Slick with Reader

slick-reader.scala

import scalaz._
import Scalaz._

trait Tables {
  val profile: scala.slick.driver.JdbcProfile
  import profile.simple._

  case class Planet(name: String, id: Long=0L)

  class PlanetTable(tag: Tag) extends Table[Planet](tag, "planet") {
    def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
    def name = column[String]("name")
    def * = (name, id) <> (Planet.tupled, Planet.unapply)
  }

  lazy val planets = TableQuery[PlanetTable]
}


import scala.slick.driver.PostgresDriver.simple._

object Tables extends {
  val profile = scala.slick.driver.PostgresDriver
} with Tables {
  val db = Database.forURL("jdbc:postgresql:some-db", user="some-user", password="trustno1", driver = "org.postgresql.Driver")
}


object Main extends App {

  import Tables._

  // Create tables:
  // db.withSession { implicit s =>
  //   (planets.ddl).create
  //   planets += Planet("Earth")
  //   planets += Planet("Mars")
  // }

  type Work[A] = Reader[Session, A]

  def run[T](work: Work[T]): T =
    db.withSession { work.run }

  def findAll: Work[Seq[Planet]] = Reader(planets.list(_))

  val result = run(findAll)
  println(result)

  //     -  vs  -

  def findAllRegular(implicit session: Session): Seq[Planet] =
    planets.list

  db.withSession { implicit session =>
    val result = findAllRegular
    println(result)
  }

  // Both produce:
  //  List(Planet(Earth,1), Planet(Mars,2))


}