RSCG – dunet

RSCG – dunet
 
 

Add union types to C# – similar with F#/TS discriminated unions

Check his examples- awesome

This is how you can use dunet .

The code that you start with is

<Project Sdk="Microsoft.NET.Sdk">

	<PropertyGroup>
		<OutputType>Exe</OutputType>
		<TargetFramework>net7.0</TargetFramework>
		<ImplicitUsings>enable</ImplicitUsings>
		<Nullable>enable</Nullable>
	</PropertyGroup>

	<ItemGroup>
		<PackageReference Include="Dunet" Version="1.8.0">
			<PrivateAssets>all</PrivateAssets>
			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
		</PackageReference>
	</ItemGroup>
	<PropertyGroup>
		<EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>
		<CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)\GX</CompilerGeneratedFilesOutputPath>
	</PropertyGroup>

</Project>

The code that you will use is

// See https://github.com/domn1995/dunet for more examples
using duneDemo;
Console.WriteLine(WhatIsTheString.FromString("1"));

Console.WriteLine(WhatIsTheString.FromString("Andrei"));

Console.WriteLine(WhatIsTheString.FromString("1970-04-16"));

Console.WriteLine("Enter something - 1,1970-04-16 or Andrei !");
var readLine = Console.ReadLine();
var opt= WhatIsTheString.FromString(readLine);
Console.WriteLine(opt);
//if if it long
opt.MatchIsLong(
    l => Console.WriteLine("is long " + l.value),
    () => Console.WriteLine("is not long")
    ) ;
//C# switch
var x=opt switch
{
    WhatIsTheString.IsLong l => "is long " +l.value,
    WhatIsTheString.IsDate d=> "is date "+ d.value,
    WhatIsTheString.IsString s=>"is string "+ s.value,
    WhatIsTheString.IsNullWhiteSpace w=>"no data",
    _ => throw new NotImplementedException()

};
Console.WriteLine(x);

using Dunet;
namespace duneDemo;

[Union]
partial record WhatIsTheString
{
    partial record IsString(string value);
    partial record IsLong(long value);
    partial record IsDate(DateTime value);

    partial record IsNullWhiteSpace();

    public static WhatIsTheString FromString(string? value)
    {
        if (string.IsNullOrWhiteSpace(value))
            return new IsNullWhiteSpace();

        if(long.TryParse(value,out var longValue))
        {
            return new IsLong(longValue);
        }
        if(DateTime.TryParse(value,out var dateTimeValue))
        {
            return new IsDate(dateTimeValue);
        }
        return new IsString(value);
    }

}

The code that is generated is

using System;

namespace Dunet;

/// <summary>
/// Enables dunet union source generation for the decorated partial record.
/// </summary>
[AttributeUsage(AttributeTargets.Class,Inherited = false,AllowMultiple = false)]
internal sealed class UnionAttribute : Attribute {}

#pragma warning disable 1591
namespace duneDemo;
abstract partial record WhatIsTheString
{
    private WhatIsTheString() {}

    public abstract TMatchOutput Match<TMatchOutput>(
        System.Func<IsString,TMatchOutput> @isString,
        System.Func<IsLong,TMatchOutput> @isLong,
        System.Func<IsDate,TMatchOutput> @isDate,
        System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
    );
    public abstract void Match(
        System.Action<IsString> @isString,
        System.Action<IsLong> @isLong,
        System.Action<IsDate> @isDate,
        System.Action<IsNullWhiteSpace> @isNullWhiteSpace
    );

    public abstract TMatchOutput Match<TState,TMatchOutput>(
        TState state,
        System.Func<TState,IsString,TMatchOutput> @isString,
        System.Func<TState,IsLong,TMatchOutput> @isLong,
        System.Func<TState,IsDate,TMatchOutput> @isDate,
        System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
    );
    public abstract void Match<TState>(
        TState state,
        System.Action<TState,IsString> @isString,
        System.Action<TState,IsLong> @isLong,
        System.Action<TState,IsDate> @isDate,
        System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace
    );

