TheFo2sh

 public Option<ReservationViewModel> AddItemToReservation(string id, string itemId)
        {
            var reservationOptinal = _restaurant.GetReservation(id);

            var itemOptional = _inventory.GetItem(itemId);
            
           return reservationOptinal.Intersect(itemOptional)
                .Select(AddItemFunc)
                .Select(reservation => (reservation, _ClientsManger.GetUser(reservation.UserId)))
                .Select(MapToViewModel);

TheFo2sh

 public static class OptionExtensions
    {
        public static Option<(TOuterA, TOuterB, TInner)> Intersect<TOuterA, TOuterB, TInner>(this Option<(TOuterA, TOuterB)> outer, Option<TInner> inner)
        {
            return outer.HasValue && inner.HasValue
                ? outer.Select(outer1 => (outer1.Item1,outer1.Item2, inner.ValueOrFailure()))
                : Option.None<(TOuterA, TOuterB, TInner)>();
        }
        public static Option<(TOuter,TInner)> Intersect<TOuter, TInner>(this Option<TOuter> outer,Option<TInner> inner)
        {

TheFo2sh

public partial FunctionaObject2 where T: class, ICloneable, new()
{
   public static Func<FunctionalObject<T>, P> NewGetLens<P>(Func<T, P> func)
        {
            return (o => func.Invoke(o.GetValue()));
        }
        
  public static Func<FunctionalObject<T>, FunctionalObject<T>> NewSetLens(Action<T> func)
        {
            return o => o.With(func);

TheFo2sh

class Model:ICloneable
    {
        public string Item { get; set; }
        public int Price { get; set; }

        public object Clone()
        {
            return new Model()
            {
                Price = this.Price,

TheFo2sh

public partial FunctionaObject2 where T: class, ICloneable, new()
{
   public static Func<FunctionalObject<T>, P> NewGetLens<P>(Func<T, P> func)
        {
            return (o => func.Invoke(o.GetValue()));
        }
        
  public static Func<FunctionalObject<T>, FunctionalObject<T>> NewSetLens(Action<T> func)
        {
            return o => o.With(func);

TheFo2sh

  public class GeneratorEnumerator<T> : IEnumerator<T>
    {
        private readonly Func<int,T> _generatorFunc;
        private int _index;
        private T _current;

        public GeneratorEnumerator(Func<int, T> generatorFunc)
        {
            _generatorFunc = generatorFunc;
        }

TheFo2sh

 public class Generator<T> : IEnumerable<T>
    {
        private GeneratorEnumerator<T> _generatorEnumerator;

        public Generator(Func<int, T> generatorFunc)
        {
            _generatorEnumerator = new GeneratorEnumerator<T>(generatorFunc);
        }

        public IEnumerator<T> GetEnumerator()

TheFo2sh

    public static class Function1
    {
        [FunctionName("kofi")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function,  "post", Route = null)]
            HttpRequest req,
            ILogger log)
        {

TheFo2sh

public class TaskAsyncEnumerable<T> : IAsyncEnumerable<T>
    {
        private Func<Task<Option<T>>> _asyncTask;
        private TimeSpan timeSpan;

        public TaskAsyncEnumerable(Func<Task<Option<T>>> asyncTask)
        {
            _asyncTask = asyncTask;
        }

TheFo2sh

    public interface IFileSystem
    {
        File CreateFile(string filename);
        void DeleteFile(string filename);
        File GetFile(string filename);

        public File GetOrCreateFile(string filename)
        {
            var file = GetFile(filename);