johnynek

/*
 * Consider a simple recursive function like:
 * f(x) = if (x > 1) f(x - 1) + x
 *        else 0
 *
 * This function isn't tail recursive (it could be, but let's set that aside for a moment).
 * How can we mechanically, which is to say without thinking about it, convert this into a stack safe recursion?
 * An approach is to model everything that happens after the recursion as a continuation, and build up that
 * continuation in a stack safe manner. Here is some example code:
 */

densh

import scalanative.native._
import SDL._
import SDLExtra._

@extern
@link("SDL2")
object SDL {
  type Window   = CStruct0
  type Renderer = CStruct0

Roland09

package application;

import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.text.Text;
import javafx.scene.text.TextBoundsType;

/**

eliangcs

Basic Security Setup for a Brand New Linode

Why

When you start a clean Linode, it isn't secured in the following aspects:

• Allows root SSH login
• Uses password authentication on SSH
• Doesn't have a firewall

mslinn

#!/bin/bash

# From ScalaCourses.com Introduction to Play Framework with Scala course
# https://www.scalacourses.com/student/showLecture/158

set -eo pipefail

function help {
  echo "Download or update Typesafe Activator on Linux and Cygwin"
  echo "Usage: $(basename $0) [options]"

alloy

The easiest way to start using the LLVM C++ API by example is to have LLVM generate the API usage for a given code sample. In this example it will emit the code required to rebuild the test.c sample by using LLVM:

$ clang -c -emit-llvm test.c -o test.ll
$ llc -march=cpp test.ll -o test.cpp

agemooij

Extremely bare example of Spray routing authentication using session cookies and XSRF tokens

This code was quickly ripped out of an active project to serve as an example. It will not compile in any way!

Any questions? Add them to the comments!

Notes

• the application uses a version of the cake pattern to compose the Spray routing application together from various traits
• a lot of those traits should be pretty self-explaining based on their name but if requested I can paste them into this Gist

nraychaudhuri

package controllers

import play.api.mvc._
import scala.concurrent._
import akka.actor.{Props, Actor}
import play.api.Play.current
import play.api.libs.concurrent.Akka
import scala.concurrent.ExecutionContext.Implicits._

object Application extends Controller {

jboner

Akka Cluster Implementation Notes

Slightly disorganized but reasonably complete notes on the algorithms, strategies and optimizations of the Akka Cluster implementation. Could use a lot more links and context etc., but was just written for my own understanding. Might be expanded later.

Links to papers and talks that have inspired the implementation can be found on the 10 last pages of this presentation.

Akka Gossip

Gossip state

This is the Gossip state representation:

johnynek

// Run this with scala <filename>

/**
 * A Two-phase commit Monad
 */
trait Transaction[+T] {
  def map[U](fn: T => U): Transaction[U] = flatMap { t => Constant(fn(t)) }
  def flatMap[U](fn: T => Transaction[U]): Transaction[U] =
    FlatMapped(this, fn)