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Re: Reasons (not) to vote Motion 27: NO

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.
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).
With Motion 27, no such error occurs, and the result is whitewashed to safe, no matter what was going on. 


Arnold Neumaier