Preface

This book is designed to help you write better Perl code: in fact, the best Perl code you possibly can. It's a collection of 256 guidelines covering various aspects of the art of coding, including layout, name selection, choice of data and control structures, program decomposition, interface design and implementation, modularity, object orientation, error handling, testing, and debugging. These guidelines have been developed and refined over a programming career spanning 22 years. They're designed to work well together, and to produce code that is clear, robust, efficient, maintainable, and concise.

Mind you, that's not easy to achieve. Conciseness can be the natural enemy of clarity; efficiency the nemesis of maintainability. And armouring code to make it sufficiently robust can undermine clarity, efficiency, conciseness, and maintainability. Sometimes it's a case of: "Choose any one."

This book doesn't try to offer the one true universal and unequivocal set of best practices. There are as many ways of measuring code quality, and as many dimensions in which code can be judged, as there are programmers to make those assessments. Each programmer and each programming team will have their own opinions about the most important and desirable attributes of code.

What this book offers instead is a set of best practices: a set that is coherent, widely applicable, balanced in its aims, and that is based on real-world experience of how code is actually written, rather than on someone's ivory-tower theories on how code ought be created. Most of all, it's a set of practices that actually work, and that many developers around the world are already using. Much like Perl itself, these guidelines are about helping you to get your job done, without getting in the way.

If you're an experienced developer, it's almost certain that you won't like all of the suggestions that follow. You will find some of them unnatural or counterintuitive; others may feel excessively rigid and un-Perlish. Maybe they'll just seem unnecessarily different from the ways you're used to writing software, and from the long-ingrained coding habits you find so comfortable.

Try to put those feelings aside as you read through the advice in this book. Review it as you would any other proposed code enhancement: analyze the arguments that are made for these new practices; ask yourself whether you've ever fallen into the traps they seek to avoid; consider whether the coding techniques suggested here might be worth trying.

Just thinking about these issuesbecoming conscious of the way you currently write codecan be of enormous benefit, even if you don't adopt a single one of the recommendations that follow.