Dealing with non-termination in DCGs

The objective of this paper is to study a practical approach to deal with non-termination in de nite clause grammars. We focus on two problems, loop and cyclic structure detection and representation, maintaining a tight balance between practical e ciency and operational completeness. In order to guarantee the validity of our conclusions, we rst map our study to a common situated framework, where the e ectiveness of each approach will be examined and, later, compared by running experiments.Eje: TeoríaRed de Universidades con Carreras en Informática (RedUNCI

Dealing with non-termination in DCGs

The objective of this paper is to study a practical approach to deal with non-termination in de nite clause grammars. We focus on two problems, loop and cyclic structure detection and representation, maintaining a tight balance between practical e ciency and operational completeness. In order to guarantee the validity of our conclusions, we rst map our study to a common situated framework, where the e ectiveness of each approach will be examined and, later, compared by running experiments.Eje: TeoríaRed de Universidades con Carreras en Informática (RedUNCI

An LALR Extension for DCGs in Dynamic Programming

We propose a parsing model for DCGs. Our work embodies in a common frame a dynamic programming construction developed for logical push-down automata, and techniques that restrict the computation to a useful part of the search space, inspired by LALR parsing. Unlike preceding approaches, our proposal avoids backtracking in all cases, providing computational sharing and operational completeness for DCGs without functional symbols. Key Words: DCG, Dynamic Programming, LALR Parsing, Push-Down Automata. 1 Introduction The popularity of DCGs is often related to natural language processing. In comparison with other formalisms, they seem to be particularly wellsuited to controlling the perspicuity with which linguistic phenomena may be understood and expressed in actual language descriptions. However, an adequate description does not guarantee operational efficiency, and computational tractability is required if we intend to use descriptions for mechanical processing. Though much research ha..

An LALR Extension for DCGs in Dynamic Programming

We propose a parsing model for natural languages based on the concept of definite clause grammar. Our work embodies in a common frame a dynamic programming construction developed for logical push-down automata, and techniques that restrict the computation to a useful part of the search space inspired by LALR parsing. Unlike preceding approaches, our proposal avoids backtracking in all cases, providing computational sharing and operational completeness for definite clause grammars without functional symbols. Introduction The popularity of definite clause grammars (DCGs) is often related to natural language processing. In comparison with other formalisms, they seem to be particularly well-suited to control the perspicuity with which linguistic phenomena may be understood and expressed in actual language descriptions. However, 2 Manuel Vilares Ferro and Miguel A. Alonso Pardo descriptive adequation does not guarantee operational efficiency, and computational tractability is required if..