1. A computer implemented method of information retrieval, comprising the steps of: retrieving structural information of memorized documents according to a document type declaration that corresponds to each of said documents; retrieving elements, attributes and values of said elements and said attributes of said documents; generating a multilevel inverted index from said structural information, said elements, said attributes and said values; accepting a specification from a user having members that comprise at least one of said elements, said attributes and said values; responsive to said specification, extracting data from said index that complies with at least one of said members; displaying virtual directory paths of corresponding ones of said documents, wherein said directory paths each comprise a sequence of said members, and wherein contents of directories that are identified in said directory paths comprise selected ones of said documents possessing said specification.