travisbrown

/**
 * Digging through arbitrarily nested case classes, tuples, and lists
 * by Travis Brown
 *
 * In response to this question by Channing Walton on the Shapeless dev list:
 *
 *     https://groups.google.com/d/msg/shapeless-dev/hn7_U21tupI/Zm9h3uNb51gJ
 *
 * Tested with Scala 2.9.2 and Shapeless 1.2.3. Should work on 1.2.2 with minor edits.
 */

etorreborre

/**
 * this is an experiment to create unboxed union types with a phantom type and a context bound.
 * All the good ideas come from @milessabin post, comments and links: http://www.chuusai.com/2011/06/09/scala-union-types-curry-howard/#comment-22
 */

/** trait for anything that can be A or B */
trait Or[A, B] {
  // a phantom type, there will be no instance of this type that we'll use
  type l[T]
  // an alias for l[t]

puffnfresh

import scalaz.WriterT
import scalaz.NonEmptyList
import scalaz.syntax.id._

import scalaz.std.option._
import scalaz.syntax.std.option._

type OptionLogger[A] = WriterT[Option, NonEmptyList[String], A]

val two: OptionLogger[Int] = WriterT.put(2.some)("The number two".wrapNel)

larsrh

object KleisliValidation extends App {
  import scalaz._
  import Scalaz._
  import scala.util.control.Exception._

  type EEither[+T] = Either[String, T]
  
  def toDouble(s: String): EEither[Double] = allCatch.either(s.toDouble).fold(_.toString.left, _.right)
  def sqrt(d: Double): EEither[Double] = if (d >= 0) math.sqrt(d).right else "sqrt(%s) is too complex for me".format(d).left
  

krasserm

import scalaz._
import Scalaz._

object MonadTransformerExamples {
  def main(args: Array[String]) = run

  def run {
    // ------------------------------------------------------
    // Combined Option/Option
    // ------------------------------------------------------