org.parboiled2.support.Lifter.scala Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of parboiled_native0.4_2.12 Show documentation

Fast and elegant PEG parsing in Scala - lightweight, easy-to-use, powerful

The newest version!

/*
 * Copyright 2009-2019 Mathias Doenitz
 *
 * 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 org.parboiled2.support

import scala.annotation.implicitNotFound
import org.parboiled2.support.hlist._

@implicitNotFound(
  "The `optional`, `zeroOrMore`, `oneOrMore` and `times` modifiers " + "can only be used on rules of type `Rule0`, `Rule1[T]` and `Rule[I, O <: I]`!"
)
sealed trait Lifter[M[_], I <: HList, O <: HList] {
  type In <: HList
  type StrictOut <: HList
  type OptionalOut <: HList
}

object Lifter extends LowerPriorityLifter {

  implicit def forRule0[M[_]]: Lifter[M, HNil, HNil] {
    type In          = HNil
    type StrictOut   = HNil
    type OptionalOut = StrictOut
  } = `n/a`

  implicit def forRule1[M[_], T]: Lifter[M, HNil, T :: HNil] {
    type In          = HNil
    type StrictOut   = M[T] :: HNil
    type OptionalOut = StrictOut
  } = `n/a`
}

sealed abstract class LowerPriorityLifter {

  implicit def forReduction[M[_], L <: HList, R <: L]: Lifter[M, L, R] {
    type In          = L
    type StrictOut   = R
    type OptionalOut = L
  } = `n/a`
}