The memory management of the HyperDoc object is also left to the application along with the definition. The Library does not use any information from the object at all - the only interaction is that the access manager checks if a HyperDoc object exists for a given anchor or not as a part of servicing a request. The application can use this to maintain a set of HyperDoc objects in memory as a fast cache. Again, the Line Mode Browser can be used as an example as it keeps the 5 latest accessed hypertext objects in memory (regardless of their size) in order to allow fast back track for the user. The relation to the HTAnchor object requires that there is a link from the HyperDoc to the corresponding anchor in order for the application to do proper garbage collection of the HyperDoc objects.
Even though the Library does not interfere with the contents of the HyperDoc object it does provide an API for managing the object. This API is known as the "HText" API and it is described further in the User's Guide