    public abstract TMatchOutput MatchIsString<TMatchOutput>(
        System.Func<IsString,TMatchOutput> @isString,
        System.Func<TMatchOutput> @else
    );
    public abstract TMatchOutput MatchIsLong<TMatchOutput>(
        System.Func<IsLong,TMatchOutput> @isLong,
        System.Func<TMatchOutput> @else
    );
    public abstract TMatchOutput MatchIsDate<TMatchOutput>(
        System.Func<IsDate,TMatchOutput> @isDate,
        System.Func<TMatchOutput> @else
    );
    public abstract TMatchOutput MatchIsNullWhiteSpace<TMatchOutput>(
        System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
        System.Func<TMatchOutput> @else
    );

    public abstract void MatchIsString(
        System.Action<IsString> @isString,
        System.Action @else
    );
    public abstract void MatchIsLong(
        System.Action<IsLong> @isLong,
        System.Action @else
    );
    public abstract void MatchIsDate(
        System.Action<IsDate> @isDate,
        System.Action @else
    );
    public abstract void MatchIsNullWhiteSpace(
        System.Action<IsNullWhiteSpace> @isNullWhiteSpace,
        System.Action @else
    );

    public abstract TMatchOutput MatchIsString<TState,TMatchOutput>(
        TState state,
        System.Func<TState,IsString,TMatchOutput> @isString,
        System.Func<TState,TMatchOutput> @else
    );
    public abstract TMatchOutput MatchIsLong<TState,TMatchOutput>(
        TState state,
        System.Func<TState,IsLong,TMatchOutput> @isLong,
        System.Func<TState,TMatchOutput> @else
    );
    public abstract TMatchOutput MatchIsDate<TState,TMatchOutput>(
        TState state,
        System.Func<TState,IsDate,TMatchOutput> @isDate,
        System.Func<TState,TMatchOutput> @else
    );
    public abstract TMatchOutput MatchIsNullWhiteSpace<TState,TMatchOutput>(
        TState state,
        System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
        System.Func<TState,TMatchOutput> @else
    );

    public abstract void MatchIsString<TState>(
        TState state,
        System.Action<TState,IsString> @isString,
        System.Action<TState> @else
    );
    public abstract void MatchIsLong<TState>(
        TState state,
        System.Action<TState,IsLong> @isLong,
        System.Action<TState> @else
    );
    public abstract void MatchIsDate<TState>(
        TState state,
        System.Action<TState,IsDate> @isDate,
        System.Action<TState> @else
    );
    public abstract void MatchIsNullWhiteSpace<TState>(
        TState state,
        System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace,
        System.Action<TState> @else
    );

    public sealed partial record IsString : WhatIsTheString
    {
        public override TMatchOutput Match<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isString(this);
        public override void Match(
            System.Action<IsString> @isString,
            System.Action<IsLong> @isLong,
            System.Action<IsDate> @isDate,
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isString(this);
        public override TMatchOutput Match<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isString(state,this);
        public override void Match<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isString(state,this);
        public override TMatchOutput MatchIsString<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<TMatchOutput> @else
        ) => @isString(this);
        public override TMatchOutput MatchIsLong<TMatchOutput>(
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsDate<TMatchOutput>(
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsNullWhiteSpace<TMatchOutput>(
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override void MatchIsString(
            System.Action<IsString> @isString,
            System.Action @else
        ) => @isString(this);
        public override void MatchIsLong(
            System.Action<IsLong> @isLong,
            System.Action @else
        ) => @else();
        public override void MatchIsDate(
            System.Action<IsDate> @isDate,
            System.Action @else
        ) => @else();
        public override void MatchIsNullWhiteSpace(
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action @else
        ) => @else();
        public override TMatchOutput MatchIsString<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,TMatchOutput> @else
        ) => @isString(state,this);
        public override TMatchOutput MatchIsLong<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsDate<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsNullWhiteSpace<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override void MatchIsString<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState> @else
        ) => @isString(state,this);
        public override void MatchIsLong<TState>(
        TState state,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsDate<TState>(
        TState state,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsNullWhiteSpace<TState>(
        TState state,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action<TState> @else
        ) => @else(state);
    }

