Intro to HLists

.gitignore

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+target
+.idea

build.sbt

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+import Dependencies._
+
+ThisBuild / scalaVersion     := "2.12.8"
+ThisBuild / version          := "0.1.0-SNAPSHOT"
+ThisBuild / organization     := "com.example"
+ThisBuild / organizationName := "example"
+
+lazy val root = (project in file("."))
+  .settings(
+    name := "copying-with-shapeless",
+    libraryDependencies ++= Seq(
+      shapeless,
+      scalaTest % Test
+  ))

project/Dependencies.scala

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+import sbt._
+
+object Dependencies {
+  lazy val shapeless = "com.chuusai" %% "shapeless" % "2.3.3"
+  lazy val scalaTest = "org.scalatest" %% "scalatest" % "3.0.5"
+}

project/build.properties

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+sbt.version=1.2.7

src/main/scala/example/Datamodel.scala

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+package example
+
+import java.time.LocalDate
+
+/* Represents the individual "pages" of our application */
+
+case class Location(pickup: String, dropOff: String, from: LocalDate, to: LocalDate)
+
+case class Vehicle(vehicleCategory: String, automatic: Boolean, numDoors: Int)
+
+case class Driver(driverAge: Int, nationality: String)
+
+/* We will merge the all data into this one class */
+
+case class Reservation(
+  pickup: String,
+  dropOff: String,
+  from: LocalDate,
+  to: LocalDate,
+  vehicleCategory: String,
+  automatic: Boolean,
+  numDoors: Int,
+  driverAge: Int,
+  nationality: String
+)

src/main/scala/example/Main.scala

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+package example
+
+import java.time.LocalDate
+import shapeless.{::, HNil}
+
+object Main {
+
+  /* Our HList representation of the case classes */
+  type LocationH = String :: String :: LocalDate :: LocalDate :: HNil
+  type VehicleH = String :: Boolean :: Int :: HNil
+  type DriverH = Int :: String :: HNil
+  type ReservationH = String :: String :: LocalDate :: LocalDate :: String :: Boolean :: Int :: Int :: String :: HNil
+
+  def main(args: Array[String]): Unit = {
+    val locationH: LocationH = "Malaga Airport" :: "Malaga Airport" :: LocalDate.of(2018,8,1) :: LocalDate.of(2018,8,10) :: HNil
+    val vehicleH: VehicleH = "Economy" :: false :: 4 :: HNil
+    val driverH: DriverH = 35 :: "British" :: HNil
+
+    val reservationH: ReservationH = locationH ++ vehicleH ++ driverH
+
+    reservationH match {
+      case
+        pickup ::
+        dropOff ::
+        from ::
+        to ::
+        vehicleCategory ::
+        automatic ::
+        numDoors ::
+        driverAge ::
+        nationality ::
+        HNil =>
+        println(s"pickup location: $pickup")
+    }
+  }
+
+}