afsalthaj

package com.telstra.dxmodel.api.interop

import cats.data.{EitherT, Writer, WriterT}
import cats.free.Free

import scala.util.Try
import cats.implicits._
import cats.{Monad, ~>}
import com.telstra.dxmodel.api.interop
import scalaz.zio.IO

afsalthaj

// This might look really simple, but people often get carried away validationNel (applicative) and disjunctions (monad) ended up having only errors (or a error) or a valid right.

// However we can go one step forward. Maximum error accumulation + Max computation (try hard, try hard)


  import scalaz._, Scalaz._

  def process1(int: Int): Int = throw new Exception("errors")
  def process2(int: Int) : Int = int + 1
  def process3(int: Int) : Int = int + 2

afsalthaj

package delta

// Use shows instance instead of toString on even primitives.
import shapeless.{::, HList, HNil, LabelledGeneric, Lazy, Witness}
import shapeless.labelled.FieldType
import cats.evidence.{As, Is}
import Delta.Meta
import cats.Eq
import cats.data.Ior
import cats.implicits._

afsalthaj

import Delta.{Changed, Deleted, DeltaOp, New}
import scalaz.\&/
import scalaz.\&/.{Both, That, This}
import scalaz.{Name => _, _}
import Scalaz._

case class Bla(someValue: String)
case class MajorResource1(bla: Bla, name: String)

afsalthaj

// Trying to find case class names using shapeless involving a tree structure
import shapeless.{::, HList, HNil, LabelledGeneric, Lazy, Witness}
import shapeless.labelled.FieldType
import cats.evidence.{As, Is}

/**
  *
  * {{{

   case class BadVal(value: String) extends AnyVal

afsalthaj

import scalaz.{Scalaz, _}
import Scalaz._

// Thanks to https://underscore.io/blog/posts/2017/03/29/free-inject.html
object CombineFreeInScalaz {
  sealed trait Logging[A]
  case class Info(s: String) extends Logging[Unit]

afsalthaj

import java.io.File

import scalaz.{Id, Monad}


// Finally tagless approach
trait  FileOperation[F[_], A] {
  def makeDir(d: File, x: A): F[A]
  def createFile(d: File, x: A): F[A]

afsalthaj

package io.atlassian.aws

import java.io.File

import scalaz.{Free, Functor}

sealed trait FileActionOp[A]
case class Pure[A](x: A) extends FileActionOp[A]
case class MakeDir[A](d: File, x: A) extends FileActionOp[A]
case class CreateFile[A](d: File, x: A) extends FileActionOp[A]

afsalthaj

Code Hint (please don't look at this until you solve it yourself)

So, here goes my code snippet thinking. Looking at the problem, it feels like a program should return another program. In fact, in our case we have lots of instances of "program" and we need to return/pass these programs.

So lets go ahead and create a program that should be returned. In our case, the main one is Notification.

{
 sealed trait Notification[A]

afsalthaj

import scalaz.Free


sealed trait Notification[A]

case class SendEmail(s: String) extends Notification[Unit]
case class SendMessage(s: String) extends Notification[Unit]
case class NothingJustLog(s: String) extends Notification[Unit]

sealed trait Table[Unit]