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authorSom Snytt <som.snytt@gmail.com>2017-03-14 14:10:50 -0700
committerSom Snytt <som.snytt@gmail.com>2017-03-14 14:10:50 -0700
commit759c90dbc7c8361901ba6a4f193ab2ea3f76952b (patch)
tree5a48d2dab502df11c2ff7c3dceea135cec2d93e8 /src
parentd0c26206e6fac16d4a24c1795628088e20228b48 (diff)
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SI-10225 Either docs compile
But without tut support, who knows. Boy scout aligns stars and updates several examples that didn't infer types in a way that compiles.
Diffstat (limited to 'src')
-rw-r--r--src/library/scala/util/Either.scala590
1 files changed, 273 insertions, 317 deletions
diff --git a/src/library/scala/util/Either.scala b/src/library/scala/util/Either.scala
index 523c10c483..4cc283c0cb 100644
--- a/src/library/scala/util/Either.scala
+++ b/src/library/scala/util/Either.scala
@@ -6,8 +6,6 @@
** |/ **
\* */
-
-
package scala
package util
@@ -24,36 +22,36 @@ package util
* received input is a String or an Int.
*
* {{{
- * val in = Console.readLine("Type Either a string or an Int: ")
+ * import scala.io.StdIn._
+ * val in = readLine("Type Either a string or an Int: ")
* val result: Either[String,Int] = try {
* Right(in.toInt)
* } catch {
- * case e: Exception =>
- * Left(in)
- * }
+ * case e: Exception => Left(in)
+ * }
*
- * println(result match {
+ * result match {
* case Right(x) => s"You passed me the Int: $x, which I will increment. $x + 1 = ${x+1}"
* case Left(x) => s"You passed me the String: $x"
- * })
+ * }
* }}}
*
* Either is right-biased, which means that Right is assumed to be the default case to
- * operate on. If it is Left, operations like map, flatMap, ... return the Left value
- * unchanged:
+ * operate on. If it is Left, operations like map, flatMap, ... return the Left value unchanged:
*
* {{{
- * Right(12).map(_ * 2) // Right(24)
- * Left(23).map(_ * 2) // Left(23)
+ * def doubled(i: Int) = i * 2
+ * Right(12).map(doubled) // Right(24)
+ * Left(23).map(doubled) // Left(23)
* }}}
*
- * As Either defines the methods `map` and `flatMap`, it can also be used in for comprehensions:
+ * Since `Either` defines the methods `map` and `flatMap`, it can also be used in for comprehensions:
* {{{
- * val right1: Right[Double, Int] = Right(1)
- * val right2 = Right(2)
- * val right3 = Right(3)
- * val left23: Left[Double, Int] = Left(23.0)
- * val left42 = Left(42.0)
+ * val right1 = Right(1) : Right[Double, Int]
+ * val right2 = Right(2)
+ * val right3 = Right(3)
+ * val left23 = Left(23.0) : Left[Double, Int]
+ * val left42 = Left(42.0)
*
* for {
* a <- right1
@@ -92,77 +90,71 @@ package util
* @since 2.7
*/
sealed abstract class Either[+A, +B] extends Product with Serializable {
- /**
- * Projects this `Either` as a `Left`.
- */
+ /** Projects this `Either` as a `Left`. */
def left = Either.LeftProjection(this)
- /**
- * Projects this `Either` as a `Right`.
+ /** Projects this `Either` as a `Right`.
*
- * Because `Either` is right-biased, this method is not normally needed.
- * (It is retained in the API for now for easy cross-compilation between Scala
- * 2.11 and 2.12.)
+ * Because `Either` is right-biased, this method is not normally needed.
+ * (It is retained in the API for now for easy cross-compilation between Scala
+ * 2.11 and 2.12.)
*/
def right = Either.RightProjection(this)
- /**
- * Applies `fa` if this is a `Left` or `fb` if this is a `Right`.
+ /** Applies `fa` if this is a `Left` or `fb` if this is a `Right`.
