That does not answer my problem. 2 both is: #fraction (with 1 denominator) and is: #integer so how do you implement? or: [super is: #number] ?
2013/6/25 Igor Stasenko <siguc...@gmail.com> > On 25 June 2013 12:47, Nicolas Cellier > <nicolas.cellier.aka.n...@gmail.com> wrote: > > But in some cases, you will end up with an object that is more than one > > thing: > > - a Number > > - an Integer > > - a Fraction > > For example 0 shall answer yes to these 3. > > So ^foo == #specialName just does not work, or you end up with caseOf: > > > > err, why? > > if you define it like: > > Number>>is: symbol > ^ symbol == #number > > > 0 is: #number => true > 0.0 is: #number => true > 0/1 is: #number => true > ? > > It is actually up to implementor how to his own classes should process > #is: message. > The only invariant (which imo best one), that Object should always > answer false to #is: message no matter what parameter you passed, to > avoid any ambiguous cases and keep things simple and easy to remember. > That means, that unless you override this method in own class, its > instances will always answer false to #is: message. > And when you override it, you are free to define it the way you like... > > MyClass>>is: foo > ^ foo class == self class > or > MyClass>>is: foo > ^ foo class name == self class name > or > > MyClass>>is: foo > ^ foo isKindOf: MyClass > > (no limits to imagination :) > > -- > Best regards, > Igor Stasenko. > >
