Introduction

Developers beginning their foray into software development often start out creating small, short-lived projects for their personal use. As they advance and gain experience, the projects they work on require occasional maintenance or upgrades. Eventually, they take on projects that span years or even decades, revisiting areas of the code hundreds of times.

If it’s been long enough since you last visited an area of the code base, the code can feel foreign even if it’s something you wrote. It’s like visiting your hometown after a decade away. If you’re working on a big enough project, this might happen more often than not each time you take on a new task. How can you help yourself stay productive?

A key practice in effective software development is writing code that doesn’t get in the way of writing more code in the future. Creating code that’s flexible enables you to reuse it in more ways. Creating code that you can extend enables others to customize portions for their own use. And when you keep your variety of concerns nice and tidy, you’ll be left with a code base you can jump into most any time or place.

This sampler draws on chapters from three Manning books to help you internalize the thought processes that lead to extensible, understandable software. Two chapters from my book, Practices of the Python Pro, lay the foundation for breaking down code into manageable chunks and making them flexible. From that base, you’ll see how to realize the benefits of extensible code with a chapter from Object Design Style Guide and The Design of Web APIs.

These concepts are applicable for people at any stage of their software development career, and you should come away from this collection of chapters with an appetite for building software that will last you an order of magnitude longer than you’re accustomed to now.