How to Use This Book

You Need a Browser, and Nothing Else

Every example in this book runs in the QF Code IDE, free, in your browser, no installation, no account. Open it in one tab, keep this book open in another, and type along as you go. Reading without typing will teach you less than typing every example yourself, even the ones that look trivial.

Read It in Order

This book builds one project, a text adventure, one chapter at a time. Chapter 4 assumes you've written chapter 3. Chapter 10 assumes chapter 9 already happened. Skipping ahead means arriving somewhere without the code the chapter expects you to have. If you want to preview later material, that's fine, but come back and work through the chapters between here and there before trying to continue the project itself.

There's exactly one exception: chapter 13, on recursion, is explicitly optional and doesn't touch the ongoing project at all. Skip it, return to it later, or skip it entirely, your game is unaffected either way.

Every Chapter Ends With a Checkpoint

At the end of each chapter, you'll find a checkpoint: the code your project should have going in, and the code it should have coming out. If something stops working partway through a chapter and you can't tell why, load that chapter's starting checkpoint and try again from there, rather than hunting through your own edits for a typo. Nothing about getting stuck here means you did something wrong. It means the checkpoint did its job.

"Make It Yours" Isn't Optional, Even Though You Can Skip It

Every chapter includes a prompt asking you to change something, your own room name, your own riddle, your own item, your own command. You can absolutely skip these and just follow along verbatim. But the actual point of this book is that by chapter 14, the game is yours, not a copy of mine. The "Make It Yours" prompts are where that actually happens, a little at a time, chapter by chapter. Skipping all of them gets you a working copy of my game. Using even half of them gets you your own.

The Appendices Aren't Meant to Be Read Straight Through

Appendices A through E are reference material, meant to be consulted, not read cover to cover the way the chapters are. Appendix A is every built-in, in detail. Appendix E is the short version, for when you just need a syntax reminder. Appendix B is every reserved word. Appendix C is for when an error message stops making sense. Appendix D is honest about what QF Code can't do yet. Skim them once so you know they exist, then come back to whichever one you need, whenever you need it, for as long as you're writing QF Code.

When You Get Stuck

Getting something wrong is a normal, expected part of working through this book, not a sign you're doing it badly. Every error message you're likely to hit is documented in Appendix C, in plain language, with the fix right next to it. If a chapter's example genuinely doesn't run, check it character for character against the checkpoint first, QF Code is exact about capitalization inside strings, matching end keywords, and parentheses, even though its own keywords are case-insensitive.

Now open the IDE, and turn the page.

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