alexandru

Monix Task: A diverging design

This document is about Task, an alternative for Scalaz's Task or Scala's Future. Note this is work in progress and this document suffered multiple modifications already:

• Jan 26, 2016
• Dec 23, 2015
• Dec 22, 2015
• Dec 21, 2015
• Dec 20, 2015

puffnfresh

scala> null.asInstanceOf[Int]
res0: Int = 0

scala> 0.asInstanceOf[String]
java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
  ... 33 elided

scala> null.asInstanceOf[Int].asInstanceOf[String]
res2: String = null

leque

;;;; Freer monad in Scheme
;;;; See also
;;;; * "Freer monads, more extensible effects"
;;;; http://dl.acm.org/citation.cfm?doid=2804302.2804319
;;;; * Free monad in Scheme https://gist.github.com/wasabiz/951b2f0b22643a59aeb2
(use gauche.record)
(use util.match)

;;; data Freer f a where
;;;   Pure   :: a -> Freer f a

pocketberserker

何か作ろうと思ったけど無理だったので使ったライブラリ紹介

自己紹介

• なかやん・ゆーき / ぺんぎん / もみあげ
• @pocketberserker / id:pocketberserker
• Microsoft MVP for F# .NET (2015/04/01～ 2016/03/31)
• そういえば Scala でアプリケーション作ったことない…

pocketberserker

関数型Scalaの集いアンケート結果

Q1. scalazを使用していますか？

• 仕事でも趣味でも使ってる 8
• 仕事で使っている 10
• 趣味で使っている 29
• 使っていない 79

Q2. Functional Programming in Scalaを持っていますか？

travisbrown

// Given the following ADT:

sealed trait Status
case object One extends Status
case object Two extends Status
case object Three extends Status

// They represent states. The natural progression, for this
// example, is : One -> Two -> Three

myuon

{-# LANGUAGE Rank2Types, ScopedTypeVariables #-}
import Prelude hiding ((<*>), abs)
import qualified Control.Applicative as A
import Control.Monad
import Test.QuickCheck

class NearSemiring m where
  (<+>) :: m a -> m a -> m a
  zero :: m a
  (<*>) :: m a -> m a -> m a

pchiusano

package streams

trait Free[+F[_],+A] {
  import Free._
  def flatMap[F2[x]>:F[x],B](f: A => Free[F2,B]): Free[F2,B] = Bind(this, f)
  def map[B](f: A => B): Free[F,B] = Bind(this, f andThen (Free.Pure(_)))
}
object Free {
  case class Pure[A](a: A) extends Free[Nothing,A]
  case class Eval[F[_],A](fa: F[A]) extends Free[F,A]

y-yu

trait Applicative[F[_]] {
  def pure[A](a: A): F[A]
  def apply[A, B](f: F[A => B], a: F[A]): F[B]
}

trait Traversable[T[_], F[_]] {
  def traverse[A, B](f: A => F[B], a: T[A]): F[T[B]]
}

trait Monoid[A] {

retronym

scala> :paste
// Entering paste mode (ctrl-D to finish)

def impl[T: c.WeakTypeTag](c: Context): c.Tree = {
  import c.universe._
  def subs = weakTypeOf[T].typeSymbol.asClass.knownDirectSubclasses
  val subs1 = subs
  println(subs1)
  val global = c.universe.asInstanceOf[tools.nsc.Global]
  def checkSubsPostTyper = if (subs1 != subs)