The Don’t Repeat Yourself Principle has swept the world, it is often the first thing new engineers are taught. It has probably affected your current code base in a big way. However, despite your code being “DRY”, your code is hard to change. The same files have to be changed over and over for seemingly unrelated reasons, and code brittleness due to tight coupling abound. You might ask yourself, “Why is this happening?”
In this talk I will teach listeners that the DRY Principle is actually about eliminating duplicate representations of ideas not duplicate code. Duplicate code is often misidentified as part of this principle, and attempts to clean it up are made. The end result is lots of divergent change (one place changes for many reasons), yielding tons of pain for the development team, and eventually a clamor for a complete rewrite of the system.
Steven Solomon