    public sealed partial record IsLong : WhatIsTheString
    {
        public override TMatchOutput Match<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isLong(this);
        public override void Match(
            System.Action<IsString> @isString,
            System.Action<IsLong> @isLong,
            System.Action<IsDate> @isDate,
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isLong(this);
        public override TMatchOutput Match<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isLong(state,this);
        public override void Match<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isLong(state,this);
        public override TMatchOutput MatchIsString<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsLong<TMatchOutput>(
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<TMatchOutput> @else
        ) => @isLong(this);
        public override TMatchOutput MatchIsDate<TMatchOutput>(
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsNullWhiteSpace<TMatchOutput>(
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override void MatchIsString(
            System.Action<IsString> @isString,
            System.Action @else
        ) => @else();
        public override void MatchIsLong(
            System.Action<IsLong> @isLong,
            System.Action @else
        ) => @isLong(this);
        public override void MatchIsDate(
            System.Action<IsDate> @isDate,
            System.Action @else
        ) => @else();
        public override void MatchIsNullWhiteSpace(
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action @else
        ) => @else();
        public override TMatchOutput MatchIsString<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsLong<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,TMatchOutput> @else
        ) => @isLong(state,this);
        public override TMatchOutput MatchIsDate<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsNullWhiteSpace<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override void MatchIsString<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsLong<TState>(
        TState state,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState> @else
        ) => @isLong(state,this);
        public override void MatchIsDate<TState>(
        TState state,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsNullWhiteSpace<TState>(
        TState state,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action<TState> @else
        ) => @else(state);
    }

    public sealed partial record IsDate : WhatIsTheString
    {
        public override TMatchOutput Match<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isDate(this);
        public override void Match(
            System.Action<IsString> @isString,
            System.Action<IsLong> @isLong,
            System.Action<IsDate> @isDate,
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isDate(this);
        public override TMatchOutput Match<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isDate(state,this);
        public override void Match<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isDate(state,this);
        public override TMatchOutput MatchIsString<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsLong<TMatchOutput>(
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsDate<TMatchOutput>(
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<TMatchOutput> @else
        ) => @isDate(this);
        public override TMatchOutput MatchIsNullWhiteSpace<TMatchOutput>(
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override void MatchIsString(
            System.Action<IsString> @isString,
            System.Action @else
        ) => @else();
        public override void MatchIsLong(
            System.Action<IsLong> @isLong,
            System.Action @else
        ) => @else();
        public override void MatchIsDate(
            System.Action<IsDate> @isDate,
            System.Action @else
        ) => @isDate(this);
        public override void MatchIsNullWhiteSpace(
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action @else
        ) => @else();
        public override TMatchOutput MatchIsString<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsLong<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsDate<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,TMatchOutput> @else
        ) => @isDate(state,this);
        public override TMatchOutput MatchIsNullWhiteSpace<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override void MatchIsString<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsLong<TState>(
        TState state,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsDate<TState>(
        TState state,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState> @else
        ) => @isDate(state,this);
        public override void MatchIsNullWhiteSpace<TState>(
        TState state,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action<TState> @else
        ) => @else(state);
    }

