[Sbcl-help] defclass reader

[Gabor M. <me...@ho...>]

Suppose I have a class with a slot and a function.

(defclass xxx ()
  ((slut :reader xxx-slut)))

(defun xxx-slot (xxx)
  1)

Then I realize the typo and try to change the class def to this:

(defclass xxx ()
  ((slot :reader xxx-slot)))

There is an error which is fine, although a continue restart would be nice:

XXX-SLOT already names an ordinary function or a macro.

=46rom this point on, all redefinition attempts of xxx fail (including the=
=20
original one) with the same error until fmakunbounding xxx-slot. Tested wit=
h=20
sbcl 8.15.7 and 8.16.45.

It seemed that the problem lies with a fix-slot-accessors trying to remove =
a=20
method from the non-generic function xxx-slot and being vocal about its=20
failure. I fixed it temporarily like this and probably broke clos too, but =
it=20
at least fixes the above behaviour :-):

Index: std-class.lisp
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /cvsroot/sbcl/sbcl/src/pcl/std-class.lisp,v
retrieving revision 1.70
diff -u -r1.70 std-class.lisp
=2D-- std-class.lisp      19 Nov 2004 16:29:06 -0000      1.70
+++ std-class.lisp      24 Nov 2004 16:18:54 -0000
@@ -745,19 +745,23 @@
 (defun fix-slot-accessors (class dslotds add/remove)
   (flet ((fix (gfspec name r/w)
            (let ((gf (if (fboundp gfspec)
=2D                         (without-package-locks
=2D                           (ensure-generic-function gfspec))
+                         (unless (and (eq add/remove 'remove)
+                                      (not (generic-function-p
+                                            (fdefinition gfspec))))
+                           (without-package-locks
+                             (ensure-generic-function gfspec)))
                          (ensure-generic-function
                           gfspec :lambda-list (case r/w
                                                 (r '(object))
                                                 (w '(new-value object)))))=
))
=2D             (case r/w
=2D               (r (if (eq add/remove 'add)
=2D                      (add-reader-method class gf name)
=2D                      (remove-reader-method class gf)))
=2D               (w (if (eq add/remove 'add)
=2D                      (add-writer-method class gf name)
=2D                      (remove-writer-method class gf)))))))
+             (when gf
+               (case r/w
+                 (r (if (eq add/remove 'add)
+                        (add-reader-method class gf name)
+                        (remove-reader-method class gf)))
+                 (w (if (eq add/remove 'add)
+                        (add-writer-method class gf name)
+                        (remove-writer-method class gf))))))))
     (dolist (dslotd dslotds)
       (let ((slot-name (slot-definition-name dslotd)))
         (dolist (r (slot-definition-readers dslotd))

G=E1bor