DougGregor

Swift 5.5 proposals:

• SE-0296: Async/await
• SE-0297: Concurrency Interoperability with Objective-C
• SE-0298: Async/Await: Sequences
• SE-0300: Continuations for interfacing async tasks with synchronous code
• SE-0302: Sendable and @Sendable closures
• SE-0304: Structured concurrency
• SE-0306: Actors
• [SE-0310: Effectful read-only properties](https://github.com/apple/swift-evolution/bl

DougGregor

Preventing Data Races in the Swift Concurrency Model

One of the goals of the concurrency effort is to prevent data races. This document describes the approach taken to preventing data races overall, by categorizing the sources of data races and describing how they are addressed with other proposals in the Swift Concurrency effort.

Data races

A data race occurs when two threads access the same memory concurrently and at least one of the accesses can change the value. Within the safe subset of Swift (e.g., ignoring the use of UnsafeMutablePointer and related types), the memory in question is always a stored property. There are several different categories of stored properties that need to be considered for data races:

• Global and static stored properties:

weissi

Swift compiler 4.0, language mode 4

>=4.0.0
NOT >=4.0.10
NOT >=4.0.50
NOT >=4.0.150
NOT >=4.0.200
NOT >=4.0.250
NOT >=4.1.0

jkubrynski

import sun.misc.Unsafe;

import java.lang.reflect.Field;
import java.util.concurrent.ForkJoinPool;

/**
 * @author Jakub Kubrynski
 */
public class ReplaceCommonPool {

acolyer

Internet Scale Services Checklist

A checklist for designing and developing internet scale services, inspired by James Hamilton's 2007 paper "On Desgining and Deploying Internet-Scale Services."

• http://mvdirona.com/jrh/talksandpapers/jamesrh_lisa.pdf

Basic tenets

• Does the design expect failures to happen regularly and handle them gracefully?
• Have we kept things as simple as possible?

johnynek

// I was reading through these examples: http://apocalisp.wordpress.com/2010/06/08/type-level-programming-in-scala/
// and I thought it would be nice to more quickly get to something useful, to show the power of the techniques.
object SizedListExample {
  // Type of all Non-negative integers
  sealed trait Nat
  // This is zero.
  sealed trait _0 extends Nat
  // Successor to some non-negative number
  sealed trait Succ[N <: Nat] extends Nat

krasserm

A list of Akka Persistence plugins is now maintained at http://akka.io/community/. Please edit this page to add a new plugin.

ktoso

// or even more plain:
testCases.foreach((case) -> {
  // given
  Object given = case.given;
  Object expected = case.expected;
  
  it.should("return [%s] when applied to [%s]", given, expected, system -> {
    // when
    Object got = system.doThing(given);
  

ktoso

ktoso@moon /Users/ktoso 
$ scalac vals_by_types.scala
warning: there were 2 deprecation warnings; re-run with -deprecation for details
one warning found

ktoso@moon /Users/ktoso 
$ scala Main

The combined names are: UserFinder and UserStatusReader

viktorklang

 /**
   * "Select" off the first future to be satisfied.  Return this as a
   * result, with the remainder of the Futures as a sequence.
   *
   * @param fs a scala.collection.Seq
   */
  def select[A](fs: Seq[Future[A]])(implicit ec: ExecutionContext): Future[(Try[A], Seq[Future[A]])] = {
    @tailrec
    def stripe(p: Promise[(Try[A], Seq[Future[A]])],
               heads: Seq[Future[A]],