Johan Torp wrote:
I developed some classes which had similar functionality to slots and signals and now I want to transition to using slots and signals.
I often find myself in the situation of wanting to listen to changes of a value type variable. I had a templated class called ConcreteObservable which encapsulated a get/set-able value and provided ways of listening to changes in the value. I.e. ConcreteObservable<bool> was a bool which you could get, set and listen to.
Your idea is essentially a 'property' whose change in value triggers a notification event. Both Java and dotnet have such functionality combined with the idea of Javabean properties in the former and dotnet component properties in the latter. I have worked on my own with the idea of a C++ 'property', but not with enough personal satisfaction to put it in the sandbox or submit it to Boost. Reece Dunn, I believe, has submitted his own idea of a C++ 'property' as an implementation to the sandbox in the past. Obviously notifiers as events can be built into the idea of a C++ 'property' whenever the property changes and Java goes so far as to actually build into their idea of a Javabeans 'property' the idea of being able to cancel the change before it happens by an event ( signal ) listener ( slot ). I do not think the idea of an event whenever a 'property' changes should be part of the signals library itself but it can, and should IMO, use the signals library whenever the change occurs. I think the idea itself of a signalled 'property' change belongs in its own separate implementation, since the signals library is sufficient enough providing just the notion of signals and slots ( or events and handlers as others may call it ).