Kotlin 스터디

KotlinConf 2017

* Introduction to Coroutines *

https://resources.jetbrains.com/storage/products/kotlinconf2017/slides/2017+KotlinConf+-+Introduction+to+Coroutines.pdf

- Synchronous
- Asynchronous

-> Callback

- Futures/Promises/Rx

-> returns promise for a future result immediately

- Coroutines

-> suspend: returns result when received
-> like regular code

- Coroutines are like very light-weight threads

http://github.com/kotlin/kotlinx-coroutines

* Deep Dive into Coroutines on JVM *

https://resources.jetbrains.com/storage/products/kotlinconf2017/slides/2017+KotlinConf+-+Deep+dive+into+Coroutines+on+JVM.pdf

- Continuation Passing Style(CPS)

-> Callback

- State Machine

- Communicating Sequential Processes(CSP)

* Kotlin Types: Exposed *

Int vs Int?

IntArray vs Array<Int>

Any vs Object

Boxing under the hood vs No boxing

Unit vs Nothing vs void

Unit

-> a type that allows only one value and thus can hold no information
-> the function completes successfully

Nothing :

-> a type that has no values
-> It means "this function never returns"

- Unit과 Nothing은 Kotlin에서 위와 같은 차이가 있지만 JVM에서 똑같이 void로 컴파일된다.

Nothing?

@Nullable -> Type? and @NotNull(@NonNull) -> Type

How to still prevent NPEs? - 자바 코드를 코틀린에서 사용하는 경우 문제가 발생

-> Annotate your Java types

compileKotlin {
  kotlinOptions {
    freeCompilerArgs += "-Xjsr305=strict"
  }
}

-> Specify types explicitly

Collections

-> Read-only : it is not immutable
-> Mutable

* Generating Kotlin Code *

KotlinPoet

A Functional Approach to Android Architecture using Kotlin

- Modeling Error and Success Cases

-- Result wrapper(Error or Success)
-- RxJava
-- KATEGORY

- Asynchronous Code and Threading

-- Java : ThreadPoolExecutor + exceptions + callbacks
-- RxJava : Schedulers + observable + error subscription
-- KATEGORY

Lazy evaluation

- Dependency Injection

-- Reader Monad: ReaderT, Monad Transformers

Exploring Kotlin's hidden costs - Part 1

Coroutine Theory

- Normal function

Call/Return

activation frame(stack)

- Coroutine

Suspend/Resume/Destroy

coroutine frame(heap) and stack frame

Kotlin Coroutines on Android: Things Wish I Knew at the Beginning

- Executor를 CoroutineDispatchers로 바꿀 수 있다.

- RxJava의 disposable 같은 것을 위해 "root" coroutine parent를 사용할 수 있다.

- CommonPool 의 크기를 조절할 수 있다.

- Async에서의 exception은 바로 발생되지 않는다.

- coroutine들을 협력적으로 cancel 하려면 CoroutineContext를 통한 parent-child 관계가 필요하다.

Async code using Kotlin Coroutines

RxJava to Kotlin coroutines

코루틴과 관련해서 Continuation에 대해서도 알면 좋을것 같다.

What's in a Continuation

Implementing a Stepping Debugger in JavaScript

Exploring Continuations: Resumable Exceptions