YoEight

{-# LANGUAGE RankNTypes #-}

newtype State s a = State { runState :: forall r. s -> (a -> s -> r) -> r }

stateReturn :: a -> State s a
stateReturn = undefined

stateMap :: (a -> b) -> State s a -> State s b
stateMap = undefined

YoEight

{-# LANGUAGE RankNTypes #-}

newtype State s a = State { runState :: forall r. s -> (a -> s -> r) -> r }

stateReturn :: a -> State s a
stateReturn a = State $ \s k -> k a s

stateMap :: (a -> b) -> State s a -> State s b
stateMap f (State sa) = State $ \s kb -> sa s (kb . f)

kwhinnery

exports.Person = function(firstName,lastName) {
    this.firstName = firstName;
    this.lastName = lastName;
};

mpilquist

import scalaz._
import Scalaz._
import scalaz.iteratee._
import EnumeratorT._

def counter[A, F[+_]: Pointed] =
  IterateeT.fold[A, F, Int](0) { (acc: Int, a: A) => acc + 1 }

def count[A, F[+_]: Monad](e: EnumeratorT[A, F]) =
  (counter[A, F] &= e).run

tonymorris

sealed trait KeyValueStore[+A] {
  def map[B](f: A => B): KeyValueStore[B] =
    this match {
      case Put(k, v, q) => Put(k, v, f compose q)
      case Get(k, q) => Get(k, f compose q)
      case Del(k, q) => Del(k, f compose q) 
    }
}
case class Put[A](k: String, v: String, q: Option[String] => A) extends KeyValueStore[A]
case class Get[A](k: String, q: Option[String] => A) extends KeyValueStore[A]

MichaelXavier

source "http://rubygems.org"

gem "guard-shell"
gem "rake"

milessabin

Welcome to Scala version 2.10.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.7.0_21).
Type in expressions to have them evaluated.
Type :help for more information.

scala> import shapeless._
import shapeless._

scala> import syntax.tuple._
import syntax.tuple._

timperrett

/* discovered njoin on this thread: https://github.com/functional-streams-for-scala/fs2/issues/251 - which also cites (adjusted to match example below):

If we increase maxQueued up to 100, and `handle` emits multiple `A` values, up to 100 will be prefetched 
before we block on the consumer of results. (Not actually blocking by occupying a thread, but semantically blocking.) 
If we increase maxOpen to 50, then we can have 50 `item` streams processing concurrently.
*/

import scalaz.stream.{Sink,Process,sink,channel}
import scalaz.stream.nondeterminism.njoin

milessabin

// An ADT+shapeless as a drop-in replacement for a standard Scala Enumeration.
//
// First the unsafe standard Scala Enumeration ...
//
object ScalaEnumDemo extends App {
  // Example from scala.Enumeration scaladoc. Terse ...
  object WeekDay extends Enumeration {
    type WeekDay = Value
    val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value
  }

fwenzel

# Upgrade to OS X Lion, notice your virtualenvs are all hosed.

# Install Xcode 4.1 from the app store (or //fs2/IT/Apple/).
# Make sure to actually *run* the install, it's an app inside Applications. Throw it away afterwards, if you want the space back.

sudo easy_install pip
sudo pip install virtualenv virtualenvwrapper ipython

# blow the old one(s) away
rmvirtualenv playdoh