Add Playground project

Rascal.sln

@@ -9,6 +9,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Rascal", "src\Rascal\Rascal
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Rascal.Tests", "src\Rascal.Tests\Rascal.Tests.csproj", "{291FDB2E-8AC8-4B7A-B6E6-6DF5DCBCEB58}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Rascal.Playground", "src\Rascal.Playground\Rascal.Playground.csproj", "{F5A7C08C-51B5-4043-9666-C8DCD4F9C1E4}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -26,9 +28,14 @@ Global
 		{291FDB2E-8AC8-4B7A-B6E6-6DF5DCBCEB58}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{291FDB2E-8AC8-4B7A-B6E6-6DF5DCBCEB58}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{291FDB2E-8AC8-4B7A-B6E6-6DF5DCBCEB58}.Release|Any CPU.Build.0 = Release|Any CPU
+		{F5A7C08C-51B5-4043-9666-C8DCD4F9C1E4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{F5A7C08C-51B5-4043-9666-C8DCD4F9C1E4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{F5A7C08C-51B5-4043-9666-C8DCD4F9C1E4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{F5A7C08C-51B5-4043-9666-C8DCD4F9C1E4}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{04DE173D-4E74-4104-94FA-2B1807FCD34D} = {D92004B4-8D01-4BC3-B76B-A80D657FEC30}
 		{291FDB2E-8AC8-4B7A-B6E6-6DF5DCBCEB58} = {D92004B4-8D01-4BC3-B76B-A80D657FEC30}
+		{F5A7C08C-51B5-4043-9666-C8DCD4F9C1E4} = {D92004B4-8D01-4BC3-B76B-A80D657FEC30}
 	EndGlobalSection
 EndGlobal

src/Rascal.Playground/.gitignore

@@ -0,0 +1 @@
+Program.cs

src/Rascal.Playground/Program.cs

@@ -0,0 +1,12 @@
+using Rascal;
+using static Rascal.Prelude;
+
+var num = Console.ReadLine()
+    .NotNull("Failed to read from stdin.")
+    .Then(s => ParseR<int>(s, null, $"{s} is not a number!"))
+    .Validate(x => x >= 0, _ => "Number cannot be negative!");
+
+num.Switch(
+    x => Console.WriteLine($"You entered {x}!"),
+    e => Console.WriteLine(e.Message)
+);

src/Rascal.Playground/README.md

@@ -0,0 +1,5 @@
+# Rascal.Playground
+
+This project is meant as a development playground for the things like core API, analyzers, etc. outside of tests.
+
+Changes to this project should be ignored.

src/Rascal.Playground/Rascal.Playground.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>nullable</WarningsAsErrors>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Rascal\Rascal.csproj" />
+  </ItemGroup>
+
+</Project>