Growing a language

Delphi is not a stagnant language—it continues to grow and evolve. Sometimes, these changes are evolutionary, while sometimes they add optional functionality. Once in a while, they cause disruption when upgrading your code, but it has surprisingly good backward compatibility.

These extensions started with the earliest versions of Turbo Pascal, the precursor to Delphi back in the 1980s.

Adding objects to Pascal

In 1989, Turbo Pascal 5.5 was released. It was this historical upgrade that took Borland's extension of Pascal from a structured language to the object-oriented arena. A completely separate manual was provided just to educate developers about the concepts of object-oriented programming:

Figure 3.1 – Turbo Pascal's object-oriented guide

This laid the groundwork for class inheritance, encapsulation of data and functionality in objects that limit access to private fields through published properties, and...