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/* Magnolia, version 0.7.1. Copyright 2018 Jon Pretty, Propensive Ltd.
*
* The primary distribution site is: http://co.ntextu.al/
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the
* License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied. See the License for the specific language governing permissions
* and limitations under the License.
*/
package magnolia.examples
import magnolia._
import scala.language.experimental.macros
trait WeakHash[T] { def hash(value: T): Int }
object WeakHash {
type Typeclass[T] = WeakHash[T]
def combine[T](ctx: CaseClass[WeakHash, T]): WeakHash[T] = new WeakHash[T] {
def hash(value: T): Int = ctx.parameters.map { param =>
param.typeclass.hash(param.dereference(value))
}.foldLeft(0)(_ ^ _)
}
implicit val string: WeakHash[String] = _.map(_.toInt).sum
implicit val int: WeakHash[Int] = identity
implicit val double: WeakHash[Double] = _.toInt
implicit def gen[T]: WeakHash[T] = macro Magnolia.gen[T]
}
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