Semantic relation based expansion of abbreviations

Identifiers account for 70% of source code in terms of characters, and thus the quality of such identifiers is critical for program comprehension and software maintenance. For various reasons, however, many identifiers contain abbreviations, which reduces the readability and maintainability of source code. To this end, a number of approaches have been proposed to expand abbreviations in identifiers. However, such approaches are either inaccurate or confined to specific identifiers. To this end, in this paper we propose a generic and accurate approach to expand identifier abbreviations. The key insight of the approach is that abbreviations in the name of software entity e have great chance to find their full terms in names of software entities that are semantically related to e. Consequently, the proposed approach builds a knowledge graph to represent such entities and their relationships with e, and searches the graph for full terms. The optimal searching strategy for the graph could be learned automatically from a corpus of manually expanded abbreviations. We evaluate the proposed approach on nine well known open-source projects. Results of our k-fold evaluation suggest that the proposed approach improves the state of the art. It improves precision significantly from 29% to 85%, and recall from 29% to 77%. Evaluation results also suggest that the proposed generic approach is even better than the state-of-the-art parameter-specific approach in expanding parameter abbreviations, improving F1 score significantly from 75% to 87%.