Added generic methods and updated C# version

MapDataReader.Benchmarks/MapDataReader.Benchmarks.csproj

@@ -5,6 +5,7 @@
     <TargetFramework>net6.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

MapDataReader.Benchmarks/Program.cs

@@ -66,7 +66,7 @@ public void MapDatareader_ViaDapper()
 		public void MapDataReader_ViaMapaDataReader()
 		{
 			var dr = _dt.CreateDataReader();
-			var list = dr.ToTestClass();
+			var list = dr.To<TestClass>();
 		}
 
 		static DataTable _dt;

MapDataReader.Tests/MapDataReader.Tests.csproj

@@ -4,8 +4,8 @@
     <TargetFramework>net6.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
-
     <IsPackable>false</IsPackable>
+    <LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

MapDataReader.Tests/TestActualCode.cs

@@ -165,7 +165,7 @@ public void TestDatatReader()
 			dt.Rows.Add(123, "ggg", true, 3213, 123, date, TimeSpan.FromSeconds(123), new byte[] { 3, 2, 1 });
 			dt.Rows.Add(3, "fgdk", false, 11123, 321, date, TimeSpan.FromSeconds(123), new byte[] { 5, 6, 7, 8 });
 
-			var list = dt.CreateDataReader().ToMyObject();
+			var list = dt.CreateDataReader().To<MyObject>();
 
 			Assert.IsTrue(list.Count == 2);
 
@@ -198,7 +198,7 @@ public void TestDatatReader()
 
 			dt2.Rows.Add(true, "alex", 123);
 
-			list = dt2.CreateDataReader().ToMyObject(); //should not throw exception
+			list = dt2.CreateDataReader().To<MyObject>(); //should not throw exception
 
 			Assert.IsTrue(list[0].Id == 123);
 			Assert.IsTrue(list[0].Name == "alex");

MapDataReader/MapDataReader.csproj

@@ -14,6 +14,7 @@
 	<PackageTags>aot;source-generator</PackageTags>
 	<Description>Super fast mapping of DataReader to custom objects</Description>
 	<GenerateDocumentationFile>True</GenerateDocumentationFile>
+	<LangVersion>latest</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

MapDataReader/MapperGenerator.cs

@@ -8,113 +8,176 @@
 
 namespace MapDataReader
 {
-	[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
+	/// <summary>
+	/// An attribute used to mark a class for which a data reader mapper will be generated.
+	/// </summary>
+	/// <remarks>
+	/// The auto-generated mappers will help in mapping data from a data reader to the class properties.
+	/// </remarks>
+	[AttributeUsage(AttributeTargets.Class)]
 	public class GenerateDataReaderMapperAttribute : Attribute
 	{
 	}
 
+	/// <summary>
+	/// A source generator responsible for creating mapping extensions that allow for setting properties of a class
+	/// based on the property name using data from a data reader.
+	/// </summary>
+	/// <remarks>
+	/// This generator scans for classes marked with specific attributes and generates an extension method
+	/// that facilitates setting properties by their names.
+	/// </remarks>
 	[Generator]
 	public class MapperGenerator : ISourceGenerator
 	{
+		private const string Newline = @"
+";
+
+		/// <summary>
+		/// Executes the source generation logic, which scans for types needing generation,
+		/// processes their properties, and generates the corresponding source code for mapping extensions.
+		/// </summary>
 		public void Execute(GeneratorExecutionContext context)
 		{
-			var targetTypeTracker = context.SyntaxContextReceiver as TargetTypeTracker;
+			if (context.SyntaxContextReceiver is not TargetTypeTracker targetTypeTracker)
+			{
+				return;
+			}
 
 			foreach (var typeNode in targetTypeTracker.TypesNeedingGening)
 			{
 				var typeNodeSymbol = context.Compilation
 					.GetSemanticModel(typeNode.SyntaxTree)
 					.GetDeclaredSymbol(typeNode);
 
