@article{SteinertThamsenFelgentreffetal.2015,
  author    = {Steinert, Bastian and Thamsen, Lauritz and Felgentreff, Tim and Hirschfeld, Robert},
  title     = {Object Versioning to Support Recovery Needs Using Proxies to Preserve Previous Development States in Lively},
  series = {ACM SIGPLAN notices},
  volume    = {50},
  journal   = {ACM SIGPLAN notices},
  number    = {2},
  publisher = {Association for Computing Machinery},
  address   = {New York},
  issn      = {0362-1340},
  doi       = {10.1145/2661088.2661093},
  pages     = {113 -- 124},
  year      = {2015},
  abstract  = {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.},
  language  = {en}
}
@article{LinckeAppeltauerSteinertetal.2011,
  author    = {Lincke, Jens and Appeltauer, Malte and Steinert, Bastian and Hirschfeld, Robert},
  title     = {An open implementation for context-oriented layer composition in ContextJS},
  series = {Science of computer programming},
  volume    = {76},
  journal   = {Science of computer programming},
  number    = {12},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {0167-6423},
  doi       = {10.1016/j.scico.2010.11.013},
  pages     = {1194 -- 1209},
  year      = {2011},
  abstract  = {Context-oriented programming (COP) provides dedicated support for defining and composing variations to a basic program behavior. A variation, which is defined within a layer, can be de-/activated for the dynamic extent of a code block. While this mechanism allows for control flow-specific scoping, expressing behavior adaptations can demand alternative scopes. For instance, adaptations can depend on dynamic object structure rather than control flow. We present scenarios for behavior adaptation and identify the need for new scoping mechanisms. The increasing number of scoping mechanisms calls for new language abstractions representing them. We suggest to open the implementation of scoping mechanisms so that developers can extend the COP language core according to their specific needs. Our open implementation moves layer composition into objects to be affected and with that closer to the method dispatch to be changed. We discuss the implementation of established COP scoping mechanisms using our approach and present new scoping mechanisms developed for our enhancements to Lively Kernel.},
  language  = {en}
}
@article{SteinertCassouHirschfeld2013,
  author    = {Steinert, Bastian and Cassou, Damien and Hirschfeld, Robert},
  title     = {CoExist overcoming aversion to change preserving immediate access to source code and run-time information of previous development states},
  series = {ACM SIGPLAN notices},
  volume    = {48},
  journal   = {ACM SIGPLAN notices},
  number    = {2},
  publisher = {Association for Computing Machinery},
  address   = {New York},
  issn      = {0362-1340},
  doi       = {10.1145/2480360.2384591},
  pages     = {107 -- 117},
  year      = {2013},
  abstract  = {Programmers make many changes to the program to eventually find a good solution for a given task. In this course of change, every intermediate development state can of value, when, for example, a promising ideas suddenly turn out inappropriate or the interplay of objects turns out more complex than initially expected before making changes. Programmers would benefit from tool support that provides immediate access to source code and run-time of previous development states of interest. We present IDE extensions, implemented for Squeak/Smalltalk, to preserve, retrieve, and work with this information. With such tool support, programmers can work without worries because they can rely on tools that help them with whatever their explorations will reveal. They no longer have to follow certain best practices only to avoid undesired consequences of changing code.},
  language  = {en}
}
@article{SteinertHirschfeld2012,
  author    = {Steinert, Bastian and Hirschfeld, Robert},
  title     = {Applying design knowledge to programming},
  year      = {2012},
  language  = {en}
}
@article{HirschfeldSteinertLincke2011,
  author    = {Hirschfeld, Robert and Steinert, Bastian and Lincke, Jens},
  title     = {Agile software development in virtual collaboration environments},
  isbn      = {978-3-642-13756-3},
  year      = {2011},
  language  = {en}
}