*
- * @example {{{
- * val result: Either[Exception, Value] = possiblyFailingOperation()
- * log(result.fold(
- * ex => s"Operation failed with $ex",
- * v => s"Operation produced value: $v"
- * ))
- * }}}
+ * @example {{{
+ * val result: Either[Exception, Value] = possiblyFailingOperation()
+ * result.fold(
+ * ex => s"Operation failed with $ex",
+ * v => s"Operation produced value: $v"
+ * )
+ * }}}
*
- * @param fa the function to apply if this is a `Left`
- * @param fb the function to apply if this is a `Right`
- * @return the results of applying the function
+ * @param fa the function to apply if this is a `Left`
+ * @param fb the function to apply if this is a `Right`
+ * @return the results of applying the function
*/
def fold[C](fa: A => C, fb: B => C): C = this match {
case Right(b) => fb(b)
case Left(a) => fa(a)
}
- /**
- * If this is a `Left`, then return the left value in `Right` or vice versa.
+ /** If this is a `Left`, then return the left value in `Right` or vice versa.
*
- * @example {{{
- * val left: Either[String, Int] = Left("left")
- * val right: Either[Int, String] = l.swap // Result: Right("left")
- * }}}
- * @example {{{
- * val right = Right(2)
- * val left = Left(3)
- * for {
- * r1 <- right
- * r2 <- left.swap
- * } yield r1 * r2 // Right(6)
- * }}}
+ * @example {{{
+ * val left: Either[String, Int] = Left("left")
+ * val right: Either[Int, String] = left.swap // Result: Right("left")
+ * }}}
+ * @example {{{
+ * val right = Right(2)
+ * val left = Left(3)
+ * for {
+ * r1 <- right
+ * r2 <- left.swap
+ * } yield r1 * r2 // Right(6)
+ * }}}
*/
def swap: Either[B, A] = this match {
case Left(a) => Right(a)
case Right(b) => Left(b)
}
- /**
- * Joins an `Either` through `Right`.
+ /** Joins an `Either` through `Right`.
*
- * This method requires that the right side of this Either is itself an
- * Either type. That is, this must be some type like: {{{
- * Either[A, Either[A, C]]
- * }}} (which respects the type parameter bounds, shown below.)
+ * This method requires that the right side of this Either is itself
+ * an Either type. That is, this must be some type like: {{{
+ * Either[A, Either[A, C]]
+ * }}} (which respects the type parameter bounds, shown below.)
*
- * If this instance is a Right[Either[A, C]] then the contained Either[A, C]
- * will be returned, otherwise this value will be returned unmodified.
+ * If this instance is a Right[Either[A, C]] then the contained Either[A, C]
+ * will be returned, otherwise this value will be returned unmodified.
*
- * @example {{{
- * Right[String, Either[String, Int]](Right(12)).joinRight // Result: Right(12)
- * Right[String, Either[String, Int]](Left("flower")).joinRight // Result: Left("flower")
- * Left[String, Either[String, Int]]("flower").joinRight // Result: Left("flower")
- * }}}
+ * @example {{{
+ * Right[String, Either[String, Int]](Right(12)).joinRight // Result: Right(12)
+ * Right[String, Either[String, Int]](Left("flower")).joinRight // Result: Left("flower")
+ * Left[String, Either[String, Int]]("flower").joinRight // Result: Left("flower")
+ * }}}
*
* This method, and `joinLeft`, are analogous to `Option#flatten`
*/
@@ -172,51 +164,48 @@ sealed abstract class Either[+A, +B] extends Product with Serializable {
}
- /**
- * Joins an `Either` through `Left`.
+ /** Joins an `Either` through `Left`.
*
- * This method requires that the left side of this Either is itself an
- * Either type. That is, this must be some type like: {{{
- * Either[Either[C, B], B]
- * }}} (which respects the type parameter bounds, shown below.)
+ * This method requires that the left side of this Either is itself an
+ * Either type. That is, this must be some type like: {{{
+ * Either[Either[C, B], B]
+ * }}} (which respects the type parameter bounds, shown below.)
