scalaprops.derive.Recursive.scala Maven / Gradle / Ivy
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package scalaprops.derive
import scalaprops.Gen
sealed abstract class Recursive[T] {
/**
* If scalaprops's size parameter prevents generating an arbitrary `T`, generate a value
* with this `Gen[T]` instead.
*/
def default: Gen[T]
}
object Recursive {
/**
* Flags type `T` as recursive. Resulting value should be marked as implicit.
*
* Makes the generation of recursive type instances deterministic: these don't fail on
* `StackOverflowError`, but via scalaprops's size parameter. In that case, `default0` is used,
* and can either decide to fail or generate fallback values.
*/
def apply[T](default0: Gen[T]): Recursive[T] =
new Recursive[T] {
def default = default0
}
case class Value[+T](valueOpt: Option[T]) extends AnyVal {
def map[U](f: T => U): Value[U] =
Value(valueOpt.map(f))
}
}