ref: 添加 OneOf，重构 ArgumentReplace

General/OneOf.cs

@@ -0,0 +1,47 @@
+using System;
+
+namespace MeloongCore;
+
+public readonly struct OneOf<T0, T1> {
+    private readonly int _index;
+    private readonly T0 _value0;
+    private readonly T1 _value1;
+    public static implicit operator OneOf<T0, T1>(T0 value) => new(0, value, default);
+    public static implicit operator OneOf<T0, T1>(T1 value) => new(1, default, value);
+    private OneOf(int index, T0 value0, T1 value1) {
+        _index = index;
+        _value0 = value0;
+        _value1 = value1;
+    }
+
+    public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1) =>
+        _index switch {0 => f0(_value0), _ => f1(_value1)};
+    public void Switch(Action<T0> f0, Action<T1> f1) {
+        if (_index == 0) f0(_value0);
+        else if (_index == 1) f1(_value1);
+    }
+}
+
+public readonly struct OneOf<T0, T1, T2> {
+    private readonly int _index;
+    private readonly T0 _value0;
+    private readonly T1 _value1;
+    private readonly T2 _value2;
+    public static implicit operator OneOf<T0, T1, T2>(T0 value) => new(0, value, default, default);
+    public static implicit operator OneOf<T0, T1, T2>(T1 value) => new(1, default, value, default);
+    public static implicit operator OneOf<T0, T1, T2>(T2 value) => new(2, default, default, value);
+    private OneOf(int index, T0 value0, T1 value1, T2 value2) {
+        _index = index;
+        _value0 = value0;
+        _value1 = value1;
+        _value2 = value2;
+    }
+
+    public TResult Match<TResult>(Func<T0, TResult> f0, Func<T1, TResult> f1, Func<T2, TResult> f2) =>
+        _index switch {0 => f0(_value0), 1 => f1(_value1), _ => f2(_value2)};
+    public void Switch(Action<T0> f0, Action<T1> f1, Action<T2> f2) {
+        if (_index == 0) f0(_value0);
+        else if (_index == 1) f1(_value1);
+        else if (_index == 2) f2(_value2);
+    }
+}

MeloongCore.csproj

@@ -9,7 +9,7 @@
 	<AppendRuntimeIdentifierToOutputPath>false</AppendRuntimeIdentifierToOutputPath>
 	<Configurations>Debug;Release;Snapshot</Configurations>
 	<Deterministic>true</Deterministic>
-	<LangVersion>12.0</LangVersion>
+	<LangVersion>13.0</LangVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">