Presented at Philippine Ruby Users Group Meetup last January 23, 2014

5. Marc Ignacio
twitter: @pd_i
github: @padi

6. Refactoring

8. Refactoring
Long Methods

9. Definitions

10. Refactoring

11. Refactoring
● “…is a disciplined technique for
restructuring an existing body of code,
altering its internal structure without
changing its external behavior.”
- refactoring.com

12. Refactoring
● “…is a disciplined technique for
restructuring an existing body of code,
altering its internal structure without
changing its external behavior.”
- refactoring.com

13. Refactoring
● “…is a disciplined technique for
restructuring an existing body of code,
altering its internal structure without
changing its external behavior.”
- refactoring.com

14. Refactoring
● “…is a disciplined technique for
restructuring an existing body of code,
altering its internal structure without
changing its external behavior.”
- refactoring.com
● “Tests are implied.” - Katrina Owen

15. Refactoring
● “…is a disciplined technique for
restructuring an existing body of code,
altering its internal structure without
changing its external behavior.”
- refactoring.com

16. Refactoring
a technique for restructuring
code without changing
behavior

17. Refactoring
a technique for making code
suck less without changing
behavior

18. Long Methods

19. Long Methods
● “a method, function, or procedure that has
grown too large”

20. Long Methods
● “a method, function, or procedure that has
grown too large”

21. Long Methods
● “a method, function, or procedure that has
grown too large”
● IMO: a method with a flog score of > 20

22. Flog
● ruby gem for analyzing code pain
● “Flog reports the most tortured code in an
easy to read pain report.”
● “The higher the score, the more pain the
code is in.”

23. Flog Scores
●
●
●
●
●
●
●
0-10 Awesome
11-20 Good enough
21-40 Might need refactoring
41-60 Possible to justify
61-100 Danger
100-200 Whoop, whoop, whoop
200 + Someone please think of the children

24. Long Methods
● If a method is long, it’s likely that it does too
many things.
● “Methods, like classes, should have single
responsibility.” - Sandi Metz
● SRP - every class should have a single
responsibility, and that responsibility
should be entirely encapsulated by the class

25. Techniques

26. Techniques
●
●
●
●
●
Extract Method
Inline Method
Inline Temp
Replace Temp with Query
Replace Method w/ Method Object

27. Examples

28. Resources

31. Resources
- "Refactoring: Improving the Design of Existing Code",
Martin Fowler
- refactoring.com
- jakescruggs.blogspot.com/2008/08/
whats-good-flog-score.html
Code:
- "Refactoring, Ruby Edition", Martin Fowler et al.
- "Therapeutic Refactoring", Katrina Owens

32. Questions?

33. Thanks!