On Mon, Apr 14, 2008 at 6:57 PM, Ken Tilton kennytilton@optonline.net wrote:
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*).
Wow, congrats for figuring that out. Sounds like one of these things that take forever ...
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.
Sounds good. And you obviously found some "unclean" stuff I was doing.
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...
Actually, the drawing area widget still gets away with it. Maybe because it does not have kids ... I don't know.
...congratulations, you are the first victim to fall into my new bug trap. :)
I'm proud :)
Peter