PROBLEM WITH FUNCTIONS IN POSTGRES

Hi...

i create a function in postgres to return a data of a table but when try
to create say

PostgreSQL ha dicho: ERROR: parser: parse error at or near "text"
Your query:

CREATE FUNCTION sinomemp(text)
RETURNS text
AS 'DECLARE sinomemp TEXT;
BEGIN
SELECT name
FROM simaemp
WHERE cod = $1;
RETURN sinomemp;
END;'
LANGUAGE 'sql'


please help me