src/main/kotlin/

app.kt

import kotlin.properties.Delegates
import io.reactivex.rxkotlin.*
import io.reactivex.Observer
import io.reactivex.disposables.Disposable
import io.reactivex.Observable
import java.util.concurrent.Callable
import java.util.concurrent.Future
import java.util.concurrent.TimeUnit
import kotlin.io.println
import arrow.syntax.function.andThen
import arrow.syntax.function.compose
import arrow.syntax.function.forwardCompose
import arrow.syntax.function.partially2
import arrow.syntax.function.partially3
import arrow.syntax.function.curried
import arrow.syntax.function.pipe
import arrow.syntax.function.reverse
import arrow.syntax.function.uncurried
import java.util.*
import java.math.BigDecimal

import arrow.optics.Lens
import arrow.optics.optics


typealias Exec<R> = ()->R
typealias Exec2<T,R> = (T)->R

data class Result<R>(val result:R)


infix fun <R,R1> Result<R>.success(exec:Exec2<R,R1>):Result<R1> = Result(exec(this.result))

infix fun <R,R1> Result<R>.then(exec:Exec2<R,R1>):R1 = exec(this.result)

fun <R> task(exec:Exec<R>) = Result(exec())

fun String.println() = println(this)

fun <A,B> Pair<A,B>.reverse():Pair<B,A> = Pair(this.second,this.first)

/////////Arrow framework//////////////////
val p:(String)->String = {body -> "<p>${body}</p>"}
val span:(String)->String = {span -> "<span>${span}</span>"}
val div:(String)->String = {div -> "<div>${div}</div>"}
val strong:(String)->(String) = {strong -> "<strong>${strong}</strong>"}
val randomNames:()->String = {
	if(Random().nextInt()%2==0) "foo" else "bar"
}

data class Bill(val amount:BigDecimal)
data class PickingOrder(val name:String)
fun Bill.println()=println(this.amount)
fun PickingOrder.println()=println(this.name)

fun partialSplitter(billAndOrder: Pair<Bill,PickingOrder>?,warehouse:(PickingOrder)->Unit,accounting: (Bill)->Unit){
	if(billAndOrder!=null) {
		warehouse(billAndOrder.second)
		accounting(billAndOrder.first)
	}
}

typealias GB = Int
//@optics data class Memory(val size: GB)
//@optics data class Motherboard(val brand: String, val memory: Memory)
//@optics data class Laptop(val price: Double, val motherBoard: Motherboard)

fun main(args:Array<String>) {
	
	task {		
		"Ananth"
	} success {	
		it.toString() + " Raghuraman"
	} then{
		it + ", Mr"
	}
	
	val myList:MutableList<Int> = mutableListOf(1,3,5,7,9)
	val observable = myList.toObservable()
	observable.subscribeBy(onNext={println(it)},onError={it.printStackTrace()},onComplete={println("Done")})
	myList.add(11)
	
	val observer:Observer<String> = object : Observer<String> {
		override fun onComplete(){
			println("Completed")
		}
		
		override fun onNext(item:String) {
			println("Received: $item")
		}
		
		override fun onError(e: Throwable) {
			println("Error Occured: ${e.message}")
		}
		
		override fun onSubscribe(d:Disposable) {
			println("Subscription")
		}
	}
	
	val list = listOf("Str 1","Str 2","Str 3","Str 4")
	val observableFromIterable:Observable<String> = Observable.fromIterable(list)
	observableFromIterable.subscribe(observer)
	
	val callable = {"Iam from Callable"}
	
	val observableFromCallable:Observable<String> = Observable.fromCallable(callable)
			
	observableFromCallable.subscribe(observer)
	
	var future:Future<String> = object:Future<String>{
		val retStr = "I'am from the Future"
		
		override fun get() = retStr
		
		override fun get(timeout:Long, unit: TimeUnit?) = retStr
		
		override fun isDone():Boolean = true
		
		override fun isCancelled():Boolean = false
		
		override fun cancel(mayInterruptIfRunning:Boolean):Boolean = false
		
	}
	
	var observableFromFuture:Observable<String> = Observable.fromFuture(future)
	observableFromFuture.subscribe(observer)
	////////////////////////////////////////////////////////
	
	listOf(1,2,3).map{i->i*2}.map(Int::toString).forEach(::println)
	
	println(Option.Some("Kotlin").map(String::toUpperCase))
	println(Option.None.map(String::toUpperCase))
	
