/// <summary> /// Returns true if the given predicate functions return true when applied to either value. /// Otherwise, returns false. /// </summary> /// <typeparam name="TLeft">The type of the left value.</typeparam> /// <typeparam name="TRight">The type of the right value.</typeparam> /// <param name="predicateWhenLeft">A function that evaluates whether the left value contained in the option is valid or not.</param> /// <param name="predicateWhenRight">A function that evaluates whether the right value contained in the option is valid or not.</param> /// <param name="either">the input either.</param> /// <returns> /// Returns true if the given predicate functions return true when applied to either value. /// </returns> public static bool Exists <TLeft, TRight>(this Either <TLeft, TRight> either, Func <TRight, bool> predicateWhenRight, Func <TLeft, bool> predicateWhenLeft) => EitherModule.Exists(predicateWhenRight, predicateWhenLeft, either);
/// <summary>
/// Creates a new <see cref="Either{TLeft, TRight}"/> whose value is the result of applying the given <paramref name="mapping"/> function when <see cref="Either{TLeft, TRight}.IsLeft"/>.
/// Otherwise, returns itself.
/// </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>
/// <param name="mapping">The function to transform either value when <see cref="Either{TLeft, TRight}.IsLeft"/>.</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, TRight> MapLeft <TLeft, TRight, TLeftResult>(
this Either <TLeft, TRight> either,
Func <TLeft, TLeftResult> mapping)
=> EitherModule.MapLeft(mapping, either);
/// <summary>Applies the given functions to <see cref="Either{TLeft, TRight}"/> value depends on its state.</summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <param name="actionWhenLeft">The action to apply to left value of input <paramref name="either"/>.</param>
/// <param name="actionWhenRight">The action to apply to right value of input <paramref name="either"/>.</param>
/// <param name="either">the input either.</param>
public static void Iterate <TLeft, TRight>(this Either <TLeft, TRight> either, Action <TRight> actionWhenRight, Action <TLeft> actionWhenLeft)
=> EitherModule.Iterate(actionWhenRight, actionWhenLeft, either);
/// <summary>
/// Returns true when <paramref name="either"/> <see cref="Either{TLeft, TRight}.IsRight"/> and given <paramref name="predicate"/> function applied to <paramref name="either"/> return true.
/// Otherwise, returns false.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <param name="predicate">A function that evaluates whether the right value contained in the option is valid or not.</param>
/// <param name="either">the input either.</param>
/// <returns>
/// Returns true if the given predicate functions return true when applied to either value.
/// </returns>
public static bool ExistsRight <TLeft, TRight>(this Either <TLeft, TRight> either, Func <TRight, bool> predicate)
=> EitherModule.ExistsRight(predicate, either);
/// <summary>
/// Convert the <see cref="Either{TLeft, TRight}"/> to a <see cref="Tuple{T1,T2}"/> where T1 and T2 are <see cref="Option{T}"/> value of <typeparamref name="TLeft"/> and <typeparamref name="TRight"/> respectively.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <param name="either">The input either.</param>
/// <returns>
/// Returns a <see cref="Tuple{T1,T2}"/> where T1 and T2 are <see cref="Option{T}"/> value of <typeparamref name="TLeft"/> and <typeparamref name="TRight"/> respectively.
/// The Tuple left value (Item1) is <see cref="Option{T}.Some(T)"/> when <paramref name="either"/> <see cref="Either{TLeft, TRight}.IsLeft"/>, otherwise is <see cref="Option{T}.None"/>
/// The Tuple right value (Item2) is <see cref="Option{T}.Some(T)"/> when <paramref name="either"/> <see cref="Either{TLeft, TRight}.IsRight"/>, otherwise is <see cref="Option{T}.None"/>
/// </returns>
public static (Option <TLeft>, Option <TRight>) ToTuple <TLeft, TRight>(this Either <TLeft, TRight> either)
=> EitherModule.ToTuple(either);
/// <summary>
/// Convert the <see cref="Either{TLeft, TRight}"/> to a <see cref="Option{T}"/> where T is <typeparamref name="TRight"/>.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <param name="either">The input either.</param>
/// <returns>
/// Returns an <see cref="Option{T}"/> where T is <typeparamref name="TRight"/>.
