deanwampler

package progscala3.erased

import scala.language.experimental.erasedDefinitions

@main def Main() =
  // Use the +: methods to construct sequences.
  val nes1 = "one" +: EmptySeq
  val nes2 = "two" +: nes1
  val nes3 = "three" +: nes2

deanwampler

package progscala3.erased

import scala.annotation.implicitNotFound
import scala.language.experimental.erasedDefinitions

sealed trait Emptiness
final class Empty extends Emptiness
final class NotEmpty extends Emptiness

@implicitNotFound("The seq must be empty")

deanwampler

// Requires a snapshot or nightly build of Scala
val scala3 = "3.1.3-RC1-bin-SNAPSHOT"

lazy val root = project
  .in(file("."))
  .settings(
    name := "erased-feature-example",
    description := "An example of the experimental 'erased' feature.",
    version := "0.0.1",
    scalaVersion := scala3,

deanwampler

package progscala3.rounding.saferexceptions
import java.io.{IOException, File}
import scala.annotation.experimental
import language.experimental.saferExceptions

@experimental
object SaferExceptionsNested:
  def main(fileNames: Array[String]): Unit =
    fileNames.foreach { fileName =>
      try

deanwampler

package progscala3.rounding.saferexceptions
import java.io.{IOException, File}
import scala.annotation.experimental
// Enable safer exceptions
import language.experimental.saferExceptions

@experimental
object SaferExceptions:
  def main(fileNames: Array[String]): Unit =
    fileNames.foreach { fileName =>

deanwampler

package progscala3.rounding.saferexceptions
import java.io.{IOException, File}
import scala.annotation.experimental
// Enable safer exceptions
import language.experimental.saferExceptions

/**
 * Currently as written, this file doesn't compile using Scala 3.1.
 * Also, the object needs the `@experimental` annotation in order to use this feature.
 */

deanwampler

package polyglotprogramming.messaging.v4
import polyglotprogramming.messaging.*
import polyglotprogramming.messaging.v4.given

object Processor:
  def apply[IM <: IncomingMessage](message: IM)(using handler: MessageHandler[IM]): OutgoingMessage =
    handler(message)

/**
 * Add a new message type!

deanwampler

package polyglotprogramming.messaging.v3
import polyglotprogramming.messaging.*

trait MessageHandler[IM <: IncomingMessage]:
  final def apply(message: IM): OutgoingMessage =
    println(s"Received message: $message")
    process(message)

  protected def process(message: IM): OutgoingMessage

deanwampler

package polyglotprogramming.messaging.v2
import polyglotprogramming.messaging.*
import polyglotprogramming.messaging.v2.given

object Processor:
  def apply[IM <: IncomingMessage](message: IM)(using handler: MessageHandler[IM]): OutgoingMessage =
    handler(message)

@main def Messaging() =
  println(Processor(Start("start")))

deanwampler

package polyglotprogramming.messaging.v2
import polyglotprogramming.messaging.*

trait MessageHandler[IM <: IncomingMessage]:
  def apply(message: IM): OutgoingMessage =
    println(s"Received message: $message")
    Succeeded(s"Successfully processed $message")

given MessageHandler[Start]()
given MessageHandler[DoWork1]()