Default values for parameters in lambda expressions (csharp-12.0)

Author: ibrahimatay

CsharpLangExamples.sln

@@ -57,6 +57,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "StaticAbstractMembersInInte
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "PrimaryConstructors", "PrimaryConstructors\PrimaryConstructors.csproj", "{161EE9F6-1074-4FAE-A38F-9871EE5BEDBF}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DefaultLambdaParameters", "DefaultLambdaParameters\DefaultLambdaParameters.csproj", "{14F8F02B-3066-408D-9330-25C54E49FD73}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -171,6 +173,10 @@ Global
 		{161EE9F6-1074-4FAE-A38F-9871EE5BEDBF}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{161EE9F6-1074-4FAE-A38F-9871EE5BEDBF}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{161EE9F6-1074-4FAE-A38F-9871EE5BEDBF}.Release|Any CPU.Build.0 = Release|Any CPU
+		{14F8F02B-3066-408D-9330-25C54E49FD73}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{14F8F02B-3066-408D-9330-25C54E49FD73}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{14F8F02B-3066-408D-9330-25C54E49FD73}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{14F8F02B-3066-408D-9330-25C54E49FD73}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

DefaultLambdaParameters/DefaultLambdaParameters.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net8.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+        <LangVersion>preview</LangVersion>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    </PropertyGroup>
+
+</Project>

DefaultLambdaParameters/Program.cs

@@ -0,0 +1,31 @@
+
+// Default values for parameters in lambda expressions
+// https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-12#default-lambda-parameters
+
+var incrementValue = (int source, int increment) => source + increment;
+var incrementValueDefaultParameters = (int source, int increment = 1) => source + increment;
+
+Console.WriteLine(incrementValue(5, 3)); // 8
+Console.WriteLine(incrementValue(5, 2)); // 7
+Console.WriteLine(incrementValueDefaultParameters(5)); // 6
+
+var addition = (int val1, int val2) => val1 + val2;
+var sum = (params int[] values) =>
+{
+    int sum = 0;
+    foreach (var value in values)
+    {
+        sum = addition(sum, value);
+    }
+
+    return sum;
+};
+
+var empty = sum();
+Console.WriteLine(empty); // 0
+
+var sequence = new[] { 1, 2, 3, 4, 5 };
+var total = sum(sequence);
+
+Console.WriteLine(total); // 15
+