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/*
 *    Copyright 2012-2017 Johannes Rudolph
 *
 *    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 spray.json
package lenses

trait Update extends (JsValue ⇒ JsValue) { outer ⇒
  def apply(value: JsValue): JsValue

  def apply(jsonString: String): String =
    apply(JsonParser(jsonString)).toString()

  def &&(next: Update): Update = new Update {
    def apply(value: JsValue): JsValue = next(outer(value))
  }
}

/**
 * The UpdateLens is the central interface for updating a child element somewhere
 * deep down a hierarchy of a JsValue.
 */
trait UpdateLens {
  /**
   * Applies function `f` on the child of the `parent` denoted by this UpdateLens
   * and returns a `Right` of the parent with the child element updated.
   *
   * The value passed to `f` may be `Left(e)` if the child could not be found
   * in which case particular operations may still succeed. Function `f` may return
   * `Left(error)` in case the operation fails.
   *
   * `updated` returns `Left(error)` if the update operation or any of any intermediate
   * lens fails.
   */
  def updated(f: Operation)(parent: JsValue): SafeJsValue

  def !(op: Operation): Update
}