Scala Library
scala

class Either
[source: scala/Either.scala]
sealed abstract class Either[+A, +B]
extends AnyRef

The Either type represents a value of one of two possible types (a disjoint union). The data constructors; Left and Right represent the two possible values. The Either type is often used as an alternative to scala.Option where Left represents failure (by convention) and Right is akin to Some.

Author
Tony Morris, Workingmouse
Version
1.0, 11/10/2008
Direct Known Subclasses:
Left, Right
Method Summary
def fold [X](fa : (A) => X, fb : (B) => X) : X
Deconstruction of the Either type (in contrast to pattern matching).
def isLeft : Boolean
Returns true if this is a Left, false otherwise.
def isRight : Boolean
Returns true if this is a Right, false otherwise.
def left : LeftProjection[A, B]
Projects this Either as a Left.
def right : RightProjection[A, B]
Projects this Either as a Right.
def swap : Either[B, A] with Product
If this is a Left, then return the left value in Right or vice versa.
Methods inherited from AnyRef
getClass, hashCode, equals, clone, toString, notify, notifyAll, wait, wait, wait, finalize, ==, !=, eq, ne, synchronized
Methods inherited from Any
==, !=, isInstanceOf, asInstanceOf
Method Details
def left : LeftProjection[A, B]
Projects this Either as a Left.
def right : RightProjection[A, B]
Projects this Either as a Right.
def fold[X](fa : (A) => X, fb : (B) => X) : X
Deconstruction of the Either type (in contrast to pattern matching).
def swap : Either[B, A] with Product
If this is a Left, then return the left value in Right or vice versa.
def isLeft : Boolean
Returns true if this is a Left, false otherwise.
def isRight : Boolean
Returns true if this is a Right, false otherwise.
Scala Library