RE: Magritte Validations

I need something like that for events in ICalMagritte where either duration or end has to be nil. I define a condition on the object (event) like this: MACondition subclass: #ICMEventCondition value: aCheckedMemento ^(self endOf: aCheckedMemento) isNil or: [ (self durationOf: aCheckedMemento) isNil ] endOf: aCheckedMemento ^aCheckedMemento cache at: ICEvent descriptionEnd durationOf: aCheckedMemento ^aCheckedMemento cache at: ICEvent descriptionDuration ICEvent class >> #descriptionContainer ^super descriptionContainer addCondition: ICMEventCondition new labelled: ICMEventCondition defaultLabel; yourself There are probably better ways but this works nice for me. Cheers Philippe