*
- * If this instance is a Left[Either[C, B]] then the contained Either[C, B]
- * will be returned, otherwise this value will be returned unmodified.
+ * If this instance is a Left[Either[C, B]] then the contained Either[C, B]
+ * will be returned, otherwise this value will be returned unmodified.
*
- * {{{
- * Left[Either[Int, String], String](Right("flower")).joinLeft // Result: Right("flower")
- * Left[Either[Int, String], String](Left(12)).joinLeft // Result: Left(12)
- * Right[Either[Int, String], String]("daisy").joinLeft // Result: Right("daisy")
- * }}}
+ * {{{
+ * Left[Either[Int, String], String](Right("flower")).joinLeft // Result: Right("flower")
+ * Left[Either[Int, String], String](Left(12)).joinLeft // Result: Left(12)
+ * Right[Either[Int, String], String]("daisy").joinLeft // Result: Right("daisy")
+ * }}}
*
- * This method, and `joinRight`, are analogous to `Option#flatten`
+ * This method, and `joinRight`, are analogous to `Option#flatten`.
*/
def joinLeft[A1 >: A, B1 >: B, C](implicit ev: A1 <:< Either[C, B1]): Either[C, B1] = this match {
case Left(a) => a
case Right(b) => this.asInstanceOf[Either[C, B1]]
}
- /**
- * Executes the given side-effecting function if this is a `Right`.
+ /** Executes the given side-effecting function if this is a `Right`.
*
- * {{{
- * Right(12).foreach(x => println(x)) // prints "12"
- * Left(12).foreach(x => println(x)) // doesn't print
- * }}}
- * @param f The side-effecting function to execute.
+ * {{{
+ * Right(12).foreach(x => println(x)) // prints "12"
+ * Left(12).foreach(x => println(x)) // doesn't print
+ * }}}
+ * @param f The side-effecting function to execute.
*/
def foreach[U](f: B => U): Unit = this match {
case Right(b) => f(b)
case Left(_) =>
}
- /**
- * Returns the value from this `Right` or the given argument if this is a `Left`.
+ /** Returns the value from this `Right` or the given argument if this is a `Left`.
*
- * {{{
- * Right(12).getOrElse(17) // 12
- * Left(12).getOrElse(17) // 17
- * }}}
+ * {{{
+ * Right(12).getOrElse(17) // 12
+ * Left(12).getOrElse(17) // 17
+ * }}}
*/
def getOrElse[BB >: B](or: => BB): BB = this match {
case Right(b) => b
@@ -245,53 +234,49 @@ sealed abstract class Either[+A, +B] extends Product with Serializable {
case Left(_) => false
}
- /**
- * Returns `true` if `Left` or returns the result of the application of
- * the given predicate to the `Right` value.
+ /** Returns `true` if `Left` or returns the result of the application of
+ * the given predicate to the `Right` value.
*
- * {{{
- * Right(12).forall(_ > 10) // true
- * Right(7).forall(_ > 10) // false
- * Left(12).forall(_ > 10) // true
- * }}}
+ * {{{
+ * Right(12).forall(_ > 10) // true
+ * Right(7).forall(_ > 10) // false
+ * Left(12).forall((_: Int) > 10) // true
+ * }}}
*/
def forall(f: B => Boolean): Boolean = this match {
case Right(b) => f(b)
case Left(_) => true
}
- /**
- * Returns `false` if `Left` or returns the result of the application of
- * the given predicate to the `Right` value.
+ /** Returns `false` if `Left` or returns the result of the application of
+ * the given predicate to the `Right` value.
*
- * {{{
- * Right(12).exists(_ > 10) // true
- * Right(7).exists(_ > 10) // false
- * Left(12).exists(_ > 10) // false
- * }}}
+ * {{{
+ * Right(12).exists(_ > 10) // true
+ * Right(7).exists(_ > 10) // false
+ * Left(12).exists((_: Int) > 10) // false
+ * }}}
*/
def exists(p: B => Boolean): Boolean = this match {
case Right(b) => p(b)
case Left(_) => false
}
- /**
- * Binds the given function across `Right`.
