Christophe Raffalli wrote:

>
> I guess that it is does not need to much work to come up with a correct
> type system infering such types (I may be wrong ... ).
> And knowing if an expression has side effects could be usefull for the
> compiler in other cases ?

You will have to consider exceptions too: if both evaluation of e1
and e2 raise a different exception then the exception raised by
(f e1 e2) depends on the evaluation order.

-Ralf.
-- 
-------------------------------------------------------------
Ralf Treinen,      L.R.I. Bât. 490,     Université Paris-Sud,
F91405 Orsay cedex, France.        http://www.lri.fr/~treinen