def recursive_children
      self.children.each do |child|
        if Parser::AST::Node === child
          yield child
          child.recursive_children { |c| yield c }
        end
      end
    end
def recursive_children
      self.children.each do |child|
        if Parser::AST::Node === child
          yield child
          child.recursive_children { |c| yield c }
        end
      end
    end
Recursively iterate all child nodes of current node.

 @yield [child] Gives a child node.
 @yieldparam child [Parser::AST::Node] child node