begin oneof

Author: bartelink

equinox-web-csharp/Domain/Aggregate.cs

@@ -6,13 +6,14 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using OneOf;
 
 namespace TodoBackendTemplate
 {
     public static class Aggregate
     {
         /// NB - these types and names reflect the actual storage formats and hence need to be versioned with care
-        public abstract class Event
+        public abstract class Event : OneOfBase<Event.Happened, Event.Compacted>
         {
             public class Happened : Event
             {
@@ -43,21 +44,10 @@ public class State
 
             internal State(bool happened) { Happened = happened; }
 
-            public static readonly State Initial = new State(false);
-
-            static void Evolve(State s, Event x)
-            {
-                switch (x)
-                {
-                    case Event.Happened e:
-                        s.Happened = true;
-                        break;
-                    case Event.Compacted e:
-                        s.Happened = e.Happened;
-                        break;
-                    default: throw new ArgumentOutOfRangeException(nameof(x), x, "invalid");
-                }
-            }
+            static void Evolve(State s, Event x) =>
+                x.Match(
+                    (Happened _) => s.Happened = true,
+                    (Compacted e) => s.Happened = e.Happened);
 
             public static State Fold(State origin, IEnumerable<Event> xs)
             {

equinox-web-csharp/Domain/Domain.csproj

@@ -2,13 +2,14 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0</TargetFrameworks>
-    <IsTestProject>false</IsTestProject>
+    <LangVersion>7.3</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="Equinox" Version="1.0.3-rc1" />
     <PackageReference Include="FSharp.Core" Version="4.5.4" />
     <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
+    <PackageReference Include="OneOf" Version="2.1.127" />
   </ItemGroup>
 
 </Project>