[Openmcl-devel] Accessing objc slots query...
beer at eecs.cwru.edu
Sat Jun 26 09:43:05 EDT 2004
On Jun 26, 2004, at 8:11 AM, Duncan Rose wrote:
> Hi all; I have a Cocoa (bridge?) query....
> I have defined a class in the following way:
> (defclass lisp-view (ns:ns-view)
> ((trckrect :foreign-type :id :accessor tracking-rect))
> (:metaclass ns:+ns-object))
This looks correct.
> My query is how I actually use the 'tracking-rect' accessor (assuming
> this is defined properly in the first place, of course - it may well
> not be). I have the following method defined:
> (define-objc-method ((:void establish-tracking-rect) lisp-view)
> ;; If the view already has a tracking rectangle (each view should
> have a single tracking
> ;; rectangle, or none) remove it.
> (when (not (eql (send self 'tracking-rectangle) (%null-ptr)))
> (send self :remove-tracking-rect (tracking-rectangle self)))
> ;; Establish a new tracking rectangle for the view's current bounds
> (setf (tracking-rectangle self) (send self :add-tracking-rect (send
> self 'bounds)
> :owner self
> :user-data (%null-ptr)
> :assume-inside #$NO)))
> Note that the '(when ...)' originally attempted to invoke the accessor
> the same way the '(setf ...)' does later on in the method - I left
> both in to show the different approaches I've tried. This fails with
> the following error:
> > Error in process Listener(3): Unknown message: "trackingRectangle"
> > While executing: CCL::MAKE-OPTIMIZED-SEND
> > Type :POP to abort.
> Type :? for other options.
> 1 >
The TRACKING-RECT is a CLOS method, not an ObjC method, so SENDing it
> When the '(when ...)' line used (tracking-rectangle self) instead of
> (send ...), there isn't an error, but I'm warned:
> ; Undefined function SETF::|CLIM-COCOA::TRACKING-RECTANGLE|, in
> CLIM-COCOA::|-[LispView establishTrackingRect]|.
> ; Undefined function CLIM-COCOA::TRACKING-RECTANGLE (2 references),
> in CLIM-COCOA::|-[LispView establishTrackingRect]|.
Should TRACKING-RECTANGLE be TRACKING-RECT? The latter works for me:
? (defclass lisp-view (ns:ns-view)
((trckrect :foreign-type :id :accessor tracking-rect))
#<OBJC:OBJC-CLASS LISP-VIEW (#x1AFB90)>
? (setq x (make-instance 'lisp-view))
#<LISP-VIEW <LispView: 0x1aaa90> (#x1AAA90)>
? (tracking-rect x)
#<A Null Mac Pointer>
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