Gradual structuring: Evolving the spreadsheet paradigm for expressiveness and learnability

© 2016 IEEE. Spreadsheets are arguably the most used form of programming and are frequently used in higher education to teach fundamental concepts about computation. Their success has shown that they are simple enough for a huge number of end users to learn and use. This is in contrast to traditional programming languages and the high dropout rate from introductory programming and computer science. However in comparison to traditional programming languages and structured modelling, spreadsheets are not expressive, placing a limit on the levels of computational thinking that can be taught using the spreadsheet paradigm. This limitation is imposed by the lack of programming language features and abstractions in the paradigm. Furthermore, more advanced spreadsheet features (e.g. array formulae, lookup formulae, R1C1 syntax) can be difficult to learn and use. This paper discusses the idea of adding language features to spreadsheets, enabling the gradual structuring of free-form spreadsheets to more structured models. We propose that this concept is termed Gradual Structuring, and is analogous to the programming language concept of gradual typing. In this analogy, spreadsheets take the place of dynamic programming and structured modelling of static programming. In programming languages, gradual typing allows dynamic programming to be mixed with static programming. It is our contention that dynamic programming is more learnable while static programming is more expressive and abstract. Gradual typing could be used to mitigate the issues in the teaching of traditional programming. Likewise Gradual Structuring can mitigate the conceptual limits that can be taught using current spreadsheets. The key language feature required to enable Gradual Structuring is the ability to logically group cells together so that a single formula can be applied to the grouped cells. This concept, termed cell grouping diminishes and can even eliminate the need for the ubiquitous and error-prone use of copy-pasted in spreadsheets. Moreover, it makes the structure present in spreadsheet models explicit. Cell grouping requires a cascade of other new languages features. Namely a more expressive referencing style, which in turned requires enabling labels to be moved to the row and column headers, and the hierarchical structuring of these headers. Respectively these language features are termed enhanced referencing and semantic axes. The ongoing research focusses on the usability and learnability of these language features. Spreadsheet applications exist that contain aspects of the features mentioned. However these applications do not enable Gradual Structuring and have taken a mainly technical, not human behavioural, approach to evolving the spreadsheet

Scope Graphs: The Story so Far

Static name binding (i.e., associating references with appropriate declarations) is an essential aspect of programming languages. However, it is usually treated in an unprincipled manner, often leaving a gap between formalization and implementation. The scope graph formalism mitigates these deficiencies by providing a well-defined, first-class, language-parametric representation of name binding. Scope graphs serve as a foundation for deriving type checkers from declarative type system specifications, reasoning about type soundness, and implementing editor services and refactorings. In this paper we present an overview of scope graphs, and, using examples, show how the ideas and notation of the formalism have evolved. We also briefly discuss follow-up research beyond type checking, and evaluate the formalism

A necessity-driven ride on the abstraction rollercoaster of CS1 programming

International audienceIntroductory programming courses (CS1) are difficult for novices. Inspired by Problem solving followed by instruction and Productive Failure approaches, we define an original "necessity driven" learning design. Students are put in an apparently well-known situation, but this time they miss an essential ingredient (the target concept) to solve the problem. Then, struggling to solve it, they experience the necessity of that concept. A direct instruction phase follows. Finally, students return to the problem with the necessary knowledge to solve it. In a typical CS1 learning path, we recognise a challenging "rollercoaster of abstraction". We provide examples of learning sequences designed with our approach to support students when the abstraction changes (both upward and downward) inside the programming language, for example, when a new construct (and the related syntactical, conceptual, and strategic knowledge) is introduced. Also, we discuss the benefits of our design in light of Informatics education literature

Teaching informatics to novices: big ideas and the necessity of optimal guidance

This thesis reports on the two main areas of our research: introductory programming as the traditional way of accessing informatics and cultural teaching informatics through unconventional pathways. The research on introductory programming aims to overcome challenges in traditional programming education, thus increasing participation in informatics. Improving access to informatics enables individuals to pursue more and better professional opportunities and contribute to informatics advancements. We aimed to balance active, student-centered activities and provide optimal support to novices at their level. Inspired by Productive Failure and exploring the concept of notional machine, our work focused on developing Necessity Learning Design, a design to help novices tackle new programming concepts. Using this design, we implemented a learning sequence to introduce arrays and evaluated it in a real high-school context. The subsequent chapters discuss our experiences teaching CS1 in a remote-only scenario during the COVID-19 pandemic and our collaborative effort with primary school teachers to develop a learning module for teaching iteration using a visual programming environment. The research on teaching informatics principles through unconventional pathways, such as cryptography, aims to introduce informatics to a broader audience, particularly younger individuals that are less technical and professional-oriented. It emphasizes the importance of understanding informatics's cultural and scientific aspects to focus on the informatics societal value and its principles for active citizenship. After reflecting on computational thinking and inspired by the big ideas of science and informatics, we describe our hands-on approach to teaching cryptography in high school, which leverages its key scientific elements to emphasize its social aspects. Additionally, we present an activity for teaching public-key cryptography using graphs to explore fundamental concepts and methods in informatics and mathematics and their interdisciplinarity. In broadening the understanding of informatics, these research initiatives also aim to foster motivation and prime for more professional learning of informatics

Understanding software through linguistic abstraction

In this essay, I argue that linguistic abstraction should be used systematically as a tool to capture our emerging understanding of domains of computation. Moreover, to enable that systematic application, we need to capture our understanding of the domain of linguistic abstraction itself in higher-level meta languages. The argument is illustrated with examples from the SDF, Stratego, Spoofax, and WebDSL projects in which I explore these ideas.Accepted Author ManuscriptProgramming LanguagesSoftware Technolog

Understanding software through linguistic abstraction

Preprint submitted to "Science of Computer Programming", Elsevier, http://dx.doi.org/10.1016/j.scico.2013.12.001 In this essay, I argue that linguistic abstraction should be used systematically as a tool to capture our emerging understanding of domains of computation. Moreover, to enable that systematic application, we need to capture our understanding of the domain of linguistic abstraction itself in higher-level meta languages. The argument is illustrated with examples from the SDF, Stratego, Spoofax, and WebDSL projects in which I explore these ideas.Software Computer TechnologyElectrical Engineering, Mathematics and Computer Scienc