Add GetUtf8Name method.

Author: prozolic

sandbox/ConsoleApp/Enums.cs

@@ -2,6 +2,12 @@
 
 namespace ConsoleApp;
 
+// uncreated.
+public enum Variant : byte
+{
+
+}
+
 public enum IpAddrVariant : byte
 {
     [VariantValueType(typeof(byte), typeof(byte), typeof(byte), typeof(byte))]
@@ -11,12 +17,19 @@ public enum IpAddrVariant : byte
     None
 }
 
-[IgnoreVariant]
 public enum TestVariant
 {
 
 }
 
+// uncreated.
+[IgnoreVariant]
+public enum TestIgnoreVariant
+{
+
+}
+
+// uncreated.
 public class A
 {
     [IgnoreVariant]

src/VariantEnum/Generator.cs

@@ -325,6 +325,7 @@ private static string EmitMethod(VariantEnumContext context, string variantEnumN
             builder.AppendLine($"    public static int Count => {context.Members.Length};");
             builder.AppendLine(EmitGetName(context, variantEnumName));
             builder.AppendLine(EmitGetNames(context, variantEnumName));
+            builder.AppendLine(EmitGetUtf8Name(context, variantEnumName));
             builder.AppendLine(EmitGetNumericValue(context, variantEnumName));
             builder.AppendLine(EmitConvertEnum(context, variantEnumName));
             builder.AppendLine(EmitParse(context, variantEnumName));
@@ -382,6 +383,38 @@ private static string EmitGetNames(VariantEnumContext context, string variantEnu
             return code;
         }
 
+        private static string EmitGetUtf8Name(VariantEnumContext context, string variantEnumName)
+        {
+            var builder = new StringBuilder();
+            var symbol = context.Symbol;
+
+            if (context.Members.Length > 0)
+            {
+                builder.AppendLine(@$"        return {variantEnumName.ToLower()} switch
+        {{");
+                foreach (var m in context.Members)
+                {
+                    var memberName = m.MemberSyntax.Identifier.Text;
+                    builder.AppendLine($"            {memberName} => \"{memberName}\"u8,");
+                }
+                builder.AppendLine($"            _ => []");
+                builder.Append(@$"        }};");
+            }
+            else
+            {
+                builder.Append($"        return [];");
+            }
+
+            var code = @$"
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static ReadOnlySpan<byte> GetUtf8Name({variantEnumName} {variantEnumName.ToLower()})
+    {{
+{builder}
+    }}";
+            return code;
+        }
+
+
         private static string EmitGetNumericValue(VariantEnumContext context, string variantEnumName)
         {
             var builder = new StringBuilder();
@@ -549,7 +582,7 @@ public static bool TryParse(ReadOnlySpan<char> s, out {variantEnumName} result)
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static bool TryParse(ReadOnlySpan<char> s, IFormatProvider? provider, [MaybeNullWhen(false)] out {variantEnumName} result)
     {{
-        return TryParse(s, false, null, out result);
+        return TryParse(s, false, provider, out result);
     }}
 
     public static bool TryParse(ReadOnlySpan<char> s, bool ignoreCase, IFormatProvider? provider, [MaybeNullWhen(false)] out {variantEnumName} result)

tests/VariantEnum.Tests/UnitTests.cs

@@ -1,5 +1,6 @@
 using Shouldly;
 using System.Buffers;
+using System.Linq;
 using System.Runtime.InteropServices.Marshalling;
 using Xunit;
 
@@ -167,6 +168,20 @@ public void GetNames()
         names.Length.ShouldBe(3);
     }
 
+    [Fact]
+    public void GetUtf8Name()
+    {
+        var v4 = new IpAddr.V4(127, 0, 0, 1);
+        var v6 = new IpAddr.V6("::1");
+        var none = new IpAddr.None();
+
+        IpAddr.GetUtf8Name(v4).SequenceEqual("V4"u8).ShouldBeTrue();
+        IpAddr.GetUtf8Name(v6).SequenceEqual("V6"u8).ShouldBeTrue();
+        IpAddr.GetUtf8Name(none).SequenceEqual("None"u8).ShouldBeTrue();
+
+        IpAddr.GetUtf8Name((IpAddr)default).SequenceEqual(""u8).ShouldBeTrue();
+    }
+
     [Fact]
     public void GetNumericValue()
     {