Short presentation related to the zipper data structure

1. Zippers!
Functional programming !

2. –Gérard Huet!

3. “Zipper is a functional cursor
into a data structure”

4. Often used where there is some concept of
'focus' or of moving around in some set of
data.!

5. Includes and generalizes
the gap buffer technique

7. Data structure?
Can be adapted to Lists, trees, and other recursively
defined data structures!

8. Data structure!
The current subtree / subset!
Trees, Paths and Locations
The current element / Zipper cursor!

9. Scalaz

10. NonEmptyList!

11. Sample list…
(2 3 5 7 11)

12. Traversing…
2 (3 5 7 11)
Zipper!

13. Traversing…
(2) 3 (5 7 11)
Zipper!

14. Traversing.…
Reverse???!
(3 2) 5 (7 11)
Zipper!

15. Traversing.…
Reverse???!
Parent retrieve = 0(1)!
(3 2) 5 (7 11)
Zipper!

16. Traversing..…
(5 3 2) 7 (11)
Zipper!

17. Traversing……
(7 5 3 2) 11
Zipper!

18. Traversed.
(11 7 5 3 2)

19. “Imm
utab
How to add an item?!
How to delete an item?!
Changes, Insertions and
Deletions?
“Laziness”?!
ility”
?
!

20. Depends on the data structure, but prefer lazy
evaluations

21. Implementation
http://scalaz.googlecode.com/svn/continuous/latest/browse.sxr/scalaz/TreeLoc.scala.html
http://scalaz.googlecode.com/svn/continuous/latest/browse.sxr/scalaz/Zipper.scala.html
!