cvogt

To: TWC.Privacy@twcable.com
Subject: Stop all advertising mail

I hereby request that you immediately stop any kind of mailing for
advertisment or any other purpose to the following address

<YOUR STREET ADDRESS>

Please confirm.

cvogt

// DEFAULT VALUES

def foo(str: String = "test") = ???
assert( foo.str == "test" ) // new: named access to default values

case class Bar(str: String = "test")
assert( Bar.apply.str == "test" ) // same for case classes via .apply method

// REPETIION-FREE .copy (aka lenses light)

cvogt

// a List isn't a Map
scala> val x: Map[Int,Int] = List(1,2,3).map(i => i -> i)
<console>:16: error: type mismatch;
 found   : List[(Int, Int)]
 required: Map[Int,Int]
       val x: Map[Int,Int] = List(1,2,3).map(i => i -> i)
                                            ^
// first create List, then create Map. Intermediate collection overhead
scala> val x: Map[Int,Int] = List(1,2,3).map(i => i -> i).toMap 
x: Map[Int,Int] = Map(1 -> 1, 2 -> 2, 3 -> 3)

cvogt

package tut

import java.io.{ OutputStream, FilterOutputStream }

// FilterOutputStream that removes ANSI escapes. This should be fairly efficient, I guess, since
// it's all case switches on constants. Can inline more if needed but it seems fine. For the
// record, the format is ESC '[' digits (';' digits)* terminal
case class AnsiFilterStream(os: OutputStream) extends FilterOutputStream(os) {

  case class State(apply: Int => State)

cvogt

object Application{
  def run(config: Config): Unit = {
    val db = connectToDb( config.dbHost, config.dbPort )
    ...
  }
}
case class Config(
  dbHost: String,
  port: Int
)

cvogt

object Application{
  def main(args: Array[String]): Unit = {
    val config = Config.get( args(0) )
    val db = connectToDb( config.dbHost, config.dbPort )
    ...
  }
}

object Config{
  def get(config: String) = {

cvogt

object DynamicConfig{
  def main(args: Array[String]): Unit = {
    Application.run(
      Config(
        sys.props.get("db.host").get,
        10000
      )
  }
}

cvogt

object PartiallyDynamicConfig{
  def main(args: Array[String]): Unit = {
    Application.run(
      Config(
        sys.props.get("db.host") getOrElse "db.test-server.com",
        10000
      )
  }
}

cvogt

object SwitchableConfig{
  def main(args: Array[String]): Unit = {
    val config = System.getProperty("config") match {
      case "test" => Config("db.test-server.com",10000)
      case "production" => Config("db.production-server.com",12345)
      case _ => throw new Exception("unknown config: "+config)
    }
    Application.run( config )
  }
}

cvogt

object ProductionConfig{
  def main(args: Array[String]): Unit = {
    val config = Config("db.production-server.com",12345)
    if(args(0) == "serialize")
      println( toJson( config ) )
    else
      Application.run( config )
  }
}