1. An apparatus configured to store data for access by an application program being executed on a data processing system, the data related to a structural description of the spatial and parametric characteristics of an element and logical connections with other elements of a non-fixed layout document, the apparatus comprising: a processor: a storage coupled to the processor: wherein the storage is configured to store a data structure, wherein the data structure includes information related to the non-fixed layout document; wherein the data structure is configured to include a plurality of assigned descriptions of logical connections of the element with the other elements, wherein the assigned descriptions of logical connections are represented as a hierarchical sequence of elements; wherein the data structure is further configured to include a plurality of assigned descriptions of spatial connections of the element, wherein the spatial connections relate to the other elements and a plurality of assigned descriptions of parametric characteristics of the element; wherein the data structure is configured to include an assigned algorithm for determining element search constraints and an assigned set of parameters for identification of a compound element on the basis of aggregate constituents, wherein the compound element is made up of a combination of the element and a plurality of the other elements.