diff --git a/README.md b/README.md
index c3223e5..47a4f28 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,8 @@ Based on C# 15's Union type support, EfficientUnionGenerator provides highly eff
 EfficientUnionGenerator regards structs which are annotated with `EfficientUnion.EfficientUnionAttribute` as union types and generates union type support for them.
 Also it regards public partial constructors with single parameter as the members of the union.
 
+#### Simple union
+
 Following code is the most simple example of how to use EfficientUnionGenerator.
 
 ```csharp
@@ -31,6 +33,94 @@ public readonly partial struct Int32OrString
 }
 ```
 
+<details>
+
+<summary>generation result</summary>
+
+```csharp
+// <auto-generated/>
+#nullable enable
+namespace EfficientUnionGenerator.SampleApp.SimpleUnionOfInt32OrString;
+
+
+partial struct Int32OrString
+{
+    private enum __TypeSpecifier : byte
+    {
+        __int = 1,
+
+        __Undefined = 0,
+    }
+
+    private const bool __defaultTypeSpecifierHasType = false;
+    [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Explicit)]
+    private struct __UnmanagedField
+    {
+        [System.Runtime.InteropServices.FieldOffset(0)] public int __int;
+    }
+
+    private readonly __UnmanagedField __unmanagedField;
+    private readonly __TypeSpecifier __typeSpecifier;
+
+    private bool HasUnmanagedValue => __typeSpecifier != __TypeSpecifier.__Undefined || __defaultTypeSpecifierHasType;
+    private object? UnmanagedValue => __typeSpecifier switch
+    {
+        __TypeSpecifier.__int => __unmanagedField.__int,
+        _ => null,
+    };
+
+    public partial Int32OrString(int x)
+    {
+        __unmanagedField = new()
+        {
+            __int = x,
+        };
+        __typeSpecifier = __TypeSpecifier.__int;
+    }
+    public bool TryGetValue(out int value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__int)
+        {
+            value = __unmanagedField.__int;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    private readonly object? __managedField;
+
+    public partial Int32OrString(string x)
+    {
+        __managedField = x;
+    }
+
+    public bool TryGetValue([System.Diagnostics.CodeAnalysis.NotNullWhen(true)] out string? value)
+    {
+        if (__managedField is string __casted)
+        {
+            value = __casted;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public bool HasValue => HasUnmanagedValue || __managedField is not null;
+    public object? Value => HasUnmanagedValue ? UnmanagedValue : __managedField;
+}
+```
+
+</details>
+
+#### Make as an unmanaged
+
 If all of the members of the union are unmanaged types, the union type gets also unmanaged type.
 
 ```csharp
@@ -47,6 +137,148 @@ public readonly partial struct SignedInteger
 }
 ```
 
