That's the Null Object Pattern! http://en.wikipedia.org/wiki/Null_Object_pattern
2009/6/4 Hernan Wilkinson <[email protected]> > I was going to suggest exactly that.As a rule, I never use nil because if > you do it you will have to check for it somewhere... nil is the root of most > of the problems! if not, look at all the errors I fixed in the other mail, > most of them are because nil is being used. > So, instead of nil, another object has to be use, and like you said in this > case an empty collection I think will work. I'm just changing that... I'll > send the changes today (I hope). > > Hernan. > > > On Thu, Jun 4, 2009 at 11:32 AM, Michael Rueger <[email protected]> wrote: > >> Sean Allen wrote: >> >> > Just as a bit more info. I used squeak for several months without ever >> > seeing this error. >> > I used pharo for 3 months without seeing this error. I've only gotten >> > this error in the latest images >> > with the latest vm and get it constantly. Not occassionally, I can get >> > this to happen at least >> > once every 120 seconds or so, sometimes more often. It would seem to be >> > as an outsider, >> > that something must have changed. >> >> it definitely sounds like it. >> Would be good to investigate what might have changed in the call path >> that *sets* the variable to check why it is ending up being nil. Maybe >> it shouldn't be set or initialized to nil but to an empty collection in >> those cases? >> >> Michael >> >> _______________________________________________ >> Pharo-project mailing list >> [email protected] >> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >> > > > _______________________________________________ > Pharo-project mailing list > [email protected] > http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >
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