See also this discussion:
For the (inevitably common, in fact overwhelming majority) case where outline structures differ between two documents, there’s no obvious or unique definition of what it would actually mean to:
“copy a column from one document to another”
The simplest option would be to define it as uncomputable, and return a message display to the user (some translation of undefined) when structural difference is detected.
If you were aiming for some kind of partial copy (when outline structures differ), then you would need to make a number of essentially arbitrary choices about:
- what you would want to discard,
- what you would want to transfer across,
- and where the copied values would go.
