cats.kernel.Eq.scala Maven / Gradle / Ivy
The newest version!
package cats.kernel
import java.util.UUID
import scala.collection.immutable.{BitSet, Queue, SortedMap, SortedSet}
import scala.concurrent.duration.{Duration, FiniteDuration}
import scala.math.Equiv
import scala.{specialized => sp}
import scala.util.{Failure, Success, Try}
import compat.scalaVersionSpecific._
/**
* A type class used to determine equality between 2 instances of the same
* type. Any 2 instances `x` and `y` are equal if `eqv(x, y)` is `true`.
* Moreover, `eqv` should form an equivalence relation.
*/
trait Eq[@sp A] extends Any with Serializable { self =>
/**
* Returns `true` if `x` and `y` are equivalent, `false` otherwise.
*/
def eqv(x: A, y: A): Boolean
/**
* Returns `false` if `x` and `y` are equivalent, `true` otherwise.
*/
def neqv(x: A, y: A): Boolean = !eqv(x, y)
}
abstract class EqFunctions[E[T] <: Eq[T]] {
def eqv[@sp A](x: A, y: A)(implicit ev: E[A]): Boolean =
ev.eqv(x, y)
def neqv[@sp A](x: A, y: A)(implicit ev: E[A]): Boolean =
ev.neqv(x, y)
}
trait EqToEquivConversion {
/**
* Implicitly derive a `scala.math.Equiv[A]` from a `Eq[A]`
* instance.
*/
implicit def catsKernelEquivForEq[A](implicit ev: Eq[A]): Equiv[A] = new Equiv[A] {
def equiv(a: A, b: A) = ev.eqv(a, b)
}
}
@suppressUnusedImportWarningForScalaVersionSpecific
object Eq
extends EqFunctions[Eq]
with EqToEquivConversion
with ScalaVersionSpecificOrderInstances
with instances.TupleOrderInstances
with PartialOrderInstances {
/**
* Access an implicit `Eq[A]`.
*/
@inline final def apply[A](implicit ev: Eq[A]): Eq[A] = ev
/**
* Convert an implicit `Eq[B]` to an `Eq[A]` using the given
* function `f`.
*/
def by[@sp A, @sp B](f: A => B)(implicit ev: Eq[B]): Eq[A] =
new Eq[A] {
def eqv(x: A, y: A) = ev.eqv(f(x), f(y))
}
/**
* Return an Eq that gives the result of the and of eq1 and eq2
* note this is idempotent
*/
def and[@sp A](eq1: Eq[A], eq2: Eq[A]): Eq[A] =
new Eq[A] {
def eqv(x: A, y: A) = eq1.eqv(x, y) && eq2.eqv(x, y)
}
/**
* Return an Eq that gives the result of the or of this and that
* Note this is idempotent
*/
def or[@sp A](eq1: Eq[A], eq2: Eq[A]): Eq[A] =
new Eq[A] {
def eqv(x: A, y: A) = eq1.eqv(x, y) || eq2.eqv(x, y)
}
/**
* Create an `Eq` instance from an `eqv` implementation.
*/
def instance[A](f: (A, A) => Boolean): Eq[A] =
new Eq[A] {
def eqv(x: A, y: A) = f(x, y)
}
/**
* An `Eq[A]` that delegates to universal equality (`==`).
