Going beyond identity mapping for views

[TomWerm]

The purpose of this discussion is to collect points to consider for the generation of more complex views.

Filtering Objects

1. If a view only displays parts of its source (i.e. parts of a list), the deletion of an object will only remove references to the deleted object in the view. Thus the changes recorded may not contain all references to the deleted object in the source. If the changes are propagated to the source its application may invalidate it (as it leaves dangling references).
2. Filtered out objects may have references on a changed object, so the changed object may have uses that cannot be seen (and taken into consideration regarding the change) by the person performing the change. This is different from 1. as it may occur on all forms of changes.

Combining Object(s)/(Parts)

1. Changes may not be unequivocally propagated back (a change of the value of a sum does not contain any information on how to propagate the changed value into the summands).