Understanding the Four Rules of Simple Design
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The document discusses the four rules of simple design according to lessons learned from observing thousands of pairs working on Conway's Game of Life: 1) Tests Pass, 2) Expresses Intent, 3) No Duplication (DRY), and 4) Small. The DRY rule aims to have each piece of knowledge represented only once to avoid duplication. The Small rule questions whether any code is unused, duplicates are extracted too far, or duplicate abstractions exist. Conway's Game of Life outlines the rules for how living and dead cells interact and change states in the game.
Understanding the Four Rules of Simple Design
- 1. Understanding the Four Rules of Simple Design
- 2. Lessons from watching thousands of pairs work on Conway's Game of Life by Corey Haines1 1 Buch bei Leanpub, Twitter
- 3. Focused on the almost continuous decisions made around things such as naming variables and extracting methods
- 4. It's not about any particular technique. It's not about any particular language.
- 5. It's about better design, not good versus bad design.
- 6. Four Rules of Simple Design 1. Tests Pass 2. Expresses Intent 3. No Duplication (DRY) 4. Small
- 7. Don't Repeat Yourself This rule isn't about code duplication; it is about knowledge duplication: Every piece of knowledge should have one and only one representation. — The Pragmatic Programmer2 2 http://pragprog.com/book/tpp/the-pragmatic-programmer
- 8. Small • Any vestigial code that is no longer used? • Any duplicate abstractions? • Extracted too far?
- 9. Conway's Game of Life 1. If a living cell has less than two living neighbors, it will die. 2. If a living cell has two or three living neighbors, it stays alive. 3. If a living cell has more than three living neighbors, it will die. 4. If a dead cell has exactly three living neighbors, it becomes alive.