The signature is
An attempt of defining the semantics:
Given ADD or MODIFY object delta OD, finds an item delta ID such that "ID has the same effect on an item specified by itemPath as OD" (simply said).
- if OD is ADD delta: ID is ADD delta that adds values of the item present in the object being added
- if OD is MODIFY delta: ID is such delta that:
- Given ANY object O, let O' be O after application of OD.
- Let I be O(itemPath), I' be O'(itemPath).
- Then I' is the same as I after application of ID.
ID is null if no such item delta exists - or cannot be found easily.
The problem with this definition is that it does not work
Namely, if OD contains more than one modification that affects itemPath the results from findItemDelta can differ from the above definition. And it is not clear what should we return in such cases.