Modular Natural Language Processing Using Declarative Attribute Grammars

A system based on a general top-down parsing algorithm has been developed which allows language processors to be created as executable specifications of arbitrary attribute grammars. Declarative notation of attribute grammars allows modular construction of executable language definitions. Syntax is defined through general context-free grammar rules, and meaning is defined by associated semantic rules with arbitrary dependencies. An innovative technique allows parses to be pruned by arbitrary semantic constraints. This new technique is useful in modelling natural-language phenomena by imposing unification-like restrictions, and accommodating long-distance and cross-serial dependencies, which cannot be handled by context-free rules alone.