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Band.scala
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Band.scala
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/*
* Copyright (c) 2015 Typelevel
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package cats.kernel
import scala.{specialized => sp}
/**
* Bands are semigroups whose operation
* (i.e. combine) is also idempotent.
*/
trait Band[@sp(Int, Long, Float, Double) A] extends Any with Semigroup[A] {
override protected[this] def repeatedCombineN(a: A, n: Int): A =
a // combine(a, a) == a
}
object Band extends SemigroupFunctions[Band] {
/**
* Access an implicit `Band[A]`.
*/
@inline final def apply[@sp(Int, Long, Float, Double) A](implicit ev: Band[A]): Band[A] = ev
/**
* Create a `Band` instance from the given function.
*/
@inline def instance[A](cmb: (A, A) => A): Band[A] = cmb(_, _)
}