djspiewak

Getting Started in Scala

This is my attempt to give Scala newcomers a quick-and-easy rundown to the prerequisite steps they need to a) try Scala, and b) get a standard project up and running on their machine. I'm not going to talk about the language at all; there are plenty of better resources a google search away. This is just focused on the prerequisite tooling and machine setup. I will not be assuming you have any background in JVM languages. So if you're coming from Python, Ruby, JavaScript, Haskell, or anywhere…  I hope to present the information you need without assuming anything.

Disclaimer It has been over a decade since I was new to Scala, and when I was new to Scala, I was coming from a Java and Ruby background. This has probably caused me to unknowingly make some assumptions. Please feel free to call me out in comments/tweets!

One assumption I'm knowingly making is that you're on a Unix-like platform. Sorry, Windows users.

Getting the JVM

jto

sealed class Match[A, B] { type τs <: HList }

object Match {
  type Aux[A0, B0, τ0 <: HList] = Match[A0, B0] { type τs = τ0 }
  sealed trait τ
  sealed trait τ1[A]

  implicit def matchEq[A0]: Aux[A0, A0, HNil] =
    new Match[A0, A0]{
      type τs = HNil

propensive

// Example usages:

// Returns true
checkTypeMismatch {
  import deferTypeErrors._
  7: String
}

// Returns false
checkTypeMismatch {

runarorama

trait λ {
  type α
}

trait Functor extends λ {
  type α <: λ

  def map[A,B](x: α { type α = A })(f: A => B): α { type α = B }
}