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We will discuss the features of ANTLR that make it an attractive tool for rapid developement of domain specific language translators and present some practical examples of its use: extraction of information from the Cassini Command Language specification, the processing of structured binary data, and IVL--an English-like language for generating VRML scene graph, which is used in configuring the jGuru.com server.
Results obtained from numerical calculations and modern (optical) diagnostics are often too complicated for manual inspection, manipulation and display. A simpler but still accurate description of these results is needed to facilitate data understanding. The paper discusses preliminary investigations into methods for the decomposition of 2-D and 3-D fluid flow data bases into elementary structures for purposes of description, analysis and comparison. An approach which involves the development of scene-like representation of the flow topology is presented. Using features such as critical points and dividing streamlines as a basis, a representation of the global topology of the flow is generated. The topology is then represented by a graph with the various structures represented by the nodes and their relationships in the flow by the connecting lines of the graph. Once the flow field has been placed in this form, it can be studied and compared with other data sets using techniques of syntactic pattern recognition or displayed using 3-D graphics techniques.