Unrestricted Gapping Grammars

Abstract

Since the introduction of metarrwrphosis gramtTUlT's (MGs) (Colmerauer. 1978). with their associated type 0-like grammar rules . there has been a desire to allow more general rule formats m Jogic grammars Gaps. which refer to strings of unspecified symbols. were added to the MG rule. resulting in extraposition gramtTUlT's (XGs) (Pereira. 1981) and gapping gramtTUlT's (GGs) (Dahl and Abramson. 1984) . Unrestricted gapping gramtTUlT's, which provide an even more general rule format, possess rules of the form "a ·- > (3" where a and f3 many contain any number of terminal nonterminal or gap symbols in any order. FIGG. a Flexihle lmplementation of Gapping Grammars . is an implementation of a !arge subset of unrestricted GGs which allows either bottom-up or top-down parsing of sentences . This system provides more built in control facilities than previous logic grammar implementations. which allows the user to restriet the applicability of the rules . and to create grammar rules that will be executed more efficiently .