arjanblokzijl’s gists

arjanblokzijl / list extensions

Created July 4, 2010 06:40

	//some nice but perhaps not so useful list operations

	object ListOps {
	//translated to Scala: http://www.haskell.org/pipermail/libraries/2010-July/013842.html
	def select[T](l: List[T]): List[(T, List[T])] = l match {
	case Nil => Nil
	case x::xs => (x, xs) :: (for {(y, ys) <- select(xs)} yield (y, x::ys))
	}

	def separate[T](l: List[T]): List[(List[T], T, List[T])] = l match {

arjanblokzijl / binomial coefficient gen

Created March 11, 2011 14:13

99 problems, P26

	def tails[T](l: List[T]): List[List[T]] = {
	if (l.isEmpty) List(Nil)
	else l :: tails(l.tail)
	}

	def comb[T](n: Int, l: List[T]): List[List[T]] = {
	if (n == 0) List(Nil) else {for (xs <- tails(l) if !xs.isEmpty; ys <- comb(n - 1, xs.tail)) yield (xs.head :: ys)}
	}

arjanblokzijl / depenciesArtifactFiles

Created August 4, 2011 18:33

sbt all artifacts

	import sbt._
	import Keys._
	import Defaults._

	//adding the Artifacts.settings to you project settings will create and publish the artifact defined as 'theMainArtifact'
	object Artifacts {
	val allTheArtifacts = TaskKey[Seq[(sbt.Artifact, java.io.File)]]("all-artifacts")
	val theMainArtifact = TaskKey[File]("zip-artifact", "Create zip with all library dependencies")
	val artifactConf = config("Artifact") hide //use this to scope the create artifact to this config

arjanblokzijl / gist:1141567

Created August 12, 2011 06:24

sbt10 - generated sources

	import sbt._
	import sbt.Keys._

	object build extends Build {
	lazy val generate = Project(
	id = "source-gen",
	base = file("."),
	settings = Defaults.defaultSettings ++ generateSourceSettings
	)

arjanblokzijl / gist:1278729

Created October 11, 2011 17:20

most basic monad state transformer example

	scala> for (s <- stateT[Int, Option, String](i => Some(("aaa", i + 1)))) yield(s + "bbb")
	res0: scalaz.StateT[Int,Option,java.lang.String] = scalaz.StateTs$$anon$1@4f837a5b

	scala> res0.runT(10)
	res31: Option[(java.lang.String, Int)] = Some((aaabbb,11))

arjanblokzijl / FingerTreeTest.scala

Created December 1, 2011 07:17 — forked from gseitz/FingerTreeTest.scala

	"FingerTree" should {
	"apply effects in order" in {
	import std.string._
	import Id._
	type StringWriter[A] = Writer[String, A]
	val s: Writer[String, FingerTree[Int, Int]] = streamToTree(intStream.take(5)).traverseTree[StringWriter, Int, Int](x => Writer(x.toString, x))
	val (w, a) = s.runT
	(w, a.toStream) must be_===("12345", streamToTree(intStream.take(5)).toStream)
	}
	}

arjanblokzijl / gist:1779556

Created February 9, 2012 12:07 — forked from einblicker/gist:1402318

encoding data families by using dependent method types

arjanblokzijl / type-class-type-member.scala

Created February 9, 2012 18:19 — forked from retronym/type-class-type-member.scala

Type Classes using type members, rather than type parameters

	trait Semigroup_ {
	type F
	def append(a: F, b: => F): F
	}

	trait Monoid_ extends Semigroup_ {
	def zero: F
	}

	trait Functor_ {

arjanblokzijl / main.hs

Created February 26, 2012 13:11 — forked from danielwaterworth/main.hs

Error conscious, pure iteratee library (based on pipes)

	{-# LANGUAGE FlexibleInstances #-}

	import Data.Char

	import Control.Monad
	import Control.Exception
	import Control.Monad.Trans

	import System.IO

arjanblokzijl / fix-sbt-compiler-interface.sh

Created March 6, 2012 06:15 — forked from gkossakowski/fix-sbt-compiler-interface.sh

Fix sbt's compiler interface for 2.10.0-M1

	#!/usr/bin/env bash
	# This is very hacky remedy to following error people using sbt
	# and 2.10.0-M1 release of Scala are going to see:
	#
	# API.scala:261: error: type mismatch;
	# found : API.this.global.tpnme.NameType
	# (which expands to) API.this.global.TypeName
	# required: String
	# sym.isLocalClass \|\| sym.isAnonymousClass \|\| sym.fullName.endsWith(LocalChild)
	#

Arjan Blokzijl arjanblokzijl