+ /** Binds the given function across `Right`.
*
- * @param f The function to bind across `Right`.
+ * @param f The function to bind across `Right`.
*/
def flatMap[AA >: A, Y](f: B => Either[AA, Y]): Either[AA, Y] = this match {
case Right(b) => f(b)
case Left(a) => this.asInstanceOf[Either[AA, Y]]
}
- /**
- * The given function is applied if this is a `Right`.
+ /** The given function is applied if this is a `Right`.
*
- * {{{
- * Right(12).map(x => "flower") // Result: Right("flower")
- * Left(12).map(x => "flower") // Result: Left(12)
- * }}}
+ * {{{
+ * Right(12).map(x => "flower") // Result: Right("flower")
+ * Left(12).map(x => "flower") // Result: Left(12)
+ * }}}
*/
def map[Y](f: B => Y): Either[A, Y] = this match {
case Right(b) => Right(f(b))
@@ -305,7 +290,7 @@ sealed abstract class Either[+A, +B] extends Product with Serializable {
* {{{
* Right(12).filterOrElse(_ > 10, -1) // Right(12)
* Right(7).filterOrElse(_ > 10, -1) // Left(-1)
- * Left(12).filterOrElse(_ > 10, -1) // Left(12)
+ * Left(12).filterOrElse(_ => false, -1) // Left(12)
* }}}
*/
def filterOrElse[AA >: A](p: B => Boolean, zero: => AA): Either[AA, B] = this match {
@@ -344,32 +329,29 @@ sealed abstract class Either[+A, +B] extends Product with Serializable {
case Left(a) => Failure(a)
}
- /**
- * Returns `true` if this is a `Left`, `false` otherwise.
+ /** Returns `true` if this is a `Left`, `false` otherwise.
*
- * {{{
- * Left("tulip").isLeft // true
- * Right("venus fly-trap").isLeft // false
- * }}}
+ * {{{
+ * Left("tulip").isLeft // true
+ * Right("venus fly-trap").isLeft // false
+ * }}}
*/
def isLeft: Boolean
- /**
- * Returns `true` if this is a `Right`, `false` otherwise.
+ /** Returns `true` if this is a `Right`, `false` otherwise.
*
- * {{{
- * Left("tulip").isRight // false
- * Right("venus fly-trap").isRight // true
- * }}}
+ * {{{
+ * Left("tulip").isRight // false
+ * Right("venus fly-trap").isRight // true
+ * }}}
*/
def isRight: Boolean
}
-/**
- * The left side of the disjoint union, as opposed to the [[scala.util.Right]] side.
+/** The left side of the disjoint union, as opposed to the [[scala.util.Right]] side.
*
- * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
- * @version 1.0, 11/10/2008
+ * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
+ * @version 1.0, 11/10/2008
*/
final case class Left[+A, +B](@deprecatedName('a, "2.12.0") value: A) extends Either[A, B] {
def isLeft = true
@@ -378,11 +360,10 @@ final case class Left[+A, +B](@deprecatedName('a, "2.12.0") value: A) extends Ei
@deprecated("Use .value instead.", "2.12.0") def a: A = value
}
-/**
- * The right side of the disjoint union, as opposed to the [[scala.util.Left]] side.
+/** The right side of the disjoint union, as opposed to the [[scala.util.Left]] side.
*
- * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
- * @version 1.0, 11/10/2008
+ * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
+ * @version 1.0, 11/10/2008
*/
final case class Right[+A, +B](@deprecatedName('b, "2.12.0") value: B) extends Either[A, B] {
def isLeft = false
@@ -396,27 +377,26 @@ object Either {
/** If the condition is satisfied, return the given `B` in `Right`,
* otherwise, return the given `A` in `Left`.
*
- * {{{
- * val userInput: String = ...
