You Used To Inject Me In Your Constructor

Presented at Functional Swift Conference 2015.

Transcript

1. You Used To Inject Me In Your Constructor - Functional Programming In Swift
2. Hello, I’m Veronica Ray!
3. –Dependency Injection Demystified “Dependency injection means giving an object its instance variables. Really. That's it.”
4. WHY
6. WHY •Clear declaration of dependencies •Composition •Easy customization
7. WHY •Clear ownership •Testability
8. FRAMEWORK
10. LAYER OF ABSTRACTION
11. SUPER LINEAR
12. SMART FRAMEWORKS
13. LAZY EVALUATION
14. –HaskellWiki “…expressions are not evaluated when they are bound to variables, but their evaluation is deferred until their results are needed by other computations. ”
15. –HaskellWiki “…Pure computations ..can be performed at any time and still yield the same result.
16. –HaskellWiki “This makes it possible to defer the computation of values until they are needed, that is, to compute them lazily. ”
17. Lazy evaluation Brought to you by functional programming
18. MEMOIZATION
19. –Python 3 Tutorial “ If the same input or a function call with the same parameters is used, the previously stored results can be used again and unnecessary calculation are avoided.”
20. SCOPES
21. TYPHOON
22. TyphoonScopeSingleton TyphoonScopeLazySingleton
23. SWINJECT
24. ObjectScope.Container
27. ISSUES
28. WE NEED A RESOLUTION
29. DI IN SWIFT •constructor injection •reader monad
30. DI IN SWIFT •constructor injection •reader monad
31. BearWithMe Find fiends to hibernate with during the winter
36. –In today’s post-OO world, is dependency injection still relevant? “Currently we use the same mechanism – parameters – to define the environment (e.g. via constructor parameters), as we use to pass data around functions.”
37. DI IN SWIFT •constructor injection •reader monad
38. –Don’t Fear The Reader “…if you break down common dependency injection libraries they are just different implementations of the Reader Monad pattern.”
41. SIMPLE EXAMPLE
42. DO NOTATION
43. DESUGARED
44. SWIFT
45. BearWithMe Find fiends to hibernate with during the winter
48. IS THIS A GOOD IDEA?
49. USE DEPENDENCY INJECTION
50. LEARN MORE
51. •Swiftz •Swift Injection •Nick Santos •objc.io •adit.io
52. THANK YOU