fancellu

package effects

import cats._
import cats.data._
import cats.free.Free
import cats.implicits._

// Example usage of the Cats Free Monad data type
// A free monad lets you build a Monad from any Functor

fancellu

import cats._
import cats.data._
import cats.implicits._
import cats.data.{NonEmptyList => NEL}
import cats.data.{NonEmptyChain => NEC}

// Example usage of the Cats Ior data type. Similar to Validated/Either/Xor, but we can
// return both types should we wish
// Note the similarity/difference with Validated
// https://gist.github.com/fancellu/b6deaed2068ff5bd91f544d178568560

fancellu

import cats._
import cats.data._
import cats.implicits._
import cats.data.{NonEmptyList => NEL}

// Example usage of the Cats Validated data type. It does not form a Monad (no flatMap)
// unlike Either, so does not stop on first failure

object ValidatedExample extends App {

fancellu

import cats._
import cats.data._
import cats.implicits._

// Example of how to use the Cats State datatype to encapsulate state changes in an immutable manner
// Helps us remove error prone boilerplate when chaining state transitions

object StateExample extends App {

  type Stack = List[String]

fancellu

import cats._
import cats.data.{Reader, _}
import cats.implicits._

import scala.util.Random

// Example of how to use the Cats Reader Monad to compose functionality and process some fixed type
// We compose pure functions with for comprehensions or map/Flatmap combinators
// Useful for when you find yourself passing some context again and again

fancellu

// Example code to show how Cats Writer can be used to add useful inline  logging to some computation

import cats._
import cats.data._
import cats.implicits._

object WriterExample extends App {

  type LOG = Vector[String]
  type LOGWRITER[A] = Writer[LOG, A]

fancellu

import cats._
import cats.data._
import cats.implicits._

object Typeclasses extends App {

  case class Item(name: String, price: Double)

  object Item {
    // note we are using SAM support to define these instances

fancellu

object SingleAbstractMethodSyntax extends App{

  // Some nice tricks with single abstract method interface, Scala 2.11+

  trait DoIt{
    def doSomething(x:Int): Int
  }
  // I am creating an instance of DoIt, and supplying doSomething
  val doit: DoIt= _+1

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case class Band(top: Double, interest: Double)

class InterestCalculator(bands: List[Band], precision: Int = 2) {

  def calc(amount: Double) = {

    val interest = bands.collectFirst {
      case Band(top, interest) if top >= amount => interest * amount
    }.getOrElse(0.0)

fancellu

case class Product(name: String)(val price: Double)

// we can choose to only supply the name, i.e. partially applied
val banana=Product("banana") _

val banana10=banana(10)
val bananafree=banana(0)
val apple=Product("apple")(5)

val list=List(banana10, apple, bananafree)