request for sql3 compliance for the update command

I have a large customer who is converting from informix to postgres and
they have made extensive use of 

update table set (col...) = ( val...)

as a first pass would it be possible to translate this in the parser to

update table set col=val

It would appear that this is SQL3 compliant

<set clause> ::=<update target> <equals operator> <row value designator>

<update target> ::=<object column>| <left paren> <object column list> <right paren>


or can someone think of another way?
-- 
Dave Cramer <dave@fastcrypt.com>
Cramer Consulting