TY - JOUR
A1 - Steinert, Bastian
A1 - Thamsen, Lauritz
A1 - Felgentreff, Tim
A1 - Hirschfeld, Robert
T1 - Object Versioning to Support Recovery Needs Using Proxies to Preserve Previous Development States in Lively
JF - ACM SIGPLAN notices
N2 - We present object versioning as a generic approach to preserve access to previous development and application states. Version-aware references can manage the modifications made to the target object and record versions as desired. Such references can be provided without modifications to the virtual machine. We used proxies to implement the proposed concepts and demonstrate the Lively Kernel running on top of this object versioning layer. This enables Lively users to undo the effects of direct manipulation and other programming actions.
KW - Programming Environments
KW - Object Versioning
KW - CoExist
KW - JavaScript
KW - Lively Kernel
Y1 - 2015
U6 - https://doi.org/10.1145/2661088.2661093
SN - 0362-1340
SN - 1558-1160
VL - 50
IS - 2
SP - 113
EP - 124
PB - Association for Computing Machinery
CY - New York
ER -
TY - JOUR
A1 - Pape, Tobias
A1 - Felgentreff, Tim
A1 - Hirschfeld, Robert
A1 - Gulenko, Anton
A1 - Bolz, Carl Friedrich
T1 - Language-independent Storage Strategies for Tracing-JIT-based Virtual Machines
JF - ACM SIGPLAN notices
N2 - Storage strategies have been proposed as a run-time optimization for the PyPy Python implementation and have shown promising results for optimizing execution speed and memory requirements. However, it remained unclear whether the approach works equally well in other dynamic languages. Furthermore, while PyPy is based on RPython, a language to write VMs with reusable components such as a tracing just-in-time compiler and garbage collection, the strategies design itself was not generalized to be reusable across languages implemented using that same toolchain. In this paper, we present a general design and implementation for storage strategies and show how they can be reused across different RPython-based languages. We evaluate the performance of our implementation for RSqueak, an RPython-based VM for Squeak/Smalltalk and show that storage strategies may indeed off er performance benefits for certain workloads in other dynamic programming languages. We furthermore evaluate the generality of our implementation by applying it to Topaz, a Ruby VM, and Pycket, a Racket implementation.
KW - Implementation
KW - collection types
KW - memory optimization
KW - dynamic typing
Y1 - 2016
U6 - https://doi.org/10.1145/2816707.2816716
SN - 0362-1340
SN - 1558-1160
VL - 51
SP - 104
EP - 113
PB - Association for Computing Machinery
CY - New York
ER -
TY - JOUR
A1 - Rein, Patrick
A1 - Ramson, Stefan
A1 - Lincke, Jens
A1 - Felgentreff, Tim
A1 - Hirschfeld, Robert
T1 - Group-Based Behavior Adaptation Mechanisms in Object-Oriented Systems
JF - IEEE software
N2 - Dynamic and distributed systems require behavior adaptations for groups of objects. Group-based behavior adaptation mechanisms scope adaptations to objects matching conditions beyond class membership. The specification of groups can be explicit or implicit.
KW - group-based behavior adaptation
KW - lively groups
KW - ContextErlang
KW - entity-component-system
KW - predicated generic functions
KW - active layers
KW - reactive object queries
KW - context groups
KW - implied methods
KW - object-oriented languages
KW - software engineering
KW - software development
KW - contextual-variability modeling
Y1 - 2017
U6 - https://doi.org/10.1109/MS.2017.4121224
SN - 0740-7459
SN - 1937-4194
VL - 34
IS - 6
SP - 78
EP - 82
PB - Inst. of Electr. and Electronics Engineers
CY - Los Alamitos
ER -
TY - JOUR
A1 - Perscheid, Michael
A1 - Siegmund, Benjamin
A1 - Taeumel, Marcel
A1 - Hirschfeld, Robert
T1 - Studying the advancement in debugging practice of professional software developers
JF - Software Quality Journal
N2 - In 1997, Henry Lieberman stated that debugging is the dirty little secret of computer science. Since then, several promising debugging technologies have been developed such as back-in-time debuggers and automatic fault localization methods. However, the last study about the state-of-the-art in debugging is still more than 15 years old and so it is not clear whether these new approaches have been applied in practice or not. For that reason, we investigate the current state of debugging in a comprehensive study. First, we review the available literature and learn about current approaches and study results. Second, we observe several professional developers while debugging and interview them about their experiences. Third, we create a questionnaire that serves as the basis for a larger online debugging survey. Based on these results, we present new insights into debugging practice that help to suggest new directions for future research.
KW - Debugging
KW - Literature review
KW - Field study
KW - Online survey
Y1 - 2016
U6 - https://doi.org/10.1007/s11219-015-9294-2
SN - 0963-9314
SN - 1573-1367
VL - 25
SP - 83
EP - 110
PB - Springer
CY - Dordrecht
ER -
TY - JOUR
A1 - Felgentreff, Tim
A1 - Perscheid, Michael
A1 - Hirschfeld, Robert
T1 - Implementing record and refinement for debugging timing-dependent communication
JF - Science of computer programming
N2 - Distributed applications are hard to debug because timing-dependent network communication is a source of non-deterministic behavior. Current approaches to debug non deterministic failures include post-mortem debugging as well as record and replay. However, the first impairs system performance to gather data, whereas the latter requires developers to understand the timing-dependent communication at a lower level of abstraction than they develop at. Furthermore, both approaches require intrusive core library modifications to gather data from live systems. In this paper, we present the Peek-At-Talk debugger for investigating non-deterministic failures with low overhead in a systematic, top-down method, with a particular focus on tool-building issues in the following areas: First, we show how our debugging framework Path Tools guides developers from failures to their root causes and gathers run-time data with low overhead. Second, we present Peek-At-Talk, an extension to our Path Tools framework to record non-deterministic communication and refine behavioral data that connects source code with network events. Finally, we scope changes to the core library to record network communication without impacting other network applications.
