fn:IsPresent in SpecialCase of "A" of "OutlineItem"

[Afloat6715]

The ISO 32000-2 Specification reads for "A": "shall not be present if a Dest entry is present".

fn:IsPresent(key) shall be interpreted as: "asserts that the current row must be present if key is present".

The current logic should, to my understanding, be evaluated as:

Dest	A	IsPresent (logical implication: Dest => A)	Not
0	0	True	False
0	1	True	False
1	0	False	True
1	1	True	False

While the condition should be interpreted as:

Dest	A	Both Present (logical and: Dest and A)	Not
0	0	False	True
0	1	False	True
1	0	False	True
1	1	True	False

In my opinion the functionality of "IsPresent" should be reworked so that it only takes one Key/Path as argument and resolves to True if that Key is present. This would be a breaking change but, in the end, a more intuitive implementation.
Additionally there could be a "Implication(A, B)" function where A and B both resolve to a boolean and the Implication function implements the first Table of this issue.

For cases where the first logic is needed a function would look like this:
fn:Implication(fn:IsPresent(Other), fn:IsPresent(CurrentRow))

And where the second logic is needed a function would look like this:
fn:Eval(fn:IsPresent(A) && fn:IsPresent(B))

I was looking at the veraPDF project and how they interpret "fn:IsPresent" and they basically change the implementation if the function is wrapped in a "fn:Not"