jonifreeman

object Sql {
  import scala.reflect.makro._
  import language.experimental.macros

  case class Query[R](/*sql: String*/)

  def execute[R](q: Query[R]): Seq[R] = sys.error("implement me")

  def sqlImpl(c: Context)(s: c.Expr[String]): c.Expr[Any] = {
    import c.universe._

sadache

Is socket.push(bytes) all you need to program Realtime Web apps?

One of the goals of Play2 architecture is to provide a programming model for what is called Realtime Web Applications.

Realtime Web Applications

Realtime Web Applications are applications that make use of Websockets, Server Sent Events, Comet or other protocols offering/simulating an open socket between the browser and the server for continuous communication. Basically, these applications let users work with information as it is published - without having to periodically ping the service.

There are quite a few web frameworks that target the development of this type of application: but usually the solution is to simply provide an API that allows developers to push/receive messages from/to an open channel, something like:

mandubian

"copy file" in {
  var i = 0
  val fileGenerator = Enumerator.fromCallback( () => 
    if(i<1000){ i+=1; Future.successful(Some((new java.util.Date).getTime.toString + "\n")) } else Future(None) 
  )

  val f = FileChannel("/tmp/testwrite.txt").delete.writing.create
  val f2 = FileChannel("/tmp/testwrite2.txt").delete.writing.create

  fileGenerator                                     // generates data

tonymorris

// Missing support libraries
object MissingLibraries {
  case class State[S, +A](run: S => (A, S))  {
    def map[B](f: A => B): State[S, B] =
      State(s => {
        val (a, t) = run(s)
        (f(a), t)
      })

    def flatMap[B](f: A => State[S, B]): State[S, B] =

tonymorris

trait Semigroup[A] {
  def op(a1: A, a2: A): A
}

trait Monoid[A] extends Semigroup[A] {
  def id: A
}

object Monoid {
  implicit def ListMonoid[A]: Monoid[List[A]] =

rokgerzelj

# to install the latest stable version:
brew install play

# to install play-2.1-RC2:
brew install https://raw.github.com/gist/4485598/play.rb

# to switch versions (from https://github.com/mxcl/homebrew/wiki/External-Commands):
brew switch play 2.0.4
brew switch play 2.1-RC2

paulp

Hello scala, my old friend
I've come to take you home again
Because a feature slowly creeping
left me plagued with doubts and weeping
and the version that was tagged in the repo
just has to go
it lacks the signs of soundness

On sleepless nights I hacked alone
applying ant and other tools of stone

bigtoast

# to install the latest stable version:
brew install play

# to install play-2.1-RC3:
# if you already have a version of play installed you will need to unlink it.
brew unlink play
brew install https://raw.github.com/gist/4675514/play.rb

# to switch versions (from https://github.com/mxcl/homebrew/wiki/External-Commands):
brew switch play 2.0.4

asflierl

Welcome to Scala version 2.10.0 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_11).
Type in expressions to have them evaluated.
Type :help for more information.

scala> trait Meep { type Moop; def f: Moop }
defined trait Meep

scala> def fnord(a: Meep): a.Moop = a.f
fnord: (a: Meep)a.Moop

sadache

Asynchronicity is the price to pay, you better know what you're paying for...

Let's share some vocabulary first:

Thread: The primitive responsible of executing code on the processor, you can give an existing (or a new) Thread some code, and it will execute it. Normally you can have a few hundreds on a JVM, arguments that you can tweak your way out to thousands. Worth noting that multitasking is achieved when using multiple Threads. Multiple Threads can exist for a single processor in which case multitasking happens when this processor switches between threads, called context switching, which will give the impression of things happenning in parallel. An example of a direct, and probably naive, use of a new Thread in Java:

public class MyRunnable implements Runnable {
  public void run(){
 System.out.println("MyRunnable running");