SQL functions and triggers?

Hi all,

In the past, when writing trigger functions, I’ve always used pl/pgsql without giving it a second thought. Today I was
modifyinga database creation script that was originally intended for Firebird to work with Postgres and the example
triggerprocedures in there were very close to pure SQL. 

Hence, I started rewriting them as SQL functions, but is that really possible? The return-type for trigger functions is
usually‘returns trigger’, which I don’t know how to translate to SQL. Next to that, what should the SQL statement
insidethe function be returning? 

This got a bit puzzling and now I wonder whether this is possible at all? And if so, what’s the correct syntax?

Say I have the below, how to actually return a value of type trigger?:

create or replace function pUpdateFoo()
returns trigger
as $$
    update    Bar
    set        baz = baz + NEW.feep - OLD.feep
    where      foo = NEW.foo;
$$;

create trigger tUpdateFoo
after update on Foo
for each row
    execute procedure pUpdateFoo();

Glad to finally have a proper opportunity to apply PG again - it’s been too long!

Alban Hertroys
--
If you can't see the forest for the trees,
cut the trees and you'll find there is no forest.