Limitations of classical event processing models

The whole purpose of making a tour of the event processing supported by various platforms was to put things into the proper perspective. The event response logic in these platforms is mostly coupled with the platform where the code is written. With the advent of multi-core programming, writing low-level multi-threaded code is difficult and declarative task-based programming models are available with the C++ programming language. But the event sources are mostly outside the C++ standard! The C++ language does not have a standard GUI programming library, an interface standard to access external devices, and so on. What is the way out? Luckily, events and data from external sources can be aggregated into streams (or sequences) and by using functional programming constructs such as Lambda functions can be processed very efficiently. The added bonus is that if we resort to some kind of restrictions regarding the mutability of variables and streams, concurrency, and parallelism are built into the stream processing model.