Uncanny Valleys in Declarative Language Design

When people write programs in conventional programming languages, they over-specify how to solve the problem they have in mind. Over-specification prevents the language\u27s implementation from making many optimization decisions, leaving programmers with this burden. In more declarative languages, programmers over-specify less, enabling the implementation to make more choices for them. As these decisions improve, programmers shift more attention from implementation to their real problems. This process easily overshoots. When under-specified programs almost always work well enough, programmers rarely need to think about implementation details. As their understanding of implementation choices atrophies, the controls provided so they can override these decisions become obscure. Our declarative language project, Yedalog, is in the midst of this dilemma. The improvements in question make our users more productive, so we cannot simply retreat back towards over-specification. To proceed forward instead, we must meet some of the expectations we prematurely provoked, and our implementation\u27s behavior must help users learn expectations more aligned with our intended semantics. These are general issues. Discussing their concrete manifestation in Yedalog should help other declarative systems that come to face these issues

Response, 1978 Summer

Response was a College news publication produced by Daemen College (known as Rosary Hill College until 1976) and distributed to alumni and friends of the College. It existed first as a quarterly news magazine (1966-1971) and then continued in various newspaper/magazine formats until 1993. By 1980, the publication had transitioned from an alumni news publication to the official publication of Daemen College. It was superseded by Daemen Today.https://digitalcommons.daemen.edu/alum_response/1034/thumbnail.jp

A study of refactorings during software change tasks

Developers frequently undertake software change tasks that could be partially or fully automated by refactoring tools. As has been reported by others, all too often, these refactoring steps are instead performed manually by developers. These missed opportunities are referred to as occasions of disuse of refactoring tools. We perform an observational study in which 17 developers with professional experience attempt to solve three change tasks with steps amenable to the use of refactoring tools. We found that the strategies developers use to approach these tasks shape their workflow, which, in turn, shape the opportunities for refactoring tool use. We report on a number of findings about developer strategies, demonstrating the difficulty of aligning the kind of refactoring steps that emerge during a change task based on the strategy with the tools available. We also report on findings about refactoring tools, such as the difficulties developers face in controlling the scope of application of the tools. Our findings can help inform the designers of refactoring tools.publishedVersio

The BG News May 9, 1972

The BGSU campus student newspaper May 9, 1972. Volume 56 - Issue 109https://scholarworks.bgsu.edu/bg-news/3722/thumbnail.jp

Identifying Overly Strong Conditions in Refactoring Implementations

Abstract-Each refactoring implementation must check a number of conditions to guarantee behavior preservation. However, specifying and checking them are difficult. Sometimes refactoring tool developers may define overly strong conditions that prevent useful behavior-preserving transformations to be performed. We propose an approach for identifying overly strong conditions in refactoring implementations. We automatically generate a number of programs as test inputs for refactoring implementations. Then, we apply the same refactoring to each test input using two different implementations, and compare both results. We use Safe Refactor to evaluate whether a transformation preserves behavior. We evaluated our approach in 10 kinds of refactorings for Java implemented by three tools: Eclipse and Netbeans, and the JastAdd Refactoring Tool (JRRT). In a sample of 42,774 transformations, we identified 17 and 7 kinds of overly strong conditions in Eclipse and JRRT, respectively

Combining Static and Dynamic Analysis for Bug Detection and Program Understanding

This work proposes new combinations of static and dynamic analysis for bug detection and program understanding. There are 3 related but largely independent directions: a) In the area of dynamic invariant inference, we improve the consistency of dynamically discovered invariants by taking into account second-order constraints that encode knowledge aboutinvariants; the second-order constraints are either supplied by the programmer or vetted by the programmer (among candidate constraints suggested automatically); b) In the area of testing dataflow (esp. map-reduce) programs, our tool, SEDGE, achieves higher testing coverage by leveraging existinginput data and generalizing them using a symbolic reasoning engine (a powerful SMT solver); c) In the area of bug detection, we identify and present the concept of residual investigation: a dynamic analysis that serves as theruntime agent of a static analysis. Residual investigation identifies with higher certainty whether an error reported by the static analysis is likely true

Interactive Data Representation Migration: Exploiting Program Dependence to Aid Program Transformation

International audienceData representation migration is a program transformation that involves changing the type of a particular data structure, and then updating all of the operations that somehow depend on that data structure according to the new type. Changing the data representation can provide benefits such as improving efficiency and improving the quality of the computed results. Performing such a transformation is challenging, because it requires applying data-type specific changes to code fragments that may be widely scattered throughout the source code, connected by dataflow dependencies. Refactoring systems are typically sensitive to dataflow dependencies, but are not programmable with respect to the features of particular data types. Existing program transformation languages provide the needed flexibility, but do not concisely support reasoning about dataflow dependencies.To address the needs of data representation migration, we propose a new approach to program transformation that relies on a notion of semantic dependency: every transformation step propagates the transformation process onward to code that somehow depends on the transformed code. Our approach provides a declarative transformation-specification language, for expressing type-specific transformation rules. We further provide scoped rules, a mechanism for guiding rule application, and tags, a device for simple program analysis within our framework, to enable more powerful program transformations.We have implemented a prototype transformation system based on these ideas for C and C++ code and evaluate it against three example specifications, including vectorization, transformation of integers to big integers, and transformation of array-of-structures data types to structure-of-arrays format. Our evaluation shows that our approach can improve program performance and the precision of the computed results, and that it scales to programs of up to 3700 lines