Functional Reactive Programming
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This document discusses functional reactive programming (FRP). It defines FRP as a programming paradigm oriented around data flows and propagation of change. Reactive programming describes systems that are responsive, resilient, elastic and message-driven. The document introduces reactive extensions (Rx) as a library for composing asynchronous and event-based programs using observable sequences and LINQ-style query operators. It provides examples of how Rx can be used to map, filter, scan and zip observable sequences.
![Give me five functions
and I’ll raise up the world
[map; filter; reduce; collect; zip]](https://image.slidesharecdn.com/dev07-150327060248-conversion-gate01/85/Functional-Reactive-Programming-9-320.jpg)
![let source = [ 1; 2; 3]
let result =
List.map (fun x -> x*2) source
val result : int list = [2; 4; 6]
map](https://image.slidesharecdn.com/dev07-150327060248-conversion-gate01/85/Functional-Reactive-Programming-10-320.jpg)
![let source = [ 1; 2; 3]
let result =
List.filter (fun x -> x > 1) source
val result : int list = [2; 3]
filter](https://image.slidesharecdn.com/dev07-150327060248-conversion-gate01/85/Functional-Reactive-Programming-11-320.jpg)
![let source = [ 1; 2; 3]
let result =
List.reduce (fun acc curr -> acc + curr) source
val result : int = 6
reduce](https://image.slidesharecdn.com/dev07-150327060248-conversion-gate01/85/Functional-Reactive-Programming-12-320.jpg)
![let source = [ [ 1; 2; 3]; [ 4; 5 ] ]
let result =
List.collect (fun x -> x) source
val result : int list = [1; 2; 3; 4; 5; 6]
collect](https://image.slidesharecdn.com/dev07-150327060248-conversion-gate01/85/Functional-Reactive-Programming-13-320.jpg)
![let source1 = [ 1; 2; 3]
let source2 = [‘A’;’B’;’C’]
let result =
List.zip source1 source2
val res : (int * char) list = [(1, 'A'); (2, 'B'); (3, 'C')]
zip](https://image.slidesharecdn.com/dev07-150327060248-conversion-gate01/85/Functional-Reactive-Programming-14-320.jpg)
Functional Reactive Programming
- 1. DEV07 Functional Reactive Programming Alessandro Melchiori [email protected] - @amelchiori http://melkio.codiceplastico.com/
- 5. It's declarative, stateless, side-effects free and immutable Functional programming
- 6. It's declarative, stateless, side-effects free and immutable Functional programming describes what we want, not how we want it
- 7. It's declarative, stateless, side-effects free and immutable Functional programming describes what we want, not how we want it system relys only on inputs, not external state
- 8. It's declarative, stateless, side-effects free and immutable Functional programming describes what we want, not how we want it system relys only on inputs, not external state once value has been set, we can't override its value Return new value, instead of altering existing ones
- 9. Give me five functions and I’ll raise up the world [map; filter; reduce; collect; zip]
- 10. let source = [ 1; 2; 3] let result = List.map (fun x -> x*2) source val result : int list = [2; 4; 6] map
- 11. let source = [ 1; 2; 3] let result = List.filter (fun x -> x > 1) source val result : int list = [2; 3] filter
- 12. let source = [ 1; 2; 3] let result = List.reduce (fun acc curr -> acc + curr) source val result : int = 6 reduce
- 13. let source = [ [ 1; 2; 3]; [ 4; 5 ] ] let result = List.collect (fun x -> x) source val result : int list = [1; 2; 3; 4; 5; 6] collect
- 14. let source1 = [ 1; 2; 3] let source2 = [‘A’;’B’;’C’] let result = List.zip source1 source2 val res : (int * char) list = [(1, 'A'); (2, 'B'); (3, 'C')] zip
- 17. A programming paradigm oriented around data flows and the propagation of change. Reactive programming
- 18. Reactive systems are responsive, resilient, elastic and message driven Reactive manifesto (http://www.reactivemanifesto.org/) Reactive programming
- 19. Reactive programming 1 2 sum 1diff 4 …readily responsive to a stimulus…
- 28. Rx is a library for composing asynchronous and event-based programs using observable sequences and LINQ-style query operators (https://msdn.microsoft.com/en-us/data/gg577609.aspx) Reactive extensions
- 29. Rx is a library for composing asynchronous and event-based programs using observable sequences and LINQ-style query operators (https://msdn.microsoft.com/en-us/data/gg577609.aspx) Reactive extensions
- 30. Rx is a library for composing asynchronous and event-based programs using observable sequences and LINQ-style query operators (https://msdn.microsoft.com/en-us/data/gg577609.aspx) Reactive extensions
- 31. Rx is a library for composing asynchronous and event-based programs using observable sequences and LINQ-style query operators (https://msdn.microsoft.com/en-us/data/gg577609.aspx) Reactive extensions
- 32. Rx is a library for composing asynchronous and event-based programs using observable sequences and LINQ-style query operators (https://msdn.microsoft.com/en-us/data/gg577609.aspx) Reactive extensions
- 33. • a set of types representing asynchronous data streams • a set of operators to query asynchronous data streams • a set of types to parameterize concurrency Reactive extensions
- 34. RX = Observables + LINQ + Schedulers
- 35. demo intro
- 40. The Observable type adds two missing semantics to the Gang of Four's Observer pattern, which are available in the Iterable type: • The ability for the producer to signal to the consumer that there is no more data available • The ability for the producer to signal to the consumer that an error has occurred Reactive extensions
- 42. RX mantra everything can be a stream
- 43. Reactive extensions: map 1 2 3 4 A B C D
- 44. Reactive extensions: filter 1 2 3 4 2 4
- 45. Reactive extensions: scan 1 2 3 4 1 3 6 10
- 46. Reactive extensions: zip 1 2 3 4 1, A 2, B 3, C 4, D A B C D
- 50. Recap • Functional programming • Reactive programming • Reactive extensions (Rx.*)
- 51. FRP is agnostic about languages. It's a mindset
- 52. Q&A Tutto il materiale di questa sessione su http://www.communitydays.it/ Lascia subito il feedback su questa sessione, potrai essere estratto per i nostri premi! Seguici su Twitter @CommunityDaysIT Facebook http://facebook.com/cdaysit #CDays15