calvinlfer

import zio.Chunk
import zio.schema._
import zio.prelude._

import scala.collection.immutable.ListMap

trait Decoder[+A] {
  def decode(in: Json): Either[String, A]
}

calvinlfer

import cats.effect._
import com.datastax.oss.driver.api.core.CqlSession
import com.datastax.oss.driver.api.core.`type`.UserDefinedType
import com.datastax.oss.driver.api.core.cql.BoundStatement
import com.datastax.oss.driver.api.core.data.UdtValue
import com.datastax.oss.driver.internal.core.`type`.{DefaultListType, DefaultSetType}
import com.ringcentral.cassandra4io.CassandraSession
import com.ringcentral.cassandra4io.cql._

import java.net.InetSocketAddress

calvinlfer

package io.kaizensolutions.jsonschema

import io.circe.Json
import io.circe.syntax._
import magnolia.{CaseClass, Magnolia}

import scala.language.experimental.macros

trait JsonSchema[A] {
  def generate: Json = Json.fromFields(JsonSchema.schema +: intermediate)

calvinlfer

import scala.compiletime._
import zio.prelude._

package safer:
  type Digit5OrMore = Digit5OrMore.Type
  object Digit5OrMore extends Subtype[Int]:
    private inline def check(i: Int): Boolean      = i >= 5
    private inline def renderError(i: Int): String = s"input $i must be at least 5"

    inline def compiletime(inline i: Int): Digit5OrMore =

calvinlfer

import better.files._
import zio._
import zio.console._

object DeduplicateByHash extends App {
  override def run(args: List[String]): URIO[zio.ZEnv, ExitCode] = {
    val program =
      for {
        raw <- Task.fromEither(
          Either.cond(

calvinlfer

object PrimeExample extends IOApp {
  override def run(args: List[String]): IO[ExitCode] = {

    val simplePrimes: Stream[Pure, Int] =
      Stream
        .iterate(1)(_ + 1)
        .flatMap(candidate =>
          Stream
            .range(2, candidate - 1) // can further optimize using sqrt(candidate)
            .exists(i => candidate % i == 0)

calvinlfer

// Unhappy with the default behavior of a particular datatype?
// You can override it as you wish, you must write a Diff and merge for the datatype you wish to override

final case class Address(
  streetNumber: Int,
  streetName: String,
  city: String,
  country: String
)

calvinlfer

Keybase proof

I hereby claim:

• I am calvinlfer on github.
• I am calvinlfer (https://keybase.io/calvinlfer) on keybase.
• I have a public key ASA7CwvEM3dYYzgHu4ZtBrxdSZBngyS79VoMI9x_ZKOnRAo

To claim this, I am signing this object:

calvinlfer

object ecommerce_marketing {
  type Event = Map[Attribute, Value]

  sealed trait Attribute
  object Attribute {
    case object EventType      extends Attribute
    case object UserName       extends Attribute
    case object ShoppingCartId extends Attribute
    case object Email          extends Attribute
    case object WebSession     extends Attribute

calvinlfer

Understanding Covariance and Contravariance

There are at least 3 aspects to consider when dealing with contravariance and covariance when using container types.

def example(x: Container[T]): Container[T]

1. What can you feed in
2. What can point to the result
3. What can the function return