/// <summary>
/// Add an assignment to default value for the given parameter/variable
/// </summary>
/// <param name="methodDeclarationSyntax">method/accessor where to inject the assignment</param>
/// <param name="outParameterParameterName">parameter/variable name</param>
/// <param name="outParameterParameterType">parameter/variable type</param>
/// <returns>the method with a block containing an initialization to default for the given variables/parameters</returns>
public BaseMethodDeclarationSyntax AddDefaultInitializer(BaseMethodDeclarationSyntax methodDeclarationSyntax, SyntaxToken outParameterParameterName, TypeSyntax outParameterParameterType)
{
if (methodDeclarationSyntax.Body == null)
{
throw new InvalidOperationException(
"Cant' add default initializer(s) to expression bodied or virtual method.");
}
IEnumerable <StatementSyntax> initializers;
IEnumerable <StatementSyntax> originalStatements;
if (methodDeclarationSyntax.Body.Statements.Count > 0 && methodDeclarationSyntax.Body.Statements[0].HasAnnotation(blockMarker))
{
// we add a new initializer, we need to get the existing ones
initializers = (methodDeclarationSyntax.Body.Statements[0] as BlockSyntax).Statements;
// we can skip the initializer helper block
originalStatements = methodDeclarationSyntax.Body.Statements.Skip(1);
}
else
{
// this is the first initializer helper, no pre existing ones
initializers = Array.Empty <StatementSyntax>();
// keep all statements
originalStatements = methodDeclarationSyntax.Body.Statements;
}
var initializer = SyntaxFactory.ExpressionStatement(SyntaxFactory.AssignmentExpression(
SyntaxKind.SimpleAssignmentExpression, SyntaxFactory.IdentifierName(outParameterParameterName),
outParameterParameterType.BuildDefaultExpression()));
var initializersBlock = SyntaxFactory.Block(initializers.Append(initializer))
.WithAdditionalAnnotations(blockMarker);
return(methodDeclarationSyntax.WithBody(methodDeclarationSyntax.Body.WithStatements(new SyntaxList <StatementSyntax>(originalStatements.Prepend(initializersBlock)))).WithAdditionalAnnotations(Marker));
}