plpgsql question

I am trying to calculate a value from a current record in a query and
can't seem to get it working.

Here is the shortened query;
SELECT
s.id,
r.the_date_time,
s.open_price,
s.high_price,
s.low_price,
s.close_price,
thesheet_onepair.symbol,
r.buy_long,
r.buy_stop,
r.sell_cl,
r.stop_sell,
r.sell_short,
r.sell_stop,
r.buy_os,
r.stop_buy,
check_long_profit ()as tst
FROM
public.thesheet_dailystats s,
public.thesheet_recommendation r,
public.thesheet_onepair
WHERE
s.one_pair_id = thesheet_onepair.id AND
s.the_date = r.the_date_time::date AND
r.one_pair_id = thesheet_onepair.id
ORDER BY
r.the_date_time DESC,
thesheet_onepair.id ASC;

check_long_profit is the function. I basically want to do some
calculations on this record and return some calculated fields.

I can't seem to figure out how to pass the row.

Here is my header for the function
create or replace function check_long_profit () returns integer AS $$

I know I am missing something easy.

Thanks