- * Either.cond(
- * userInput.forall(_.isDigit) && userInput.size == 10,
- * PhoneNumber(userInput),
- * "The input (%s) does not look like a phone number".format(userInput)
- * }}}
+ * {{{
+ * val userInput: String = ...
+ * Either.cond(
+ * userInput.forall(_.isDigit) && userInput.size == 10,
+ * PhoneNumber(userInput),
+ * "The input (%s) does not look like a phone number".format(userInput)
+ * }}}
*/
def cond[X, Y](test: Boolean, right: => Y, left: => X): Either[X, Y] =
if (test) Right(right) else Left(left)
- /**
- * Allows use of a `merge` method to extract values from Either instances
- * regardless of whether they are Left or Right.
+ /** Allows use of a `merge` method to extract values from Either instances
+ * regardless of whether they are Left or Right.
*
- * {{{
- * val l = Left(List(1)): Either[List[Int], Vector[Int]]
- * val r = Right(Vector(1)): Either[List[Int], Vector[Int]]
- * l.merge: Seq[Int] // List(1)
- * r.merge: Seq[Int] // Vector(1)
- * }}}
+ * {{{
+ * val l = Left(List(1)): Either[List[Int], Vector[Int]]
+ * val r = Right(Vector(1)): Either[List[Int], Vector[Int]]
+ * l.merge: Seq[Int] // List(1)
+ * r.merge: Seq[Int] // Vector(1)
+ * }}}
*/
implicit class MergeableEither[A](private val x: Either[A, A]) extends AnyVal {
def merge: A = x match {
@@ -425,62 +405,58 @@ object Either {
}
}
- /**
- * Projects an `Either` into a `Left`.
+ /** Projects an `Either` into a `Left`.
*
- * This allows for-comprehensions over the left side of Either instances,
- * reversing Either's usual right-bias.
+ * This allows for-comprehensions over the left side of Either instances,
+ * reversing Either's usual right-bias.
*
- * For example {{{
- * for (s <- Left("flower").left) yield s.length // Left(6)
- * }}}
- *
- * Continuing the analogy with [[scala.Option]], a `LeftProjection` declares
- * that `Left` should be analogous to `Some` in some code.
+ * For example {{{
+ * for (s <- Left("flower").left) yield s.length // Left(6)
+ * }}}
*
- * {{{
- * // using Option:
- * def interactWithDB(x: Query): Option[Result] =
- * try {
- * Some(getResultFromDatabase(x))
- * } catch {
- * case ex => None
- * }
- *
- * // this will only be executed if interactWithDB returns a Some
- * val report =
- * for (r <- interactWithDB(someQuery)) yield generateReport(r)
- * if (report.isDefined)
- * send(report)
- * else
- * log("report not generated, not sure why...")
- * }}}
+ * Continuing the analogy with [[scala.Option]], a `LeftProjection` declares
+ * that `Left` should be analogous to `Some` in some code.
*
- * {{{
- * // using Either
- * def interactWithDB(x: Query): Either[Exception, Result] =
- * try {
- * Right(getResultFromDatabase(x))
- * } catch {
- * case ex => Left(ex)
- * }
- *
- * // this will only be executed if interactWithDB returns a Right
- * val report =
- * for (r <- interactWithDB(someQuery).right) yield generateReport(r)
- * if (report.isRight)
- * send(report)
- * else
- * log("report not generated, reason was " + report.left.get)
- * }}}
+ * {{{
+ * // using Option:
+ * def interactWithDB(x: Query): Option[Result] =
+ * try {
+ * Some(getResultFromDatabase(x))
+ * } catch {
+ * case ex => None
+ * }
+ *
+ * // this will only be executed if interactWithDB returns a Some
+ * val report = for (r <- interactWithDB(someQuery)) yield generateReport(r)
+ * if (report.isDefined)
+ * send(report)
+ * else
+ * log("report not generated, not sure why...")
