SteefH

Amorphous: Writing a Scala library for boilerplate-free object mapping

At Infi, we started our first Scala project (link in Dutch) in mid-2016. When it became clear that Scala might be one of the technologies used in the project, I jumped at the chance to be part of it, because I'm always eager to learn new tech, and doing a project in a functional programming language was already near the top of my professional wish list.

As always when learning new technology, I like to push the envelope to see where things start to break down. I think that's a nice way to get to know the limits of that technology. As it turns out, Scala is a powerful language, with a strong type system that lets you use many advanced concepts I won't detail here (eg. type classes, high-level abstractions like the ones in the Typeclassopedia with the help of scalaz or [Cats](https://github.com

bastman

Docker - How to cleanup (unused) resources

Once in a while, you may need to cleanup resources (containers, volumes, images, networks) ...

delete volumes

// see: https://github.com/chadoe/docker-cleanup-volumes

$ docker volume rm $(docker volume ls -qf dangling=true)

$ docker volume ls -qf dangling=true | xargs -r docker volume rm

jeroenr

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.stream.ActorMaterializer

object Boot extends App with Service with CorsSupport {
  override implicit val system = ActorSystem()
  override implicit val executor = system.dispatcher
  override implicit val materializer = ActorMaterializer()

  Http().bindAndHandle(corsHandler(routes), "0.0.0.0", 1337)

robjens

; http://www.ietf.org/rfc/rfc3339.txt
; and http://www.odata.org/documentation/odata-version-3-0/abnf/

oneToNine = "01" / "02" / "03" / "04" / "05" / "06" / "07" / "08" / "09"
zeroToNine = "00" / oneToNine

oneToTwelve = oneToNine / "1" ( "0" / "1" / "2" )

oneToThirteen = oneToTwelve / "13"

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)

darkone23

(ns example.net
  (:require [goog.net.WebSocket]
            [goog.events :refer (listen)]
            [cljs.core.async :as async :refer (chan <! >! put! close)]
            [cljs.core.async.impl.protocols :as proto])
  (:require-macros [cljs.core.async.macros :refer (go)]))

(defn ws
  "WebSocket as a core.async channel
  returns a channel which delivers the ws chan then closes"