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license: gpl-3.0
height: 600

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// Coproduct is extension of Either concept, to N multually exlusive choices

type ISB = Int :+: String :+: Boolean :+: CNil

val isb = Coproduct[ISB]("foo")                   //> isb  : qaaz.ISB = foo

isb.select[Int]                                   //> res0: Option[Int] = None

isb.select[String]                                //> res1: Option[String] = Some(foo)

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object MergeSort {

		// recursive merge of 2 sorted lists
	def merge(left: List[Int], right: List[Int]): List[Int] =
        (left, right) match {
	        case(left, Nil) => left
	        case(Nil, right) => right
	        case(leftHead :: leftTail, rightHead :: rightTail) =>
	          if (leftHead < rightHead) leftHead::merge(leftTail, right)
	          else rightHead :: merge(left, rightTail)

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object Scala3TypeClassWithUsingGiven {

  trait MyMonoid[A] {
    def combine(x: A, y: A): A
    def empty: A
  }

  def combineList[A](li: List[A])(using monoid: MyMonoid[A]): A = li.foldLeft(monoid.empty)(monoid.combine)

  def main(args: Array[String]): Unit = {

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import java.util

import org.apache.kafka.clients.consumer.KafkaConsumer

import scala.collection.JavaConverters._

object ConsumerExample extends App {

  import java.util.Properties

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import scala.util.{Success, Failure}

val seq=Seq(Success(1), Failure(new Exception("bang")), Success(2))

// all emit         List(1, 2)

seq.map(_.toOption).flatten
seq.flatMap(_.toOption)
seq.filter(_.isSuccess).map(_.get)
seq.collect{case Success(x) => x}

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import cats._
import cats.implicits._

// Example usage of Cats Flatmap

object CatsFlatmap extends App {

  val listFlatMap=FlatMap[List]

  val li=List(1,2,3)

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import cats.effect._
import fs2._
import scala.concurrent.duration._
import cats.effect.std._

// FS2 cats.effect.Queue example using flatMap or for comprehension
// Both streams emit nothing, but are effectful, communicating via the queue and updating a sum via the ref

object Fs2Queues extends IOApp.Simple {

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import MyErrsIO.Controller.{Request, postTransfer}
import MyErrsIO.Models.Account
import cats.data.Validated.{Invalid, Valid}
import cats.data.{EitherT, OptionT, Validated, ValidatedNec}
import cats.effect._
import cats.implicits._

import scala.util.control.NonFatal

// A simple example of cat-effect and error handling, with MonadTransformers

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val li=List(1,2,10,20,30)                         //> li  : List[Int] = List(1, 2, 10, 20, 30)

def insert[T](li:List[T],x:T)(implicit cmp:Ordering[T])={
 val (first,last)=li.partition {cmp.lteq(_, x) }
 first:::x::last
}                                                 //> insert: [T](li: List[T], x: T)(implicit cmp: Ordering[T])List[T]

insert(li,11)                                     //> res0: List[Int] = List(1, 2, 10, 11, 20, 30)
insert(li,10)                                     //> res1: List[Int] = List(1, 2, 10, 10, 20, 30)
insert(li,9)                                      //> res2: List[Int] = List(1, 2, 9, 10, 20, 30)