Functional Reactive Programming

Slides for a talk by Wilkes Joiner at Nashville Code Co-op Talk Day.

Transcript

1. Functional Reactive Programming
2. “Everything flows, nothing stands still.” Heraclitus
3. Streams of Events
4. Streams of Events • Fire and forget events are relatively easy to create.
5. Streams of Events • Fire and forget events are relatively easy to create. • UIs
6. Streams of Events • Fire and forget events are relatively easy to create. • UIs • Ajax posts
7. Streams of Events • Fire and forget events are relatively easy to create. • UIs • Ajax posts • Messaging queues
8. Processing Events
9. Processing Events • A little trickier
10. Processing Events • A little trickier • difficult to compose
11. Processing Events • A little trickier • difficult to compose • lots of plumbing
12. Processing Events • A little trickier • difficult to compose • lots of plumbing • Callback Hell
13. “We’re going to need a bigger boat.”
14. FRP • A model for values that vary over time • Originates from Haskell Community • Several different implementation styles • We are focusing on Microsoft’s ReactiveExtenions style
15. Observable
16. Observable • A marriage of Iterables and the Observer Pattern
17. Observable • A marriage of Iterables and the Observer Pattern • Typical Sequence functions - Map, Filter, Reduce, Take
18. Observable • A marriage of Iterables and the Observer Pattern • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext
19. Observable • A marriage of Iterables and the Observer Pattern • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext • Error Handling
20. Observable • A marriage of Iterables and the Observer Pattern • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext • Error Handling • Timing function - Delay
21. Observable • A marriage of Iterables and the Observer Pattern • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext • Error Handling • Timing function - Delay • Buffering - Last N events
22. Observable • A marriage of Iterables and the Observer Pattern • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext • Error Handling • Timing function - Delay • Buffering - Last N events • Composable - SelectMany/FlatMap
23. Marble Diagrams
24. A Marble Diagrams
25. A Marble Diagrams
26. A B Marble Diagrams
27. A B Marble Diagrams
28. A B A.merge(B Marble Diagrams
29. A B A.merge(B Marble Diagrams
30. A B A.merge(B Marble Diagrams
31. A B A.merge(B Marble Diagrams
32. A B A.merge(B Marble Diagrams
33. A B A.merge(B Marble Diagrams
34. A B A.merge(B Marble Diagrams
35. A B A.merge(B Marble Diagrams
36. A B A.merge(B Marble Diagrams
37. A B A.merge(B Marble Diagrams
38. A B A.merge(B Marble Diagrams
39. Autocomplete • On Keyup • Get the value of the field • Only values of length 3 or more • Make remote call • Filter out bad response • Display results
40. Autocomplete in reality • On Keyup • Get the value of the field • Throttle to 500ms • Only values of length 3 or more • Skip duplicates • Make remote call • Filter out bad response • Display results
41. Demo Source code: https://github.com/Cicayda/yolk-examples