Stack Conditions for Exporting card data

[Francis Nugent Dixon]

Hi from Paris,

I'm trying to identify stack structures that can exist, with the object
of developing MY standard Data Export/Import functions, if the stack
structure permits. The object of this function is to drop onto "certain"
stacks, a few buttons which will allow Export/Import functions to  
standalone
stacks, to render them dynamically "updateable".

A simple Data Export function such as I am creating, would
be permissible (for the majority of MY stacks)in the following cases :

1 - A stack containing "n" data cards, with a single group defined
for these cards, and declared as a background,

2 - A stack containing "n" data cards, as in case 1, but preceded
by one or more "Header" cards, whose information content
does not interest me in the export function.

Information readily available (that I know of) is :

the number of cards in the stack,
the number of groups in each card,
the number of backgrounds in a stack,
the groupIDs on each card.

I could assume that any "front" cards of a stack containing
"0" groups could be considered as header cards, and could
be ignored in the Export function.
By examining the LAST card of a stack, I could check if it
contained a single group, and check to see if its background
behaviour was "true", unless of course, I check all the cards
of the stack to get their background behaviour status.
I can get the backgroundNames of a stack and ensure that
there is only one background within the stack.
I can check the groupID of each card to ensure that the same
group ID (i.e. background) is used within all the cards.

However, I am not convinced that these checks will guarantee
either of the two stack structures I wish to "accept" in my Data
Export/import function.

Questions :

Are there any possible tests I didn't see ?
Are there any global system values that can provide interesting
information which can help me in this area ?
Has anybody got any ideas about how to improve my analysis ?
Has anybody solved the Export/Import problem for standalone stacks
with a standard solution ?

-Francis Nugent Dixon

"Nothing should ever be done for the first time !"