Programming Languages and Compilers Commons^™

Grace's Inheritance, James Noble, Andrew P. Black, Kim B. Bruce, Michael Homer, Timothy Jones

Computer Science Faculty Publications and Presentations

This article is an apologia for the design of inheritance in the Grace educational programming language: it explains how the design of Grace’s inheritance draws from inheritance mechanisms in predecessor languages, and defends that design as the best of the available alternatives. For simplicity, Grace objects are generated from object constructors, like those of Emerald, Lua, and Javascript; for familiarity, the language also provides classes and inheritance, like Simula, Smalltalk and Java. The design question we address is whether or not object constructors can provide an inheritance semantics similar to classes.

Interactive Ambient Visualizations For Soft Advice, Emerson Murphy-Hill, Titus Barik, Andrew P. Black

Computer Science Faculty Publications and Presentations

Some software packages offer the user soft advice: recommendations that are intended to help the user create high quality artifacts, but which may turn out to be bad advice. It is left to the user to determine whether the soft advice really will improve quality, and to decide whether or not to adopt it. Visualizations can help the user in making this decision, but we believe that conventional visualizations are less than ideal. In this paper, we describe an interactive ambient visualization to help users identify, understand and interpret soft advice.

Our visualization was developed to help programmers interpret code …

The Grace Programming Language Draft Specification Version 0.3.1261, Andrew P. Black, Kim B. Bruce, James Noble

Computer Science Faculty Publications and Presentations

This is a specification of the Grace Programming Language. This specification is notably incomplete, and everything is subject to change.

Squeak By Example, Andrew P. Black, Stéphane Ducasse, Oscar Nierstrasz, Damien Pollet, Damien Cassou, Marcus Denker

Computer Science Faculty Publications and Presentations

Squeak is a modern open-source development environment for the classic Smalltalk-80 programming language. This book, intended for both students and developers, will guide you gently through the language and tools by means of a series of examples and exercises.

Additional material is available from the book's web page at SqueakByExample.org.

Better Refactoring Tools For A Better Refactoring Strategy, Andrew P. Black

Computer Science Faculty Publications and Presentations

Refactoring tools can improve the speed and accuracy with which we create and maintain software – but only if they are used. In practice, tools are not used as much as they could be; this seems to be because they do not align with the refactoring strategy preferred by the majority of programmers: floss refactoring. We propose five principles that characterize successful floss refactoring tools – principles that can help programmers to choose the most appropriate refactoring tools and also help toolsmiths to design more usable tools.

A Framework For Relationship Pattern Languages, Sudarshan Murthy, David Maier

Computer Science Faculty Publications and Presentations

A relationship pattern is an abstraction of a recurring need when establishing relationships among information elements in specific contexts. By developing or leveraging a relationship pattern, modelers can solve a class of problems once and describe many relationship types at once. We have developed a framework for specifying relationship patterns and pattern languages (sets of patterns) in both modeling-language-independent and modeling-language-specific ways. We describe this framework both informally and formally. We provide examples of some commonly observed relationship patterns and show how to use them in ER with the help of a relationship pattern language called Exemplar. We also provide …

Patterns Of Aspect-Oriented Design, Black P. Andrew, James Noble, David J. Pearce, Arno Scmidmeir

Computer Science Faculty Publications and Presentations

Aspect-oriented programming languages are becoming commonplace, and programmers are accumulating experience in building and maintaining aspect-oriented systems. This paper addresses how the use of these languages affects program design: how aspect-oriented languages change the design space, which designs should be emulated and which avoided, and the strengths and weaknesses of particular kinds of design. We identify five patterns of aspect-oriented design: Spectator, Regulator, Patch, Extension, and Heterarchical Design. For each pattern, we describe the problem it solves, show how aspect-oriented language features are used in the pattern, give characteristic examples of the pattern’s use, and assess its benefits and liabilities. …

Directflow: A Domain-Specific Language For Information-Flow Systems, Andrew P. Black, Chuan-Kai Lin

Computer Science Faculty Publications and Presentations

Programs that process streams of information are commonly built by assembling reusable information-flow components. In some systems the components must be chosen from a pre-defined set of primitives; in others the programmer can create new custom components using a general-purpose programming language. Neither approach is ideal: restricting programmers to a set of primitive components limits the expressivity of the system, while allowing programmers to define new components in a general-purpose language makes it difficult or impossible to reason about the composite system. We advocate defining information-flow components in a domain-specific language (DSL) that enables us to infer the properties of …

Why Don’T People Use Refactoring Tools?, Andrew P. Black, Emerson Murphy-Hill

Computer Science Faculty Publications and Presentations

Tools that perform refactoring are currently under-utilized by programmers. As more advanced refactoring tools are designed, a great chasm widens between how the tools must be used and how programmers want to use them. In this position paper, we characterize the dominant process of refactoring, demonstrate that many research tools do not support this process, and initiate a call to action for designers of future refactoring tools.

A Browser For Incremental Programming, Andrew P. Black

Computer Science Faculty Publications and Presentations

Much of the elegance and power of Smalltalk comes from its programming environment and tools. First introduced more than 20 years ago, the Smalltalk browser enables programmers to “home in” on particular methods using a hierarchy of manually-defined classifications. By its nature, this classification scheme says a lot about the desired state of the code, but little about the actual state of the code as it is being developed. We have extended the Smalltalk browser with dynamically computed virtual categories that dramatically improve the browser’s support for incremental programming. We illustrate these improvements by example, and describe the algorithms used …