+ * }}}
*
- * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
- * @version 1.0, 11/10/2008
+ * {{{
+ * // using Either
+ * def interactWithDB(x: Query): Either[Exception, Result] =
+ * try {
+ * Right(getResultFromDatabase(x))
+ * } catch {
+ * case ex => Left(ex)
+ * }
+ *
+ * // this will only be executed if interactWithDB returns a Right
+ * val report = for (r <- interactWithDB(someQuery).right) yield generateReport(r)
+ * if (report.isRight)
+ * send(report)
+ * else
+ * log("report not generated, reason was " + report.left.get)
+ * }}}
+ *
+ * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
+ * @version 1.0, 11/10/2008
*/
final case class LeftProjection[+A, +B](e: Either[A, B]) {
- /**
- * Returns the value from this `Left` or throws `java.util.NoSuchElementException`
- * if this is a `Right`.
+ /** Returns the value from this `Left` or throws `java.util.NoSuchElementException`
+ * if this is a `Right`.
*
* {{{
* Left(12).left.get // 12
@@ -494,8 +470,7 @@ object Either {
case Right(_) => throw new NoSuchElementException("Either.left.get on Right")
}
- /**
- * Executes the given side-effecting function if this is a `Left`.
+ /** Executes the given side-effecting function if this is a `Left`.
*
* {{{
* Left(12).left.foreach(x => println(x)) // prints "12"
@@ -508,116 +483,105 @@ object Either {
case Right(_) =>
}
- /**
- * Returns the value from this `Left` or the given argument if this is a `Right`.
- *
- * {{{
- * Left(12).left.getOrElse(17) // 12
- * Right(12).left.getOrElse(17) // 17
- * }}}
+ /** Returns the value from this `Left` or the given argument if this is a `Right`.
*
+ * {{{
+ * Left(12).left.getOrElse(17) // 12
+ * Right(12).left.getOrElse(17) // 17
+ * }}}
*/
def getOrElse[AA >: A](or: => AA): AA = e match {
case Left(a) => a
case Right(_) => or
}
- /**
- * Returns `true` if `Right` or returns the result of the application of
- * the given function to the `Left` value.
- *
- * {{{
- * Left(12).left.forall(_ > 10) // true
- * Left(7).left.forall(_ > 10) // false
- * Right(12).left.forall(_ > 10) // true
- * }}}
+ /** Returns `true` if `Right` or returns the result of the application of
+ * the given function to the `Left` value.
*
+ * {{{
+ * Left(12).left.forall(_ > 10) // true
+ * Left(7).left.forall(_ > 10) // false
+ * Right(12).left.forall(_ > 10) // true
+ * }}}
*/
def forall(@deprecatedName('f) p: A => Boolean): Boolean = e match {
case Left(a) => p(a)
case Right(_) => true
}
- /**
- * Returns `false` if `Right` or returns the result of the application of
- * the given function to the `Left` value.
- *
- * {{{
- * Left(12).left.exists(_ > 10) // true
- * Left(7).left.exists(_ > 10) // false
- * Right(12).left.exists(_ > 10) // false
- * }}}
+ /** Returns `false` if `Right` or returns the result of the application of
+ * the given function to the `Left` value.
*
+ * {{{
+ * Left(12).left.exists(_ > 10) // true
+ * Left(7).left.exists(_ > 10) // false
+ * Right(12).left.exists(_ > 10) // false
+ * }}}
*/
def exists(@deprecatedName('f) p: A => Boolean): Boolean = e match {
case Left(a) => p(a)
case Right(_) => false
}
- /**
- * Binds the given function across `Left`.
+ /** Binds the given function across `Left`.
*
- * {{{
- * Left(12).left.flatMap(x => Left("scala")) // Left("scala")
- * Right(12).left.flatMap(x => Left("scala") // Right(12)
- * }}}
- * @param f The function to bind across `Left`.
+ * {{{
+ * Left(12).left.flatMap(x => Left("scala")) // Left("scala")
+ * Right(12).left.flatMap(x => Left("scala")) // Right(12)
+ * }}}
+ * @param f The function to bind across `Left`.
