2. 2

3. 3

4. • •
f : X → Y
int main() {
return 42;
}
a
b
c
1
2
3
X Y
f
4

5. a
b
c
1
2
3
X Y
f : X → Y
ㄱ
ㄴ
ㄷ
Z
g : Y → Z
f g
5

6. a
b
c
X
ㄱ
ㄴ
ㄷ
Z
g ∘ f : X → Z
g ∘ f
6

7. …
int y = f(x);
int z = g(y);
…
7

8. f g
8

9. g ∘ f
9

10. 10

11. ANYTHING
11

12. 12

13. 13

14. 14

15. 15

17. 17

18. A = 3
B = 4
C = A + B
A = 4
B = 5
print C
18

19. 19

20. C = A + B
+
A
C
B
20

21. 21

22. 22

23. © Behringer
23

24. © Manu Cornet
24

25. 25

26. 1
•
•
•
26

27. 10-3•
•
•
27

28. 10-6•
•
• 컨텍스트 스위치
28

29. 10-9•
•
•
29

30. •
•
•
•
•
•
•
•
30
너무 느림!!

31. OUTPUT foo(INPUT a);
31

32. •
•
•
•
•
•
•
•
32
너무 느림!!

33. © Peter Thomas
33

34. 34

35. 35

36. 36

37. •
•
•
•
•
•
•
37

38. function foo(a, callback);
38

39. foo(a, function(err, result) {
if (err) {
// handle error
} else {
// use result
}
);
39

40. // 흔한 콜백 지옥
function compositeTask(t0, callback) {
task1(t0, function(err, t1) {
if (err) {
callback(err);
}
task2(t1, function(err, t2) {
if (err) {
callback(err);
}
task3(t2, function(err, t3) {
if (err) {
callback(err);
}
callback(null, t3);
});
});
});
}
40

41. 41
OUTPUT foo(INPUT a);

42. Future<OUTPUT> foo(INPUT a);
42

43. Stream<OUTPUT> foo(INPUT a);
43

44. INPUT => Future<OUTPUT>
INPUT => OUTPUT
44
INPUT => Stream<OUTPUT>

45. 45

46. 46

47. •
•
•
•
•
•
47

48. 48
https://www.dartlang.org/performance/

49. 49

50. 하나 다수
동기 T Iterable<T>
비동기 Future<T> Stream<T>
50

51. File file = new File("foo.txt");
print(file.readAsStringSync());

52. File file = new File("foo.txt");
Future future = file.readAsString();
future.then((content) => process(content))
.catchError((e) => handleError(e));

53. File file = new File("foo.txt");
Future future = file.readAsString();
future.then(expensiveA)
.then(expensiveB)
.then(expensiveC)
.catchError((e) => handleError(e));

54. 하나 다수
동기 T Iterable<T>
비동기 Future<T> Stream<T>
54

55. 55

56. Iterable (pull) Stream (push)
getDataFromLocalMemory()
.skip(10)
.take(5)
.map((s) => s + "foo")
.forEach(print)
getDataFromNetwork()
.skip(10)
.take(5)
.map((s) => s + "foo")
.forEach(print)
56

57. +3
+4
Stream<int> add(Stream<int> input)
{
return input.map((x) => x+3)
.map((y) => y+4);
}
57

58. query1
query2
Future<int> query1(int input);
Future<int> query2(int input);
Stream<int> query(Stream<int> input)
{
return input.asyncMap(query1)
.asyncMap(query2);
}
58

59. stdin Stream<List<Int>
HttpServer Stream<HttpRequest>
HttpRequest Stream<List<int>>
HttpClientResponse Stream<List<int>>
RawServerSocket Stream<RawSocket>
RawSocket Stream<RawSocketEvent>
WebSocket Stream<List<int>> 또는
Stream<String>
59

60. 60

61. 61

62. http://www.reactive-streams.org/
62

63. 63

64. 64

65. 65

67. 67