runarorama

import scalaz._

// A right Kan extension of `F` along itself, constrained by `C`.
trait RCodensity[C[_], F[_], A] {
  def apply[R:C](k: A => F[R]): F[R]
}

object RCodensity {
  implicit def codensityMonad[C[_], F[_]]: Monad[({type f[x] = RCodensity[C,F,x]})#f] =
      new Monad[({type f[x] = RCodensity[C,F,x]})#f] {

jen20

public class MessageIdentity
{
    public Guid NameSpace;
    private readonly byte[] _namespaceBytes;

    public MessageIdentity(Guid guidNameSpace)
    {
        NameSpace = guidNameSpace;
        _namespaceBytes = guidNameSpace.ToByteArray();
        SwapByteOrder(_namespaceBytes);

coldnebo

[
  { "keys": ["ctrl+shift+x"], "command": "tidy_xml" },
  { "keys": ["ctrl+shift+j"], "command": "prettify_json" }
]

tugberkugurlu

    public class MvcApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            /* usual sh** ommitted for brevity */

            var resolver = new CustomDependencyResolver();
            DependencyResolver.SetResolver(resolver);
            
            DataAnnotationsModelValidatorProvider.RegisterDefaultAdapterFactory(

andrejbauer

A bijection between numbers and pairs of numbers

Every once in a while I am faced with someone who denies that the rational numbers (or fractions, or pairs of integers) can be put into a bijective correspondence with natural numbers. To deal with the situation, I coded up the bijection. So now I can just say: "Really? Interesting. Please provide a pair of numbers (i,j) which is not enumerated by f, as defined in my gist." I am still waiting for a valid counter-example.

Anyhow, here is a demo of f and g at work. I am using the Python version, but a Haskell variant is included as well.

The 100-th pair is:

>>> f(100)

(10, 4)

SzymonPobiega

If you have two days to learn the very basics of modelling, Domain-Driven Design, CQRS and Event Sourcing, here's what you should do:

In the evenings read the [Domain-Driven Design Quickly Minibook]{http://www.infoq.com/minibooks/domain-driven-design-quickly}. During the day watch following great videos (in this order):

1. Eric Evans' [What I've learned about DDD since the book]{http://www.infoq.com/presentations/ddd-eric-evans}
2. Eric Evans' [Strategic Design - Responsibility Traps]{http://www.infoq.com/presentations/design-strategic-eric-evans}
3. Udi Dahan's [Avoid a Failed SOA: Business & Autonomous Components to the Rescue]{http://www.infoq.com/presentations/SOA-Business-Autonomous-Components}
4. Udi Dahan's [Command-Query Responsibility Segregation]{http://www.infoq.com/presentations/Command-Query-Responsibility-Segregation}
5. Greg Young's [Unshackle Your Domain]{http://www.infoq.com/presentations/greg-young-unshackle-qcon08}
6. Eric Evans' [Acknowledging CAP at the Root -- in the Domain Model]{ht