Implementation of Two - dimensional Filters for StructuredDocuments

Filtering is used to select a subset, corresponding to the information interests of a user, from a set of information items. The information interests are described in a lter which is created to control the selection. In our earlier work we have described a theoretical framework for specifying lters to express content-based and structure-oriented constraints on structured text. In the lters, the information interests of the user are expressed by constraints and annotations on two-dimensional templates. The templates are created from the grammar associated with the structured text. This report describes a prototype for the ltering method in a syntax-directed document processing system called SYNDOC. In SYNDOC, a lter is applied to documents associated with a common grammar. The application of a lter means nding the documents that match the lter. From the user's point of view, ltering a subset of a given document collection consists of the following six steps. First, a lter for a given grammar is deened; second, a directory containing documents associated with the grammar is chosen; third, indexing is applied to the documents (unless indexed documents were chosen); fourth, the lter is applied to the indexed documents of the chosen directory; fth, the form of the output is deened; and sixth, the ltered documents are displayed in the speciied form. In the current phase of the implementation, the matching test is applied to one document at the time, and in case of matching, the document is displayed using the default output form.