
Scala example source code file (Equiv.scala)
The Equiv.scala Scala example source code/* __ *\ ** ________ ___ / / ___ Scala API ** ** / __/ __// _  / / / _  (c) 20032013, LAMP/EPFL ** ** __\ \/ /__/ __ / /__/ __  http://scalalang.org/ ** ** /____/\___/_/ _/____/_/   ** ** / ** \* */ package scala package math import java.util.Comparator /** A trait for representing equivalence relations. It is important to * distinguish between a type that can be compared for equality or * equivalence and a representation of equivalence on some type. This * trait is for representing the latter. * * An [[http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation]] * is a binary relation on a type. This relation is exposed as * the `equiv` method of the `Equiv` trait. The relation must be: * * 1. reflexive: `equiv(x, x) == true` for any x of type `T`. * 1. symmetric: `equiv(x, y) == equiv(y, x)` for any `x` and `y` of type `T`. * 1. transitive: if `equiv(x, y) == true` and `equiv(y, z) == true`, then * `equiv(x, z) == true` for any `x`, `y`, and `z` of type `T`. * * @author Geoffrey Washburn, Paul Phillips * @version 1.0, 20080403 * @since 2.7 */ trait Equiv[T] extends Any with Serializable { /** Returns `true` iff `x` is equivalent to `y`. */ def equiv(x: T, y: T): Boolean } trait LowPriorityEquiv { self: Equiv.type => implicit def universalEquiv[T] : Equiv[T] = universal[T] } object Equiv extends LowPriorityEquiv { def reference[T <: AnyRef] : Equiv[T] = new Equiv[T] { def equiv(x: T, y: T) = x eq y } def universal[T] : Equiv[T] = new Equiv[T] { def equiv(x: T, y: T) = x == y } def fromComparator[T](cmp: Comparator[T]): Equiv[T] = new Equiv[T] { def equiv(x: T, y: T) = cmp.compare(x, y) == 0 } def fromFunction[T](cmp: (T, T) => Boolean): Equiv[T] = new Equiv[T] { def equiv(x: T, y: T) = cmp(x, y) } def by[T, S: Equiv](f: T => S): Equiv[T] = fromFunction((x, y) => implicitly[Equiv[S]].equiv(f(x), f(y))) def apply[T: Equiv] : Equiv[T] = implicitly[Equiv[T]] } Other Scala source code examplesHere is a short list of links related to this Scala Equiv.scala source code file: 
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