+				if (typeNodeSymbol is null)
+				{
+					continue;
+				}
+
 				var allProperties = typeNodeSymbol.GetAllSettableProperties();
 
-				var src = $@"
+				var src = $$"""
 					// <auto-generated/>
 					#pragma warning disable 8019 //disable 'unnecessary using directive' warning
 					using System;
 					using System.Data;
 					using System.Linq;
 					using System.Collections.Generic; //to support List<T> etc
 
-					namespace MapDataReader
-					{{
-						public static partial class MapperExtensions
-						{{
-							public static void SetPropertyByName(this {typeNodeSymbol.FullName()} target, string name, object value)
-							{{
-								SetPropertyByUpperName(target, name.ToUpperInvariant(), value);
-							}}
-
-							private static void SetPropertyByUpperName(this {typeNodeSymbol.FullName()} target, string name, object value)
-							{{
-								{"\r\n" + allProperties.Select(p =>
+					namespace MapDataReader;
+
+					/// <summary>
+					/// MapDataReader extension methods
+					/// </summary>
+					/// <seealso cref="{{typeNodeSymbol.FullName()}}">{{typeNode.Identifier}}</seealso>
+					public static class {{typeNode.Identifier}}Extensions
+					{
+						/// <summary>
+						/// Fast compile-time method for setting a property value by name
+						/// </summary>
+						/// <seealso cref="{{typeNodeSymbol.FullName()}}">{{typeNode.Identifier}}</seealso>
+						public static void SetPropertyByName(this {{typeNodeSymbol.FullName()}} target, string name, object value)
+						{
+							SetPropertyByUpperName(target, name.ToUpperInvariant(), value);
+						}
+
+						private static void SetPropertyByUpperName(this {{typeNodeSymbol.FullName()}} target, string name, object value)
+						{   {{
+								Newline + allProperties.Select(p =>
 								{
 									var pTypeName = p.Type.FullName();
 
 									if (p.Type.IsReferenceType) //ref types - just cast to property type
 									{
-										return $@"	if (name == ""{p.Name.ToUpperInvariant()}"") {{ target.{p.Name} = value as {pTypeName}; return; }}";
+										return $"\t\tif (name == \"{p.Name.ToUpperInvariant()}\") {{ target.{p.Name} = value as {pTypeName}; return; }}";
 									}
-									else if (pTypeName.EndsWith("?") && !p.Type.IsNullableEnum()) //nullable type (unless nullable Enum)
+
+									if (pTypeName.EndsWith("?") && !p.Type.IsNullableEnum()) //nullable type (unless nullable Enum)
 									{
 										var nonNullableTypeName = pTypeName.TrimEnd('?');
 
-										//do not use "as" operator becasue "as" is slow for nullable types. Use "is" and a null-check
-										return $@"	if (name == ""{p.Name.ToUpperInvariant()}"") {{ if(value==null) target.{p.Name}=null; else if(value is {nonNullableTypeName}) target.{p.Name}=({nonNullableTypeName})value; return; }}";
+										// do not use "as" operator because "as" is slow for nullable types. Use "is" and a null-check
+										return $"\t\tif (name == \"{p.Name.ToUpperInvariant()}\") {{ if(value==null) target.{p.Name}=null; else if(value is {nonNullableTypeName}) target.{p.Name}=({nonNullableTypeName})value; return; }}";
 									}
-									else if (p.Type.TypeKind == TypeKind.Enum || p.Type.IsNullableEnum()) //enum? pre-convert to underlying type then to int, you can't cast a boxed int to enum directly. Also to support assigning "smallint" database col to int32 (for example), which does not work at first (you can't cast a boxed "byte" to "int")
-									{
-										return $@"	if (value != null && name == ""{p.Name.ToUpperInvariant()}"") {{ target.{p.Name} = ({pTypeName})(value.GetType() == typeof(int) ? (int)value : (int)Convert.ChangeType(value, typeof(int))); return; }}"; //pre-convert enums to int first (after unboxing, see below)
-									}
-									else //primitive types. use Convert.ChangeType before casting. To support assigning "smallint" database col to int32 (for example), which does not work at first (you can't cast a boxed "byte" to "int")
+
+									if (p.Type.TypeKind == TypeKind.Enum || p.Type.IsNullableEnum())
 									{
-										return $@"	if (value != null && name == ""{p.Name.ToUpperInvariant()}"") {{ target.{p.Name} = value.GetType() == typeof({pTypeName}) ? ({pTypeName})value : ({pTypeName})Convert.ChangeType(value, typeof({pTypeName})); return; }}";
+										// enum? pre-convert to underlying type then to int, you can't cast a boxed int to enum directly.
+										// Also to support assigning "smallint" database col to int32 (for example), which does not work at first (you can't cast a boxed "byte" to "int")
+										return $"\t\tif (value != null && name == \"{p.Name.ToUpperInvariant()}\") {{ target.{p.Name} = ({pTypeName})(value.GetType() == typeof(int) ? (int)value : (int)Convert.ChangeType(value, typeof(int))); return; }}"; //pre-convert enums to int first (after unboxing, see below)
 									}
-								}).StringConcat("\r\n") } 
 
