Support the writing of enum literals.

specs/Qowaiv.CodeGeneration.Specs/Syntax/Attribute_decoration_specs.cs

@@ -1,4 +1,5 @@
 using Qowaiv.CodeGeneration.Syntax;
+using System.Text.Json.Serialization;
 
 namespace Syntax.Attribute_decoration_specs;
 
@@ -19,6 +20,11 @@ public void parameter_sets()
         => new AttributeInfo(typeof(TestAttribute),
             null, KeyValuePair.Create("Author", (object?)"Qowaiv"))
        .Should().HaveContent("[NUnit.Framework.Test(Author = \"Qowaiv\")]\r\n");
+
+    [Test]
+    public void Enum_values()
+        => AttributeInfo.System_Text_Json_Serialization_JsonIgnoreAttribute(JsonIgnoreCondition.WhenWritingDefault)
+        .Should().HaveContent("[System.Text.Json.Serialization.JsonIgnore(Condition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingDefault)]");
 }
 
 public class Equaly

src/Qowaiv.CodeGeneration/CSharpWriter.cs

@@ -95,7 +95,7 @@ public CSharpWriter Write(Type type, bool attribute)
 
     /// <summary>Writes a literal to the code file.</summary>
     [FluentSyntax]
-    public CSharpWriter Literal(object? value) => Write(new Syntax.Literal(value));
+    public CSharpWriter Literal(object? value) => Write(new Literal(value));
 
     /// <summary>Indents the current line of the code file.</summary>
     [FluentSyntax]

src/Qowaiv.CodeGeneration/Syntax/AttributeInfo.Constants.cs

@@ -73,6 +73,11 @@ public static AttributeInfo Qowaiv_Validation_DataAnnotations_MultipleOf(double
     public static AttributeInfo System_Text_Json_Serialization_JsonDerivedTypeAttribute(Type type)
         => new(typeof(System.Text.Json.Serialization.JsonDerivedTypeAttribute), [type]);
 
+    /// <summary><see cref="System.Text.Json.Serialization.JsonDerivedTypeAttribute"/>.</summary>
+    [Pure]
+    public static AttributeInfo System_Text_Json_Serialization_JsonIgnoreAttribute(System.Text.Json.Serialization.JsonIgnoreCondition condition)
+        => new(typeof(System.Text.Json.Serialization.JsonIgnoreAttribute), null, Kvp(nameof(System.Text.Json.Serialization.JsonIgnoreAttribute.Condition), condition));
+
     /// <summary><see cref="System.Text.Json.Serialization.JsonPropertyNameAttribute"/>.</summary>
     [Pure]
     public static AttributeInfo System_Text_Json_Serialization_JsonPropertyName(string name)
@@ -81,5 +86,8 @@ public static AttributeInfo System_Text_Json_Serialization_JsonPropertyName(stri
     /// <summary><see cref="System.Runtime.Serialization.EnumMemberAttribute"/>.</summary>
     [Pure]
     public static AttributeInfo System_Runtime_Serialization_EnumMember(string? value)
-        => new(typeof(System.Runtime.Serialization.EnumMemberAttribute), null, KeyValuePair.Create("Value", (object?)value));
+        => new(typeof(System.Runtime.Serialization.EnumMemberAttribute), null, Kvp("Value", (object?)value));
+
+    [Pure]
+    private static KeyValuePair<string, object?> Kvp(string key, object? value) => new(key, value);
 }

src/Qowaiv.CodeGeneration/Syntax/AttributeInfo.cs

@@ -35,11 +35,11 @@ public void WriteTo(CSharpWriter writer)
         if (CtorArguments.Any() || PropertyValues.Any())
         {
             writer.Write('(');
-            writer.Write(CtorArguments.Select(a => CtorArgument(a)), writer => writer.Write(", "));
+            writer.Write(CtorArguments.Select(CtorArgument), writer => writer.Write(", "));
 
             if (CtorArguments.Any() && PropertyValues.Any()) writer.Write(", ");
 
-            writer.Write(PropertyValues.Select(a => PropertyValue(a)), writer => writer.Write(", "));
+            writer.Write(PropertyValues.Select(PropertyValue), writer => writer.Write(", "));
             writer.Write(')');
         }
 

src/Qowaiv.CodeGeneration/Syntax/Literal.cs

@@ -13,22 +13,25 @@ public sealed class Literal : Code
     public void WriteTo(CSharpWriter writer)
     {
         Guard.NotNull(writer);
-
-        if (Value is null) writer.Write("null");
-        else if (Value is Type type) writer.Write("typeof(").Write(type).Write(')');
-        else if (Value is bool logical) writer.Write(logical ? "true" : "false");
-        else if (Value is int int32) writer.Write(int32.ToString(CultureInfo.InvariantCulture));
-        else if (Value is double dbl) writer.Write(Double(dbl));
-        else if (Value is decimal dec) writer.Write(dec.ToString(CultureInfo.InvariantCulture)).Write('m');
-        else if (Value is string str) writer.Write(String(str));
-        else throw new NotSupportedException($"Literals of type {Value.GetType()} are not supported");
+        _ = Value switch
+        {
+            null /*.........*/ => writer.Write("null"),
+            Type type /*....*/ => writer.Write("typeof(").Write(type).Write(')'),
+            bool boolean /*.*/ => writer.Write(boolean ? "true" : "false"),
+            int int32 /*....*/ => writer.Write(int32.ToString(CultureInfo.InvariantCulture)),
+            double dbl /*...*/ => writer.Write(Double(dbl)),
+            decimal dec /*..*/ => writer.Write(dec.ToString(CultureInfo.InvariantCulture)).Write('m'),
+            string str /*...*/ => writer.Write(String(str)),
+            Enum @enum /*...*/ => writer.Write(@enum.GetType()).Write('.').Write(@enum.ToString()),
+            _ => throw new NotSupportedException($"Literals of type {Value.GetType()} are not supported"),
+        };
     }
 
     [Pure]
     private static string Double(double dbl)
     {
-        if (dbl == double.MinValue) return "double.MinValue";
-        else if (dbl == double.MaxValue) return "double.MaxValue";
+        if (dbl <= double.MinValue) return "double.MinValue";
+        else if (dbl >= double.MaxValue) return "double.MaxValue";
         else if (double.IsNaN(dbl)) return "double.NaN";
         else if (double.IsPositiveInfinity(dbl)) return "double.PositiveInfinity";
         else if (double.IsNegativeInfinity(dbl)) return "double.NegativeInfinity";