I would like to share two bugs and fixes:

In "Choice", add $ret = "(?:".$ret.")"; after the join. When combining a Choice with other values, the Choice values need to be separated from the other ones, because precedence for | is low.

In "Repetition", there must not be space between the min and max values: $ret .= " (?: ". Value($$v{value}  , $dent+1)." ){$$v{min},$$v{max}} ";