Lightweight syntactic analysis tools like Semgrep and Comby leverage the tree structure of code, making them more expressive than string and regex search. Unlike traditional language frameworks (e.g., ESLint) that analyze codebases via explicit syntax tree manipulations, these tools use query languages that closely resemble the source language. However, state-of-the-art matching techniques for these tools require queries to be complete and parsable snippets, which makes in-progress query specifications useless. We propose a new search architecture that relies only on tokenizing (not parsing) a query. We introduce a novel language and matching algorithm to support tree-aware wildcards on this architecture by building on tree automata. We also present stsearch , a syntactic search tool leveraging our approach. In contrast to past work, our approach supports syntactic search even for previously unparsable queries. We show empirically that stsea rch can support all tokenizable queries, while still providing results comparable to Semgrep for existing queries. Our work offers evidence that lightweight syntactic code search can accept in-progress specifications, potentially improving support for interactive settings. CCS Concepts: • Software and its engineering → Formal language definitions ; Software maintenance tools; • Information systems → Query representation; • Theory of computation → Tree languages.

Programming support methods, like discussion fo-rums and office hours, are important in CS education, but difficult to scale. In this paper, we introduce EdCode, a system that allows students to seek remote instructional support within their IDE in a way that resembles in-person support. It also allows instructors to provide contextualized responses by referencing students' code, and curate and publish their answers for an entire class by selecting only the relevant part of the code referenced, thereby helping to avoid plagiarism. We evaluated EdCode with a series of usability studies and identified benefits and challenges for its use in programming courses. Students found that the perceived quality of support from EdCode was comparable to that of support from in-person office hours, and both students and instructors found publishing and viewing other students' answers helpful.

Predictive models are susceptible to errors called unknown unknowns, in which the model assigns incorrect labels to instances with high confidence. These commonly arise when training data does not represent variations of a class encountered at model deployment. Prior work showed that crowd workers can identify instances of unknown unknowns, but asking the crowd to identify a sufficient number of individual instances can be costly to acquire [2]. Instead, this paper presents an approach that leverages people’s ability to find patterns to retrain classifiers more effectively with fewer examples. We ask crowd workers to suggest and verify patterns in unknown unknowns. We then use these patterns to train an expansion classifier to identify additional examples from existing data that the primary classifier has encountered (and potentially misclassified) in the past. Our experiments show that our approach outperforms existing unknown unknown detection methods at improving classifier performance. This work is the first to leverage crowds to identify error patterns in large datasets to improve ML training.