There is no such thing. You would have to re-create all transforms inside the expressions code using real hard math, so I suggest you explore other venues and structure your project suitably rather than making it require convoluted expressions.
Well, sort-of. You can directly link the "child's" position to the "parents" position. For scaling and rotation you need a "relative link" (adding the parent's and child's values), if you still want to be able to animate the child's scaling and rotation. Important is that to animate/set the child's position, you need to use its anchor instead of its position value.
See it in action here:
Download the AAE document at: