public static Tuple<ExpressionSyntax, Func<IdentifierNameSyntax, ExpressionSyntax>> GetNullabledQueryAndValueGetter(TypeSymbol itemType, SyntaxToken iterator, ExpressionSyntax collection)
{
if (!itemType.IsReferenceType && itemType.SpecialType != SpecialType.System_Nullable_T) {
//wrap it in Nullable<T>
return Tuple.Create<ExpressionSyntax, Func<IdentifierNameSyntax, ExpressionSyntax>>(
collection.Accessing(Syntax.Identifier("Cast").Genericed(itemType.Name.AsIdentifier().Nullable())).Invoking(),
e => e.Accessing("Value"));
}
//wrap it in Tuple<T>
var wrappedRead = Syntax.IdentifierName("Tuple").Accessing("Create").Invoking(Syntax.IdentifierName(iterator).Args1());
return Tuple.Create<ExpressionSyntax, Func<IdentifierNameSyntax, ExpressionSyntax>>(
collection.Accessing("Select").Invoking(iterator.Lambdad(wrappedRead).Args1()),
e => e.Accessing("Item1"));
}