User Defined Named Placeholders for Regular Expression Segments in Complex Regular Expressions

This paper describes an own implementation of a regular expression preprocessor written in PHP. It extends the regular expression functionality by allowing users to define named segments. These segments include custom character classes, matching groups etc. The pre-processor allows for writing complex regular expressions that are simpler to maintain. In addition, this paper presents a use case of the practical utilisation of the pre-processor. Furthermore, it includes a comparison of expressions written with and without user-defined segments.