Repairing Regex-Dependent String Functions

Regex-dependent string functions are string functions that take regular expressions (regexes) as parameters and are popular means of manipulating strings. They are frequently used for, e.g., string transformation and substring search. Despite the importance, writing these functions is far from easy. To rectify this situation, recent research made significant progress by proposing automated methods for synthesizing regexes based on Programming by Examples (PBE). However, there still is a gap between these methods and the goal of synthesizing regex-dependent string functions. First, the existing methods focus on whole-string matching, whereas most regex-dependent string functions adopt substring matching. Second, the existing methods focus only on the regex, but many commonly used regex-dependent string functions, such as replace and replaceAll, also take as parameter a replacement to specify how the substrings matched to the regex will be replaced.