13. The system of claim 12 , further comprising a design module configured to associate explicitly a first set of elements of the plurality of elements of the tree-structured data with explicit meta-data levels.
13. The system of claim 12 , further comprising a design module configured to associate explicitly a first set of elements of the plurality of elements of the tree-structured data with explicit meta-data levels. 14. The system of claim 13 , wherein the design module is further configured to associate by inheritance a second set of elements of the plurality of elements of the tree-structured data with explicit meta-data levels of closest ancestor elements of the first set of elements.