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/*
 * Copyright 2001-2013 Artima, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.scalactic

/**
 * Trait providing an implicit class that adds a toOr method to
 * Option, which converts Some to Good,
 * None to Bad.
 *
 * 
 * You can use the toOr method to record information about why
 * a processing of nested Options resulted in None.
 * For example, the following for expression results in
 * None if either the passed optional Person is
 * None or else if the contained optional age is None:
 * 
 *
 *  * scala> case class Person(name: String, age: Option[Int])
 * defined class Person
 *
 * scala> def ageOf(person: Option[Person]) =
     |   for {
     |     per <- person
     |     age <- per.age
     |   } yield age
 * ageOf: (person: Option[Person])Option[Int]
 *
 * scala> ageOf(Some(Person("Ralph", Some(32))))
 * res0: Option[Int] = Some(32)
 *
 * scala> ageOf(Some(Person("Curt", None)))
 * res3: Option[Int] = None
 *
 * scala> ageOf(None)
 * res2: Option[Int] = None
 * 
 *
 * 
 * If you instead populate the for expression with Ors,
 * supplying an error message or other "bad" value to the toOr method
 * in case of None, you'll get an indication of which part
 * failed if a None is encountered:
 * 
 *
 *  * scala> import OptionSugar._
 * import OptionSugar._
 *
 * scala> def ageOf(person: Option[Person]) =
 *      |   for {
 *      |     per <- person toOr "no person here"
 *      |     age <- per.age toOr "ageless person"
 *      |   } yield age
 * ageOf: (person: Option[Person])org.scalactic.Or[Int,String]
 *
 * scala> ageOf(Some(Person("Ralph", Some(32))))
 * res1: org.scalactic.Or[Int,String] = Good(32)
 *
 * scala> ageOf(Some(Person("Curt", None)))
 * res2: org.scalactic.Or[Int,String] = Bad(ageless person)
 *
 * scala> ageOf(None)
 * res3: org.scalactic.Or[Int,String] = Bad(no person here)
 * 
 */
trait OptionSugar {

  /**
   * Implicit class that adds a toOr method to
   * Option, which converts Some to Good,
   * None to Bad.
   */
  implicit class Optionizer[G](option: Option[G]) {

    /**
     * Converts the wrapped Option to an Or.
     */
    def toOr[B](orElse: => B): G Or B = Or.from(option, orElse)
  }
} 

/**
 * Companion object for OptionSugar enabling its members to be
 * imported as an alternative to mixing them in.
 */
object OptionSugar extends OptionSugar