public void EitherMapWhenLeft()
{
int expected = 10;
Either <string, int> either = "10";
Either <int, bool> eitherResult =
EitherModule.Map(
_isEven,
left => Convert.ToInt32(left),
either);
int result = eitherResult.Match(right => 0, left => left);
Assert.AreEqual(expected, result);
}
public void EitherMapWhenRight()
{
bool expected = true;
Either <string, int> either = 10;
Either <int, bool> eitherResult =
EitherModule.Map(
_isEven,
left => Convert.ToInt32(left),
either);
bool result = eitherResult.Match(right => right, left => false);
Assert.AreEqual(expected, result);
}
/// <summary>
/// Creates a new <see cref="Either{TLeft, TRight}"/> whose value is the result of applying the given mapping functions.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <typeparam name="TLeftResult">The type of the left value returned by mapping functions.</typeparam>
/// <typeparam name="TRightResult">The type of the right value returned by mapping functions</typeparam>
/// <param name="mappingWhenLeft">The function to transform either value when <see cref="Either{TLeft, TRight}.IsLeft"/>.</param>
/// <param name="mappingWhenRight">The function to transform either value when <see cref="Either{TLeft, TRight}.IsRight"/>.</param>
/// <param name="either">the input either.</param>
/// <returns>
/// Returns a new <see cref="Either{TLeft, TRight}"/> whose value is the result of applying the given mapping functions.
/// </returns>
public static Either <TLeftResult, TRightResult> Map <TLeft, TRight, TLeftResult, TRightResult>(
this Either <TLeft, TRight> either,
Func <TRight, TRightResult> mappingWhenRight,
Func <TLeft, TLeftResult> mappingWhenLeft)
=> EitherModule.Map(mappingWhenRight, mappingWhenLeft, either);
