Many resources are needed to download a project. Please understand that we have to compensate our server costs. Thank you in advance. Project price only 1 $
You can buy this project and download/modify it how often you want.
package monocle.state
import cats.{Eval, Now}
import monocle.POptional
import cats.data.{IndexedStateT, State}
trait StateOptionalSyntax {
implicit def toStateOptionalOps[S, T, A, B](optional: POptional[S, T, A, B]): StateOptionalOps[S, T, A, B] =
new StateOptionalOps[S, T, A, B](optional)
}
final class StateOptionalOps[S, T, A, B](private val optional: POptional[S, T, A, B]) extends AnyVal {
/** transforms a POptional into a State */
def toState: State[S, Option[A]] =
State(s => (s, optional.getOption(s)))
/** alias for toState */
def st: State[S, Option[A]] =
toState
/** extracts the value viewed through the optional */
def extract: State[S, Option[A]] =
toState
/** extracts the value viewed through the optional and applies `f` over it */
def extracts[B](f: A => B): State[S, Option[B]] =
extract.map(_.map(f))
/** modify the value viewed through the Optional and return its *new* value, if there is one */
def mod(f: A => B): IndexedStateT[Eval, S, T, Option[B]] =
modo(f).map(_.map(f))
/** modify the value viewed through the Optional and return its *old* value, if there was one */
def modo(f: A => B): IndexedStateT[Eval, S, T, Option[A]] =
IndexedStateT(s => Now((optional.modify(f)(s), optional.getOption(s))))
/** modify the value viewed through the Optional and ignores both values */
def mod_(f: A => B): IndexedStateT[Eval, S, T, Unit] =
IndexedStateT(s => Now((optional.modify(f)(s), ())))
/** set the value viewed through the Optional and returns its *new* value */
def assign(b: B): IndexedStateT[Eval, S, T, Option[B]] =
mod(_ => b)
/** set the value viewed through the Optional and return its *old* value, if there was one */
def assigno(b: B): IndexedStateT[Eval, S, T, Option[A]] =
modo(_ => b)
/** set the value viewed through the Optional and ignores both values */
def assign_(b: B): IndexedStateT[Eval, S, T, Unit] =
mod_(_ => b)
}
