Book Image

C++ Reactive Programming

By : Praseed Pai, Peter Abraham
Book Image

C++ Reactive Programming

By: Praseed Pai, Peter Abraham

Overview of this book

Reactive programming is an effective way to build highly responsive applications with an easy-to-maintain code base. This book covers the essential functional reactive concepts that will help you build highly concurrent, event-driven, and asynchronous applications in a simpler and less error-prone way. C++ Reactive Programming begins with a discussion on how event processing was undertaken by different programming systems earlier. After a brisk introduction to modern C++ (C++17), you’ll be taken through language-level concurrency and the lock-free programming model to set the stage for our foray into the Functional Programming model. Following this, you’ll be introduced to RxCpp and its programming model. You’ll be able to gain deep insights into the RxCpp library, which facilitates reactive programming. You’ll learn how to deal with reactive programming using Qt/C++ (for the desktop) and C++ microservices for the Web. By the end of the book, you will be well versed with advanced reactive programming concepts in modern C++ (C++17).
Table of Contents (20 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Integrating the RxCpp library with the Qt event model


We already saw the Qt framework from a bird's eye view in the previous sections. We learned how to handle Qt events, especially mouse events and the signals/slots mechanism. We also learned about the RxCpp library and its programming model in the previous two chapters. In the process, we came across many significant reactive operators that matter while writing programs leveraging the reactive approach.

In this section, we are going to write an application to handle mouse events in a label widget, which is similar to the previous example. In this example, instead of handling mouse events to emit signals (like we did in the last example), we will be subscribing to Qt mouse events using the RxCpp subscriber and will filter different mouse events from the resultant mouse events Stream. The events (that are not filtered out) will be related to the subscribers.

Qt event filter – a reactive approach

As mentioned previously, the Qt framework has...