// original code by @dfurmans: https://scalafiddle.io/sf/ZPLl2L1/4

​

using System;

​

var travel = TravelServiceLiftedImp.Instance.CreateTravelRequest("Łódź", "Malaga");

var database = new TravelRepositoryArangoDb();

travel(database);

Console.WriteLine(travel);

​

public interface ITravel { }

public interface IRepository<T> 

{ 

    public T Save(T a); 

}

public interface ITravelRepository : IRepository<ITravel> { }

​

public class TravelRepositoryArangoDb : ITravelRepository

{

    public ITravel Save(ITravel t)

    {

        Console.WriteLine($"Saving travel { t }");

        return t;

    }

}

​

public interface ITravelServiceLifted

{

    public Func<ITravelRepository, ITravel> CreateTravelRequest(string from, string to);

}

​

public class TravelServiceLiftedImp : ITravelServiceLifted

{

    private static readonly TravelServiceLiftedImp _instance = new TravelServiceLiftedImp();

​

    private TravelServiceLiftedImp() { }

​

    public static TravelServiceLiftedImp Instance => _instance;

​

    public Func<ITravelRepository, ITravel> CreateTravelRequest(string from, string to) =>

        tr =>

        {

            return tr.Save(new SimpleTravel(from, to));

        };

​

    public record SimpleTravel(string From, string To) : ITravel;

}

​