Aleksandra A Vilkina

Applied Functional Programming with Scala - Notes

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

	def copyChunk(from: AsynchronousFileChannel,
	to : AsynchronousFileChannel) =
	for {
	chunk <- from.read(1024, 0)
	_ <- to.write(chunk, 0)
	} yield ()

	package com.oleksandrah.cakes

	import com.oleksandrah.cakes.model.{Cake, Cakes, Tables}
	import org.scalatra.ScalatraServlet
	import org.scalatra.scalate.ScalateSupport
	import slick.jdbc.H2Profile
	import slick.jdbc.H2Profile.api._
	import zio.{Exit, IO, Task, ZIO, _}

	package ziolist.http4s

	import org.http4s._
	import zio._
	import zio.interop.catz._
	import org.http4s.server.blaze.BlazeServerBuilder

	object Service {

	//E for Effect

	package ziolist
	import zio.{ ZEnv, ZIO }
	import zio._


	sealed trait MyList[+ A] {
	def head: Option[A]
	def tail: MyList[A]
	def isEmpty: Boolean
	def add[B >: A](element: B): MyList[B]

	def zipAllWith[@specialized B, @specialized C](that: Chunk[B])(left: A => C, right: B => C)(both: (A, B) => C): Chunk[C] = {
	val size = self.length.max(that.length)
	val minln = self.length.min(that.length)

	if (size == 0 && minln == 0) Chunk.empty

	else {
	var j = 0
	val c = both(self(j), that(j))
	implicit val C: ClassTag[C] = Chunk.Tags.fromValue(c)

	// Array#update
	val array = Array("a", "b", "c")
	array.update(0, "z")