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PathAlg.scala
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PathAlg.scala
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/*
* Copyright 2023 Valdemar Grange
*
* 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 gql.preparation
import gql.GraphArc
import cats.mtl.Local
import gql.Cursor
trait PathAlg[F[_]] {
def ambientEdge[A](edge: GraphArc)(fa: F[A]): F[A]
def ambientField[A](name: String)(fa: F[A]): F[A] =
ambientEdge(GraphArc.Field(name))(fa)
def ambientIndex[A](i: Int)(fa: F[A]): F[A] =
ambientEdge(GraphArc.Index(i))(fa)
}
object PathAlg {
def apply[F[_]](implicit ev: PathAlg[F]): PathAlg[F] = ev
implicit def pathAlgForLocal[F[_]](implicit L: Local[F, Cursor]): PathAlg[F] = new PathAlg[F] {
override def ambientEdge[A](edge: GraphArc)(fa: F[A]): F[A] = L.local(fa)(_.add(edge))
}
}