On Wednesday, August 28, 2002, at 10:54 PM, Richard A. O'Keefe wrote:

> I fully and completely agree that when a programmer writes an 
> iteration,
> *THAT* programmer is responsible for making sure that the collection is
> not changed.  But when someone calls #addAll:, they are not writing an
> iteration.  It was the author of the #addAll: implementation who wrote
> the iteration, and it was the author of the #addAll: implementation who
> had the responsibility for making sure that it either worked or was
> documented as not working.

Here is the crux of the argument.  In my view, the iteration is implied 
and, moreover, is impossible to define meaningfully without using some 
language of iteration, directly or indirectly.  Whether the iterand is 
a receiver, parameter or the result of an expression does not, to me, 
seem relevant.  So, too, it seems that many Smalltalk illuminati agree. 
  Richard does not.

But at least he agrees with the first principle.  That is a good basis 
for proceeding.