Ken, thanks for shadding some light on the issue. I think I found a decent solution to the problem by abusing (what a contradiction) the rule for the id slot and dropping in my two lines: #+libcellsgtk (gtk-signal-connect-swap id "configure-event" (cffi:get-callback 'reshape-widget-handler) :data id) (gtk-signal-connect-swap id "delete-event" (cffi:get-callback 'delete-widget-handler) :data id) This way I can use id -- the local lexical variable holding the brand new id -- and work with it without any cells dependency. And one could argue that I do the required stuff right where it belongs. Cheers, Peter On Mon, Apr 14, 2008 at 6:57 PM, Ken Tilton <kennytilton@optonline.net> wrote:
Peter Hildebrandt wrote:
As you saw in my other mail, I found the intermediate cause of the problem: I had included a reference to (id self) in initialize-instance of widget. For some reason that causes the circularity detection to raise its voice.
What I don't understand, however, is why a reference to the slot in initialize-instance :after brings out circularity.
For now, I moved the stuff into the rule for the id slot itself, so when the id is calculated, I use it right away, and don't have to worry about cell access. slot-value would have been another option, I suppose.
But still: why???
Recently some evil programming took forever to debug because I was re-entering a rule without realizing it. After figuring out that that was happening and fixing the cause of that, I looked to see why rule re-entrance had not been detected, which I seemed to recall it always had been.
Turns out the rule began with without-c-dependency as a trick to run only once. That macro simply:
`(let ((cells::*call-stack* nil)) ,@body)
And that worked because the dependent cell was always identifed as (car cells::*call-stack*).
Well, I like early bug detection you may have noticed recently <g>, so I decided the macro without-c-dependency should leave the *call-stack* intact and instead bind a separate new *depender* special to nil, with *depender* being the, well, depender honored by the Cells machinery.
You should not have been doing cells-y stuff in i-i, but you got away with it because of the old without-c-dependency behavior, so...
...congratulations, you are the first victim to fall into my new bug trap. :)
kt