Norman M. Delisle

Neptune: a hypertext system for CAD applications

Even though many of the essential notions of hypertext were first contained in the description of a “memex,” written by Vannevar Bush in 1945 [Bus45], there are today only a few scattered implementations of hypertext, let alone any serious use of it in a CAD environment. In what follows, we describe what hypertext is all about. We describe a prototype hypertext system, named Neptune, that we have built. We show how it is useful, especially its broad applicability to CAD.

Contexts—a partitioning concept for hypertext

Hypertext systems provide good information management support for a wide variety of documentation efforts. These efforts range from developing software to writing a book. However, existing hypertext systems provide poor support for collaboration among teams of authors. This paper starts by briefly describing properties of several existing hypertext systems. Then several models for forming partitions in a hypertext database are examined and contexts, a partitioning scheme that supports multiperson cooperative efforts, are introduced. The semantic issues involved in defining contexts are explored in detail.

Viewing a programming environment as a single tool

Programming environments support the creation, modification, execution and debugging of programs. The goal of integrating a programming environment is more than simply building tools that share a common data base and provide a consistent user interface. Ideally, the programming environment appears to the programmer as a single tool; there are no firewalls separating the various functions provided by the environment. This paper describes the techniques used to integrate Magpie, an interactive programming environment for Pascal. Display windows, called browsers, provide a consistent approach for interacting with the Pascal source code or the execution state of the program. Incremental compilation allows the programmer to specify debugging actions in Pascal, eliminating the need for a separate debugging language.

Incremental compilation in Magpie

Magpie is an interactive, integrate programming environment that supports the development of Pascal programs a powerful, single-user workstation. Incremental compilation techniques are used to provide quick feedback on static errors and to ensure that a program is always ready for execution even while it is being edited. Magpie performs syntax and static semantic analysis with the unit of incrementality of a single character. Magpie uses incremental compilation to achieve performance levels that allow Pascal to be used interactively and as its own debugging language.

Formal Specifications as Reusable Frameworks

We use our experience in applying formal methods to the development of electronic instrumentation systems to argue the value of developing formal, domain-specific models that serve as reusable frameworks for a family of software products. To illustrate what we mean by “framework” we present a non-trivial specification for a family of instruments, and show how certain properties of that specification lead to its potential for reusability. Finally, we outline the important research issues that are raised by this approach. In particular, we examine the suitability of existing formal specification notations for explicitly characterizing and instantiating such frameworks.

Contexts: a partitioning concept for hypertext

A hypertext system makes a good information management system for a software development environment. However, existing hypertext systems provide poor support for collaboration among members of development teams. We examine several models for forming partitions in a hypertext data base and define our notion of contexts, a partitioning scheme that supports multi-person cooperative efforts.

Formally specifying electronic instruments

This paper shows how formal specification techniques can be beneficially applied in the develop ment of electronic instrumentation. As an example of our approach we present a specification of a simple electronic instrument, written in the Z specification language. We argue that such specifications can be used to gain insight into software/hardware systems and to clarify the resulting design. A consequence is that formal specifications can assume a pivotal role in system design as non-executable prototypes and lead to a cost-effect application of formal techniq,ues in industrial settings.

Collaborative writing with hypertext

The authors introduce the concept of hypertext and focus on how hypertext can facilitate writing activities. A survey of the capabilities of existing hypertext systems and current research activities is included. >

A programming environment for CSP

This paper describes a programming environment that supports the development and execution of CSP programs. The prototype environment is primarily intended as a vehicle for learning CSP. Its strengths include graphical animations that illustrate the interactions of CSP processes as they execute. Its main limitations are that CSP programs do not execute particularly fast and that true parallelism is not supported. Both the functionality of the CSP environment and its somewhat unusual multi-language implementation are discussed.