DRY

External

• Pragmatic Programmer, The: From Journeyman to Master by Andrew Hunt and David Thomas

Internal

• Software Engineering
• Designing|Designing Modular Systems

Overview

Don't Repeat Yourself (DRY) principle sys: "Every piece of knowledge should have a single, unambiguous, authoritative representation within a system."

If you are in the position to write the second time the same behavior (copy-and-paste) that means the behavior belongs into a reusable function. Duplication forces people to make a change in multiple places, and that is not good.

DRY and Coupling

DRY and Coupling

Organizatorium

• The "rule of three" for software reuse suggests the you should turn something into a reusable component when you find three places that you need to use it. https://blog.codinghorror.com/the-delusion-of-reuse/ Facts and Fallacies of Software Engineering https://www.amazon.com/exec/obidos/ASIN/0321117425/