GALENA: tabular DCG parsing for natural languages

[Abstract] We present a definite clause based parsing environment for natural languages, whose operational model is the dynamic interpretation of logical push-down automata. We attempt to briefly explain our design decisions in terms of a set of properties that practical natural language processing systems should incorporate. The aim is to show both the advantages and the drawbacks of our approach.España. Gobierno; HF96-36Xunta de Galcia; XUGA10505B96Xunta de Galcia; XUGA20402B9

Semantics of programming languages : a tool-oriented approach

By paying more attention to semantics-based tool generation, programming language semantics can significantly increase its impact. Ultimately, this may lead to ``Language Design Assistants'' incorporating substantial amounts of semantic knowledge

Semantics of programming languages : a tool-oriented approach

By paying more attention to semantics-based tool generation, programming language semantics can significantly increase its impact. Ultimately, this may lead to ``Language Design Assistants'' incorporating substantial amounts of semantic knowledge

Comparing generators for language-based tools

The first step in any language development project is the Compiler Generator choice. Nowadays there are many offers, based on translation grammars, attribute grammars or other language specification formalisms. To make up a decision, more factors than just the tool user-friendliness and the processor’s quality should be taken into account. To aid the language developer, we analyze in this paper three Compiler Generators. The traditional and well known YACC, and two more recent ones, LISA and AnTLR-3. The first produces a Syntax-Directed Translator, while the others generate a Semantic-Directed Translator based on attribute evaluation. Moreover both the AG-based generators also produce other Language-based Tools that are mentioned and compared.FC

Semantics of programming languages : a tool-oriented approach

By paying more attention to semantics-based tool generation, programming language semantics can significantly increase its impact. Ultimately, this may lead to ``Language Design Assistants\'\' incorporating substantial amounts of semantic knowledge

Phobos: A front-end approach to extensible compilers (long version)

This paper describes a practical approach for implementing certain types of domain-specific languages with extensible compilers. Given a compiler with one or more front-end languages, we introduce the idea of a "generic" front-end that allows the syntactic and semantic specification of domain-specific languages. Phobos, our generic front-end, offers modular language specification, allowing the programmer to define new syntax and semantics incrementally

PSLR(1): Pseudo-Scannerless Minimal LR(1) for the Deterministic Parsing of Composite Languages

Composite languages are composed of multiple sub-languages. Examples include the parser specification languages read by parser generators like Yacc, modern extensible languages with complex layers of domain-specific sub-languages, and even traditional programming languages like C and C++. In this dissertation, we describe PSLR(1), a new scanner-based LR(1) parser generation system that automatically eliminates scanner conflicts typically caused by language composition. The fundamental premise of PSLR(1) is the pseudo-scanner, a scanner that only recognizes tokens accepted by the current parser state. However, use of the pseudo-scanner raises several unique challenges, for which we describe a novel set of solutions. One major challenge is that practical LR(1) parser table generation algorithms merge parser states, sometimes inducing incorrect pseudo-scanner behavior including new conflicts. Our solution is a new extension of IELR(1), an algorithm we have previously described for generating minimal LR(1) parser tables. Other contributions of our work include a robust system for handling the remaining scanner conflicts, a correction for syntax error handling mechanisms that are also corrupted by parser state merging, and a mechanism to enable scoping of syntactic declarations in order to further improve the modularity of sub-language specifications. While the premise of the pseudo-scanner has been described by other researchers independently, we expect our improvements to distinguish PSLR(1) as a significantly more robust scanner-based parser generation system for traditional and modern composite languages

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