1. Refactoring via Program Slicing and Sliding Ran Ettinger Programming Tools Group University of Oxford In Panayas Reading Group 2 November, 2006

2. Are the two programs equivalent? ?=

3. Refactoring enables iterative and incremental software development

4. The gap: Refactoring tools are important but weak

5. Example: Fowlers video-store

10. Programmers use slices when refactoring

11. Challenge: Automatic slice-extraction Approach: Program Sliding

12. Sliding 1: statement-duplication

13. Rule of statement-duplication

14. Sliding 2: slicing on both sides

15. Sliding 2: a refinement rule

16. Example of over-duplication

17. Solution (sliding 3): final-use substitution

18. Sliding 3: statement-duplication with final-use substitution

19. Sliding 4: Slicing after final-use substitution

20. Sliding 4: a refinement rule

21. Sliding 5: compensation-free sliding

22. Sliding 5: a refinement rule

23. Potential implications of slides and sliding: Refactoring and beyond

24. Thanks!