Re: [Sbcl-bugs] SBCL: Is this a bug???

[Nikodemus S. <nik...@ra...>]

On 30 May 2012 04:56, Paul Bowyer <pb...@ol...> wrote:

I don't know what you think the error is.

As is, the code compiles, and

  (defclass clx-dialog () ())
  (set-var-info (make-instance 'clx-dialog) '(:g1 :g2))
  (set-var-info nil '(:g1 :g2))

works as expected.

Note that if you uncomment the first XLIB:DISPLAY-FINISH-OUTPUT while
keeping the FORMAT call in place, you end up with a three-legged IF:

; caught ERROR:
;   error while parsing arguments to special form IF:
;     invalid number of elements in
;       ((AND (NOT (NULL DINSTANCE)) (EQUAL (TYPE-OF DINSTANCE) 'CLX-DIALOG))
;        (FORMAT T "dinstance: ~A, groups: ~A~%" DINSTANCE GROUPS)
;        (XLIB:DISPLAY-FINISH-OUTPUT *DISPLAY*)
;        (LET ((VLST #) (GRPNO 0) (BOXNO 0) (INDEX 0) BLST)
;          (FORMAT T "vlst: ~A, blst: ~A, grpno: ~A, boxno: ~A, index:
~A~%" VLST
;                  BLST GRPNO BOXNO INDEX)))
;     to satisfy lambda list
;       (SB-C::TEST SB-C::THEN &OPTIONAL SB-C::ELSE):
;     between 2 and 3 expected, but 4 found

...which isn't going to work.

You need to eg. wrap the them in a PROGN,

  (progn
    (Format t "dinstance: ~A, groups: ~A~%" dinstance groups)
    ;; (xlib:display-finish-output *display*)
    )

or use COND.

You might also want to use TYPEP instead of EQUAL TYPE-OF, and the
MAKE-LIST :INITIAL-ELEMENT probably isn't what you want: '('()) ==
(list '(quote nil)). I'm assuming you probably want plain '() == NIL.

(defun set-var-info (dinstance groups)
  (cond ((typep dinstance 'clx-dialog)
         (Format t "dinstance: ~A, groups: ~A~%" dinstance groups)
         #+nil
         (xlib:display-finish-output *display*))
        (t
         (let ((vlst (make-list (length groups) :initial-element '()))
               (grpno 0)
               (boxno 0)
               (index 0)
               blst)
           (format t "vlst: ~A, blst: ~A, grpno: ~A, boxno: ~A, index: ~A~%"
                   vlst blst grpno boxno index)
           #+nil
           (xlib:display-finish-output *display*)))))

Cheers,

 -- Nikodemus