Regular Expression Data Type - Mailing list pgsql-sql

Hi.
I appreciate that I can query the database and find records that  
match a regular expression.
What I'd like to be able to do is to define a field in the database  
as a regular expression so that when I select, i.e.,

select price from shipping_prices where shipFromZip = '23773' and  
shipToZip ~ '87927'

because shipToZip is defined as a regular expression, I'd match a row  
where shipToZip held the value '879[0-9]{2,2}' or '87[0-9]*'.

Wouldn't that be cool? Does anyone know whether this is already  
possible?

Thanks.