pcre:re_matchsub/4

re_matchsub(+Regex, +String, -Sub:dict, +Options) is semidet

Match String against Regex. On success, Sub is a dict containing integer keys for the numbered capture group and atom keys for the named capture groups. The associated value is determined by the capture_type(Type) option passed to re_compile/3, may be specified using flags if Regex is of the form Pattern/Flags and may be specified at the level of individual captures using a naming convention for the caption name. See re_compile/3 for details.

The example below exploits the typed groups to parse a date specification:

?- re_matchsub("(?<date> (?<year_I>(?:\\d\\d)?\\d\\d) -
                (?<month_I>\\d\\d) - (?<day_I>\\d\\d) )"/e,
               "2017-04-20", Sub, []).
Sub = re_match{0:"2017-04-20", date:"2017-04-20",
               day:20, month:4, year:2017}.