C# LocalDeclarationStatementSyntax.GetFirstToken方法代码示例

        private async Task<Document> MakeConstAsync(Document document, LocalDeclarationStatementSyntax localDeclaration, CancellationToken cancellationToken)
        {
            var firstToken = localDeclaration.GetFirstToken();
            var leadingTrivia = firstToken.LeadingTrivia;
            var trimmedLocal = localDeclaration.ReplaceToken(firstToken, firstToken.WithLeadingTrivia(SyntaxTriviaList.Empty));

            var constToken = SyntaxFactory.Token(leadingTrivia, SyntaxKind.ConstKeyword, SyntaxFactory.TriviaList(SyntaxFactory.ElasticMarker));

            var newModifiers = trimmedLocal.Modifiers.Insert(0, constToken);

            var variableDeclaration = localDeclaration.Declaration;
            var variableTypeName = variableDeclaration.Type;
            if (variableTypeName.IsVar)
            {
                var semanticModel = await document.GetSemanticModelAsync(cancellationToken);

                var aliasInfo = semanticModel.GetAliasInfo(variableTypeName);
                if (aliasInfo == null)
                {
                    var type = semanticModel.GetTypeInfo(variableTypeName).ConvertedType;

                    if (type.Name != "var")
                    {
                        var typeName = SyntaxFactory.ParseTypeName(type.ToDisplayString())
                            .WithLeadingTrivia(variableTypeName.GetLeadingTrivia())
                            .WithTrailingTrivia(variableTypeName.GetTrailingTrivia());

                        var simplifiedTypeName = typeName.WithAdditionalAnnotations(Simplifier.Annotation);

                        variableDeclaration = variableDeclaration.WithType(simplifiedTypeName);
                    }
                }
            }

            var newLocal = trimmedLocal.WithModifiers(newModifiers)
                                       .WithDeclaration(variableDeclaration);

            var formattedLocal = newLocal.WithAdditionalAnnotations(Formatter.Annotation);

            var root = await document.GetSyntaxRootAsync(cancellationToken);
            var newRoot = root.ReplaceNode(localDeclaration, formattedLocal);

            return document.WithSyntaxRoot(newRoot);
        }

        private async Task<Document> MakeConstAsync(Document document, LocalDeclarationStatementSyntax localDeclaration, CancellationToken cancellationToken)
        {
            // Remove the leading trivia from the local declaration.
            var firstToken = localDeclaration.GetFirstToken();
            var leadingTrivia = firstToken.LeadingTrivia;
            var trimmedLocal = localDeclaration.ReplaceToken(
                firstToken, firstToken.WithLeadingTrivia(SyntaxTriviaList.Empty));

            // Create a const token with the leading trivia.
            var constToken = SyntaxFactory.Token(leadingTrivia, SyntaxKind.ConstKeyword, SyntaxFactory.TriviaList(SyntaxFactory.ElasticMarker));

            // Insert the const token into the modifiers list, creating a new modifiers list.
            var newModifiers = trimmedLocal.Modifiers.Insert(0, constToken);

            // If the type of declaration is 'var', create a new type name for the
            // type inferred for 'var'.
            var variableDeclaration = localDeclaration.Declaration;
            var variableTypeName = variableDeclaration.Type;
            if (variableTypeName.IsVar)
            {
                var semanticModel = await document.GetSemanticModelAsync(cancellationToken);

                // Special case: Ensure that 'var' isn't actually an alias to another type
                // (e.g. using var = System.String).
                var aliasInfo = semanticModel.GetAliasInfo(variableTypeName);
                if (aliasInfo == null)
                {
                    // Retrieve the type inferred for var.
                    var type = semanticModel.GetTypeInfo(variableTypeName).ConvertedType;

                    // Special case: Ensure that 'var' isn't actually a type named 'var'.
                    if (type.Name != "var")
                    {
                        // Create a new TypeSyntax for the inferred type. Be careful
                        // to keep any leading and trailing trivia from the var keyword.
                        var typeName = SyntaxFactory.ParseTypeName(type.ToDisplayString())
                            .WithLeadingTrivia(variableTypeName.GetLeadingTrivia())
                            .WithTrailingTrivia(variableTypeName.GetTrailingTrivia());

                        // Add an annotation to simplify the type name.
                        var simplifiedTypeName = typeName.WithAdditionalAnnotations(Simplifier.Annotation);

                        // Replace the type in the variable declaration.
                        variableDeclaration = variableDeclaration.WithType(simplifiedTypeName);
                    }
                }
            }

            // Produce the new local declaration.
            var newLocal = trimmedLocal.WithModifiers(newModifiers)
                                       .WithDeclaration(variableDeclaration);

            // Add an annotation to format the new local declaration.
            var formattedLocal = newLocal.WithAdditionalAnnotations(Formatter.Annotation);

            // Replace the old local declaration with the new local declaration.
            var root = await document.GetSyntaxRootAsync(cancellationToken);
            var newRoot = root.ReplaceNode(localDeclaration, formattedLocal);

            // Return document with transformed tree.
            return document.WithSyntaxRoot(newRoot);
        }