Actually the point of a question was trying to invent a way to optionally provide those variables on demand, and not how it is done now - once seen in a script, those variables are provided for every regex, thus slowing program down significantly.

That question sometimes arise on p5p, and, as I remember, an answer is probably because all bits for modifiers are occupied, and there is no way to add another one without enlarging corresponding C struct.

Courage, the Cowardly Dog