Understanding Digits in Identifier Names: An Exploratory Study

TL;DR

This study investigates the role and evolution of digits in identifier names across 800 Java systems to enhance understanding and tooling for software maintenance.

Contribution

It provides an empirical analysis of how digits are used in identifier names and their impact on semantics and renaming over time.

Findings

Digits contribute to identifier semantics.

Digits influence renaming patterns.

Study covers 800 open-source Java projects.

Abstract

Before any software maintenance can occur, developers must read the identifier names found in the code to be maintained. Thus, high-quality identifier names are essential for productive program comprehension and maintenance activities. With developers free to construct identifier names to their liking, it can be difficult to automatically reason about the quality and semantics behind an identifier name. Studying the structure of identifier names can help alleviate this problem. Existing research focuses on studying words within identifiers, but there are other symbols that appear in identifier names -- such as digits. This paper explores the presence and purpose of digits in identifier names through an empirical study of 800 open-source Java systems. We study how digits contribute to the semantics of identifier names and how identifier names that contain digits evolve over time through renaming. We envision our findings improving the efficiency of name appraisal and recommendation tools and techniques.