*
* This can be useful for case classes, which have reasonable `equals`
* implementations
*/
def fromUniversalEquals[A]: Eq[A] =
new Eq[A] {
def eqv(x: A, y: A) = x == y
}
/**
* Everything is the same
*/
def allEqual[A]: Eq[A] = new Eq[A] {
def eqv(x: A, y: A) = true
}
/**
* This is a monoid that creates an Eq that
* checks that all equality checks pass
*/
def allEqualBoundedSemilattice[A]: BoundedSemilattice[Eq[A]] = new BoundedSemilattice[Eq[A]] {
def empty = allEqual[A]
def combine(e1: Eq[A], e2: Eq[A]): Eq[A] = Eq.and(e1, e2)
override def combineAllOption(es: IterableOnce[Eq[A]]): Option[Eq[A]] =
if (es.iterator.isEmpty) None
else {
val materialized = es.iterator.toVector
Some(new Eq[A] {
def eqv(x: A, y: A) = materialized.forall(_.eqv(x, y))
})
}
}
/**
* This is a monoid that creates an Eq that
* checks that at least one equality check passes
*/
def anyEqualSemilattice[A]: Semilattice[Eq[A]] = new Semilattice[Eq[A]] {
def combine(e1: Eq[A], e2: Eq[A]): Eq[A] = Eq.or(e1, e2)
override def combineAllOption(es: IterableOnce[Eq[A]]): Option[Eq[A]] =
if (es.iterator.isEmpty) None
else {
val materialized = es.iterator.toVector
Some(new Eq[A] {
def eqv(x: A, y: A) = materialized.exists(_.eqv(x, y))
})
}
}
implicit def catsKernelInstancesForBitSet: PartialOrder[BitSet] with Hash[BitSet] =
cats.kernel.instances.bitSet.catsKernelStdOrderForBitSet
implicit def catsKernelPartialOrderForSet[A]: PartialOrder[Set[A]] =
cats.kernel.instances.set.catsKernelStdPartialOrderForSet[A]
implicit def catsKernelOrderForEither[A: Order, B: Order]: Order[Either[A, B]] =
cats.kernel.instances.either.catsStdOrderForEither[A, B]
implicit def catsKernelInstancesForUnit: Order[Unit] with Hash[Unit] =
cats.kernel.instances.unit.catsKernelStdOrderForUnit
implicit def catsKernelInstancesForBoolean: Order[Boolean] with Hash[Boolean] =
cats.kernel.instances.boolean.catsKernelStdOrderForBoolean
implicit def catsKernelInstancesForByte: Order[Byte] with Hash[Byte] =
cats.kernel.instances.byte.catsKernelStdOrderForByte
implicit def catsKernelInstancesForShort: Order[Short] with Hash[Short] =
cats.kernel.instances.short.catsKernelStdOrderForShort
implicit def catsKernelInstancesForInt: Order[Int] with Hash[Int] = cats.kernel.instances.int.catsKernelStdOrderForInt
implicit def catsKernelInstancesForLong: Order[Long] with Hash[Long] =
cats.kernel.instances.long.catsKernelStdOrderForLong
implicit def catsKernelInstancesForBigInt: Order[BigInt] with Hash[BigInt] =
cats.kernel.instances.bigInt.catsKernelStdOrderForBigInt
implicit def catsKernelInstancesForBigDecimal: Order[BigDecimal] with Hash[BigDecimal] =
cats.kernel.instances.bigDecimal.catsKernelStdOrderForBigDecimal
implicit def catsKernelInstancesForDuration: Order[Duration] with Hash[Duration] =
cats.kernel.instances.duration.catsKernelStdOrderForDuration
implicit def catsKernelInstancesForFiniteDuration: Order[FiniteDuration] with Hash[FiniteDuration] =
cats.kernel.instances.all.catsKernelStdOrderForFiniteDuration
implicit def catsKernelInstancesForChar: Order[Char] with Hash[Char] =
cats.kernel.instances.char.catsKernelStdOrderForChar
implicit def catsKernelInstancesForSymbol: Order[Symbol] with Hash[Symbol] =
cats.kernel.instances.symbol.catsKernelStdOrderForSymbol
implicit def catsKernelInstancesForString: Order[String] with Hash[String] =
cats.kernel.instances.string.catsKernelStdOrderForString
implicit def catsKernelInstancesForUUID: Order[UUID] with Hash[UUID] =
cats.kernel.instances.uuid.catsKernelStdOrderForUUID
implicit def catsKernelInstancesForDouble: Order[Double] with Hash[Double] =
cats.kernel.instances.double.catsKernelStdOrderForDouble
implicit def catsKernelInstancesForFloat: Order[Float] with Hash[Float] =
cats.kernel.instances.float.catsKernelStdOrderForFloat
implicit def catsKernelOrderForOption[A: Order]: Order[Option[A]] =
cats.kernel.instances.option.catsKernelStdOrderForOption[A]
implicit def catsKernelOrderForList[A: Order]: Order[List[A]] =
cats.kernel.instances.list.catsKernelStdOrderForList[A]
implicit def catsKernelOrderForVector[A: Order]: Order[Vector[A]] =
