using System;

using System.Threading.Tasks;

using CSharpFunctionalExtensions;

public class Program

{

    public static async Task<Result<string>> GetAResultAsync() 

    {

        return await Task.FromResult(Result.Success<string>("a"));

    }

    public static Result<string> GetBResult(string a) 

    {

        return Result.Success<string>(a + "b");

    }

    public static async Task<string> GetCResultAsync(string b) 

    {

        return await Task.FromResult(b + "c");

    }

    public static async Task<Result<string>> GetDResultAsync(string c) 

    {

        return await Task.FromResult(Result.Success<string>(c + "d"));

    }

    public static async Task WriteResult()

    {

        var r = await Result.Success()

            .Bind(GetAResultAsync)

            .Bind(GetBResult)

            .Tap(b => Console.WriteLine(b))

            .Map(GetCResultAsync)

            .Bind(GetDResultAsync)

            .Tap(d => Console.WriteLine(d))

            .TapError(error => Console.WriteLine(error));

        var y = Result.Success().Bind(() => Result.Success());

        Console.WriteLine(y);

    }

    public static async Task Main()

    {

        await WriteResult();

    }

}