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NewType.scala
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NewType.scala
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/*
* Copyright 2021 Loránd Szakács
*
* 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 sprout
/** The purpose of this type class is to give further application code
* a way to talk about this "new type" encoding. So that converting
* to and from the underlying type can be done with as little
* boilerplate as possible in inter-op with 3rd party libraries,
* and other classes.
*
* @see [[sprout.SproutShow]] as an example. We can easily provide
* a Show instance for N if the underlying representation has
* one. And it's opt in.
*
* This principle is then extended to a host of 3rd party libraries
* to eliminate boilerplate. See the sprout-interop github repo
* for many other examples.
*
* @tparam O
* O for old type. i.e. the underlying runtime type
* @tparam N
* N for new type. i.e. the type that ought to live only in the compiler
*/
trait NewType[O, N] extends OldType[O, N] {
@inline def newType(o: O): N
}
object NewType {
@inline def apply[O, N](implicit i: NewType[O, N]): NewType[O, N] = i
}