In this chapter, we have discussed the foundations of object-oriented programming (OOP) in Delphi. We have considered the definition of classes and the use of methods, encapsulation, and memory management, but also some more advanced concepts such as properties and the dynamic creation of components. Then we moved to inheritance, virtual and abstract methods, polymorphism, safe typecasting, interfaces, exceptions, and class references.
This is certainly a lot of information if you are a newcomer. But if you are fluent in another OOP language or if you've already used past versions of Delphi, you should be able to apply the topics covered in this chapter to your programming.
Understanding the secrets of Delphi's language and library is vital for becoming an expert Delphi programmer. These topics form the foundation of working with the VCL and CLX class libraries; after exploring them in the next two chapters, we'll finally go on to explore the development of real applications using all the various components provided by Delphi.
In the meantime, Chapter 3 will give you an overview of the Delphi run-time library (mainly a collection of functions with little OOP involved). The RTL is a collection of assorted routines for performing basic tasks with Delphi. Chapter 4 will give you more information about the language, discussing features related to the structure of the Delphi class library, such as the effect of the published keyword and the role of events. That chapter, as a whole, will discuss the overall architecture of the component library.