In April 2009, Shaun Smith posted the following on his blog:

Over the following six months, Shaun’s Robotlegs concept gradually picked up support, gathered momentum, and through the collective efforts of a group of people who had never met in person, Robotlegs 1.0 was born.

Open source development is well understood in our community. But we shouldn’t take it for granted. I (Stray) was working on some of the diagrams for the book on a flight back from the first ever Robotlegs team meet-up, and the man next to me started asking questions about what I was doing. When I told him I was working on a book about a project that was the collective effort of strangers from all over the world, none of whom expected to be paid, he was amazed.

Robotlegs has brought coding-joy to thousands of AS3 developers. There is something about using Robotlegs that not only solves our immediate coding problems but gives us insight into our architecture on a much deeper level. Joel and I each have many, many experiences of people sharing with us how Robotlegs has clarified concepts that were previously confusing to them. After only a short time using Robotlegs, developers tell us that they have become better programmers and architects generally.

The most rewarding part of being involved with Robotlegs has been witnessing people grow as programmers to the point where they become contributors of utilities and patches for the framework. Robotlegs owes its success not just to Shaun, Till, Robert and Joel, but to the dozens of people who got involved in the early discussions, the scores who have built utilities and extensions, the hundreds of early-adopters who have written tutorials and shared their enthusiasm with others, and the thousands of users who have put their trust in the framework and given Robotlegs a shot.

Shaun could never have dreamed that his little framework idea would grow and grow until O’Reilly commissioned a book about it. We hope this book does justice to Robotlegs, and the collective energy that has brought it into our world.

ActionScript Developer’s Guide to Robotlegs is for Flash, Flex and AIR application developers interested in using, or already using, the Robotlegs AS3 framework. It demonstrates and explains the core functionality of the Robotlegs framework and also explores the deeper issues in AS3 architecture generally and how developers can solve those problems in clean and flexible ways using Robotlegs.

This book also covers testing (TDD) of Robotlegs applications, and the rich example applications come with extensive tests.

This book is not for developers who are brand new to object-oriented programming. It assumes some understanding of classes, interfaces and inheritance as implemented in AS3. It is not a quick reference guide to the Robotlegs API.

The following typographical conventions are used in this book:

This book is here to help you get your job done. In general, you may use the code in this book in your programs and documentation. You do not need to contact us for permission unless you’re reproducing a significant portion of the code. For example, writing a program that uses several chunks of code from this book does not require permission. Selling or distributing a CD-ROM of examples from O’Reilly books does require permission. Answering a question by citing this book and quoting example code does not require permission. Incorporating a significant amount of example code from this book into your product’s documentation does require permission.

We appreciate, but do not require, attribution. An attribution usually includes the title, author, publisher, and ISBN. For example: “ActionScript Developer’s Guide to Robotlegs by Joel Hooks and Stray (Lindsey Fallow) (O’Reilly). Copyright 2011 Newloop Ltd. and Visual Empathy LLC, 978-1-449-30890-2.”

If you feel your use of code examples falls outside fair use or the permission given above, feel free to contact us at [email protected].

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Shaun Smith, Till Schneidereit and Robert Penner—without you there would be no Robotlegs. You rock.

We’d like to thank our tech reviewers, who contributed insights that greatly improved the book, as well as encouraging us over the finish line: Simon Bailey, Angela Relle, Sean Moore, Doug Reynolds, Neil Manuell, Dave Hunter, Mike Cann, Weyert de Boer and James Wagstaff.

Stray says: “I need to thank my wife and family for unending support and ensuring I still ate, drank and slept while working on this book. And the amazing twitter AS3 community who boost me regularly with their love for Robotlegs. And Joel for sharing this opportunity with me and tolerating my bossiness.”

Joel says: “Kristina, Cree, Haze, Tripp and Cyan—thanks for putting up with me!”

A huge thank you to Rich Tretola, Meghan Blanchette, Mary Treseler and all at O’Reilly who made this book possible.