partition insert question

Hello -

I find myself trying to find a way to have the table name used with the
insert command be generated on the fly in a rule. For example, consider
the following:

create table foobars (
   id bigserial,
   created_at timestamp not null,
   name
);

create table foobars_200612 (
   check (created_at >= timestamp '2006-12-01 00:00:00' and created_at < timestamp '2007-01-01 00:00:00')
) inherits (foobars);

create table foobars_200701 (
   check (created_at >= timestamp '2007-01-01 00:00:00' and created_at < timestamp '2007-02-01 00:00:00')
) inherits (foobars);

create rule foobars_insert as
on insert to foobars do instead
   insert into (select 'foobars_' || extract(year from NEW.created_at) || extract(month from NEW.created_at))
   (created_at,name) values (now(),'hello');

I realize that I could craft a list of many ON INSERT TO foobars WHERE xxx
constructs, but am trying to be a bit more maintainable than having each
of the where clauses hard-defined. Any suggestions?

Thanks in advance - Marc