*/
def flatMap[BB >: B, X](f: A => Either[X, BB]): Either[X, BB] = e match {
case Left(a) => f(a)
case Right(b) => e.asInstanceOf[Either[X, BB]]
}
- /**
- * Maps the function argument through `Left`.
+ /** Maps the function argument through `Left`.
*
- * {{{
- * Left(12).left.map(_ + 2) // Left(14)
- * Right[Int, Int](12).left.map(_ + 2) // Right(12)
- * }}}
+ * {{{
+ * Left(12).left.map(_ + 2) // Left(14)
+ * Right[Int, Int](12).left.map(_ + 2) // Right(12)
+ * }}}
*/
def map[X](f: A => X): Either[X, B] = e match {
case Left(a) => Left(f(a))
case Right(b) => e.asInstanceOf[Either[X, B]]
}
- /**
- * Returns `None` if this is a `Right` or if the given predicate
- * `p` does not hold for the left value, otherwise, returns a `Left`.
+ /** Returns `None` if this is a `Right` or if the given predicate
+ * `p` does not hold for the left value, otherwise, returns a `Left`.
*
- * {{{
- * Left(12).left.filter(_ > 10) // Some(Left(12))
- * Left(7).left.filter(_ > 10) // None
- * Right(12).left.filter(_ > 10) // None
- * }}}
+ * {{{
+ * Left(12).left.filter(_ > 10) // Some(Left(12))
+ * Left(7).left.filter(_ > 10) // None
+ * Right(12).left.filter(_ > 10) // None
+ * }}}
*/
def filter[Y](p: A => Boolean): Option[Either[A, Y]] = e match {
case Left(a) => if(p(a)) Some(Left(a)) else None
case Right(b) => None
}
- /**
- * Returns a `Seq` containing the `Left` value if it exists or an empty
- * `Seq` if this is a `Right`.
+ /** Returns a `Seq` containing the `Left` value if it exists or an empty
+ * `Seq` if this is a `Right`.
*
- * {{{
- * Left(12).left.toSeq // Seq(12)
- * Right(12).left.toSeq // Seq()
- * }}}
+ * {{{
+ * Left(12).left.toSeq // Seq(12)
+ * Right(12).left.toSeq // Seq()
+ * }}}
*/
def toSeq: Seq[A] = e match {
case Left(a) => Seq(a)
case Right(_) => Seq.empty
}
- /**
- * Returns a `Some` containing the `Left` value if it exists or a
- * `None` if this is a `Right`.
+ /** Returns a `Some` containing the `Left` value if it exists or a
+ * `None` if this is a `Right`.
*
- * {{{
- * Left(12).left.toOption // Some(12)
- * Right(12).left.toOption // None
- * }}}
+ * {{{
+ * Left(12).left.toOption // Some(12)
+ * Right(12).left.toOption // None
+ * }}}
*/
def toOption: Option[A] = e match {
case Left(a) => Some(a)
@@ -625,26 +589,24 @@ object Either {
}
}
- /**
- * Projects an `Either` into a `Right`.
+ /** Projects an `Either` into a `Right`.
*
- * Because `Either` is already right-biased, this class is not normally needed.
- * (It is retained in the library for now for easy cross-compilation between Scala
- * 2.11 and 2.12.)
+ * Because `Either` is already right-biased, this class is not normally needed.
+ * (It is retained in the library for now for easy cross-compilation between Scala
+ * 2.11 and 2.12.)
*
- * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
- * @version 1.0, 11/10/2008
+ * @author <a href="mailto:research@workingmouse.com">Tony Morris</a>, Workingmouse
+ * @version 1.0, 11/10/2008
*/
final case class RightProjection[+A, +B](e: Either[A, B]) {
- /**
- * Returns the value from this `Right` or throws
- * `java.util.NoSuchElementException` if this is a `Left`.
+ /** Returns the value from this `Right` or throws
+ * `java.util.NoSuchElementException` if this is a `Left`.
