preg_match() option for anchored offset?

What do you think about adding another option to preg_match() to allow the $offset parameter to be treated as the start anchor? The manual proposes to do this: $subject = "abcdef"; $pattern = '/^def/'; $offset = 3; preg_match($pattern, substr($subject, $offset), $matches); In other words, use substr() to copy the entire remainder of the string. I just wrote a simple SQL parser tonight, and had to use this approach, which (I imagine) must be pretty inefficient? I'd like to be able to do the following: $subject = "abcdef"; $pattern = '/^def/'; $offset = 3; preg_match($pattern, $subject, $matches, PREG_ANCHOR_OFFSET, $offset); This new option would make the ^ anchor work from the given $offset, which allows me to parse the entire $subject without copying anything. Thoughts?