Introduction

"Learning the fundamentals of a programming language is one thing: learning how to design and write effective programs in that language is something else entirely." What Scott Meyers wrote in the Introduction to Effective C++ is just as true for Perl.

Perl is a very high level languagea VHLL for the acronym-aware. It incorporates high-level functionality like regular expressions, networking, and process management into a context-sensitive grammar that is more "human," in a way, than that of other programming languages. Perl is a better text processing language than any other widely used computer language, or perhaps any other computer language, period. Perl is an incredibly effective scripting tool for Unix administrators, and it is the first choice of most Unix CGI scripters worldwide. Perl also supports object-oriented programming, modular software, cross-platform development, embedding, and extensibility.

There is a lot to learn about Perl.

Once you have worked your way through an introductory book or class on Perl, you have learned to write what Larry Wall, Perl's creator, fondly refers to as " baby talk." Perl baby talk is plain, direct, and verbose. It's not badyou are allowed and encouraged to write Perl in whatever style works for you.

You may reach a point at which you want to move beyond plain, direct, and verbose Perl toward something more succinct and individualistic. This book is written for people who are setting off down that path . Effective Perl Programming endeavors to teach you what you need to know to become a fluent and expressive Perl programmer. This book will provide you several different kinds of advice to help you on your way.

• Knowledge, or perhaps, "Perl trivia." Many different complex tasks in Perl have been or can be reduced to extremely simple statements. A lot of learning to program effectively in Perl is acquiring an adequate reservoir of experience and knowledge about the "right" ways to do things. Once you know good solutions, you can apply them to your own problems. Furthermore, once you know what good solutions look like, you can invent your own and judge their "rightness" accurately.

• How to solve problems. You may already have good analytical and/or debugging skills from your work in another programming language. This book will teach you how to beat your problems using Perl, by showing you a lot of problems and their solutions in Perl. It will also teach you how to beat the problems that Perl gives you, by showing you how to efficiently debug and improve your programs.

• Style. This book will teach you idiomatic Perl style, primarily by example. You will learn to write Perl more succinctly and elegantly. If succinctness isn't your goal, you will at least learn to avoid certain awkward constructs. You will also learn to evaluate your efforts and those of others.

• How to grow further. This book is a little less than three hundred pages long. Although it purports to be a book on intermediate to advanced Perl, not a whole lot of advanced Perl will actually fit between its covers. A real compendium of advanced Perl would require thousands of pages. What this book is really about is how you can make yourself an advanced Perl programmer how you can find the resources you need to grow, how to structure your learning and experiments, and how to recognize that you have grown.

This is intended to be a thought-provoking book. There are subtleties to many of the examples. Anything really tricky will be explained, but a lot of other things that are simple but not always obvious will be left to stand on their own. Don't be alarmed if you find yourself puzzling something out for a while. Perl is an idiosyncratic language and in many ways is very different from other programming languages. Remember that fluency and style only come through practice and reflection, and that while learning is hard work, it is also enjoyable and rewarding .