+<details>
+
+<summary>generation result</summary>
+
+```csharp
+// <auto-generated/>
+#nullable enable
+namespace EfficientUnionGenerator.SampleApp.SimpleUnionOfSignedInteger;
+
+
+partial struct SignedInteger
+{
+    private enum __TypeSpecifier : byte
+    {
+        __sbyte = 1,
+        __short = 2,
+        __int = 3,
+        __long = 4,
+
+        __Undefined = 0,
+    }
+
+    private const bool __defaultTypeSpecifierHasType = false;
+    [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Explicit)]
+    private struct __UnmanagedField
+    {
+        [System.Runtime.InteropServices.FieldOffset(0)] public sbyte __sbyte;
+        [System.Runtime.InteropServices.FieldOffset(0)] public short __short;
+        [System.Runtime.InteropServices.FieldOffset(0)] public int __int;
+        [System.Runtime.InteropServices.FieldOffset(0)] public long __long;
+    }
+
+    private readonly __UnmanagedField __unmanagedField;
+    private readonly __TypeSpecifier __typeSpecifier;
+
+    private bool HasUnmanagedValue => __typeSpecifier != __TypeSpecifier.__Undefined || __defaultTypeSpecifierHasType;
+    private object? UnmanagedValue => __typeSpecifier switch
+    {
+        __TypeSpecifier.__sbyte => __unmanagedField.__sbyte,
+        __TypeSpecifier.__short => __unmanagedField.__short,
+        __TypeSpecifier.__int => __unmanagedField.__int,
+        __TypeSpecifier.__long => __unmanagedField.__long,
+        _ => null,
+    };
+
+    public partial SignedInteger(sbyte x)
+    {
+        __unmanagedField = new()
+        {
+            __sbyte = x,
+        };
+        __typeSpecifier = __TypeSpecifier.__sbyte;
+    }
+    public bool TryGetValue(out sbyte value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__sbyte)
+        {
+            value = __unmanagedField.__sbyte;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public partial SignedInteger(short x)
+    {
+        __unmanagedField = new()
+        {
+            __short = x,
+        };
+        __typeSpecifier = __TypeSpecifier.__short;
+    }
+    public bool TryGetValue(out short value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__short)
+        {
+            value = __unmanagedField.__short;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public partial SignedInteger(int x)
+    {
+        __unmanagedField = new()
+        {
+            __int = x,
+        };
+        __typeSpecifier = __TypeSpecifier.__int;
+    }
+    public bool TryGetValue(out int value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__int)
+        {
+            value = __unmanagedField.__int;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public partial SignedInteger(long x)
+    {
+        __unmanagedField = new()
+        {
+            __long = x,
+        };
+        __typeSpecifier = __TypeSpecifier.__long;
+    }
+    public bool TryGetValue(out long value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__long)
+        {
+            value = __unmanagedField.__long;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public bool HasValue => HasUnmanagedValue;
+    public object? Value => UnmanagedValue;
+}
+```
+
+</details>
+
+#### Field mask
+
 You can specify the bit mask for type identifier by `unmanagedFieldMask` property of `EfficientUnionAttribute`.
 
 ```csharp
@@ -71,6 +303,117 @@ public static class Program
 }
 ```
 
+<details>
+
+<summary>generation result</summary>
+
+```csharp
+// <auto-generated/>
+#nullable enable
+namespace EfficientUnionGenerator.SampleApp.PositiveOnlyIntOrFloat;
+
+
+partial struct PositiveOnlyIntOrFloat
+{
+    private enum __TypeSpecifier : uint
+    {
+        __int = 0,
+        __float = 2147483648,
+
+        __Undefined = 0,
+    }
+
+    private const bool __defaultTypeSpecifierHasType = true;
+    private const __TypeSpecifier __typeSpecifierBitMask = unchecked((__TypeSpecifier)2147483648);
+
+    [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Explicit)]
+    private struct __UnmanagedField
+    {
+        [System.Runtime.InteropServices.FieldOffset(0)] public __TypeSpecifier __typeSpecifier;
+        [System.Runtime.InteropServices.FieldOffset(0)] public int __int;
+        [System.Runtime.InteropServices.FieldOffset(0)] public float __float;
+    }
+
+    private readonly __UnmanagedField __unmanagedField;
+    private readonly __TypeSpecifier __typeSpecifier
+    {
+        get => __unmanagedField.__typeSpecifier & __typeSpecifierBitMask;
+        init => __unmanagedField.__typeSpecifier |= value;
+    }
+
+    private bool HasUnmanagedValue => __typeSpecifier != __TypeSpecifier.__Undefined || __defaultTypeSpecifierHasType;
+    private object? UnmanagedValue
+    {
+        get
+        {
+            var maskedField = __unmanagedField;
+            maskedField.__typeSpecifier &= ~__typeSpecifierBitMask;
+            return __typeSpecifier switch
+            {
+                __TypeSpecifier.__int => maskedField.__int,
+                __TypeSpecifier.__float => maskedField.__float,
+                _ => null,
+            };
+        }
+    }
+
+    public partial PositiveOnlyIntOrFloat(int value)
+    {
+        __unmanagedField = new()
+        {
+            __int = value,
+        };
+        __typeSpecifier = __TypeSpecifier.__int;
+    }
+    public bool TryGetValue(out int value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__int)
+        {
+            var maskedField = __unmanagedField;
+            maskedField.__typeSpecifier &= ~__typeSpecifierBitMask;
+            value = maskedField.__int;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public partial PositiveOnlyIntOrFloat(float value)
+    {
+        __unmanagedField = new()
+        {
+            __float = value,
+        };
+        __typeSpecifier = __TypeSpecifier.__float;
+    }
+    public bool TryGetValue(out float value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__float)
+        {
+            var maskedField = __unmanagedField;
+            maskedField.__typeSpecifier &= ~__typeSpecifierBitMask;
+            value = maskedField.__float;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public bool HasValue => HasUnmanagedValue;
+    public object? Value => UnmanagedValue;
+}
+```
+
+</details>
+
+#### Explicit type identifier value
+
 You can specify the type identifier value by using `EfficientUnion.EnumBitPatternAttribute`.
 This is useful for such case of struct unions identified by version number field.
 
