relation model vs SQL1999 conformance vs PostgreSQL

hello all,

In general my question to all PostgreSQL community is stated in the subject
line.
Looks like I am missing something 'cause I am new to this list, but I don't
see much info
on this subject in your web page.
Perhaps the only information I have found is in v.7.4 dev. documents about
SQL1999 conformace.
How much from SQL1999 are you going to implement?
(I mean in the long run, say any plans for next 3 years, kind of TODO
lists?)
As far as I see there are features (i.e. kind of array support) in
PostgreSQL that are implemented looong before SQL99.
Do you feel you have to conform to SQL99 for marketing considerations? or
else?
I don't know nothing about any conformance tests for SQL99, kind of strange?

In particular I am interested how do you feel about REF type (or using
pointers) to join tables.
Any pointers to additional information on the subject will be highly
appreciated.
Hope it is right list for these questions.

Regards,
Alvis Tunkelis