Proceedings of the First Conference on Applied Natural Language Processing

Parsing with Logical Variables


Logic-based programming systems have enjoyed increasing popularity in applied AI work in the last few years. One of the contributions to Computational Linguistics made by the Logic Programming Paradigm has been the Definite Clause Grammar. In comparing DCGs with previous parsing mechanisms such as ATNs, certain clear advantages are seen. We feel that the most important of these advantages are due to the use of Logical Variables with Unification as the fundamental operation on them. To illustrate the power of the Logical Variable, we have implemented an experimental ATN system that treats ATN registers as Logical Variables and provides a unification operation over them. We would like to simultaneously encourage the use of the powerful mechanisms available in DCGs and demonstrate that some of these techniques can be captured without reference to a resolution theorem prover.

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atn, dcg, natural language processing, parsing


Association for Computational Linguistics

Donald E. Walker

A revised version of this paper was in the 1987 book Natural Language Parsing Systems, edited by Leonard Bolc. See here..

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