Regular expression matching on text.
System.regex.match_result: Regular expression result object.make System.regex(regex): Construct new regular expression object.regex: Regular expression to use.case_insensitive: Is match case-insensitive?internal_regex_obj: match(str): Match regular expression on text.str: String to search.match(str, start): Match regular expression on text.str: String to search.start: Starting location to search.