A program specializer employs input specialized data structures by generating an input specialized definition of a set of data elements, and parsing an application program to identify data element references to data elements in the generated input specialized definitions of data elements. The program specializer replaces or rewrites the identified data element references with the corresponding input specialized definition. The input specialized data elements from the input specialized program are employed in a particular view by generating a mapping of source data types to preferred data types, such that the preferred data types have access advantages over the source data types, and receiving a markup application program having source data types operable to be modified in the input specialized program. A view mapper maps, using the generated mapping, a source data type to a preferred data type, and applies the mapped preferred data type to occurrences of the corresponding source data type.