Download Rita - an editor and user interface for manipulating

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D. D. COWAN, E. W. MACKIE, G. M. PIANOSI AND G. DE V. SMIT
and placement. The paper focuses on the details of Rita’s dynamic user interface and the
algorithms required for its implementation. There are several systems available from both
software houses and research laboratories which have design objectives similar to the ones
proposed for Rita. However the authors have not been able to locate any publications
which describe both the user view and the methods used for implementation.
A tool such as Rita is invaluable as it minimizes errors, thus significantly reducing the
use of computing resources, and making the creators of documents more productive. Rita
has been tested successfully with different groups of users including word-processing staff,
programmers, and secretarial staff with minimal computer skills. Experiences with Rita in
these and other contexts have led to the conclusion that use of such a tool almost always
ensures that a document will be structurally correct as it is entered into the computer.
Similar experiences have been reported in References [10–15].
A number of other structured document editors have been proposed and/or developed.
These include Etude [16] and its derivative the Interleaf Publishing System (IPS) [17],
PEN [18], W [19], Grif [20], Quill [12], Author/Editor[21], WRITE-IT SGML Editor [22],
and systems by Kimura [23], van Huu [24], Coray et al. [25], and Furuta [26].
The version of Rita being described in this paper is designed to operate with GML or
SGML tag sets and produce output which can be processed by several different formatting
systems including LATEX [1], DCF [2], Waterloo Script [3], and WATCOM GML [4].
Rita was developed with certain views about the computing environment, the users, and
the set of documents that could be handled. These three design parameters are described in
the remainder of this section.
The layout or style sheet for a document is not really needed until the document is being
formatted. However, while text is being prepared, it is desirable to view the approximate
appearance of the document, and at least confirm that no serious structural deficiencies
exist. Thus Rita was designed to accept a layout or style sheet for the terminal or computer
screen being used, and can adapt itself to a particular computing and viewing environment.
Documents can be prepared and viewed on displays ranging from character or simple
graphics screens to high-resolution bit-mapped displays.
Many people who want to prepare documents are not necessarily interested in the
“secrets” of computing; they want to produce a document which appears as if it was
produced by an expert, and yet perform this task with minimum fuss and bother. This
type of user was the model that guided the development of Rita. Such users were further
subdivided into novices, casual users and experienced non-technical users.
Novices have minimal computing skills; they want to learn as little as possible,
and yet start producing perfectly formatted documents. Casual users may or may not
have substantial computer skills, but they produce documents infrequently, and hence
tend to forget many of the techniques of document preparation between uses of the
computer. Experienced non-technical users are those individuals who might belong to a
word-processing group, but have little knowledge of markup languages. Of course as the
system was developed, we tried not to forget the expert; often a feature was implemented
remembering all members of this broad spectrum of users.
Different types of documents have different structures, for example, books are different
from legal documents such as contracts. Hence certain tags which define entities such as
titles and chapter headings might be “illegal” in a given document type or context. Rita
was designed to “understand” the structure of classes of documents so that Rita can be
tailored to aid the user in preparing any type of document. Rita accepts different document