Task Synthesis for Elementary Visual Programming in XLogoOnline Environment

In recent years, the XLogoOnline programming platform has gained popularity among novice learners. It integrates the Logo programming language with visual programming, providing a visual interface for learning computing concepts. However, XLogoOnline offers only a limited set of tasks, which are inadequate for learners to master the computing concepts that require sufficient practice. To address this, we introduce XLogoSyn, a novel technique for synthesizing high-quality tasks for varying difficulty levels. Given a reference task, XLogoSyn can generate practice tasks at varying difficulty levels that cater to the varied needs and abilities of different learners. XLogoSyn achieves this by combining symbolic execution and constraint satisfaction techniques. Our expert study demonstrates the effectiveness of XLogoSyn. We have also deployed synthesized practice tasks into XLogoOnline, highlighting the educational benefits of these synthesized practice tasks.