Access NEW and OLD from function called by a rule

Hello,

I was wondering if it was possible to get a hold of the NEW and OLD
variables available in a Rule and pass them to a function? Maybe there
is another (better) way of accomplishing what I try to do, so I'll
sketch you my testing layout:

CREATE TABLE clients (
id SERIAL PRIMARY KEY,
name text
);

CREATE TABLE persons (
id SERIAL PRIMARY KEY,
first_name text,
last_name text
);

CREATE TABLE t_workers (
id SERIAL PRIMARY KEY,
person_id integer REFERENCES persons(id),
client_id integer REFERENCES clients(id)
);

CREATE TABLE t_contacts (
id SERIAL PRIMARY KEY,
person_id integer REFERENCES persons(id),
client_id integer REFERENCES clients(id)
);

-- view containing all worker data
CREATE VIEW workers
AS
SELECT w.*, p.first_name, p.last_name FROM t_workers AS w
INNER JOIN persons AS p ON ( w.person_id = p.id );

Now for inserting data in the workers view I created a rule:

CREATE OR REPLACE RULE insert_worker AS ON INSERT TO workers DO INSTEAD (
INSERT INTO persons ( first_name, last_name )
VALUES ( NEW.first_name, NEW.last_name );

INSERT INTO t_workers ( person_id, client_id )
VALUES ( currval('persons_id_seq'), NEW.client_id );
);

This works. Then I also have a t_contacts table where I want do the same
with, I create a view called contacts and a rule called insert_contact.
Later on I will be having more views containing data from persons. So I
thought I could make some kind of macro of the "INSERT INTO persons .."
part. I saw PostgreSQL has support for CREATE FUNCTION (something I'm
not really familiar with). This is what I wanted to do:

I create a FUNCTION to insert data into persons:

CREATE OR REPLACE FUNCTION insert_person() RETURNS OPAQUE AS '
BEGIN
INSERT INTO persons ( first_name, last_name )
VALUES ( NEW.first_name, NEW.last_name );
RETURN NULL;
END
' LANGUAGE 'plpgsql';

And I will call the FUNCTION from the isnert_worker RULE

CREATE OR REPLACE RULE insert_worker AS ON INSERT TO workers DO INSTEAD (
SELECT insert_person();

INSERT INTO t_workers ( person_id, client_id )
VALUES ( currval('persons_id_seq'), NEW.client_id );
);

If I try to insert data into workers, the following happens:

test_db=# insert into workers ( first_name, last_name ) VALUES ( 'John',
'Doe');
ERROR: record "new" is not assigned yet
DETAIL: The tuple structure of a not-yet-assigned record is indeterminate.
CONTEXT: PL/pgSQL function "insert_person" line 2 at SQL statement

PostgreSQL obviously complains about NEW not available, how can I make
it available? Is this the way to do it?

Sincerely,

Frodo Larik