Summary

In this chapter, we defined what OOP is and why we’d want to take advantage of it. Then, we clearly defined what classes and objects are in PHP. We then went through some examples for each of the Four Pillars of OOP. We learned what abstraction, encapsulation, inheritance, and polymorphism are and how they work in PHP. We’ve also briefly gone through the PSRs because we don’t just want to go ahead and invent standards and start writing codes – we want to produce clean PHP code that is easy to understand and maintain, especially in an enterprise environment where you can expect to work with a lot of other developers, and where your codes will have to be very readable and maintainable for years to come.

This chapter should have prepared you to start writing actual object-oriented PHP code – and in our TDD example project, we will take advantage of the OOP capabilities of PHP.

In the next chapter, we will talk about unit testing. We will...