FancyOpenStruct is a subclass of OpenStruct, and is a variant of RecursiveOpenStruct. This allows you to convert nested hashes into a structure where keys and values can be navigated and modified via dot-syntax, like: foo.bar = :something. This particular gem also adds support for Hash methods (such as length or merge), and also allows you to access and modify the data structure the same way that you would handle a normal Hash.