drstevens

Keybase proof

I hereby claim:

• I am drstevens on github.
• I am drstevens (https://keybase.io/drstevens) on keybase.
• I have a public key whose fingerprint is FC3A 884C F064 48BC 315E 205C B797 C6B5 C281 822B

To claim this, I am signing this object:

drstevens

  import monocle.function.Each
  import monocle.macros.GenLens
  import monocle.{Lens, Optional}

  sealed trait Foo
  object Foo {
    // This is similar to scalaz.PLens
    val _foo1Opt: Optional[Foo, Foo1] = Optional[Foo, Foo1] {
      case f1: Foo1 => Some(f1)

drstevens

Advanced Functional Programming with Scala - Notes

Copyright © 2017 Fantasyland Institute of Learning. All rights reserved.

1. Mastering Functions

A function is a mapping from one set, called a domain, to another set, called the codomain. A function associates every element in the domain with exactly one element in the codomain. In Scala, both domain and codomain are types.

val square : Int => Int = x => x * x

drstevens

trait Writes[T] {
  def writes(o: T): JsValue
}

trait Reads[T] {
  def reads(json: JsValue): T
}

trait Format[T] extends Writes[T] with Reads[T]

drstevens

import com.nicta.rng.Rng
import org.joda.time.DateTime
import scalaz._
import Scalaz._

object Foo extends App {

  def time[A](f: => A): (Long, Long, Long) = {
    val t0 = System.currentTimeMillis
    val a = f

drstevens

import scalaz.Id.Id
import scalaz.BijectionT._
import scalaz.Lens

trait Bijectionz[A, C] {

  def apply(str: C): A
  def unapply(a: A): Option[C]

drstevens

import scalaz._, Scalaz._
 
def setS(i: Int): State[List[Int], Unit] = modify(i :: _)
 
val s = (1 to 10000).foldLeft(state[List[Int], Unit](()).lift[Free.Trampoline]) {
  case (st, i) => st *> setS(i).lift[Free.Trampoline]
}
 
s(Nil).run

drstevens

Welcome to Scala version 2.10.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_25).
Type in expressions to have them evaluated.
Type :help for more information.

scala> import play.api.libs.json._; import play.api.libs.functional.Applicative;
import play.api.libs.json._
import play.api.libs.functional.Applicative

scala> val expected = JsSuccess(10, JsPath(List(KeyPathNode("somekey"))))
expected: play.api.libs.json.JsSuccess[Int] = JsSuccess(10,/somekey)

drstevens

Welcome to Scala version 2.10.3 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_25).
Type in expressions to have them evaluated.
Type :help for more information.

scala> val map0 = Map.empty[Int, Int] withDefaultValue 0
map0: scala.collection.immutable.Map[Int,Int] = Map()

scala> val map1 = map0 mapValues(identity)
map1: scala.collection.immutable.Map[Int,Int] = Map()

drstevens

//scala 2.10.2
//"org.scalaz" %% "scalaz-core" % "7.0.3"
//"org.specs2" %% "specs2" % "2.1.1" % "test"
//"org.mockito" % "mockito-all" % "1.9.0" % "test"

import scalaz.State._
import org.specs2.mutable.Specification
import org.specs2.mock._

trait Builder {