chris-hatton

package datasizeformatter

import kotlin.math.abs
import kotlin.math.pow
import kotlin.math.roundToLong

/**
 * Format a human-readable representation of data size, in binary base form.
 * e.g. 1024 -> 1 KiB
 * @param byteCount The number of bytes to represent in human-readable form. `Long.MIN_VALUE` is unsupported.

LordRaydenMK

@Retention(AnnotationRetention.BINARY)
@Target(AnnotationTarget.CLASS)
annotation class ValueClass

androidfred

Kotlin Arrow

A lot of Kotlin features can be traced back to functional programming languages, eg

• Heavy use of immutability-by-default and map, filter etc functions
• Type inference
• Data classes (which enable pattern matching)
• Null safety and dealing with the absence of values

However, Kotlin is missing many incredibly useful data types that are ubiquitous in functional programming languages, eg Either, Try etc.

elizarov

import kotlinx.coroutines.*
import kotlin.coroutines.*

/**
 * Scope interface to control (pause & resume) timeout
 */
interface TimerScope : CoroutineScope {
    fun pause()
    fun resume()
}

colomboe

// Porting of https://gist.github.com/jdegoes/dd66656382247dc5b7228fb0f2cb97c8

typealias UserID = String
data class UserProfile(val name: String)

// The database module:
interface DatabaseService {
    suspend fun dbLookup(id: UserID): UserProfile
    suspend fun dbUpdate(id: UserID, profile: UserProfile)
}

gildor

import com.google.protobuf.gradle.protobuf
import com.google.protobuf.gradle.protoc

plugins {
    java
    idea
    id("com.google.protobuf") version "0.8.7"
}

repositories {

raulraja

import arrow.Kind
import arrow.core.Option
import arrow.core.Try
import arrow.core.functor
import arrow.effects.IO
import arrow.effects.fix
import arrow.effects.functor
import arrow.typeclasses.Functor

/* algebras */

raulraja

import arrow.Kind
import arrow.core.Option
import arrow.core.left
import arrow.core.right
import arrow.effects.typeclasses.Async
import arrow.typeclasses.ApplicativeError

data class UserId(val value: String)
data class User(val userId: UserId)
data class Task(val value: String)

raulraja

import arrow.*
import arrow.core.*
import arrow.typeclasses.*
import arrow.data.*

sealed class ValidationError(val msg: String)
data class DoesNotContain(val value: String) : ValidationError("Did not contain $value")
data class MaxLength(val value: Int) : ValidationError("Exceeded length of $value")
data class NotAnEmail(val reasons: Nel<ValidationError>) : ValidationError("Not a valid email")

djspiewak

Thread Pools

Thread pools on the JVM should usually be divided into the following three categories:

1. CPU-bound
2. Blocking IO
3. Non-blocking IO polling

Each of these categories has a different optimal configuration and usage pattern.