The document discusses different programming paradigms and which one may be best. It describes object-oriented programming, imperative programming, and declarative programming. For each, it provides examples in code to illustrate the paradigm. It argues that while imperative programming is popular and easy, it can be error-prone and not scale well. Declarative programming is described as simpler, safer, and more scalable by declaring intent rather than implementation. In the end, the document concludes that no single paradigm is best, and that they are often used together in practice.

1. PROGRAMMING
PARADIGMS
WHICH ONE IS THE BEST?
@akashivskyy

2. PROGRAMMING
PARADIGMS

3. WAY OF LOOKING AT
CONTROL FLOW AND
EXECUTION OF A PROGRAM

4. 1. OBJECT-ORIENTED
PROGRAMMING

5. PROGRAM IS DEFINED BY
OBJECTS WHICH COMBINE
STATE AND BEHAVIOR

6. 3 ASSUMPTIONS

7. 1. ABSTRACTION
2. ENCAPSULATION
3. INHERITANCE

8. protocol Shape !
var area: Double
"
func printShapeArea(shape: Shape) !
println("area = (shape.area)")
"

9. struct Square: Shape !
let side: Double
let area: Double !
return side # side
"
"
printShapeArea(Square(side: 4)) // 16.$

10. struct Circle: Shape !
var radius: Double
var area: Double !
return M_PI # radius # radius
"
"
printShapeArea(Circle(radius: 2)) // 12.56

11. struct Plane: Shape !
var area: Double !
return Double.infinity
"
"
printShapeArea(Plane()) // infinity

12. 1. ABSTRACTION
2. ENCAPSULATION
3. INHERITANCE

13. class EncryptionAssistant !
private var key = "42$mlg$crub"
public func encrypt(pass: String) -> String !
return rsaEncrypt(pass, key)
"
"

14. let assistant = EncryptionAssistant()
assistant.encrypt("secret") // 1Ll$$Myn4RtY
assistant.key // compile error!

15. 1. ABSTRACTION
2. ENCAPSULATION
3. INHERITANCE

16. VEHICLE
RAILWAY ROAD
TRAM TRAIN BICYCLE CAR

17. class Car !
var color: String = "red"
var name: String !
return "(color) car"
"
"
class BlueCar: Car !
override var color = "blue"
"

18. Car().name // red car
BlueCar().name // blue car

19. 2. IMPERATIVE
PROGRAMMING

20. IMPERATIVE PHRASES WHICH
CHANGE THE GLOBAL STATE OF
A PROGRAM

21. let numbers = [1, 2, 3, 4, 5, 6]
var sum = $
var odds: [Int] = []
for number in numbers !
sum += number
if number % 2 == 1 !
odds.append(number)
"
"

22. getRemoteData("url", ! data, error in
if error == nil !
parseData(data, ! parsed, error in
if error == nil !
handleParsedData(parsed)
" else !
displayError(error)
"
")
" else !
displayError(error)
"
")

23. IMPERATIVE
PROGRAMMING IS
THE MOST POPULAR

24. IMPERATIVE
PROGRAMMING IS
THE EASIEST

25. IMPERATIVE
PROGRAMMING IS
THE WORST

26. 1. ERROR-PRONE
2. NOT SCALABLE
3. TOO COMPLICATED

27. getRemoteData("example.com", ! data, error in
if error == nil !
parseData(data, ! parsed, error in
if error == nil !
handleParsedData(parsed)
" else !
displayError(error)
"
")
" else !
displayError(error)
"
")

28. getRemoteData("example.com", ! data, error in
if error == nil !
parseData(data, ! parsed, error in
if error == nil !
if parsedDataValid(parsed) !
handleParsedData(parsed)
"
" else !
displayError(error)
"
")
" else !
displayError(error)
"

29. getRemoteData("example.com", ! data, error in
if error == nil !
parseData(data, ! parsed, error in
if error == nil !
if parsedDataValid(parsed) !
saveParsedDataInCache(parsed, ! error in
if error == nil !
handleParsedData(parsed)
" else !
displayError(error)
"
")
"
" else !

30. getRemoteData("example.com", ! data, error in
if error == nil !
parseData(data, ! parsed, error in
if error == nil !
if parsedDataValid(parsed) !
saveParsedDataInCache(parsed, ! error in
if error == nil !
handleParsedData(parsed, ! error in
if error == nil !
displaySuccess()
" else !
displayError(error)
"
")

32. 3. DECLARATIVE
PROGRAMMING

33. DECLARE WHAT YOU’RE
TRYING TO ACCOMPLISH, NOT
HOW TO DO IT

34. let numbers = [1, 2, 3, 4, 5, 6]
var sum = $
var odds: [Int] = []
for number in numbers !
sum += number
if number % 2 == 1 !
odds.append(number)
"
"

35. var sum = $
var odds: [Int] = []
let numbers = [1, 2, 3, 4, 5, 6]
for number in numbers !
sum += number // reduction
if number % 2 == 1 ! // filtration
odds.append(number)
"
"

36. let numbers = [1, 2, 3, 4, 5, 6]
let sum = reduce(numbers, $, ! memo, number in
return memo + number
")
let odds = filter(numbers, ! number in
return number % 2 == 1
")

37. let numbers = [1, 2, 3, 4, 5, 6]
let sum = reduce(numbers, $, +)
let odds = filter(numbers, ! $$ % 2 == 1 ")

38. getRemoteData("example.com"
iferror==nil!
parseData(data,!parsed,
iferror==nil!
ifparsedDataValid(pars
saveParsedDataInCach
iferror==nil!
handleParsedData(
iferror==nil!
displaySuccess
"else!
displayError(e
"
")
"else!
displayError(error
"
")
"
"else!
displayError(error)
"
")
"else!
displayError(error)
"
")

39. PIPES

40. DOWNLOAD PARSE SAVE IN CACHE DISPLAY
ERRORS

41. DOWNLOAD PARSE SAVE IN CACHE DISPLAY
ERRORS

42. DOWNLOAD PARSE SAVE IN CACHE DISPLAY
ERRORS

43. getRemoteData("example.com")
.then(! data in parseData(data) ")
.filter(! parsed in parsedDataValid(parsed) ")
.then(! parsed in saveInCache(parsed) ")
.then(! parsed in handleParsedData(parsed) ")
.error(! error in displayError(error) ")

44. getRemoteData("example.com")
.then(! data in parseData(data) ")
.filter(! parsed in parsedDataValid(parsed) ")
.filter(! parsed in !alreadyInCache(parsed) ")
.then(! parsed in saveInCache(parsed) ")
.then(! parsed in handleParsedData(parsed) ")
.error(! error in displayError(error) ")

45. getRemoteData("example.com")
.then(! data in parseData(data) ")
.filter(! parsed in parsedDataValid(parsed) ")
.filter(! parsed in !alreadyInCache(parsed) ")
.then(! parsed in saveInCache(parsed) ")
.then(! parsed in handleParsedData(parsed) ")
.error(! error in displayError(error) ")

46. DECLARATIVE
PROGRAMMING IS
MUCH SIMPLER

47. DECLARATIVE
PROGRAMMING IS
MUCH SAFER

48. DECLARATIVE
PROGRAMMING IS
MORE SCALABLE

49. WHICH PARADIGM IS
THE BEST?

50. 1. OBJECT-ORIENTED
2. IMPERATIVE
3. DECLARATIVE

51. 1. OBJECT-ORIENTED
2. IMPERATIVE
3. DECLARATIVE

52. TOGETHER

53. THANK YOU
ADRIAN KASHIVSKYY
@akashivskyy
github.com/akashivskyy/talks