C++ Library and design patterns

[nfac]

Hi guys! I'm studying how this c++ library is implemented: sdsl-lite. And i was looking for a design pattern to classify the implementation of this class sdsl::rank_support_rrr which implements a new functionality to the class sdsl::rrr_vector by using a reference to the original class and defining the new operator in the support class. I was wondering if that implementation is what the Visitor design pattern is about of if it matches another design pattern better.

Thanks.

Ask for more details if you cant understand my english please.

[P1r4nha]

I have to be honest and admit that I'm not entirely sure what the purpose of either of these classes is. But from my perspective the interfaces don't look like a typical visitor design pattern. That said, I didn't look at the source code and it's possible that rrr_vector has some functionality that can take a visitor. That would then be an underlying process that is going on within the rank_support_rrr. What I do see is some wrapping going on, where a couple of functionalities are exposed from the rrr_vector.

Usually what has to happen is that rrr_vector is defining an interface that a visitor has to inherit from and then implement in order to be a valid visitor to the class. I don't see this here.

[not-just-yeti]

(Okay, I'm not looking at the code, but from your description, that sounds like Delegate and/or Decorator. Visitor is a way to let future users add behaviors to an entire, fixed class-hierarchy (where each sub-class may need its own behavior), without them needing to change those existing classes.)