Deftly Introducing Procedural Elements into Unification Parsing.

摘要

Unification grammars based on complex feature structures are theoretically well-founded, and their declarative nature facilitates exploration of various parsing strategies. However, a straightforward implementation of such parsers can be painfully inefficient, exploding lists of possibilities and failing to take advantage of search control methods long utilized in more procedurally-oriented parsers. In the context of BBN's Delphi NL system, we have explored modifications that gain procedural efficiency without sacrificing the theoretical advantages of unification-based CFG's.