    public sealed partial record IsNullWhiteSpace : WhatIsTheString
    {
        public override TMatchOutput Match<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isNullWhiteSpace(this);
        public override void Match(
            System.Action<IsString> @isString,
            System.Action<IsLong> @isLong,
            System.Action<IsDate> @isDate,
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isNullWhiteSpace(this);
        public override TMatchOutput Match<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
        ) => @isNullWhiteSpace(state,this);
        public override void Match<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace
        ) => @isNullWhiteSpace(state,this);
        public override TMatchOutput MatchIsString<TMatchOutput>(
            System.Func<IsString,TMatchOutput> @isString,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsLong<TMatchOutput>(
            System.Func<IsLong,TMatchOutput> @isLong,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsDate<TMatchOutput>(
            System.Func<IsDate,TMatchOutput> @isDate,
            System.Func<TMatchOutput> @else
        ) => @else();
        public override TMatchOutput MatchIsNullWhiteSpace<TMatchOutput>(
            System.Func<IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TMatchOutput> @else
        ) => @isNullWhiteSpace(this);
        public override void MatchIsString(
            System.Action<IsString> @isString,
            System.Action @else
        ) => @else();
        public override void MatchIsLong(
            System.Action<IsLong> @isLong,
            System.Action @else
        ) => @else();
        public override void MatchIsDate(
            System.Action<IsDate> @isDate,
            System.Action @else
        ) => @else();
        public override void MatchIsNullWhiteSpace(
            System.Action<IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action @else
        ) => @isNullWhiteSpace(this);
        public override TMatchOutput MatchIsString<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsString,TMatchOutput> @isString,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsLong<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsLong,TMatchOutput> @isLong,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsDate<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsDate,TMatchOutput> @isDate,
            System.Func<TState,TMatchOutput> @else
        ) => @else(state);
        public override TMatchOutput MatchIsNullWhiteSpace<TState,TMatchOutput>(
        TState state,
            System.Func<TState,IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
            System.Func<TState,TMatchOutput> @else
        ) => @isNullWhiteSpace(state,this);
        public override void MatchIsString<TState>(
        TState state,
            System.Action<TState,IsString> @isString,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsLong<TState>(
        TState state,
            System.Action<TState,IsLong> @isLong,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsDate<TState>(
        TState state,
            System.Action<TState,IsDate> @isDate,
            System.Action<TState> @else
        ) => @else(state);
        public override void MatchIsNullWhiteSpace<TState>(
        TState state,
            System.Action<TState,IsNullWhiteSpace> @isNullWhiteSpace,
            System.Action<TState> @else
        ) => @isNullWhiteSpace(state,this);
    }

}
#pragma warning restore 1591

#pragma warning disable 1591

namespace duneDemo;

