Keyword

Default value:

(or (delivery-value :keep-debug-mode)

    (<= *delivery-level* 2)) 

If nil , the generic function print-object is redefined to be the ordinary function x-print-object :

(defun x-print-object (object stream)

  (t-print-object object stream))

(defun t-print-object (object stream)

  (print-unreadable-object (object stream :identity t)

    (if (and (fboundp 'find-class)

             (find-class 'undefined-function nil)

             (ignore-errors

               (typep object 'undefined-function)))

        (progn

          (write-string "Undefined function " stream)

          (prin1 (cell-error-name object) stream))

      (progn

        (princ (or (ignore-errors (type-of object))

                   "<Unknown type>")

               stream)

        (ignore-errors

          (when-let (namer (find-symbol "NAME" "CLOS"))

            (when-let (name (and (slot-exists-p object namer)

                                 (slot-boundp object namer)

                                 (slot-value object namer)))

              (format stream " ~a" name))))))))

You may redefine x-print-object .

Affected by: :keep-debug-mode