/// The option value state is <see cref="Option{T}.Some(T)"/> when <paramref name="either"/> <see cref="Either{TLeft, TRight}.IsRight"/>, otherwise is <see cref="Option{T}.None"/>
/// </returns>
public static Option <TRight> ToOptionRight <TLeft, TRight>(this Either <TLeft, TRight> either)
=> EitherModule.ToOptionRight(either);
/// <summary>
/// Creates a new <typeparamref name="TState"/> value by applying the given folder functions
/// to <see cref="Either{TLeft, TRight}"/> value and <paramref name="state"/>.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <typeparam name="TState">The type of initial and final states</typeparam>
/// <param name="folderWhenLeft">The function to transform either value from the input <paramref name="either"/> to a new state value.</param>
/// <param name="folderWhenRight">The function to transform either value from the input <paramref name="either"/> to a new state value.</param>
/// <param name="state">The initial state.</param>
/// <param name="either">the input either.</param>
/// <returns>
/// Returns a new <typeparamref name="TState"/> value by applying the given folder functions
/// to <see cref="Either{TLeft, TRight}"/> value and <paramref name="state"/>
/// </returns>
public static TState FoldBack <TLeft, TRight, TState>(this Either <TLeft, TRight> either, Func <TRight, TState, TState> folderWhenRight, Func <TLeft, TState, TState> folderWhenLeft, TState state)
=> EitherModule.FoldBack(folderWhenRight, folderWhenLeft, either, state);
/// <summary>
/// Creates a new <see cref="Either{TLeft, TRight}"/> value by swapping <see cref="Either{TLeft, TRight}.Left"/> and <see cref="Either{TLeft, TRight}.Right"/> values.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <param name="either">the input either.</param>
/// <returns>
/// Returns a new <see cref="Either{TLeft, TRight}"/> value by swapping <see cref="Either{TLeft, TRight}.Left"/> and <see cref="Either{TLeft, TRight}.Right"/> values.
/// </returns>
public static Either <TRight, TLeft> Swap <TLeft, TRight>(this Either <TLeft, TRight> either)
=> EitherModule.Swap(either);
/// <summary>Applies the given function to <see cref="Either{TLeft, TRight}"/> value when <see cref="Either{TLeft, TRight}.IsRight"/>.</summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <param name="action">The action to apply to right value of input <paramref name="either"/>.</param>
/// <param name="either">the input either.</param>
public static void IterateRight <TLeft, TRight>(this Either <TLeft, TRight> either, Action <TRight> action)
=> EitherModule.IterateRight(action, either);
/// <summary>
/// Creates a new <typeparamref name="TState"/> value by applying the given <paramref name="folder"/> function
/// to <see cref="Either{TLeft, TRight}"/> value and <paramref name="state"/> when the <paramref name="either"/> <see cref="Either{TLeft, TRight}.IsRight"/>.
/// Otherwise, returns the <paramref name="state"/>.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <typeparam name="TState">The type of initial and final states</typeparam>
/// <param name="folder">The function to transform either value from the input <paramref name="either"/> to a new state value.</param>
/// <param name="state">The initial state.</param>
/// <param name="either">the input either.</param>
/// <returns>
/// Returns a new <typeparamref name="TState"/> value by applying the given <paramref name="folder"/> function
/// to <see cref="Either{TLeft, TRight}"/> value and <paramref name="state"/> when the <paramref name="either"/> <see cref="Either{TLeft, TRight}.IsRight"/>.
/// Otherwise, returns the input <paramref name="either"/>.
/// </returns>
public static TState FoldBackRight <TLeft, TRight, TState>(this Either <TLeft, TRight> either, Func <TRight, TState, TState> folder, TState state)
=> EitherModule.FoldBackRight(folder, either, state);
/// <summary>
/// Creates a new <typeparamref name="TState"/> value by applying the given folder functions
/// to <paramref name="state"/> and <see cref="Either{TLeft, TRight}"/> value.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <typeparam name="TState">The type of initial and final states</typeparam>
/// <param name="folderWhenLeft">The function to transform either value from the input <paramref name="either"/> to a new state value.</param>
/// <param name="folderWhenRight">The function to transform either value from the input <paramref name="either"/> to a new state value.</param>
/// <param name="state">The initial state.</param>
/// <param name="either">the input either.</param>
/// <returns>
/// Returns a new <typeparamref name="TState"/> value by applying the given folder functions
/// to <paramref name="state"/> and <see cref="Either{TLeft, TRight}"/> value.
/// </returns>
public static TState Fold <TLeft, TRight, TState>(this Either <TLeft, TRight> either, TState state, Func <TState, TRight, TState> folderWhenRight, Func <TState, TLeft, TState> folderWhenLeft)
=> EitherModule.Fold(folderWhenRight, folderWhenLeft, state, either);
/// <summary>
/// Creates a new <typeparamref name="TState"/> value by applying the given <paramref name="folder"/> function
/// to <paramref name="state"/> and <see cref="Either{TLeft, TRight}"/> value when <paramref name="either"/> <see cref="Either{TLeft, TRight}.IsLeft"/>.
/// Otherwise, returns the <paramref name="state"/>.
/// </summary>
/// <typeparam name="TLeft">The type of the left value.</typeparam>
/// <typeparam name="TRight">The type of the right value.</typeparam>
/// <typeparam name="TState">The type of initial and final states</typeparam>
/// <param name="folder">The function to transform either value from the input <paramref name="either"/> to a new state value.</param>
/// <param name="state">The initial state.</param>
/// <param name="either">the input either.</param>
/// <returns>
/// Returns a new <typeparamref name="TState"/> value by applying the given folder functions
/// to <paramref name="state"/> and <see cref="Either{TLeft, TRight}"/> value <see cref="Either{TLeft, TRight}.IsLeft"/>.
/// Otherwise, returns the input <paramref name="either"/>.
/// </returns>
public static TState FoldLeft <TLeft, TRight, TState>(this Either <TLeft, TRight> either, TState state, Func <TState, TLeft, TState> folder)
=> EitherModule.FoldLeft(folder, state, either);
/// <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);
