Execution patterns are a new metaphor for visualizing execution traces of object-oriented programs. We present an execution pattern view that lets a programmer visualize and explore a program's execution at varied levels of abstraction. The view employs visual, navigational, and analytical techniques that accommodate lengthy, real-world traces. By classifying repetitive behavior automatically into high-order execution patterns, we drastically reduce the information a programmer must assimilate, with little loss of insight.

This report is a discussion of various techniques for representing type information in dynamically typed languages, as implemented on general-purpose machines (and costs are discussed in terms of modern RISC machines). It is intended to make readily available a large body of knowledge that currently has to be absorbed piecemeal from the literature or re-invented by each language implementer. This discussion covers not only tagging schemes but other forms of representation as well, although the discussion is strictly limited to the representation of type information. It should also be noted that this report does not purport to contain a survey of the relevant literature. Instead, this report gathers together a body of folklore, organizes it into a logical structure, makes some generalizations, and then discusses the results in terms of modern hardware.

Reflection remains a second-class citizen in current programming models, where it’s assumed to be imperative and tightly bound to its implementation. In contrast, most object-oriented APIs allow interfaces to vary independently of their implementations. Components take this separation a step further by describing unforeseeable attributes—the key to pluggable third-party components. This paper describes how reflection can benefit from a similar evolutionary path. 1.

We describe the design and the implementation of Lua, a simple, yet powerful, language for extending applications. Although Lua is a procedural language, it has data description facilities, and has been extensively used in production for several tasks including user configuration, general-purpose data-entry, description of user interfaces, description of application objects, and storage of structured graphical metafiles.

A generalized arithmetic package allows a programmer to think of numbers as abstract quantities, without regard to whether they are represented as integers, floating point values, fractions, complex numbers, or even polynomials. In this paper we describe two implementation techniques that can be used to produce a generalized arithmetic package in the programming language C++, and evaluate the advantages and disadvantages of the two approaches. The second approach uses a technique called multiple polymorphism that has applicability to many other problem areas. Keywords: C++, Object Oriented Programming, Arithmetic, Polymorphism 1 Introduction One of the philosophical principles of object oriented programming is that objects should be characterized by their behavior rather than by their structure. Distinct types of objects that share a common behavior, in C++ terms that implement a set of virtual methods derived from a common parent class, should be logically interchangeable. In everyd...

: A conceptual analysis of modelling is undertaken. The major challenges posed by the growth of open and integrated systems prompts a careful rethinking of the basis of modelling. Particular attention is paid to object-oriented modelling. Our approach is characterized by an analytic framework borrowed from the philosophy of language called theories of reference (ToRs). This body of theories aims at accounting for how expressions of language may actually refer to the real world, very much the same task as in modelling. As opposed to most of the related work in the literature, we see this body of theories as a rich class. We argue that a number of the alternative approaches to modelling should be acknowledged to have important and relevant similarities with a rich body of ToRs. Our principal aim, besides the more immediate one to correct what we argue are philosophically inaccurate interpretations, is to encourage a more fruitful discussion regarding modelling. Working out a basis...

Multiparadigm programming is a term used to describe a style of software development that makes use of facilities originally designed in support of a number of different programming language paradigms. In this paper we illustrate our conception of multiparadigm programming, by describing how various data structures can be implemented in the programming language Leda. Leda is a strongly-typed compiled multiparadigm programming language that we have been developing over the past several years. Our exposition serves both to illustrate the idea of multiparadigm programming, and to describe the features of the language Leda. 1 Introduction Programming languages are often divided into different schools, or paradigms. The term "paradigm", meaning model or world view, is intended to indicate the difference is one of outlook or perception, rather than a fundamental incomparability. From a simple theoretical point of view, all programming languages which have sufficient power to simulate a Turi...

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MACS stands for 'Management Architecture for teleCommunication Services' and denotes a project which is undertaken at Humboldt University. It investigates problems in the context of distributed applications management. After introducing the preconditions and the objectives of our approach, an architecture for modelling application management as a distributed application is presented. We use a Smalltalk-based distributed processing environment (Redlich 94) as implementation base. Our architecture includes contracts for enabling different management views on a service. In fact, a management application is formed by groups of objects collaborating and interacting to solve a management problem. Keywords Application management, distributed systems, views, contracts, Little Smalltalk 1 INTRODUCTION In the past, management has concentrated on the administration of networks. This can be recognized at the structure of MIB-II (McCloghrie 1991) in the Internet management, which mainly includes...

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