Language-Based Environment For Natural Language Parsing

This paper introduces a special programming environment for the definition of grammars and for the implementation of corresponding parsers. In natural language processing systems it is advantageous to have linguistic knowledge and processing mechanisms separated. Our environment accepts grammars consisting of binary dependency relations and grammatical functions. Well-formed expressions of functions and relations provide constituent surroundings for syntactic categories in the form of two-way automata. These relations, functions, and automata are described in a special definition language. In focusing on high level descriptions a linguist may ignore computational details of the parsing process. He writes the grammar into a DPL-description and a compiler translates it into efficient LISP-code. The environment has also a tracing facility for the parsing process, grammar-sensitive lexical maintenance programs, and routines for the interactive graphic display of parse trees and grammar definitions. Translator routines are also available for the transport of compiled code between various LISP-dialects. The environment itself exists currently in INTERLISP and FRANZLISP. This paper focuses on knowledge engineering issues and does not enter linguistic argumentation.