PL/SQL trouble

Hi,

I really don't understand following PostgreSQL 7.2.3 behaviour:

$ psql mydb
mydb=> CREATE FUNCTION MONDAY(timestamp) RETURNS DATE AS 'DECLARE  var1 date;BEGIN select into var1
to_date($1::date-(casewhen extract(DOW from
 
timestamp $1) = 0 then 6 else (extract(DOW from timestamp $1)-1) end)); RETURN var1;END'
language 'plpgsql';

CREATE
mydb=> select MONDAY('now'::timestamp);
NOTICE:  Error occurred while executing PL/pgSQL function MONDAY
NOTICE:  line 4 at select into variables
ERROR:  parser: parse error at or near "$2"
mydb=> \q

But I've not inserted any $2 there.
I've rewritten the same function in other ways but I've got the same error.

I thank you in advance for any hints.


Bye,                 \fer