GeeCon: Typeclasses, Monads - functional and simple!

I am quite excited how elegantly we can solve IO-bound problems like DB access with this new set of tools Scala and functional programming provides. I've recently built a simple Cassandra client using actors, type classes and monads while migrating one of our systems at Zeebox from Amazon S3 to Cassandra. It is simple and elegant (I believe :)) and it shows the real power of the language. So no more Java-like code written in Scala - It is functional but simple and powerful. Until recently, I was scared myself whenever I've heard the phrase "type class" let alone monad or theory of categories. I realised that all it is, is just that mathematicians tend to overcomplicate things hiding it behind theorems and proofs. Real life examples of monoids, monads or type classes can be quite simple and understandable for everybody.

Video will be available here:
http://2013.geecon.org/speakers/piotr-gabryanczyk

Transcript

1. Typeclasses, Monads, etc. Functional programming in Scala can be simple!
2. “The plan” • Implicit parameters - readability
3. “The plan” • Implicit parameters - readability • Typeclasses - code reuse
4. “The plan” • Implicit parameters - readability • Typeclasses - code reuse • Monads - composition
5. Implicit Parameters Demo
6. • Keyspace =~ db schema • Column family =~ db table
7. Operations on rows
8. Operations on objects
9. Typeclasses Demo
10. What is type class? Type class == Group of types
11. What is type class? Type class == Group of types
12. What is type class? Type class == Group of types T belongs to CassandraObject typeclass if there is class X such that X extends CassandraObject[T]
13. Type class instance
14. Serialization
15. Typecalass
16. Typeclass Instance
17. Multiple Instances
18. Numeric
19. Matrix multiplication
20. Matrix multiplication
21. Typeclasses summary
22. Typeclasses summary
23. Typeclasses summary
24. Typeclasses summary Numeric[T] Serializable[T]
25. JVM Cassandra Actor Router Actor Cassandra Actor Connection Cassandra Get(...) Cassandra Actor Connection
26. JVM Cassandra Actor Router Actor Cassandra Actor Connection Cassandra Get(...) Cassandra Actor Connection
27. JVM Cassandra Actor Router Actor Cassandra Actor Connection Cassandra Get(...)
28. JVM Cassandra Actor Router Actor Cassandra Actor Connection Cassandra Get(...) Cassandra Actor Connection
29. Async Action
30. Save as Async
31. Composition
32. Composition Demo
33. Monad Monad laws:
34. Functor
35. Functor Monad is a Functor:
36. For comprehension
37. For comprehension ==
38. For comprehension ==
39. Option is a Monad
40. Future is a Monad
41. Collections are Monads
42. Option -> Iterable
43. Questions? Peter Gabryanczyk @piotrga peter@scala-experts.com http://blog.scala4java.com