Extraction not always resolving indices right.

[jjg-123]

The parser ought to resolve A\B\C as (A\B)\C (so the lhs is another extraction). For unclear reasons it may linearize these. Therefore, always check if this is the case. It resulted in a very hard to track down bug where on the command line it would work one way but (when variables and complex state are involved) in an OA4MP script, it would resolved the other.