Rainer Deyke wrote:
Rainer Deyke wrote:
Andrei Alexandrescu wrote:
I honestly believe the whole "old" thing can't be made to work. Shall we
move on to other possibilities instead of expending every effort on
making this bear dance?
It definitely /can/ be made to work, for some value of "work". It
sacrifices the natural order of evaluation to gain a concise and
intuitive syntax. I don't think it should be dismissed out of hand.
Also, from the Eiffel docs
(http://archive.eiffel.com/doc/online/eiffel50/intro/language/invitation-07.html):
The notation 'old expression' is only valid in a routine
postcondition. It denotes the value the expression had on routine entry.
It seems that Eiffel had 'old' semantics that I've proposed all along.
Great. Others brought it up too, inspired from Eiffel.
Any significant problems with this approach would have been discovered
by the Eiffel community by now.
There is no problem if a copy of the object is made upon entry in the
procedure. That's what I think Eiffel does. I was hoping to avoid that
by allowing the "out" contract to see the definitions in the "in" contract.
Andrei
