C++ Reactive Programming

Converting events to IObservable<T>

We have now understood how one can convert an IEnumerable<T>-based pull program to an IObservable<T>/IObserver<T>-based push program. In real life, the event source is not as simple as we found in the number stream example given earlier. Let us see how we can convert a MouseMove event into a stream with a small MFC program:

We have chosen MFC for this particular implementation because we have a chapter dedicated to Qt-based reactive programming. In that chapter, we will be implementing Reactive programs in idiomatic asynchronous push-based streams. In this MFC program, we simply do a filtering operation to see whether the mouse is moving in a bounding rectangle and, if so, notify the observer. We are using ...