substitute for array functions in postgresql v7.3 ?

Hello!

Does anybody know whether ther is a substitue for the array_to_string
function available from v7.4, that would allow a query equivalent to this
one to run on v7.3:

select array_to_string(array[1,2,3]); (ok from v7.4)

Having a 7.3 substitute for select array[1,2,3] would already be a good
starting point...

Thanks in advance for any hint,
Alain

_____________________
Alain BAUDHUIN
alain.baudhuin@swing.be