milessabin

import scala.language.experimental.macros

import scala.reflect.macros.whitebox

trait Foo[T]

object Foo {
  implicit def mkFoo[T]: Foo[T] = macro FooMacros.mkFooImpl[T]
}

d6y

/*
The Oracle Java enum Planets example using the Klang DIY Enum, modified to include ordering.
*/
object KlangEnumPlanets extends App {

  trait Enum { //DIY enum type
    import java.util.concurrent.atomic.AtomicReference //Concurrency paranoia

    type EnumVal <: Value //This is a type that needs to be found in the implementing class

milessabin

// Used as a term `the[T]` yields the unique implicit value of type `T` in the current
// implicit scope, if any. It is a compile time error if there is no such value. Its
// primary advantage over `Predef.implicitly` is that it will preserve any refinement that
// the implicit definition has, resulting in more precisely typed, and hence often more
// useful, values,

scala> trait Foo { type T ; val t: T }
defined trait Foo

scala> implicit val intFoo: Foo { type T = Int } = new Foo { type T = Int ; val t = 23 }

negator

    
    
    /**
      The Play (2.3) json combinator library is arguably the best in the scala world. However it doesnt
      work with case classes with greater than 22 fields.
      The following gist leverages the shapeless 'Automatic Typeclass Derivation' facility to work around this
      limitation. Simply stick it in a common location in your code base, and use like so:
      Note: ** Requires Play 2.3 and shapeless 2.0.0  
      
  

fancellu

// Coproduct is extension of Either concept, to N multually exlusive choices

type ISB = Int :+: String :+: Boolean :+: CNil

val isb = Coproduct[ISB]("foo")                   //> isb  : qaaz.ISB = foo

isb.select[Int]                                   //> res0: Option[Int] = None

isb.select[String]                                //> res1: Option[String] = Some(foo)

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

kevinwright

As compiled by Kevin Wright a.k.a @thecoda

(executive producer of the movie, and I didn't even know it... clever huh?)

please, please, please - If you know of any slides/code/whatever not on here, then ping me on twitter or comment this Gist!

This gist will be updated as and when I find new information. So it's probably best not to fork it, or you'll miss the updates!

Monday June 16th

runarorama

sealed trait Interact[A]

case class Ask(prompt: String)
  extends Interact[String]

case class Tell(msg: String)
  extends Interact[Unit]

trait Monad[M[_]] {
  def pure[A](a: A): M[A]

milessabin

scala> trait Assoc[K] { type V ; val value: V }
defined trait Assoc

scala> def mkAssoc[V0](k: String, v: V0): Assoc[k.type] { type V = V0 } =
     |   new Assoc[k.type] { type V = V0 ; val value = v }
mkAssoc: [V0](k: String, v: V0)Assoc[k.type]{type V = V0}

scala> implicit def nameAssoc = mkAssoc("Name", "Mary")
nameAssoc: Assoc[String("Name")]{type V = String}

cvogt

import scala.slick.lifted.CanBeQueryCondition
// optionally filter on a column with a supplied predicate
case class MaybeFilter[X, Y](val query: scala.slick.lifted.Query[X, Y]) {
  def filter[T,R:CanBeQueryCondition](data: Option[T])(f: T => X => R) = {
    data.map(v => MaybeFilter(query.filter(f(v)))).getOrElse(this)
  }
}

// example use case
import java.sql.Date