Compiere ERP and SQL quirks

Hello

We made Compiere (Open source ERP system) to Firebird (Fyracle)
This is special version of Firebird with added Oracle compatibility (Oracle
PL/SQL).
It made porting much easier, but our experience show that it
would be now also not very difficult with other databases like PostgreSQL.

Compiere contained lot of PL/SQL which size is now largely reduced.
Main problem is some SQL constructions which are not supported.
Particulary something like this is very important:
UPDATE sometable set (col1,col2) = (select col_a,col_b from another_table
where ....)
This construction seems to be quite useful in another cases.

Would be it diffcult and possible to add such syntax to PostgreSQL ?

Marek Mosiewicz
http://www.jotel.com.pl