Generating SGML specific editors: from DTDs to attribute grammars

Abstract

SGML (Standard Generalized Markup Language) is well established in electronic publishing industry. The number of users and the number of applications grows everyday.

If we look at the market the choice of available tools is very wide. We have tools for every purpose and for each price.

However, from a technical point of view there are still some open areas for research and improvement. In this work we will address the parsing technology. Can we improve it? Or, is there another way to do it? Can we achieve better results? These are some of the questions that we will try to answer along this paper.

SGML parsers are normally implemented using traditional technology: syntax directed translation. In the SGML context these parsers are good and offer a good performance. The problems emerge when we want to do something else besides structural validation. For example, to build an extension to perform semantic checking or to have on-line validation instead of batch validation.

The focus of this paper will be a DTD (Document Type Definition) editor that generates specific editors for each specific type of document. To implement this editor we develop an AG (Attribute Grammar) for SGML syntax. But the most important part it is not this grammar. The editor has a built-in generator that at any moment translates the DTD being edited to a generic AG.

In this paper we will discuss the methodology used to develop this DTD editor and we will make a detailed presentation of the conversion performed between DTDs and Attribute Grammars. At the end we will show a glimpse of the intended environment that along with this editor includes a style editor and a semantics editor.