Roslyn CTP: Three Introductory Projects

using System;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using System.Linq;
using System.Threading;
using Roslyn.Compilers;
using Roslyn.Compilers.CSharp;
using Roslyn.Services;
using Roslyn.Services.Editor;
using RoslynCTPLibrary.Refactoring;

namespace RefactoringExtension {

    [ExportCodeRefactoringProvider("RefactoringExtension", LanguageNames.CSharp)]
    class CodeRefactoringProvider : ICodeRefactoringProvider {
        private readonly ICodeActionEditFactory editFactory;

        [ImportingConstructor]
        public CodeRefactoringProvider(ICodeActionEditFactory editFactory) {
            this.editFactory = editFactory;
        }

        public CodeRefactoring GetRefactoring(IDocument document, TextSpan textSpan, CancellationToken cancellationToken) {
            var token = document.GetSyntaxTree().Root.FindToken(textSpan.Start);

            if (token.Parent == null) return null;

            var methodDeclaration = token.Parent.FirstAncestorOrSelf<BaseMethodDeclarationSyntax>();

            if (methodDeclaration == null || methodDeclaration.BodyOpt == null || methodDeclaration.BodyOpt.Statements.Count < 1) return null;

            return new CodeRefactoring(new[] { new CodeAction(editFactory, document, methodDeclaration) }, 
                methodDeclaration is ConstructorDeclarationSyntax ? ((ConstructorDeclarationSyntax)methodDeclaration).Identifier.Span :
                methodDeclaration is MethodDeclarationSyntax ? ((MethodDeclarationSyntax)methodDeclaration).Identifier.Span :
                methodDeclaration.BodyOpt.OpenBraceToken.Span);
        }


        class CodeAction : ICodeAction {
            public string Description { get { return "Declare variables at the begining of the method"; } }
            public System.Windows.Media.ImageSource Icon { get { return null; } }

            private ICodeActionEditFactory editFactory;
            private IDocument document;
            private BaseMethodDeclarationSyntax methodDeclaration;

            public CodeAction(ICodeActionEditFactory editFactory, IDocument document, BaseMethodDeclarationSyntax methodDeclaration) {
                this.editFactory = editFactory;
                this.document = document;
                this.methodDeclaration = methodDeclaration;
            }

            public ICodeActionEdit GetEdit(CancellationToken cancellationToken) {
                var tree = document.GetSyntaxTree(cancellationToken) as SyntaxTree;
                var sm = document.GetSemanticModel(cancellationToken) as SemanticModel;

                return editFactory.CreateTreeTransformEdit(document.Project.Solution, tree, 
                    ((SyntaxNode)tree.Root).ReplaceNode(methodDeclaration, DeclarationExtractor.ProcessMethod(methodDeclaration, sm)));
            }
        }
    }
}