Language workbenches have been segregated into those supporting textual languages and those supporting visual languages. The projectional editor based MPS has been making some first steps in combining text-like projections and more graphical projections. In the Spoofax project we have stayed away from visual languages. (There is plenty to do in supporting design of textual languages well.) Until this year.

In the Spring of 2012 TU Delft student Oskar van Rest started his Master's thesis project at the University of Queensland (Australia). He has been working on the integration of visual languages in the Spoofax Language Workbench. As case study of the integration he constructed ComBE:

ComBE provides an integrated textual and graphical editor for Behavior Engineering. It synchronises text and graphics in real-time and allows you to switch between editors at any moment in time.

He recently presented a poster about the project and created a screencast showing off the side-by-side editing of text and diagram.

Update 24/3/2013: paper Robust Real-Time Synchronization between Textual and Graphical Editors to appear in ICMT 2013

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The citation count of a scientific publication is considered to be an indicator for its impact. Google Scholar includes citation counts for publications and uses this as an important metric for ranking search results. Thus, a paper with many citations is more likely to show up in search results. That makes it more likely that it will be read and cited, resulting in even more citations. This makes literature search with Scholar quite effective. But one effect is that new papers (no citations initially) in an existing field may not be noticed, even if they have relevant results. Papers with many citations hide (shadow) papers with few citations. This mechanism may even be at work in the publications of a single author.

When I examined my Google Scholar author profile before, it was mostly to examine my h-index and top cited publications. And I was happy enough to see that a good number of my publications are being cited well (today my h-index is 35). However, there are more publications with fewer citations. That is to be expected. Not all publications are equally good or important. What I noticed however, is that some papers that I consider to be among the best work of me and my students, are poorly cited. Therefore, I decided to compose a list of recommended publications for the front page of my web site, instead of the usual suspects from the hit list. If you like those other papers, you may like these as well (or even better):

Recommendations

Syntax definition and parsing

Language composition

Transformation and analysis

Integrated development environments

Abstractions for web programming

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In 2008, error recovery for generalized (scannerless) LR parsing appeared to be an unsolvable problem. Now, users of Spoofax get an error recovering parser for free, based on the SDF syntax definition of a language. The integration of our earlier OOPSLA 2009 and SLE 2009 papers into a journal article has now been accepted for publication in ACM TOPLAS. (It may take a while before the paper is actually published; we'll provide a pre-print as soon as possible.)

Maartje de Jonge, Lennart C. L. Kats, Emma Soderberg, Eelco Visser. Natural and Flexible Error Recovery for Generated Modular Language Environments. ACM Transactions on Programming Languages and Systems, 2013 (to appear).

Abstract: Integrated development environments (IDEs) increase programmer productivity, providing rapid, interactive feedback based on the syntax and semantics of a language. Unlike conventional parsing algorithms, scannerless generalized-LR parsing supports the full set of context-free grammars, which is closed under composition, and hence can parse languages composed from separate grammar modules. To apply this algorithm in an interactive environment, this paper introduces a novel error recovery mechanism. Our approach is language-independent, and relies on automatic derivation of recovery rules from grammars. By taking layout information into consideration it can efficiently suggest natural recovery suggestions.

Update: The publication process went faster than expected and the article was published in December 2012.

Today I gave a mini-tutorial at the 5th International Conference on Software Language Engineering (SLE 2012) attempting to explain grammarware to meta-modeling researchers. Since grammarware is a huge area, I chose to discuss a selection of memes from grammarware, illustrated with examples from the Spoofax 'technological space' (as they say). Here are the slides. A recording of the talk may be published as well. Note that the slides do not have much text explaining what they are about. We plan to elaborate the tutorial material in an associated paper for the SLE 2012 post-proceedings.

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