+									// primitive types. use Convert.ChangeType before casting.
+									// To support assigning "smallint" database col to int32 (for example),
+									// which does not work at first (you can't cast a boxed "byte" to "int")
+									return $"\t\tif (value != null && name == \"{p.Name.ToUpperInvariant()}\") {{ target.{p.Name} = value.GetType() == typeof({pTypeName}) ? ({pTypeName})value : ({pTypeName})Convert.ChangeType(value, typeof({pTypeName})); return; }}";
+								}).StringConcat(Newline)
+							}}
+						}
+
+					""";
 
-							}} //end method";
 
 				if (typeNodeSymbol.InstanceConstructors.Any(c => !c.Parameters.Any())) //has a constructor without parameters?
 				{
-					src += $@"
-
-							public static List<{typeNodeSymbol.FullName()}> To{typeNode.Identifier}(this IDataReader dr)
-							{{
-								var list = new List<{typeNodeSymbol.FullName()}>();
+					src += $$"""
+
+						/// <summary>
+						/// Map the data reader to <see cref="{{typeNodeSymbol.FullName()}}">{{typeNode.Identifier}}</see>
+						/// </summary>
+						/// <seealso cref="{{typeNodeSymbol.FullName()}}">{{typeNode.Identifier}}</seealso>
+						public static List<{{typeNodeSymbol.FullName()}}> To{{typeNode.Identifier}}(this IDataReader dr)
+						{
+							return dr.To<{{typeNodeSymbol.FullName()}}>();
+						}
+
+						/// <summary>
+						/// Map the data reader to <see cref="{{typeNodeSymbol.FullName()}}">{{typeNode.Identifier}}</see>
+						/// </summary>
+						/// <seealso cref="{{typeNodeSymbol.FullName()}}">{{typeNode.Identifier}}</seealso>
+						public static List<{{typeNodeSymbol.FullName()}}> To<T>(this IDataReader dr) where T : {{typeNodeSymbol.FullName()}}
+						{
+							var list = new List<{{typeNodeSymbol.FullName()}}>();
+
+							if (dr.Read())
+							{
+								string[] columnNames = new string[dr.FieldCount];
 
