plpgsql return setof integer?

Greetings,

 I've got a fairly simple function that I'm trying to return a set, but
seem to have come across a stumbling block. When I execute the function
below (the input params are not used at the moment) I get this:

chris=# select htdig('foo', 'foo');
ERROR:  set-valued function called in context that cannot accept a set
CONTEXT:  PL/pgSQL function "htdig" line 14 at return next


CREATE OR REPLACE FUNCTION htdig(text, text) RETURNS SETOF integer AS '
DECLARE
  result text[];
  low integer;
  high integer;
  item integer;
BEGIN
    result := htsearch(''sample_return.txt'',''dbname'');
    low  := 2;
    high := array_upper(result, 1);

    FOR i IN low..high LOOP
      item := result[i];
      RETURN NEXT item;
    END LOOP;
  RETURN;
END;
' LANGUAGE 'plpgsql' STABLE STRICT;


The function htsearch is working as expected (other than a strange HASH
as the first element, but I've compensated for that by starting at array
index 2). This is what it outputs:

chris=# select htsearch('sample_return2.txt','dbname');
             htsearch
----------------------------------
 {HASH(0x835c298),2100,2113,2114}
(1 row)

Any obvious thing that I'm doing wrong? I'm using 7.4RC2. As always, any
help or info would be much appreciated. Bonus points if someone knows
what the HASH is. :-)

Cheers,

Chris

--
Christopher Murtagh
Enterprise Systems Administrator
ISR / Web Communications Group
McGill University
Montreal, Quebec
Canada

Tel.: (514) 398-3122
Fax:  (514) 398-2017