internal static class WhatIsTheStringMatchExtensions
{
    public static async System.Threading.Tasks.Task<TMatchOutput> MatchAsync<TMatchOutput>(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsString,TMatchOutput> @isString,
        System.Func<WhatIsTheString.IsLong,TMatchOutput> @isLong,
        System.Func<WhatIsTheString.IsDate,TMatchOutput> @isDate,
        System.Func<WhatIsTheString.IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
    )
    => (await unionTask.ConfigureAwait(false)).Match(
            @isString,
            @isLong,
            @isDate,
            @isNullWhiteSpace
        );
    public static async System.Threading.Tasks.ValueTask<TMatchOutput> MatchAsync<TMatchOutput>(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsString,TMatchOutput> @isString,
        System.Func<WhatIsTheString.IsLong,TMatchOutput> @isLong,
        System.Func<WhatIsTheString.IsDate,TMatchOutput> @isDate,
        System.Func<WhatIsTheString.IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace
    )
    => (await unionTask.ConfigureAwait(false)).Match(
            @isString,
            @isLong,
            @isDate,
            @isNullWhiteSpace
        );
    public static async System.Threading.Tasks.Task MatchAsync(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsString> @isString,
        System.Action<WhatIsTheString.IsLong> @isLong,
        System.Action<WhatIsTheString.IsDate> @isDate,
        System.Action<WhatIsTheString.IsNullWhiteSpace> @isNullWhiteSpace
    )
    => (await unionTask.ConfigureAwait(false)).Match(
            @isString,
            @isLong,
            @isDate,
            @isNullWhiteSpace
        );
    public static async System.Threading.Tasks.ValueTask MatchAsync(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsString> @isString,
        System.Action<WhatIsTheString.IsLong> @isLong,
        System.Action<WhatIsTheString.IsDate> @isDate,
        System.Action<WhatIsTheString.IsNullWhiteSpace> @isNullWhiteSpace
    )
    => (await unionTask.ConfigureAwait(false)).Match(
            @isString,
            @isLong,
            @isDate,
            @isNullWhiteSpace
        );
    public static async System.Threading.Tasks.Task<TMatchOutput> MatchIsStringAsync<TMatchOutput>(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsString,TMatchOutput> @isString,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsString(
                    @isString,
                    @else
                );
    public static async System.Threading.Tasks.Task<TMatchOutput> MatchIsLongAsync<TMatchOutput>(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsLong,TMatchOutput> @isLong,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsLong(
                    @isLong,
                    @else
                );
    public static async System.Threading.Tasks.Task<TMatchOutput> MatchIsDateAsync<TMatchOutput>(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsDate,TMatchOutput> @isDate,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsDate(
                    @isDate,
                    @else
                );
    public static async System.Threading.Tasks.Task<TMatchOutput> MatchIsNullWhiteSpaceAsync<TMatchOutput>(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsNullWhiteSpace(
                    @isNullWhiteSpace,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask<TMatchOutput> MatchIsStringAsync<TMatchOutput>(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsString,TMatchOutput> @isString,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsString(
                    @isString,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask<TMatchOutput> MatchIsLongAsync<TMatchOutput>(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsLong,TMatchOutput> @isLong,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsLong(
                    @isLong,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask<TMatchOutput> MatchIsDateAsync<TMatchOutput>(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsDate,TMatchOutput> @isDate,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsDate(
                    @isDate,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask<TMatchOutput> MatchIsNullWhiteSpaceAsync<TMatchOutput>(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Func<WhatIsTheString.IsNullWhiteSpace,TMatchOutput> @isNullWhiteSpace,
        System.Func<TMatchOutput> @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsNullWhiteSpace(
                    @isNullWhiteSpace,
                    @else
                );
    public static async System.Threading.Tasks.Task MatchIsStringAsync(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsString> @isString,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsString(
                    @isString,
                    @else
                );
    public static async System.Threading.Tasks.Task MatchIsLongAsync(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsLong> @isLong,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsLong(
                    @isLong,
                    @else
                );
    public static async System.Threading.Tasks.Task MatchIsDateAsync(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsDate> @isDate,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsDate(
                    @isDate,
                    @else
                );
    public static async System.Threading.Tasks.Task MatchIsNullWhiteSpaceAsync(
        this System.Threading.Tasks.Task<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsNullWhiteSpace> @isNullWhiteSpace,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsNullWhiteSpace(
                    @isNullWhiteSpace,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask MatchIsStringAsync(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsString> @isString,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsString(
                    @isString,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask MatchIsLongAsync(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsLong> @isLong,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsLong(
                    @isLong,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask MatchIsDateAsync(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsDate> @isDate,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsDate(
                    @isDate,
                    @else
                );
    public static async System.Threading.Tasks.ValueTask MatchIsNullWhiteSpaceAsync(
        this System.Threading.Tasks.ValueTask<WhatIsTheString> unionTask,
        System.Action<WhatIsTheString.IsNullWhiteSpace> @isNullWhiteSpace,
        System.Action @else
    )
        =>
            (await unionTask.ConfigureAwait(false))
                .MatchIsNullWhiteSpace(
                    @isNullWhiteSpace,
                    @else
                );
}
#pragma warning restore 1591

Code and pdf at

https://ignatandrei.github.io/RSCG_Examples/v2/docs/dunet