
+  string)