jedws’s gists

jedws / console.scala

Created October 22, 2013 06:37

something very odd going on with scalaz-stream

	Welcome to Scala version 2.10.3 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_37).
	Type in expressions to have them evaluated.
	Type :help for more information.

	scala> import scalaz._, Scalaz._, stream._
	import scalaz._
	import Scalaz._
	import stream._

	scala> val chan = io.fileChunkR("build.sbt").mapOut { s => new String(s) }

jedws / veryOdd.scala

Last active December 23, 2015 19:09

@hg_ just showed me this, pretty odd: can't create a subInstance Root as a val, but can as an object

	import scalaz._, Scalaz._

	trait Root {
	type FT[A[+_], +B]
	val FT: MonadTrans[FT]
	def value: FT[Id, Unit]
	}

	trait Child extends Root { child =>
	// error: an't existentially abstract over parameterized type A

jedws / Times.scala

Last active December 21, 2015 04:09

	import scalaz.{ Free, Functor, Monad, Scalaz, \/, syntax }
	import Free._
	import Scalaz.Id
	import syntax.id._
	import syntax.monad._

	package times {
	case class Times[+A](times: Vector[(Long, String)], a: A)

	object Times {

jedws / box.scala

Created August 15, 2013 07:15

template for implementing Monads that are executed using Free so they don't StackOverflowError

	package koto

	import scalaz.{Comonad, Equal, Free, Functor, Scalaz }
	import scalaz.syntax.equal._
	import scalaz.syntax.monad._

	object box extends Interpreted {
	trait Box[+A] extends HasFree[A] {
	def get: A = free.go { _.a }
	}

jedws / Folder.scala

Created August 13, 2013 04:41

	import scalaz.Monad
	import scalaz.syntax.monad._

	/**
	* Non stack-using Foldable substitute
	*/
	trait Folder[F[_], A] {
	def foldLefterM[G[_], B](z: B)(f: (B, A) => G[B])(implicit M: Monad[G]): G[B]
	}

jedws / Optional.java

Last active December 19, 2015 17:48

Optional.flatMap must declare the output type of the supplied function to be covariant

	package com.atlassian.variance.test;

	import static org.hamcrest.MatcherAssert.assertThat;
	import static org.hamcrest.Matchers.notNullValue;
	import org.junit.Test;
	import com.google.common.base.Function;

	final class Optional<A> {

	private final A a;

jedws / gist:5914678

Last active December 19, 2015 06:49

Parameterized type tags

	import scalaz._
	import Scalaz._
	import java.lang.{Long => JLong}

	object ParameterizedTags {
	trait Nanoseconds[A]

	type SampleDuration[A] = JLong @@ Nanoseconds[A]

	case class Bar(a: BarDuration)

jedws / tuples.scala

Last active December 14, 2015 15:09

generic type-class composition for ProductN

	object Tuples {

	type AsMap[A] = A => Map[String, String]

	case class Dooby(a: String)
	case class Foo(b: String)

	implicit val DoobyMapper =
	(ev: Dooby) => Map("a" -> ev.a)

jedws / scala2.10.1-RC1broken.scala

Last active December 14, 2015 04:19 — forked from michaelpj/scala2.10.1-RC1broken.scala

	trait Higher[F[_]]

	trait Box[A]
	object Box {
	implicit def HigherBox = new Higher[Box] {}
	}

	object Foo {
	val box = implicitly[Higher[Box]] // compiles fine !!!

jedws / CSVParser.scala

Created November 26, 2012 20:48 — forked from fayimora/CSVParser.scala

	package com.fayi.ftp

	object CSVParser {
	val ADDRESS = "ftp://mirrors.kernel.org/gnu/README.DESCRIPTIONS"
	val ADDRESS2 = "ftp://ftp.gnu.org/README"

	def main(args: Array[String]) {

	def parse(s: Stream[String]) = {
	val cells = (_: String).split(",")

Jed Wesley-Smith jedws