Patent US 6,563,518

A credit card processing system includes a layer of abstraction between the presentation layer and the display, which enables rapid modification of the display by a user who is not necessarily knowledgeable about the inner workings of the presentation layer. To enable rapid modification of the program that controls a graphical user interface, the present invention uses generic statements in the commands in the underlying computer program that reference a series of tables (termed “Meta Data Tables”), in which are stored the values necessary to effect the desired command. These tables are known as Meta Data Tables because they store Meta Data, which is defined as data or information about other data. A powerful example of the use of the Meta Data Table is to define the nodes within the tree of screens presented to the user in a Graphical User Interface (GUI). By defining the nodes in the tree in a Meta Data Table, these nodes can be changed easily, but even more significant, the underlying code can be significantly reduced in size.