- author = "Felix Adler and Gordon Fraser and Eva Gruendinger and Nina Koerber and Simon Labrenz and Jonas Lerchenberger and Stephan Lukasczyk and Sebastian Schweikl",
- title = "Improving Readability of {Scratch} Programs with Search-based Refactoring",
- howpublished = "arXiv",
- year = "2021",
- month = "16 " # aug,
- keywords = "genetic algorithms, genetic programming, genetic improvement, SBSE",
- eprint = "2108.07114",
-
URL = "
https://arxiv.org/abs/2108.07114",
- size = "13 pages",
- abstract = "Block-based programming languages like Scratch have become increasingly popular as introductory languages for novices. These languages are intended to be used with a tinkering approach which allows learners and teachers to quickly assemble working programs and games, but this often leads to low code quality. Such code can be hard to comprehend, changing it is error-prone, and learners may struggle and lose interest. The general solution to improve code quality is to refactor the code. However, Scratch lacks many of the common abstraction mechanisms used when refactoring programs written in higher programming languages. In order to improve Scratch code, we therefore propose a set of atomic code transformations to optimise readability by (1) rewriting control structures and (2) simplifying scripts using the inherently concurrent nature of Scratch programs. By automating these transformations it is possible to explore the space of possible variations of Scratch programs. In this paper, we describe a multi-objective search-based approach that determines sequences of code transformations which improve the readability of a given Scratch program and therefore form refactorings. Evaluation on a random sample of 1000 Scratch programs demonstrates that the generated refactorings reduce complexity and entropy in 70.4percent of the cases, and 354 projects are improved in at least one metric without making any other metric worse. The refactored programs can help both novices and their teachers to improve their code.",
-
notes = "p4 'we need the search to evolve sequences of
refactorings that explain the changes'
p10 'Solutions are transformed 10.1 times on average, and the most common transformations are Swap Statements, Merge Scripts and Split Scripts'
p10 'our modification operators are designed to preserve the program semantics'
Published as \cite{DBLP:conf/scam/AdlerFGKLLLS21} University of Passau, Germany",
