Affix Grammars over a Finite Lattice (agfls), a simple form of two-level grammars admitting quite efficient implementations, are proposed as a formalism to express the syntax of natural languages. In this paper the concepts and notation of agfls are described. A brief example is given of their use in describing a fragment of the English language, followed by a discussion of issues like parsing and ambiguity.

In this paper we describe the ideas behind the Grammar Workbench (GWB). The GWB is one of a series of tools for the development of AGFLs (affix grammars over a finite lattice) for natural languages. Its functions comprise a specialised editor, computation of properties, a random generator of sentences, and special functions to provide an overview of a grammar. This paper discusses the functions of the GWB, the grammatical formalism AGFLs, and the AGFL project. We also discuss the relationship between the complete development environment for AGFLs and other development environments, both for other grammatical formalisms and for computer programs. 1 Introduction Formal grammars for natural languages tend to become unmanageable as they get larger. Similar problems occur in the development of large computer programs. To overcome these problems with large programs, a number of techniques have been invented in the field of software engineering to ffl structure programs so as to permit deco...

This paper proposes Update Plans as a specification formalism for abstract machines for parallel architectures. Update Plans are a formal specification language for abstract and concrete machines. First results in using Update Plans to specify parallel architectures are illustrated, and some suggestions for further research are made.

The framework of the research is the automatic syntactic and semantic analysis of natural language data. A hypothesis about the linguistic structure of a natural language is drafted according to the conditions and conventions of the AGFL 1 formalism and consequently tested at raw ( = untagged) authentic data of the language variety involved to obtain analyzed data and a verified theory. The AGFL formalism is a two-level context-free affix grammar for which a compiler has been made to automatically translate a set of rules into a parser. This formalism, developed for the definition of programming languages, proved to be adequate enough to describe natural languages such as Dutch, English, Hungarian, Spanish as well as Modern Standard Arabic (MSA). We are looking for an answer to the question: How to get good control over the information flow in a linguistic communication system and how to formalize it? In this paper we discuss an improvement in the description of the structure of the noun phrase (NP) and the verb phrase (VP) in MSA as a short introduction to its representation in terms of the AGFL formalism.

It is a truism that a programme is a function from machine state to machine state, composed from the functions represented by individual machine "instructions". However, specifying these instructions in a functional formalism is often unwieldy and frequently far removed from potential concrete implementations. If a prototype implementation is produced using a functional language (e.g. [Koo90]) 2 it is usually unacceptably inefficient. Other abstract machine specification methods also have drawbacks. Transition systems (e.g. [FW87]) quickly reach their limit of readability, writability and comprehensibility as the structure of machine configurations becomes complex. An imperative programming style (e.g. [Loc90, PS89]) is often ad hoc and quite often contains (hidden) machine dependence. An informal description (e.g. [War83]) is often incomplete and hard to implement. In recent years the Bird-Meertens formalism [BMF89] has been gaining in popularity. Work on abstract machine descriptio...

In this paper we discuss an efficient and robust parser that is used in an information retrieval system. We present a principle-based approach to robustness and we discuss optimizations for improving the efficiency of top-down backtrack parsers. Preliminary results are presented. The authors wish to thank Bas van Bakel, Paul Jones and three anonymous referees for valuable comments on earlier versions of this paper. 1 Robustness and Syntax-directedness 2 Introduction There is a growing demand, coming from natural language based applications like information filtering, full-text information retrieval and automatic translation, for fast and robust parsers for natural languages. Furthermore, grammar formalisms should allow for clear expression of linguistic knowledge in such a way that its formalization is clearly separated from procedural information. In this paper, we discuss an efficient and robust parser that is used in an large-scale information retrieval project. In Section 1, ...

... This article is concerned with the historical development of the role of syntax in informatics and its relevance for linguistics. Informatics is full of artificial languages, not only many programming languages, specification languages and mathematical notations, but also the user interfaces of innumerable program systems. The greater part of informatics is paper work: the description and realization of the figments of the programmer's mind. The price of invention is description: what has been invented must be described, so that it can be communicated to others. All those artificial languages need some description, be it informal or formal. Syntax comes in whenever a concept has to be described. Syntax describes the form of things. Semantics ascribes meanings to things, depending on their form. It is natural for us to describe concepts recursively in terms of other concepts and, ultimately, in terms of some atomic concepts typical for the frame of reference in which the description is intended to be understood. Semantical description is based on syntactical description, through some homomorphism. Thus, semantics presupposes syntax.