On Fri, 6 Oct 2000, Ken Wakita wrote:

> Scheme also has its evaluation orders of function parameters
> undefined.  I remember one of the reasons for this decision is to
> leave possibility for parallel evaluation of the arguments.

This is not correct.  In scheme, parallel evaluation of the arguments is
explicitly disallowed (unless the compiler can prove that evaluating them 
in parallel does not have any observable effect, of course).

The real reason of the unspecified order in Scheme, is that when the first 
reports on scheme were being drafted, there already were implementations
which evaluated arguments in different order.  And this has never been
fixed afterwards.

(People interested in the history of Scheme can check the archives of the
scheme authors mailing list at MIT).

Gxis,
  Pierpaolo Bernardi