mpilquist

import scalaz.std.option._ // Import the some and none functions
import scalaz.syntax.std.option._ // Import the syntax for calling ~ on Option
import scalaz.std.AllInstances._ // Import all typeclass instances for standard datatypes

~some(10) // 10
~none[Int] // 0

~some("test") // "test"
~none[String] // ""

mpilquist

// Put in src/test/scala
object Foo {
  // From main slf4j-api JAR
  val logger = org.slf4j.LoggerFactory.getLogger("Foo")
  // From test slf4j-api JAR
  val bp = new org.slf4j.helpers.BogoPerf
}

mpilquist

import scala.collection.JavaConverters._
import scalaz.std.option._
import java.net.URL
import java.util.Enumeration

class CompositeClassLoader(parent: ClassLoader, members: List[ClassLoader]) extends ClassLoader(parent) {

  override def findClass(name: String): Class[_] = {
    def tryLoadClass(cl: ClassLoader): Option[Class[_]] =
      try some(cl.loadClass(name))

mpilquist

import scala.collection.JavaConverters._
import java.net.URL
import java.util.Enumeration
import com.typesafe.config._
import org.osgi.framework.Bundle
import org.osgi.framework.wiring._


object OsgiConfigFactory {

mpilquist

import shapeless._

trait F[A] {
  def xmap[B](f: A => B, g: B => A): F[B]
  def as[B] = new AsAux[B]
  class AsAux[B] {
    def apply[C](implicit gen: Generic.Aux[B, C], ev: A =:= C): F[B] =
      xmap(a => gen.from(ev(a)), b => gen.to(b).asInstanceOf[A])
  }
}

mpilquist

scala> import org.scalatest._
scala> import Matchers._
scala> import Inspectors._

scala> trap { List('a', 'b') should have length 1 }
res0: Throwable = org.scalatest.exceptions.TestFailedException: List(a, b) had length 2 instead of expected length 1

scala> trap { List(1, 2, 3) should contain (4) }
res1: Throwable = org.scalatest.exceptions.TestFailedException: List(1, 2, 3) did not contain element 4

mpilquist

Distribution of Option, Either, Try, scalaz.\/, scalaz.Validation on a large project that started in 2009 and has about ~425,000 SLOC of Scala:

› find . -name '*.scala' -exec grep -o "Option" {} \; | wc -l
    7747
› find . -name '*.scala' -exec grep -o "Either" {} \; | wc -l
     547
› find . -name '*.scala' -exec grep -o "Try" {} \; | wc -l
     129         
› find . -name '*.scala' -exec grep -o "\\\/" {} \; | wc -l

2159

mpilquist

import sbt.complete.DefaultParsers

object MyApp extends App {
  println(DefaultParsers.validID("test"))
}

mpilquist

package scodec.bits

import java.nio.ByteBuffer
import java.util.concurrent.atomic.AtomicLong
import scala.collection.GenTraversableOnce

/**
 * Persistent vector of bits, stored as bytes.
 *
 * Bits are numbered left to right, starting at 0.

mpilquist

import scalaz.{ Lens, LensFamily }
import scalaz.stream.{ Process, process1 }
import Process._

object Example extends App {

  /**
   * Lifts a `Process1[B, B]` to a `Process1[A, A]` using the provided lens.
   *
   * Values fed to this process are converted to type `B` and fed to