Now I'm just guessing, but it seems to me that what they want is the text that most closely corresponds to a given action. The concern is the text, not the regex. Since I haven't seen the data you work with, this might be way off base, but perhaps a better way would be to find all regexes that will match with the text and then choose the text with the smallest "edit distance" against a target text?

Edit distance is generally concerned with the number of additions, deletions and substitutions necessary to transform one string into another. There are a number of CPAN modules which can calculate this for you. See Text::LevenshteinXS for a representative example.