Roslyn Scripting Symbol Visitor

The SymbolVisitor is equivalent to SyntaxVisitor, but it works at the symbol level. When you are using the SymbolVisitor, you must construct the scaffolding code to visit all the nodes, which is not the case when you are using the CSharpSyntaxWalker and CSharpSyntaxRewriter.

Let's add a class and replace the following code, which simply lists all the types available to a compilation.

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

namespace RoslynDemo
{
    class CustomSymbolVisitor : SymbolVisitor
    {
        public override void VisitNamespace(INamespaceSymbol symbol)
        {
            Console.WriteLine(symbol);

            foreach (var childSymbol in symbol.GetMembers())
            {
                childSymbol.Accept(this);
            }
        }

        public override void VisitNamedType(INamedTypeSymbol symbol)
        {
            Console.WriteLine(symbol);

            foreach (var childSymbol in symbol.GetTypeMembers())
            {
                childSymbol.Accept(this);
            }
        }
    }

}

We can now create an instance of the CustomSymbolVisitor class and use that instance to visit the compilation of the parsed tree and iterate over the GlobalNamespace as shown below.

static void SymbolVisitorExample()
{
    SyntaxTree tree = CSharpSyntaxTree.ParseText(
        @"using System;
        using System.Collections;
        using System.Linq;
        using System.Text;
        using Microsoft.CodeAnalysis;
         
        namespace HelloWorld
        {
            class Program
            {
                static void Main(string[] args)
                {
                    Console.WriteLine(""Hello, World!"");
                }
            }
        }");

    var mscorlib = MetadataReference.CreateFromFile(typeof(object).Assembly.Location);
    var compilation = CSharpCompilation.Create("MyCompilation",
        syntaxTrees: new[] { tree }, references: new[] { mscorlib });

    var visitor = new CustomSymbolVisitor();
    visitor.Visit(compilation.GlobalNamespace);
}