Functional Reactive Programming

Transcript

1. 1.

   Functional Reactive Programming

2. 2.

   “Everything flows, nothing stands still.” Heraclitus

3. 3.

   Streams of Events

4. 4.

   Streams of Events • Fire and forget events are relatively

   easy to create.
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   Streams of Events • Fire and forget events are relatively

   easy to create. • UIs
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   Streams of Events • Fire and forget events are relatively

   easy to create. • UIs • Ajax posts
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   Streams of Events • Fire and forget events are relatively

   easy to create. • UIs • Ajax posts • Messaging queues
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   Processing Events

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   Processing Events • A little trickier

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    Processing Events • A little trickier • difficult to compose

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    Processing Events • A little trickier • difficult to compose

    • lots of plumbing
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    Processing Events • A little trickier • difficult to compose

    • lots of plumbing • Callback Hell
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    “We’re going to need a bigger boat.”

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    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
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    Observable

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    Observable • A marriage of Iterables and the Observer Pattern

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    Observable • A marriage of Iterables and the Observer Pattern

    • Typical Sequence functions - Map, Filter, Reduce, Take
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    Observable • A marriage of Iterables and the Observer Pattern

    • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext
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    Observable • A marriage of Iterables and the Observer Pattern

    • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext • Error Handling
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    Observable • A marriage of Iterables and the Observer Pattern

    • Typical Sequence functions - Map, Filter, Reduce, Take • Subscribe/OnNext • Error Handling • Timing function - Delay
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    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
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    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
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    Marble Diagrams

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    A Marble Diagrams

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    A Marble Diagrams

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    A B Marble Diagrams

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    A B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    A B A.merge(B Marble Diagrams

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    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
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    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
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    Demo Source code: https://github.com/Cicayda/yolk-examples