David A. Workman

Automatically generating visual syntax-directed editors

Since inexpensive computers possessing sophisticated graphics were introduced in the late 1970s, program development research has focused on syntax-directed editors that are based on the grammars of their underlying languages. The system presented here automatically generates object-oriented, syntax-directed editors for visual languages, which are described by a family of editing operations.

Quality guidelines = designer metrics

In spite of the significant body of research on traditional source code metrics, there has been a general failure to produce conclusive evidence as to their effectiveness for measuring software quality. We describe and recommend a potentially much more powerful and sensitive quality assessment alternative, software quality guidelines. Software quality guidelines are presented as “designer metrics”, that is, user-defined rules or constraints relating to measurable features of a programs structure, semantics, and syntax that affect its quality. To provide a methodology for designing, applying, and validating software quality guidelines, we recommend and briefly summarize IEEE standard 1061. This standard gives a process for constructing and implementing a software quality metrics framework that can be tailor-made to meet quality requirements for a particular project and/or organization. Our paper then demonstrates how software quality guidelines fit within the IEEE framework and gives an example illustrating how user-defined guidelines can be applied to evaluate or assess the quality of an Ada source unit. This guideline-based assessment of quality is then compared with an analysis based on traditional McCabe and Halstead metrics. Finally, we introduce a tool being developed by SAIC, called AdaReVu, as an effective mechanism for implementing and applying user-defined quality guidelines for Ada source code.

The object-oriented design of a visual syntax-directed editor generator

A language specification mechanism is reported which is oriented around the automatic generation of editors as well as the conventional goals of parsing and semantic analysis. The primary result is a means by which a specification in the notation can be used to produce a visual editor automatically. In particular, it is demonstrated how well suited the modern techniques of object-oriented software are to this task.<<ETX>>

An Incremental Editor for Dynamic Hierarchical Drawing of Trees

We present an incremental tree editor based on algorithms for manipulating shape functions. The tree layout is hierarchical, left-to-right. Nodes of variable size and shape are supported. The paper presents algorithms for basic tree editing operations, including cut and paste. The layout algorithm for positioning child-subtrees rooted at a given parent is incrementally recomputed with each edit operation; it attempts to conserve the total display area allocated to child-subtrees while preserving the user’s mental map. The runtime and space efficiency is good as a result of exploiting a specially designed Shape abstraction for encoding and manipulating the geometric boundaries of subtrees as monotonic step functions to determine their best placement. All tree operations, including loading, saving trees to files, and incremental cut and paste, are worst case O(N) in time, but typically cut and paste are O(log(N)2), where N is the number of nodes.

SR(s, k) parsers: A class of shift-reduce bounded-context parsers

Abstract We introduce a class of bottom-up parsers called SR( s, k ) parsers, where s denotes a stack bound and k the lookahead bound. The importance of this class of parsers is the fact that states are formed by the union of item-sets associated with a canonical LR( k ) parser. One of our major results states that the class of SR( s, k ) grammars properly includes the ( s, k )-weak precedence grammars but is properly included within the class of ( s, k )-bounded right-context grammars.

GRASP: an interactive environment for software development and maintenance

Significant reductions in software development and maintenance costs can be realized by providing a total environment for the software life-cycle . This environment mus t provide automated tools for each phase of the cycle . At the macro level, the environment will assist in the development , documentation and maintenance of software systems . The development phase includes requirements specifications , design, coding and testing . Maintenance is required to eliminate latent errors introduced during the development phase, to improve performance of a software system or to enhance its capabilities . The probtem of providing adequate documentation for softwar e is a concern equal in magnitude to those of design an d implementation . GRASP (GRAphic SPecification), an interactive graphics system for software specification, is currently being de veloped by the authors at the University of Central Florida . GRASP is intended to be a total environment for software specification . The activities associated with software development an d maintenance produce a product which is the result of man machine interactions . This product should have a structur e that amalgamates the requirements of both man and ma chine . Figure 1 illustrates the components of progra m structure and design that form the adhesive substance binding man to machine . Programming languages and othe r documentation aids represent the program component s that attempt to satisfy the requirements of man ; algorithm s and data structures are objects born out of the requirement s dictated by machine . GRASP attempts to optimize th e