Gerolf Seitz gseitz

Hi, looking for scalac flags?

This gist has been upgraded to a blog post here.

Introduction to scalaz-stream

Every application ever written can be viewed as some sort of transformation on data. Data can come from different sources, such as a network or a file or user input or the Large Hadron Collider. It can come from many sources all at once to be merged and aggregated in interesting ways, and it can be produced into many different output sinks, such as a network or files or graphical user interfaces. You might produce your output all at once, as a big data dump at the end of the world (right before your program shuts down), or you might produce it more incrementally. Every application fits into this model.

The scalaz-stream project is an attempt to make it easy to construct, test and scale programs that fit within this model (which is to say, everything). It does this by providing an abstraction around a "stream" of data, which is really just this notion of some number of data being sequentially pulled out of some unspecified data source. On top of this abstraction, sca

Take-home functional programming interview

This document is licensed CC0.

These are some questions to give a sense of what you know about FP. This is more of a gauge of what you know, it's not necessarily expected that a single person will breeze through all questions. For each question, give your answer if you know it, say how long it took you, and say whether it was 'trivial', 'easy', 'medium', 'hard', or 'I don't know'. Give your answers in Haskell for the questions that involve code.

Please be honest, as the interviewer may do some spot checking with similar questions. It's not going to look good if you report a question as being 'trivial' but a similar question completely stumps you.

Here's a bit more guidance on how to use these labels:

	scala> val buf = ListBuffer(1)
	buf: scala.collection.mutable.ListBuffer[Int] = ListBuffer(1)

	scala> val xs = buf.toIterable match { case xs: List[Int] => xs }
	xs: List[Int] = List(1)

	scala> buf ++= 1 to 100
	res11: buf.type = ListBuffer(1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100)

	scala> xs

	import Web.Scotty.Trans
	import Network.Wai.Middleware.RequestLogger
	import Network.Wai.Middleware.Static
	import Text.Blaze.Html.Renderer.Text (renderHtml)
	import System.Environment
	import Database.Persist.Sql (SqlPersistT(..), Connection, runMigration, runSqlPersistM, runSqlConn, unSqlPersistT)
	import Database.Persist.Postgresql (withPostgresqlConn)

	setup :: ScottyT Text (SqlPersistT (NoLoggingT (ResourceT IO))) () -> IO ()
	setup m = do

	import scala.util.control.Exception
	import scalaz._
	import scalaz.Free.FreeC
	import scalaz.Scalaz._

	object Kasten {

	/////////////////////////
	// The State stuff
	/////////////////////////

	import scalaz._
	import \/._
	import Free._
	import scalaz.syntax.monad._
	import java.util.concurrent.atomic.AtomicReference
	import java.util.concurrent.CountDownLatch

	object Experiment {
	sealed trait OI[A] {
	def map[B](f: A => B): OI[B]

	-- http://hackage.haskell.org/package/base-4.6.0.1/docs/src/GHC-Base.html#map

	map :: (a -> b) -> [a] -> [b]
	map _ [] = []
	map f (x:xs) = f x : map f xs

	trait ConsoleAlg[F[_]] {
	def readLine: F[Option[String]]
	def printLine(line: String): F[Unit]
	}

	trait Console[+A] {
	def run[F[+_]](F: ConsoleAlg[F]): F[A]
	}

	object Console {

	# thanks to this gist for the iTerm2 tab naming stuff: https://gist.github.com/phette23/5270658
	# can't remember where I cribbed the rest of this from!
	# hacked it a bit to work on OS X

	_bold=$(tput bold)
	_normal=$(tput sgr0)

	__vcs_dir() {
	local vcs base_dir sub_dir ref
	sub_dir() {