A computer automatically identifies multiple occurrences of an abstract data type that is embedded within an object of metadata of another abstract data type (hereinafter "top-level" abstract data type), e.g. by recursively visiting each element of the top-level abstract data type. Then the computer automatically generates, for the top-level abstract data type, a tap-level description that contains a description of each embedded abstract data type. At several locations in the top-level description that correspond to occurrences of a given embedded abstract data type in the top-level abstract data type, the computer automatically inserts offsets that identify a common position where the single description of that given embedded abstract data type is present in the tap-level description. Use of multiple offsets that identify a common position of an embedded description reduces space. The space was otherwise occupied by multiple embedded descriptions in prior art's top-level descriptions.