cats.kernel.instances.vector.catsKernelStdOrderForVector[A]
implicit def catsKernelOrderForQueue[A: Order]: Order[Queue[A]] =
cats.kernel.instances.queue.catsKernelStdOrderForQueue[A]
implicit def catsKernelOrderForSortedSet[A: Order]: Order[SortedSet[A]] =
cats.kernel.instances.sortedSet.catsKernelStdOrderForSortedSet[A]
implicit def catsKernelOrderForFunction0[A: Order]: Order[() => A] =
cats.kernel.instances.function.catsKernelOrderForFunction0[A]
/**
* you may wish to do equality by making `implicit val eqT: Eq[Throwable] = Eq.allEqual`
* doing a fine grained equality on Throwable can make the code very execution
* order dependent
*/
implicit def catsStdEqForTry[A, T](implicit A: Eq[A], T: Eq[Throwable]): Eq[Try[A]] =
new Eq[Try[A]] {
def eqv(x: Try[A], y: Try[A]): Boolean = (x, y) match {
case (Success(a), Success(b)) => A.eqv(a, b)
case (Failure(a), Failure(b)) => T.eqv(a, b)
case _ => false
}
}
}
private[kernel] trait PartialOrderInstances extends HashInstances {
implicit def catsKernelPartialOrderForOption[A: PartialOrder]: PartialOrder[Option[A]] =
cats.kernel.instances.option.catsKernelStdPartialOrderForOption[A]
implicit def catsKernelPartialOrderForList[A: PartialOrder]: PartialOrder[List[A]] =
cats.kernel.instances.list.catsKernelStdPartialOrderForList[A]
implicit def catsKernelPartialOrderForVector[A: PartialOrder]: PartialOrder[Vector[A]] =
cats.kernel.instances.vector.catsKernelStdPartialOrderForVector[A]
implicit def catsKernelPartialOrderForQueue[A: PartialOrder]: PartialOrder[Queue[A]] =
cats.kernel.instances.queue.catsKernelStdPartialOrderForQueue[A]
implicit def catsKernelPartialOrderForFunction0[A: PartialOrder]: PartialOrder[() => A] =
cats.kernel.instances.function.catsKernelPartialOrderForFunction0[A]
}
private[kernel] trait HashInstances extends EqInstances {
implicit def catsKernelHashForSet[A]: Hash[Set[A]] = cats.kernel.instances.set.catsKernelStdHashForSet[A]
implicit def catsKernelHashForOption[A: Hash]: Hash[Option[A]] =
cats.kernel.instances.option.catsKernelStdHashForOption[A]
implicit def catsKernelHashForList[A: Hash]: Hash[List[A]] = cats.kernel.instances.list.catsKernelStdHashForList[A]
implicit def catsKernelHashForVector[A: Hash]: Hash[Vector[A]] =
cats.kernel.instances.vector.catsKernelStdHashForVector[A]
implicit def catsKernelHashForQueue[A: Hash]: Hash[Queue[A]] =
cats.kernel.instances.queue.catsKernelStdHashForQueue[A]
implicit def catsKernelHashForSortedSet[A: Order: Hash]: Hash[SortedSet[A]] =
cats.kernel.instances.sortedSet.catsKernelStdHashForSortedSet[A]
implicit def catsKernelHashForFunction0[A: Hash]: Hash[() => A] =
cats.kernel.instances.function.catsKernelHashForFunction0[A]
implicit def catsKernelHashForMap[K: Hash, V: Hash]: Hash[Map[K, V]] =
cats.kernel.instances.map.catsKernelStdHashForMap[K, V]
implicit def catsKernelHashForSortedMap[K: Order: Hash, V: Hash]: Hash[SortedMap[K, V]] =
cats.kernel.instances.sortedMap.catsKernelStdHashForSortedMap[K, V]
implicit def catsKernelHashForEither[A: Hash, B: Hash]: Hash[Either[A, B]] =
cats.kernel.instances.either.catsStdHashForEither[A, B]
}
private[kernel] trait EqInstances {
implicit def catsKernelEqForOption[A: Eq]: Eq[Option[A]] = cats.kernel.instances.option.catsKernelStdEqForOption[A]
implicit def catsKernelEqForList[A: Eq]: Eq[List[A]] = cats.kernel.instances.list.catsKernelStdEqForList[A]
implicit def catsKernelEqForVector[A: Eq]: Eq[Vector[A]] = cats.kernel.instances.vector.catsKernelStdEqForVector[A]
implicit def catsKernelEqForQueue[A: Eq]: Eq[Queue[A]] = cats.kernel.instances.queue.catsKernelStdEqForQueue[A]
implicit def catsKernelEqForFunction0[A: Eq]: Eq[() => A] = cats.kernel.instances.function.catsKernelEqForFunction0[A]
implicit def catsKernelEqForMap[K, V: Eq]: Eq[Map[K, V]] = cats.kernel.instances.map.catsKernelStdEqForMap[K, V]
implicit def catsKernelEqForSortedMap[K: Order, V: Eq]: Eq[SortedMap[K, V]] =
cats.kernel.instances.sortedMap.catsKernelStdEqForSortedMap[K, V]
implicit def catsKernelEqForEither[A: Eq, B: Eq]: Eq[Either[A, B]] =
cats.kernel.instances.either.catsStdEqForEither[A, B]
}