Given an ANTLR ParserRuleContext, how do I find the first parent of a given type?

Question

I'm using ANTLR's XPath to get database views' table dependencies:

//create_view//from_clause//tableview_name

Now I need to get the view name that each table name belongs to. Eg, if there were a FirstParentOfType method, the code might look like this:

context.FirstParentOfType<Create_viewContext>().tableview_name().GetText();

But that method doesn't exist as far as I can tell. How is this done?

Answer 1

Pending a better way, here's an extension method that does it:

public static class RuleContextExtensions
{
    public static T FirstParentOfType<T>(this RuleContext context) where T : RuleContext => context as T ?? (context.Parent != null ? FirstParentOfType<T>(context.Parent) : null);
}