3.5 Guide to the Advanced Chapters

Now that we're familiar with metacharacters, flavors, syntactic packaging, and the like, it's time to start getting into the nitty-gritty details of the third concern raised at the start of this chapter, the specifics of how a tool's regex engine goes about applying a regex to some text. In Chapter 4, The Mechanics of Expression Processing, we see how the implementation of the match engine influences whether a match is achieved, which text is matched, and how much time the whole thing takes. We'll look at all the details. As a byproduct of this knowledge, you'll find it much easier to craft complex expressions with confidence. Chapter 5, Practical Regex Techniques helps to solidify that knowledge with extended examples.

That brings us to Chapter 6, Crafting an Efficient Expression. Once you know the basics about how an engine works, you can learn techniques to take full advantage of that knowledge. Chapter 6 looks at regex pitfalls that often lead to unwelcome surprises, and turns the tables to put them to use for us.

Chapters 4, 5, and 6 are the central core of this book. These first three chapters merely lead up to them, and the discussions in the tool-specific chapters that follow rely on them. They're not necessarily what you would call "light reading," but I've taken great care to stay away from math, algebra, and all that stuff that's just mumbo-jumbo to most of us. As with any large amount of new information, it likely takes time to sink in and internalize.