Information Dictionary – New Design

The original design of the information dictionary made the assumption that the additional information would be contained in a vector and was given a structure for the information.  The definition was a class template where the information structure was the argument, which was put into the vector, which the information dictionary handled directly.  However, in the case of the constant number dictionary, two vectors are needed so that memory is not wasted (see last post).

The details of the additional information need to be separated from the information dictionary.  In other words, the information dictionary should not know (or assume) that the additional information is a vector.  An abstract information class can be used that defines the interface to the additional information.  The interface requires several functions for accessing the information:

add element - add a new element to the end of the additional information

set element - set an element from information in a token used when a new element is added or an element previously deleted is reused

clear element - clear the contents of an element when the dictionary entry is removed (made available for reuse)

The actual information classes are derived from the abstract class and implement these functions to manipulate their information as required, which could be stored as a vector, two vectors, or something completely different.  The information dictionary has no knowledge of the information class internals and simply uses the interface functions.

The information dictionary class can be a normal class derived from the dictionary class containing a reference to the additional information.  The abstract information interface functions are used to manipulate the additional information.  The information dictionary needs re-implement these functions from the base dictionary class:

add - adds a new dictionary entry and additional information if not already in the dictionary and returns its index

remove - removes the additional information if the dictionary entry was removed