Functional Data Structures

Transcript

1. by Alexander Lomov
2. Agenda: 1. Functional data primitives. What are they? 2. How to live with immutable things? 3. Evaluating space and time. 4. Benefits for web developers.
4. Functional data primitives.
5. atoms sexprs
6. What is an atom?
7. ϷКίДЙОЛЙ㽞 ЂЕάНТЗ "UPNJTN
8. An atom is the smallest constituent unit of ordinary matter that has the properties of a structural element. In our case atoms are fundamental data types such as numbers, string, bytes and etc.
9. atoms / s-expressions (sexp интимного тут нет) атомисты atomic symbols" represented as "strings of capital Latin letters and digits with single embedded blanks" (i.e., character string and numeric literals).
10. s-expressions, sexprs or sexps - “symbolic expression”, are a notation for nested list tree-structured data in Lisp. s-expression = ((x . y) | atom), where x and y are s-expressions
11. (2 * (3 + 4))
12. (* 2 (+ 3 4)) (2 * (3 + 4)) “Польская нотация”
13. cons cat cdr
14. cons = constructor (cons 1 (cons 2 (cons 3 nil))) == (list 1 2 3)
15. car = the first element (content of address register) head (cons 1 (cons 2 (cons 3 nil)))
16. cdr - the second element (content of decrement register) tail (cons 1 (cons 2 (cons 3 nil)))
17. How to live with immutable things?
18. Are we really can live without changing variable values?
20. http://valve.github.io/blog/2014/07/04/from-object-to- functional-immutability/ Actually we already do
21. http://valve.github.io/blog/2014/07/04/from-object-to- functional-immutability/ But we can avoid it
22. How does it work in functional languages?
25. The Tralfamadorians are described as being able to see in four dimensions, allowing them to simultaneously observe any and every point in the space-time continuum.
26. https://www.cs.cmu.edu/~sleator/papers/making-data- structures-persistent.pdf
28. Really worth reading
29. Evaluating space and time.
30. We all know what O(n) means.
31. We all know what O(n) means. It means the worst case.
32. amor tiza tion
33. Amortized Analysis is a method for analyzing a given algorithm's time complexity, or how much of a resource, especially time or memory in the context of computer programs, it takes to execute.
34. Benefits for web developers
35. We use Linux
36. We love Linux
37. RCU read-create-update libcds concurrent data structures http://libcds.sourceforge.net/
38. http://tonsky.me/talks/2015-codefest/
39. Laziness