CREATE VIEW (dynamically)

code
<<
CREATE FUNCTION "requests_insert_after" () RETURNS opaque AS '
DECLARE
view_name text;
BEGIN
view_name := ''request_'' || NEW.id;
CREATE VIEW view_name AS select * from groups;
return NEW;
END' LANGUAGE 'plpgsql';

CREATE TRIGGER "requests_insert_after" AFTER INSERT ON "requests" FOR EACH ROW
EXECUTE PROCEDURE "requests_insert_after" ();>>

This code after an insertion on table "requests" give me this message :
<<
PostgreSQL said: ERROR: parser: parse error at or near "$1"
>>

Why ?

Thx for any help.

Emmanuel Engelhart