	//////Arrow framework///////////////////
	
	val divStrong:(String)->(String) = div compose strong
	val spanP:(String)->String = p forwardCompose span
	val randomStrong:()->String = randomNames andThen strong
	
	randomStrong().println()
	spanP("Ananth").println()
	divStrong("Raghuraman").println()
	
	val strog:(String,String,String)->String = {body,id,style->"<strong id=\"$id\" style=\"$style\">$body</strong>"}
	val redStrong:(String,String) -> String = strog.partially3("font: red")
	redStrong("A","B").println()
	/////////////////////////////////////////
	val splitter: (Pair<Bill,PickingOrder>?)->Unit = ::partialSplitter.partially2 { pickingOrder ->pickingOrder.println() }.partially2 { bill -> bill.println() }
	splitter(Pair(Bill(BigDecimal.TEN),PickingOrder("Ananth's picking order")))
	/////////////////////////////////////////
	////Currying//////////////////
	val strong1:(String,String,String)->String = {a,b,c->"$a;$b;$c"}
	
	val p:(Int)->(Int) ->String = {it->{a->
		println("it is $it from the outer function. a is $a")
		"${it*2} is the inner function"
	}
		
	}
	
	p(3)(4).println()
	
	val curriedStrong:(String)->(String)->(String)->String = strong1.curried()
	val aStrong:(String)->(String)->String = curriedStrong("a")
	val abStrong:(String)->String = aStrong("b")
	val abcStrong:String = abStrong("c")
	abcStrong pipe ::println
	
	
}
	     

build.gradle

buildscript{
    ext.kotlin_version = '1.2.21'

    repositories {
        mavenCentral()
    }

    dependencies {
        classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version'
    }
}

plugins {
    id 'org.jetbrains.kotlin.jvm' version '1.2.21'
    id 'org.jetbrains.kotlin.kapt' version '1.2.21'
}

apply plugin: 'idea'
apply plugin: 'eclipse'
apply plugin: 'java'
apply plugin: 'kotlin'
apply plugin: 'kotlin-kapt'
apply plugin: 'application'

mainClassName="AppKt"
defaultTasks 'run'

//apply from: rootProject.file('gradle/generated-kotlin-sources.gradle')

repositories{
    mavenCentral()
    jcenter()
}
allprojects {
    repositories {
        jcenter()
        mavenCentral()
    }
}

dependencies{
    compile 'org.jetbrains.kotlin:kotlin-stdlib-jdk8'
    compile 'org.jetbrains.kotlin:kotlin-reflect'
    compile 'io.reactivex.rxjava2:rxkotlin:2.2.0'
    compile 'io.arrow-kt:arrow-core:0.7.2'
    compile 'io.arrow-kt:arrow-syntax:0.7.2'
    compile 'io.arrow-kt:arrow-typeclasses:0.7.2'
    compile 'io.arrow-kt:arrow-data:0.7.2'
    compile 'io.arrow-kt:arrow-instances-core:0.7.2'
    compile 'io.arrow-kt:arrow-instances-data:0.7.2'
    kapt    'io.arrow-kt:arrow-annotations-processor:0.7.2'
    compile 'io.arrow-kt:arrow-free:0.7.2' //optional
    compile 'io.arrow-kt:arrow-mtl:0.7.2' //optional
    compile 'io.arrow-kt:arrow-effects:0.7.2' //optional
    compile 'io.arrow-kt:arrow-effects-rx2:0.7.2' //optional
    //compile 'io.arrow-kt:arrow-effects-reactor:0.7.3' //optional
    compile 'io.arrow-kt:arrow-effects-kotlinx-coroutines:0.7.2' //optional
    compile 'io.arrow-kt:arrow-optics:0.7.2' //optional
    compile 'io.arrow-kt:arrow-generic:0.7.2' //optional
    //compile 'io.arrow-kt:arrow-recursion:0.7.3' //optional
}

configurations{
    compile.exclude group:'org.jetbrains.kotlin', module:'kotlin-stdlib-jre7'
}

kotlin{
    experimental {
        coroutines 'enable'
    }
}

kapt{
    useBuildCache=true
}

compileKotlin {
    kotlinOptions.jvmTarget="1.8"
}

compileTestKotlin{
    kotlinOptions.jvmTarget="1.8"
}

sourceSets {
    main{
        kotlin {
            srcDirs += "${build}/generated/source/kapt/main"
            srcDirs += "${build}/generated/source/kaptKotlin/main"
            srcDirs += "${build}/tmp/kapt/main/kotlinGenerated"
        }
    }


}