-								if (dr.Read())
-								{{
-									string[] columnNames = new string[dr.FieldCount];
-
-									for (int i = 0; i < columnNames.Length; i++)
-										columnNames[i] = dr.GetName(i).ToUpperInvariant();
-
-									do
-									{{
-										var result = new {typeNodeSymbol.FullName()}();
-										for (int i = 0; i < columnNames.Length; i++)
-										{{
-											var value = dr[i];
-											if (value is DBNull) value = null;
-											SetPropertyByUpperName(result, columnNames[i], value);
-										}}
-										list.Add(result);
-									}} while (dr.Read());
-								}}
-								dr.Close();
-								return list;
-							}}";
+								for (int i = 0; i < columnNames.Length; i++)
+								    columnNames[i] = dr.GetName(i).ToUpperInvariant();
+
+								do
+								{
+								    var result = new {{typeNodeSymbol.FullName()}}();
+								    for (int i = 0; i < columnNames.Length; i++)
+								    {
+								        var value = dr[i];
+								        if (value is DBNull) value = null;
+								        SetPropertyByUpperName(result, columnNames[i], value);
+								    }
+									list.Add(result);
+								} while (dr.Read());
+							}
+							dr.Close();
+							return list;
+						}
+
+					""";
 				}
-
-				src += "\n}"; //end class
-				src += "\n}"; //end namespace
+				
+				// end class
+				src += $"{Newline}}}";
 
 				// Add the source code to the compilation
 				context.AddSource($"{typeNodeSymbol.Name}DataReaderMapper.g.cs", src);
 			}
 		}
 
+		/// <summary>
+		/// Initializes the generator. This method is called before any generation occurs and allows
+		/// for setting up any necessary context or registering for specific notifications.
+		/// </summary>
 		public void Initialize(GeneratorInitializationContext context)
 		{
 			context.RegisterForSyntaxNotifications(() => new TargetTypeTracker());
@@ -127,25 +190,27 @@ internal class TargetTypeTracker : ISyntaxContextReceiver
 
 		public void OnVisitSyntaxNode(GeneratorSyntaxContext context)
 		{
-			if (context.Node is ClassDeclarationSyntax cdecl)
-				if (cdecl.IsDecoratedWithAttribute("GenerateDataReaderMapper"))
-					TypesNeedingGening = TypesNeedingGening.Add(cdecl);
+			if (context.Node is not ClassDeclarationSyntax classDec) return;
+
+			if (classDec.IsDecoratedWithAttribute("GenerateDataReaderMapper"))
+				TypesNeedingGening = TypesNeedingGening.Add(classDec);
 		}
 	}
 
 	internal static class Helpers
 	{
-		internal static bool IsDecoratedWithAttribute(this TypeDeclarationSyntax cdecl, string attributeName) =>
-			cdecl.AttributeLists
+		internal static bool IsDecoratedWithAttribute(this TypeDeclarationSyntax typeDec, string attributeName) =>
+			typeDec.AttributeLists
 				.SelectMany(x => x.Attributes)
 				.Any(x => x.Name.ToString().Contains(attributeName));
 
-
 		internal static string FullName(this ITypeSymbol typeSymbol) => typeSymbol.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
 
 		internal static string StringConcat(this IEnumerable<string> source, string separator) => string.Join(separator, source);
 
-		// returns all properties with public setters
+		/// <summary>
+		/// Returns all properties with public setters
+		/// </summary>
 		internal static IEnumerable<IPropertySymbol> GetAllSettableProperties(this ITypeSymbol typeSymbol)
 		{
 			var result = typeSymbol
@@ -162,18 +227,19 @@ internal static IEnumerable<IPropertySymbol> GetAllSettableProperties(this IType
 			return result;
 		}
 
-		//checks if type is a nullable num
+		/// <summary>
+		/// Checks if type is a nullable Enum
+		/// </summary>
 		internal static bool IsNullableEnum(this ITypeSymbol symbol)
 		{
 			//tries to get underlying non-nullable type from nullable type
 			//and then check if it's Enum
 			if (symbol.NullableAnnotation == NullableAnnotation.Annotated
-				&& symbol is INamedTypeSymbol namedType
-				&& namedType.IsValueType
-				&& namedType.IsGenericType
-				&& namedType.ConstructedFrom?.ToDisplayString() == "System.Nullable<T>"
-			)
+			    && symbol is INamedTypeSymbol { IsValueType: true, IsGenericType: true } namedType
+			    && namedType.ConstructedFrom.ToDisplayString() == "System.Nullable<T>")
+			{
 				return namedType.TypeArguments[0].TypeKind == TypeKind.Enum;
+			}
 
 			return false;
 		}