lifthrasiir

/* The world's smallest Brainfuck interpreter in C, by Kang Seonghoon
 * http://j.mearie.org/post/1181041789/brainfuck-interpreter-in-2-lines-of-c */
s[99],*r=s,*d,c;main(a,b){char*v=1[d=b];for(;c=*v++%93;)for(b=c&2,b=c%7?a&&(c&17
?c&1?(*r+=b-1):(r+=b-1):syscall(4-!b,b,r,1),0):v;b&&c|a**r;v=d)main(!c,&a);d=v;}

milessabin

def unexpected : Nothing = sys.error("Unexpected invocation")

// Encoding for "A is not a subtype of B"
trait <:!<[A, B]

// Uses ambiguity to rule out the cases we're trying to exclude
implicit def nsub[A, B] : A <:!< B = null
implicit def nsubAmbig1[A, B >: A] : A <:!< B = unexpected
implicit def nsubAmbig2[A, B >: A] : A <:!< B = unexpected

missingfaktor

trait Isomorphism[A, B] {
  def fw: A => B
  def bw: B => A
}
 
object Isomorphism {
  implicit def anyIso[A](a: A) = new {
    def as[B](implicit ev: Isomorphism[A, B]) = ev fw a
  }
 

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

SystemFw

Balaji Sivaraman @balajisivaraman_twitter

Hi all, I need some help understanding a piece of Doobie code from the examples. It is the StreamingCopy one: (https://github.com/tpolecat/doobie/blob/series/0.4.x/yax/example/src/main/scala/example/StreamingCopy.scala). I am using a modified version of the fuseMap2 example from that file. Here’s how I’ve modified it for my requirements:

  def fuseMap[F[_]: Catchable: Monad, A, B](
      source: Process[ConnectionIO, A],
      sink: Vector[A] => ConnectionIO[B],
      delete: ConnectionIO[Unit]
  )(
 sourceXA: Transactor[F],

timvisee

Falsehoods programmers believe about time

This is a compiled list of falsehoods programmers tend to believe about working with time.

Don't re-invent a date time library yourself. If you think you understand everything about time, you're probably doing it wrong.

Falsehoods

• There are always 24 hours in a day.
• February is always 28 days long.
• Any 24-hour period will always begin and end in the same day (or week, or month).

cartermp

My LambdaConf experience

I just finished an incredible (and exhausting) week at LambdaConf in Boulder, Colorado. I can say with confidence that it's the best programming conference I've attended, and I'm anxious to be able to attend it again in the future.

Stepping outside my comfort zone

I wouldn't call myself terribly experienced - 28 years old and only 4 years out of college - but I have developed a professional comfort in a few areas:

• Interacting with F# developers
• Interacting with C# developers

vil1

This is a witch hunt.

When you exclude a relentless innovator from a conference, when this exclusion results in excluding the young woman from North-Africa who was supposed to share the stage with him, it has nothing to do with promoting innovation and inclusivity. It is a witch hunt.

When you bar someone from contributing to a FLOSS project based on alleged aggressive communication without providing any concrete example of the said behavior nor explaining what you did to make this behavior stop before taking such extreme decision, it has nothing to do with making your community a better place. It is a witch hunt.

Witch hunts are bad. Not because they burn people with no fair trial and that some of the burnt people may not have been witches in the first place.

Witch hunts are bad because they burn people. Period.

johnynek

// unfortunately
// opaque type Fix[F[_]] = F[Fix[F]]
// won't work (no recursion in opaque type), but this implementation is safe, but scary due to asInstanceOf
object FixImpl {
  type Fix[F[_]]

  inline def fix[F[_]](f: F[Fix[F]]): Fix[F] = f.asInstanceOf[Fix[F]]
  inline def unfix[F[_]](f: Fix[F]): F[Fix[F]] = f.asInstanceOf[F[Fix[F]]]
}

tonymorris

foldRight' ::
  (b -> z -> z)
  -> (a -> b)
  -> z
  -> [a]
  -> z
foldRight' _ _ z [] =
  z
foldRight' k f z (x:xs) =
  k (f x) (foldRight' k f z xs)