debasishg

// for comprehension
scala> for {
     |   l <- List(2,5,10)
     |   m <- List(8,10,11)
     | } yield l * m
res17: List[Int] = List(16, 20, 22, 40, 50, 55, 80, 100, 110)

// map a pure function into applicatives
scala> List(8,10,11) <*> (List(2,5,10) map (((_: Int) * (_: Int)).curried))
res18: List[Int] = List(16, 20, 22, 40, 50, 55, 80, 100, 110)

viktorklang

//Usage: 
//override def pomPostProcess(node: Node): Node = mcPom(moduleConfigurations)(super.pomPostProcess(node))

trait McPom { self: DefaultProject =>
  import scala.xml._

  def mcPom(mcs: Set[ModuleConfiguration])(node: Node): Node = {
    //make sure we have a trailing slash so we deduplicate URLs properly
    def cleanUrl(url: String) = url match {
      case null => ""

fedesilva

#!/bin/bash -e
#
# Since unicorn creates a new pid on restart/reload, it needs a little extra love to 
# manage with runit. Instead of managing unicorn directly, we simply trap signal calls
# to the service and redirect them to unicorn directly.
#
# To make this work properly with RVM, you should create a wrapper for the app's gemset unicorn.
#

function is_unicorn_alive {

gclaramunt

case class ListZipper[T](rev:List[T], fwd:List[T]){
    override def toString = rev.reverse.toString ++" " ++ fwd.toString  
    
    def read:T= fwd.head
    def add(c:T)=ListZipper(rev,c::fwd)
    def update(c:T)=ListZipper(rev,c::fwd.tail)
    def remove()=ListZipper(rev,fwd.tail)  

    def back=ListZipper(rev.tail,rev.head::fwd)
    def forward=ListZipper(fwd.head::rev,fwd.tail)

fedesilva

import sbt._
import Keys._
/**
 *   How in the world do I make bye depend on hello?
 *   And how do I depend on a task like test?
 *   I have not been able to make this work
     goodbyeTask <<= goodbyeTask.dependsOn(helloTask) as in https://github.com/harrah/xsbt/wiki/Tasks
     no matter where I stick it!
     Halp!
 */

fedesilva

trait Flying
trait Landed

case class Plane[Status]()

def land(p:Plane[Flying])=Plane[Landed]()
def takeOff(p:Plane[Landed])= Plane[Flying]()

val plane = new Plane[Landed]()

fedesilva

// Mersenne Twister 19937
// Based on code from: http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
// Note: This implementation is not thread-safe!
final class MersenneTwister (seed: Int = 5489) {
  private val N = 624
  private val M = 397

  private val MatrixA = 0x9908b0dfL

  private val UpperMask = 0x80000000L

gclaramunt

trait Entity
trait User extends Entity
trait Product extends Entity

case class Id[T<:Entity](id:String)


def buy(pId:Id[Product],uId:Id[User])="Bought product %s for user %s".format(pId.id,uId.id)

val pId=new Id[Product]("1")

puffnfresh

Where TDD Fails

I've just gotten back from the awesome mloc.js conference. There was a talk about compiling C# to JavaScript and one of the benefits explained was static types. Someone from the audience asked, who needs types when you do Test Driven Development?

I tried to address the question in my talk on Roy but I talked to some developers afterwards and they thought that TDD

fedesilva

scala> val rp = pipeline(rq) 
rp: scala.concurrent.Future[spray.http.HttpResponse] = scala.concurrent.impl.Promise$DefaultPromise@597aa1d

scala> rp fp2013-08-216 20:18:26.560 INFO  akka.actor.DeadLetterActorRef - Message [spray.http.HttpResponse] from Actor[akka://test/user/IO-HTTP/host-connector-0/0#229322353] to Actor[akka://test/deadLetters] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
2013-08-216 20:18:26.561 INFO  akka.actor.LocalActorRef - Message [akka.io.Tcp$Write] from Actor[akka://test/user/IO-HTTP/group-0/0#-1483684089] to Actor[akka://test/system/IO-TCP/selectors/$a/0#634853586] was not delivered. [2] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
2013-08-216 20:18:26.561 INFO  akka.actor.LocalActorRef - Message [akka.io.Tcp$ConfirmedClos