Lift up Conditional - the Magical Refactoring

(These slides are from the O'Reilly Quality Code Bootcamp that was delivered online in April and July 2023).

The first time I saw this powerful refactoring technique demonstrated, I was confused. It seemed like some dark magic indeed. But then I tried a practical example for myself, got my head around it and fell in love.

“Lift up conditional” allows you to take messy code filled with nested conditionals and repetitious code, and detangle it into something simple and beautiful that will suddenly be easier to understand and cheaper to maintain. Join me for a hands-on example and your own moment of revelation.

Transcript

1. Samman Learning Hour Lift up conditional License: CC-BY-SA-4.0 Attribution: sammancoaching.org @ClareSudbery Day 3 Part 4
2. Hands-on techniques to improve your code base @ClareSudbery Quality Code Bootcamp Day 3 Continuous improvement – refactoring legacy code
3. POLL: Parsing if statements Which of the below if statements is equivalent to this one? if(colour1 == colour1 && colour2 == colour2) @ClareSudbery Day 3 Part 4
4. POLL: Parsing if statements Which of the below if statements is equivalent to this one? if(!(colour1 == "green" && colour2 == "blue")) @ClareSudbery Day 3 Part 4
5. POLL: Parsing if statements Which of the below if statements is equivalent to this one? if(colour1 != "green" && colour2 != "blue") @ClareSudbery Day 3 Part 4
6. POLL: Parsing if statements Which of the below if statements is equivalent to this one? if(colour1 == "green" && colour1 == "blue") @ClareSudbery Day 3 Part 4
7. POLL: Parsing if statements Which of the below if statements is equivalent to this one? if(!(colour1 != "green" && colour2 != "blue")) @ClareSudbery Day 3 Part 4
8. @ClareSudbery Parsing if statements - solutions Day 3 Part 4
9. @ClareSudbery Lift up conditional - schematic Day 3 Part 4
10. @ClareSudbery Starting point Day 3 Part 4
11. @ClareSudbery END RESULT Part 1 - Tidied if statement Day 3 Part 4
12. @ClareSudbery END RESULT Part 2 - Switch statement (ready for polymorphism) Day 3 Part 4
13. @ClareSudbery STEP 1 - Duplicate nasty code inside if..else Day 3 Part 4
14. @ClareSudbery STEP 2 - Replace relevant conditions with true / false Day 3 Part 4
15. @ClareSudbery STEP 3 - Remove falses Day 3 Part 4
16. @ClareSudbery STEP 4 - Remove unnecessary conditions Day 3 Part 4
17. @ClareSudbery BACK TO STEP 1 - Duplicate code inside if..else Day 3 Part 4
18. @ClareSudbery END RESULT Part 1 - Tidied if statement Day 3 Part 4
19. @ClareSudbery END RESULT Part 2 - Switch statement (ready for polymorphism) Day 3 Part 4
20. @ClareSudbery Lift up conditional - schematic Day 3 Part 4
21. Demo Lift up conditional @ClareSudbery Lift up conditional Day 3 Part 4
22. @ClareSudbery • Code is here: https://github.com/emilybache/GildedRose-Refactoring-Kata • Requirements are in the readme • Visit this url to fork (top right), then clone the code: • https://github.com/emilybache/GildedRose-Refactoring-Kata.git • Choose your language Use the demonstrated method to “lift up” the conditional Day 3 Part 4 Lift up conditional
23. Mid-exercise check-in @ClareSudbery Day 3 Part 4 Lift up conditional
24. @ClareSudbery • Code is here: https://github.com/emilybache/GildedRose-Refactoring-Kata • Requirements are in the readme • Visit this url to fork (top right), then clone the code: • https://github.com/emilybache/GildedRose-Refactoring-Kata.git • Choose your language Use the demonstrated method to “lift up” the conditional Day 3 Part 4 Lift up conditional
25. POLL: Lift up conditional – Conclusions, part 1 How confident do you feel about your ability to use the "lift up conditional" technique? @ClareSudbery Day 3 Part 4
26. POLL: Lift up conditional – Conclusions, part 2 How confident do you feel that this is an effective technique? @ClareSudbery Day 3 Part 4
27. Questions? @ClareSudbery Day 3 Part 4 Lift up conditional
28. Day 3 – Links @ClareSudbery Day 3 Part 5 Useful links from today: github.com/claresudbery/OReilly-Bootcamp- Resources/blob/main/README.md#day-three
29. Sudbery Software Engineering Ltd Does your team want help to improve their software delivery? I offer coaching and workshops Email: Sudbery.software@gmail.com Mastodon: @claresudbery@mastodon.social LinkedIn: linkedin.com/in/clare-sudbery-she-her-35939540/ Podcast: madetech.com/podcast/
30. @ClareSudbery O'Reilly learning Day 3 Part 1