iOS_meetup.pdf

Transcript

1. Let’s Talk About `Function` Ambas Chobsanti
2. About me Ambas Chobsanti iOS Developer @ Agoda
3. Agenda 1. Function in Fruit of Knowledge 2. Price of Changing 3. Function Biology 4. The Coming of the Feature
4. Function “In programming, a named section of a program that performs a specific task. In this sense, a function is a type of procedure or routine. Some programming languages make a distinction between a function, which returns a value, and a procedure, which performs some operation but does not return a value. Most programming languages come with a prewritten set of functions that are kept in a library. You can also write your own functions to perform specialized tasks.”
5. Function in Fruit of Knowledge
6. Function in Fruit of Knowledge • Objective-C was originally developed in the early 1980s • used by NeXT for its NeXTSTEP operating system (1988) • Swift was introduced at WWDC’ 14
7. Function in Fruit of Knowledge Objective-C Swift
8. Function in Fruit of Knowledge • Objective-C is Dynamic Dispatch • Swift is (Almost) Static Dispatch
9. Static vs Dynamic Dispatch • Dynamic Dispatch • Message passing • Dynamic binding • Static Dispatch • Know location of method at compile time • Static type
10. Performances
11. Performances Before Optimize https://yalantis.com/blog/is-swift-faster-than-objective-c/
12. Performances After Optimize https://yalantis.com/blog/is-swift-faster-than-objective-c/
13. iOS Meetup #12 Thongchai, Rakuten Viki
14. Price of Changing
15. At WWDC 2014
16. At WWDC 2014
17. Can swift do this?
18. Can swift do this?
19. What we lost • Method swizzling • PerformSelector: • KVO • etc.
20. About Swift WWDC 2014
22. Swift Feature • Optional • Tuples and multiple return values • Struct • Powerful error handling • Generic • Functional programming patterns, e.g., map and filter • Etc.
23. Function Biology
24. Function Biology 1. Functions can be assigned to variables and passed in and out of other functions as arguments. 2. Functions can capture variables that exist outside of their local scope. 3. Functions can be declared using the { } syntax for closure expressions.
25. 1. Functions can be assigned to variables and passed in and out of other functions as arguments. • Function is first class objects • Assign function as a variable
26. 1. Functions can be assigned to variables and passed in and out of other functions as arguments. • Function can take a function as an argument
27. 1. Functions can be assigned to variables and passed in and out of other functions as arguments. • Function can also return a functions
28. 2. Functions can capture variables that exist outside of their local scope. • When function reference to variable outside function’s scope, those variable are capture
29. 2. Functions can capture variables that exist outside of their local scope.
30. 3. Functions can be declared using the { } syntax for closure expressions. • In swift we can define function in two ways
31. 3. Functions can be declared using the { } syntax for closure expressions. • Closure expression
32. 3. Functions can be declared using the { } syntax for closure expressions. • Closure expression
33. The Coming of the Feature
34. Change observer
35. Lazy Store Property
36. Subscription
37. Subscription
38. KeyPath • Close a big hole for swift type system
39. KeyPath
40. KeyPath
41. KeyPath
42. KeyPath • So what?
43. KeyPath • So what? (again?)
44. KeyPath • So what? (again?)
45. KeyPath
46. KeyPath
47. Conclusions • We are in the long way of history but swift is so young • We lose something but… • Writing code for understanding at a glance • Improve, improve and improve
48. Thank You
49. References • Advance Swift Book https://www.objc.io/books/advanced-swift/ • Function Definition https://en.wikipedia.org/wiki/Closure_(computer_programming) • Memory management https://medium.com/@itchyankles/memory-management-in-rust-and-swift-8ecda3cdf5b7 • Swift performance measurement https://yalantis.com/blog/is-swift-faster-than-objective-c/ • Dynamic binding https://developer.apple.com/library/archive/documentation/General/Conceptual/DevPedia- CocoaCore/DynamicBinding.html#//apple_ref/doc/uid/TP40008195-CH15-SW1 • KVO https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/KeyValueObserving/ KeyValueObserving.html • Using Collection Operators https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/ KeyValueCoding/CollectionOperators.html#//apple_ref/doc/uid/20002176-BAJEAIEE • Compile Time vs. Run Time Type Checking in Swift http://blog.benjamin-encz.de/post/compile-time-vs-runtime- type-checking-swift/ • 5 things you can do with Objective-C but can’t do with pure Swift https://medium.com/@markohlebar/5-things-you- can-do-in-objective-c-but-cant-do-in-pure-swift-31bb66b4aab8 • Closures https://docs.swift.org/swift-book/LanguageGuide/Closures.html