Part 1. Tools and concepts
When you have a job to do, a natural way to start is to first find the tools you need. In the object-oriented world, the distinction between tools and concepts is blurry. There are tools to describe and implement conceptual relationships, and there are conceptual strategies that act as tools for the design process.
This first part of the book is about these tools and concepts; most of them belong to the category of object-oriented programming and application design. We will be applying these to the challenges of web programming in parts 3 and 4. We will look at the syntax of objects and classes in PHP, why and how these can be put to use, and how to use design patterns and object-oriented principles.