Topics in Semantics-based Program Manipulation

1996

This paper offers an assessment of what has been achieved in three decades of work on the semantics of programming languages and pinpoints some practical problems in computing which might stimulate further research. The examples sketched in this paper come from the author's own research on concurrent object oriented languages, from database practice, and from more speculative research on Internet issues.

2007

The origins of “formal methods” lie partly in language description (although applications of methods like VDM, RAISE or B to areas other than programming languages are probably more widely known). This paper revisits the language description task but uses operational (rather than denotational) semantics to illustrate that the crucial idea is thinking about an abstract model of something that one is trying to understand or design.

Lecture Notes in Computer Science, 1986

me too is a functional language in which executable specifications of software components are constructed from abstract models and operations defined on them. The principal data type provided by the language is the set. This paper examines in detail the extent to which the objects manipulated by me too programs do in fact behave like the mathematical ideal of sets. It draws conclusions about the design of the language, and about the feasibility of such projects in 'applied semantics'. * This work was supported in part by an SERC grant.

created the initial versions of the handouts from photocopies of my sloppy and tersely written personal lecture notes. She also drew the figures in the document. After the semester, she helped me integrate my expanded versions of the various handouts into a single document. I also thank the students in the Spring 2006 CSCI 550 class, who did not complain too much about the many typos and other errors in the versions of the notes I handed out in class. Their error corrections and comments (particularly those of Chuck Jenkins) assisted me in improving the notes. In the 1990s my course used Ed Cohen's textbook, so my selection of material and my presentation is similar to that book in several places.

2020

In the 1960s, a full formal description was seen as a crucial and unavoidable part of creating a new programming language. A key part of that was a thorough and rigorous description of the semantics. However, in the decades since, the focus on providing this has somewhat diminished. Why was formal semantics once seen as so critical? Why did it not succeed in the ways hoped? These questions are explored by considering the history of modelbased approaches to describing programming languages, with a particular focus on the IBM Laboratory Vienna under Heinz Zemanek, and the Programming Research Group at Oxford University under Christopher Strachey. It is shown that there were a variety of different approaches to the problem, stemming from the different backgrounds of the people and groups involved. The story of formal language description is in some ways also the story of early programming languages and the integration of mathematics into the emerging new field of computer science, resu...

2008

Unlike natural languages, programming languages are strictly stylized entities created to facilitate human communication with computers. In order to make programming languages recognizable by computers, one of the key challenges is to describe and implement language syntax and semantics such that the program can be translated into machine-readable code. This process is normally considered as the front-end of a compiler, which is mainly related to the programming language, but not the target machine.

2003

Abstract The tasks of maintenance and reengineering of an existing software system require a great deal of effort to be spent on understanding the source code to determine the behavior, organization, and architecture of the software. Different types of information (eg, static, dynamic, source code, documentation, etc.) will describe different features of the software system.

Electronic Notes in Theoretical Computer Science, 1999

The virtual class [15] construct was first introduced in the language Beta to provide added expressiveness when used with inheritance. Unfortunately, the virtual class construct in Beta is not statically type-safe. In this paper we show how a generalization of the semantics of object-oriented languages with a MyType construct leads to a variant of virtual classes which needs no run-time checks. This results in an object-oriented language in which both parametric types and virtual classes (or types) are well-integrated, and which is statically ...

1998

Current object-oriented design notations such as OMT 14], Booch 3] and UML 16] are syntax-bound and semantic-free in the sense that they typically employ a large and rigorously enforceable collection of construction rules, but rarely provide a model to explain what is being constructed.

2017

Programming language definitions assign formal meaning to complete programs. Programmers, however, spend a substantial amount of time interacting with incomplete programs - programs with holes, type inconsistencies and binding inconsistencies - using tools like program editors and live programming environments (which interleave editing and evaluation). Semanticists have done comparatively little to formally characterize (1) the static and dynamic semantics of incomplete programs; (2) the actions available to programmers as they edit and inspect incomplete programs; and (3) the behavior of editor services that suggest likely edit actions to the programmer based on semantic information extracted from the incomplete program being edited, and from programs that the system has encountered in the past. This paper serves as a vision statement for a research program that seeks to develop these "missing" semantic foundations. Our hope is that these contributions, which will take th...

Theoretical Computer Science, 1994

Science 135 (I 994) 267-288 Elsevier 267

Mathematical Foundations of Programming Semantics, 1992

A formal system of describing semantics of programming languages, based on the denotational approach is presented. That approach is modified with some operational view for formal description, combined with the object oriented methods of programming.

Econtent, 2010