last_match

/*
 *  call-seq:
 *     Regexp.last_match           => matchdata
 *     Regexp.last_match(fixnum)   => str
 *  
 *  The first form returns the <code>MatchData</code> object generated by the
 *  last successful pattern match. Equivalent to reading the global variable
 *  <code>$~</code>. The second form returns the nth field in this
 *  <code>MatchData</code> object.
 *     
 *     /c(.)t/ =~ 'cat'       #=> 0
 *     Regexp.last_match      #=> #<MatchData:0x401b3d30>
 *     Regexp.last_match(0)   #=> "cat"
 *     Regexp.last_match(1)   #=> "a"
 *     Regexp.last_match(2)   #=> nil
 */

static VALUE
rb_reg_s_last_match(argc, argv)
    int argc;
    VALUE *argv;
{
    VALUE nth;

    if (rb_scan_args(argc, argv, "01", &nth) == 1) {
        return rb_reg_nth_match(NUM2INT(nth), rb_backref_get());
    }
    return match_getter();
}