KW - Distributed debugging
KW - Record and replay
KW - Dynamic analysis
KW - Record and refinement
Y1 - 2016
U6 - https://doi.org/10.1016/j.scico.2015.11.006
SN - 0167-6423
SN - 1872-7964
VL - 134
SP - 4
EP - 18
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Rein, Patrick
A1 - Taeumel, Marcel
A1 - Hirschfeld, Robert
T1 - Making the domain tangible
BT - implicit object lookup for source code readability
JF - Design Thinking Research
N2 - Programmers collaborate continuously with domain experts to explore the problem space and to shape a solution that fits the users’ needs. In doing so, all parties develop a shared vocabulary, which is above all a list of named concepts and their relationships to each other. Nowadays, many programmers favor object-oriented programming because it allows them to directly represent real-world concepts and interactions from the vocabulary as code. However, when existing domain data is not yet represented as objects, it becomes a challenge to initially bring existing domain data into object-oriented systems and to keep the source code readable. While source code might be comprehensible to programmers, domain experts can struggle, given their non-programming background. We present a new approach to provide a mapping of existing data sources into the object-oriented programming environment. We support keeping the code of the domain model compact and readable while adding implicit means to access external information as internal domain objects. This should encourage programmers to explore different ways to build the software system quickly. Eventually, our approach fosters communication with the domain experts, especially at the beginning of a project. When the details in the problem space are not yet clear, the source code provides a valuable, tangible communication artifact.
KW - Source Code Readability
KW - Domain Objects
KW - StackOverflow
KW - Squeak
KW - Custom Writable Class
Y1 - 2017
SN - 978-3-319-60967-6
SN - 978-3-319-60966-9
U6 - https://doi.org/10.1007/978-3-319-60967-6_9
SP - 171
EP - 194
PB - Springer
CY - New York
ER -
TY - JOUR
A1 - Pape, Tobias
A1 - Bolz, Carl Friedrich
A1 - Hirschfeld, Robert
T1 - Adaptive just-in-time value class optimization for lowering memory consumption and improving execution time performance
JF - Science of computer programming
N2 - The performance of value classes is highly dependent on how they are represented in the virtual machine. Value class instances are immutable, have no identity, and can only refer to other value objects or primitive values and since they should be very lightweight and fast, it is important to optimize them carefully. In this paper we present a technique to detect and compress common patterns of value class usage to improve memory usage and performance. The technique identifies patterns of frequent value object references and introduces abbreviated forms for them. This allows to store multiple inter-referenced value objects in an inlined memory representation, reducing the overhead stemming from meta data and object references. Applied to a small prototype and an implementation of the Racket language, we found improvements in memory usage and execution time for several micro-benchmarks. (C) 2016 Elsevier B.V. All rights reserved.
KW - Meta-tracing
KW - JIT
KW - Data structure optimization
KW - Value classes
Y1 - 2017
U6 - https://doi.org/10.1016/j.scico.2016.08.003
SN - 0167-6423
SN - 1872-7964
VL - 140
SP - 17
EP - 29
PB - Elsevier
CY - Amsterdam
ER -
TY - JOUR
A1 - Mattis, Toni
A1 - Beckmann, Tom
A1 - Rein, Patrick
A1 - Hirschfeld, Robert
T1 - First-class concepts
BT - Reified architectural knowledge beyond dominant decompositions
JF - Journal of object technology : JOT / ETH Zürich, Department of Computer Science
N2 - Ideally, programs are partitioned into independently maintainable and understandable modules. As a system grows, its architecture gradually loses the capability to accommodate new concepts in a modular way. While refactoring is expensive and not always possible, and the programming language might lack dedicated primary language constructs to express certain cross-cutting concerns, programmers are still able to explain and delineate convoluted concepts through secondary means: code comments, use of whitespace and arrangement of code, documentation, or communicating tacit knowledge.
Secondary constructs are easy to change and provide high flexibility in communicating cross-cutting concerns and other concepts among programmers. However, such secondary constructs usually have no reified representation that can be explored and manipulated as first-class entities through the programming environment.
In this exploratory work, we discuss novel ways to express a wide range of concepts, including cross-cutting concerns, patterns, and lifecycle artifacts independently of the dominant decomposition imposed by an existing architecture. We propose the representation of concepts as first-class objects inside the programming environment that retain the capability to change as easily as code comments. We explore new tools that allow programmers to view, navigate, and change programs based on conceptual perspectives. In a small case study, we demonstrate how such views can be created and how the programming experience changes from draining programmers' attention by stretching it across multiple modules toward focusing it on cohesively presented concepts. Our designs are geared toward facilitating multiple secondary perspectives on a system to co-exist in symbiosis with the original architecture, hence making it easier to explore, understand, and explain complex contexts and narratives that are hard or impossible to express using primary modularity constructs.
KW - software engineering
KW - modularity
KW - exploratory programming
KW - program
KW - comprehension
KW - remodularization
KW - architecture recovery
Y1 - 2022
U6 - https://doi.org/10.5381/jot.2022.21.2.a6
SN - 1660-1769
VL - 21
IS - 2
SP - 1
EP - 15
PB - ETH Zürich, Department of Computer Science
CY - Zürich
ER -