@@ -91,3 +434,105 @@ public readonly partial struct ElfHeader
     [EnumBitPattern(0x00_00_00_02_00_00_00_00uL)] public partial ElfHeader(Elf64Header x);
 }
 ```
+
+<details>
+
+<summary>generation result</summary>
+
+```csharp
+// <auto-generated/>
+#nullable enable
+namespace EfficientUnionGenerator.SampleApp.ElfHeader;
+
+
+partial struct ElfHeader
+{
+    private enum __TypeSpecifier : ulong
+    {
+        __EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf32Header = 4294967296,
+        __EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf64Header = 8589934592,
+
+        __Undefined = 0,
+    }
+
+    private const bool __defaultTypeSpecifierHasType = false;
+    private const __TypeSpecifier __typeSpecifierBitMask = unchecked((__TypeSpecifier)1095216660480);
+
+    [System.Runtime.InteropServices.StructLayout(System.Runtime.InteropServices.LayoutKind.Explicit)]
+    private struct __UnmanagedField
+    {
+        [System.Runtime.InteropServices.FieldOffset(0)] public __TypeSpecifier __typeSpecifier;
+        [System.Runtime.InteropServices.FieldOffset(0)] public EfficientUnionGenerator.SampleApp.ElfHeader.Elf32Header __EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf32Header;
+        [System.Runtime.InteropServices.FieldOffset(0)] public EfficientUnionGenerator.SampleApp.ElfHeader.Elf64Header __EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf64Header;
+    }
+
+    private readonly __UnmanagedField __unmanagedField;
+    private readonly __TypeSpecifier __typeSpecifier
+    {
+        get => __unmanagedField.__typeSpecifier & __typeSpecifierBitMask;
+        init => __unmanagedField.__typeSpecifier |= value;
+    }
+
+    private bool HasUnmanagedValue => __typeSpecifier != __TypeSpecifier.__Undefined || __defaultTypeSpecifierHasType;
+    private object? UnmanagedValue
+    {
+        get
+        {
+            var maskedField = __unmanagedField;
+            return __typeSpecifier switch
+            {
+                __TypeSpecifier.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf32Header => maskedField.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf32Header,
+                __TypeSpecifier.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf64Header => maskedField.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf64Header,
+                _ => null,
+            };
+        }
+    }
+
+    public partial ElfHeader(EfficientUnionGenerator.SampleApp.ElfHeader.Elf32Header x)
+    {
+        __unmanagedField = new()
+        {
+            __EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf32Header = x,
+        };
+    }
+    public bool TryGetValue(out EfficientUnionGenerator.SampleApp.ElfHeader.Elf32Header value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf32Header)
+        {
+            value = __unmanagedField.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf32Header;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public partial ElfHeader(EfficientUnionGenerator.SampleApp.ElfHeader.Elf64Header x)
+    {
+        __unmanagedField = new()
+        {
+            __EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf64Header = x,
+        };
+    }
+    public bool TryGetValue(out EfficientUnionGenerator.SampleApp.ElfHeader.Elf64Header value)
+    {
+        if (__typeSpecifier == __TypeSpecifier.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf64Header)
+        {
+            value = __unmanagedField.__EfficientUnionGenerator_u002E_SampleApp_u002E_ElfHeader_u002E_Elf64Header;
+            return true;
+        }
+        else
+        {
+            value = default;
+            return false;
+        }
+    }
+
+    public bool HasValue => HasUnmanagedValue;
+    public object? Value => UnmanagedValue;
+}
+```
+
+</details>