BalmungSan

// IO: A Monad for side-effects.
import $ivy.`org.typelevel::cats-effect:1.3.1`

import cats.effect.IO
import scala.concurrent.ExecutionContext

implicit val IOTimer = IO.timer(ExecutionContext.global)
implicit val IOShift = IO.contextShift(ExecutionContext.global)
// ----------------------------------------------

BalmungSan

Polymorphism in Scala

This document aims to show and compare three alternatives for achieving polymorphism in Scala.

• Subtyping, common in object-oriented languages like Java.
• Duck typing, common in dynamically typed languages like Python.
• Typeclasses, common in functional languages like Haskell.

Additionally, when implementing the typeclass pattern in Scala,

BalmungSan

import cats.Applicative
import cats.effect.IO
import fs2.Stream
import io.circe.Encoder
import io.circe.generic.semiauto.deriveEncoder
import io.circe.syntax.EncoderOps
import org.http4s.{EntityEncoder, MediaType}
import org.http4s.dsl.io._
import org.http4s.headers.`Content-Type`

BalmungSan

import cats.effect.IO
import io.circe.Encoder
import io.circe.generic.semiauto.deriveEncoder
import io.circe.java8.time.encodeZonedDateTimeDefault
import io.circe.syntax.EncoderOps
import org.bson.{BsonReader, BsonType, BsonWriter}
import org.bson.codecs.{DecoderContext, Codec, EncoderContext}
import org.bson.codecs.configuration.{CodecConfigurationException, CodecRegistries}
import org.mongodb.scala.MongoClient
import org.mongodb.scala.bson.codecs.{DEFAULT_CODEC_REGISTRY, Macros}