Add fold as an alias to mapBoth

This commit is contained in:
Michael Bull 2018-11-01 11:17:40 +00:00
parent 7e45bfb7f2
commit 4eb5d80f91
1 changed files with 25 additions and 2 deletions

View File

@ -56,20 +56,43 @@ inline infix fun <V, E, U> Result<Iterable<V>, E>.mapAll(transform: (V) -> Resul
* - Elm: [Result.Extra.mapBoth](http://package.elm-lang.org/packages/elm-community/result-extra/2.2.0/Result-Extra#mapBoth)
* - Haskell: [Data.Either.either](https://hackage.haskell.org/package/base-4.10.0.0/docs/Data-Either.html#v:either)
*/
inline fun <V, E, U> Result<V, E>.mapBoth(success: (V) -> U, failure: (E) -> U): U {
inline fun <V, E, U> Result<V, E>.mapBoth(
success: (V) -> U,
failure: (E) -> U
): U {
return when (this) {
is Ok -> success(value)
is Err -> failure(error)
}
}
/**
* Maps this [Result<V, E>][Result] to `U` by applying either the [success] function if this
* [Result] is [Ok], or the [failure] function if this [Result] is an [Err]. Both of these
* functions must return the same type (`U`).
*
* This is functionally equivalent to [mapBoth].
*
* - Elm: [Result.Extra.mapBoth](http://package.elm-lang.org/packages/elm-community/result-extra/2.2.0/Result-Extra#mapBoth)
* - Haskell: [Data.Either.either](https://hackage.haskell.org/package/base-4.10.0.0/docs/Data-Either.html#v:either)
*/
inline fun <V, E, U> Result<V, E>.fold(
success: (V) -> U,
failure: (E) -> U
): U {
return mapBoth(success, failure)
}
/**
* Maps this [Result<V, E>][Result] to [Result<U, F>][Result] by applying either the [success]
* function if this [Result] is [Ok], or the [failure] function if this [Result] is an [Err].
*
* - Haskell: [Data.Bifunctor.Bimap](https://hackage.haskell.org/package/base-4.10.0.0/docs/Data-Bifunctor.html#v:bimap)
*/
inline fun <V, E, U, F> Result<V, E>.mapEither(success: (V) -> U, failure: (E) -> F): Result<U, F> {
inline fun <V, E, U, F> Result<V, E>.mapEither(
success: (V) -> U,
failure: (E) -> F
): Result<U, F> {
return when (this) {
is Ok -> Ok(success(value))
is Err -> Err(failure(error))