oxbowlakes

This is how we create an inclusive/exclusive range of Ints:

  val ie = 0 until 500

//1. Fill in the missing item to create a range of Ints from 1 to 100 inclusive

  val ints = 1 ??? 100

//2. Find the sum of the integers in this range

oxbowlakes

// The declaration of a value in scala looks like this:

    val x = 1
//  ^   ^   ^
//  ^   ^   the value we wish to assign our new value to
//  ^   identifier (ie name of value)
//  type of value (val or var)

// Each identifier in scala has an associated type (or, more accurately, it has many types ranging from the least to the most specific)

oxbowlakes

// In scala a def (called a "method") is defined as follows:

    def foo(arg: String): Int = expr
//  ^   ^  ^^    ^        ^     ^
//  ^   ^  ^^    ^        ^     an expression, whose type must match the declared return type, if specified
//  ^   ^  ^^    ^        ^     
//  ^   ^  ^^    ^        the declared return type (optional).
//  ^   ^  ^^    ^        
//  ^   ^  ^^    the type of each argument must be declared
//  ^   ^  ^^

oxbowlakes

import scalaz._;import Scalaz._; import concurrent._

/* Imagine you have some expensive calculations you wish to make: */
trait RawApi {
  def expensiveInt: Int = Int.MaxValue
  def expensiveString: String = "expensive"
}

/* You wish to write a program using this API */
case class Result(i: Int, s: String)

oxbowlakes

<?xml version="1.0" encoding="UTF-8"?>
<scheme name="OxbowSolarizedDark2" version="124" parent_scheme="Default">
  <option name="LINE_SPACING" value="1.2" />
  <option name="EDITOR_FONT_SIZE" value="13" />
  <option name="EDITOR_FONT_NAME" value="Consolas" />
  <colors>
    <option name="ADDED_LINES_COLOR" value="" />
    <option name="ANNOTATIONS_COLOR" value="2b36" />
    <option name="ANNOTATIONS_MERGED_COLOR" value="" />
    <option name="CARET_COLOR" value="dc322f" />

oxbowlakes

import java.math.BigInteger

/**
 * Clients can use this class instead, which means they only need fill in the 
 * V compute(K) method
 */ 
abstract class ConcCache2<K, V> {
  
  private final ConcCache<K, V> cache = new ConcCache<>();
  

oxbowlakes

package fewchaz

import scala.util.{Failure, Success, Try}
import scala.concurrent.{CanAwait, ExecutionContext}
import java.util.concurrent._
import scala.util.control.NonFatal

trait Fewcha[T] extends scala.concurrent.Future[T] {
  def futr: Future[T]
  private[this] final def toTry: Try[T] = try util.Success(futr.get()) catch { case NonFatal(t) => util.Failure(t)}

oxbowlakes

//requires scala 2.10.x
//requires scalaz-2.10-7.0.x


package fpx

// Furnace types (in reality, these come from a Java API and are real!)

trait FurnaceService {
  def createSession(user: String, password: String): FurnaceSession

oxbowlakes

//I have a Java interface which looks like this

trait ConsumableResource[A <: AnyRef] extends AutoCloseable {
  /** returns `null` when we are ended */
  def take(): A 
  
}

//I would like to make this viewable as a scala `TraversableOnce` where the resource is automatically closed at the end of the traversal

oxbowlakes

scala> val it = Traversable(1); it foreach (i => println(s"$i and ${it.isEmpty}"))
1 and false

scala> val it = Iterator(1); it foreach (i => println(s"$i and ${it.isEmpty}"))
1 and true