Don’t Don’t Repeat Yourself

Summary

• “Don’t repeat yourself” (DRY) is a widely accepted programming principle, but it has several limitations
• An alternative derivation of DRY is presented, that aims to alleviate some of these limitations
• Programs are made up of functions, and to make functions maximally reusable they should:
  - Have the most lenient preconditions
  - Have the most strict postconditions
  - Perform the smallest amount of non-trivial work

If you think this article is too long, you can skip to Should I refactor my code…