*
- * {{{
- * Right(12).right.get // 12
- * Left(12).right.get // NoSuchElementException
- * }}}
+ * {{{
+ * Right(12).right.get // 12
+ * Left(12).right.get // NoSuchElementException
+ * }}}
*
* @throws java.util.NoSuchElementException if the projection is `Left`.
*/
@@ -653,80 +615,74 @@ object Either {
case Left(_) => throw new NoSuchElementException("Either.right.get on Left")
}
- /**
- * Executes the given side-effecting function if this is a `Right`.
+ /** Executes the given side-effecting function if this is a `Right`.
*
- * {{{
- * Right(12).right.foreach(x => println(x)) // prints "12"
- * Left(12).right.foreach(x => println(x)) // doesn't print
- * }}}
- * @param f The side-effecting function to execute.
+ * {{{
+ * Right(12).right.foreach(x => println(x)) // prints "12"
+ * Left(12).right.foreach(x => println(x)) // doesn't print
+ * }}}
+ * @param f The side-effecting function to execute.
*/
def foreach[U](f: B => U): Unit = e match {
case Right(b) => f(b)
case Left(_) =>
}
- /**
- * Returns the value from this `Right` or the given argument if this is a `Left`.
+ /** Returns the value from this `Right` or the given argument if this is a `Left`.
*
- * {{{
- * Right(12).right.getOrElse(17) // 12
- * Left(12).right.getOrElse(17) // 17
- * }}}
+ * {{{
+ * Right(12).right.getOrElse(17) // 12
+ * Left(12).right.getOrElse(17) // 17
+ * }}}
*/
def getOrElse[BB >: B](or: => BB): BB = e match {
case Right(b) => b
case Left(_) => or
}
- /**
- * Returns `true` if `Left` or returns the result of the application of
- * the given function to the `Right` value.
+ /** Returns `true` if `Left` or returns the result of the application of
+ * the given function to the `Right` value.
*
- * {{{
- * Right(12).right.forall(_ > 10) // true
- * Right(7).right.forall(_ > 10) // false
- * Left(12).right.forall(_ > 10) // true
- * }}}
+ * {{{
+ * Right(12).right.forall(_ > 10) // true
+ * Right(7).right.forall(_ > 10) // false
+ * Left(12).right.forall(_ > 10) // true
+ * }}}
*/
def forall(f: B => Boolean): Boolean = e match {
case Right(b) => f(b)
case Left(_) => true
}
- /**
- * Returns `false` if `Left` or returns the result of the application of
- * the given function to the `Right` value.
+ /** Returns `false` if `Left` or returns the result of the application of
+ * the given function to the `Right` value.
*
- * {{{
- * Right(12).right.exists(_ > 10) // true
- * Right(7).right.exists(_ > 10) // false
- * Left(12).right.exists(_ > 10) // false
- * }}}
+ * {{{
+ * Right(12).right.exists(_ > 10) // true
+ * Right(7).right.exists(_ > 10) // false
+ * Left(12).right.exists(_ > 10) // false
+ * }}}
*/
def exists(@deprecatedName('f) p: B => Boolean): Boolean = e match {
case Right(b) => p(b)
case Left(_) => false
}
- /**
- * Binds the given function across `Right`.
+ /** Binds the given function across `Right`.
*
- * @param f The function to bind across `Right`.
+ * @param f The function to bind across `Right`.
*/
def flatMap[AA >: A, Y](f: B => Either[AA, Y]): Either[AA, Y] = e match {
case Right(b) => f(b)
case Left(a) => e.asInstanceOf[Either[AA, Y]]
}
- /**
- * The given function is applied if this is a `Right`.
+ /** The given function is applied if this is a `Right`.
*
- * {{{
- * Right(12).right.map(x => "flower") // Result: Right("flower")
- * Left(12).right.map(x => "flower") // Result: Left(12)
- * }}}
+ * {{{
+ * Right(12).right.map(x => "flower") // Result: Right("flower")
+ * Left(12).right.map(x => "flower") // Result: Left(12)
+ * }}}
*/
def map[Y](f: B => Y): Either[A, Y] = e match {
case Right(b) => Right(f(b))