C# Roslyn Demo

RoslynTry.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;

namespace GettingStartedCS
{
    class RoslynTry
    {
        static void Main(string[] args){
       
            SyntaxTree tree = CSharpSyntaxTree.ParseText(
                @"using System;
                using System.Collections;
                using System.Linq;
                using System.Text;
                    #define TEST_1_0
                    #define TEST_1_1
                 
                namespace HelloWorld
                {
                    [CompilerGenerated()]
                    class Program
                    {   
                        public static String s1 {get; set;} = ""utsav"";

                        public int s2 => s1.Length;
 
                        static void Main(string[] args)
                        {
                            
                            String s = null;
                            int? i = s?.Length; 
                            
                            #if TEST_1_0
                                int TEST_1_0 = 1;
                            #if TEST_1_1
                                int TEST_1_1 = 1;
                            #endif
                        }
                        
                    }
                }");


      var root = (CompilationUnitSyntax)tree.GetRoot();

			var firstMember = root.Members[0];

      Console.WriteLine(firstMember.ToString());

			var helloWorldDeclaration = (NamespaceDeclarationSyntax)firstMember;


			var programDeclaration = (ClassDeclarationSyntax)helloWorldDeclaration.Members[0];
      Console.WriteLine(programDeclaration.AttributeLists.ToArray().ToString());

			//Checking initial value of property is accessible or not ? : Yes it is
      var propDeclaration1 = (PropertyDeclarationSyntax)programDeclaration.Members[0];
			Console.WriteLine(propDeclaration1.Initializer.Value.ToString());

      //Checking lambda operator works with property declaration ? : Yes it is
			var propDeclaration2 = (PropertyDeclarationSyntax)programDeclaration.Members[1];
      Console.WriteLine(propDeclaration2.Modifiers.ToString());
      Console.WriteLine(propDeclaration2.ExpressionBody.Expression);

			//Checking preprocessing directives is properly logged or not ? : Yes it is
			var mainDeclaration = (MethodDeclarationSyntax)programDeclaration.Members[2];
      Console.WriteLine(mainDeclaration.Body.GetFirstDirective().ToString());
			Console.WriteLine(mainDeclaration.Body.GetLastDirective().ToString());


      //Checking null conditional operator is detected ? : Yes it is
      var localDeclaration = (LocalDeclarationStatementSyntax)mainDeclaration.Body.Statements.ToArray()[1];
      var varDeclaration = (VariableDeclarationSyntax)localDeclaration.Declaration;
      Console.WriteLine(((EqualsValueClauseSyntax)varDeclaration.Variables.ToArray()[0].Initializer));

		}
	}
}

Before running this file,
Install following packages using nuget :

• Microsoft.Net.Compilers
• Microsoft.CodeAnalysis

For more information , check : official github repository for roslyn