Re: Reasons (not) to vote Motion 27: NO
Arnold Neumaier wrote:
On 08/04/2011 07:09 PM, Nate Hayes wrote:
Arnold Neumaier wrote:
Motion 26 protects the inexperienced user, while the expert user can
judge
for themselves how to make use of the decorations.
All Motion 26 does in this regard is allow users to write unreliable
programs. Since there is no standard, a user may run a program on one
conforming implementation that uses a certain set of semantics and get
valid
results (by coincidence) and then run the same program on another
conforming
implementation and fail catastrophically.
One can write unreliable programs no matter how the decoration system
works, since the user can always set decorations arbitrarily.
As I noted to john, the difference is where can the source of the failure be
traced back to.
With motion 27, the decorations never lie: the failure is traced back to the
user's buggy code.
With motion 26, the decorations may lie: the failure is traced back to this
P1788 committe for designing a standard that, when used "properly" still may
give unreliable results.
With Motion 26, the user gets type errors when trying to use an
intersection result in a decorated operation (which is the potentially
unreliable bit) without having set decorations explicitly (and thereby
declaing that what is done is intentional).
It doesn't matter. See my post to John.
In any case. Most interval programs use lots of intersection and union
operations. So this means none of them will compile if users are trying to
perform decorated calculations.
With Motion 27, no such error occurs, and the result is whitewashed to
safe, no matter what was going on.
You have not given any of the examples I requested.
Nate