Re: A case where Ada defaults to unsafe?

["Pat Rogers" <progers@classwide.com>]

"Hyman Rosen" <hyrosen@mail.com> wrote in message
news:3C39E520.6030508@mail.com...
> Pat Rogers wrote:
>
> > Well of course "and" is allowed to ignore one of the operands; if the first
one
> > evaluated is false, there is no need to evaluate the second.  We are just
not
> > guaranteed which is evaluated first.
>
>
> You are quite wrong. So much for the claim that experienced Ada
> programmers simply learn the difference between "and" and "and then"!
> See, for example, 3.8 in the Ada83 Rationale.

Although it is questionable to base arguments on the Rationale, especially for
the obsolete version of the language, let me suggest you consider 3.10 of the
Ada 83 Rationale, which says in part, when introducing the short-circuit forms:

"The operands of a boolean expression such as A and B can be evaluated in any
order. Depending on the complexity of the term B, it may be more efficient ...
to evaluate B only when the term A has the value TRUE.  This, however, is an
optimization decision taken by the compiler ..."

But thanks for the compliment anyway.  :-)

---
Patrick Rogers                       Consulting and Training in:
http://www.classwide.com          Real-Time/OO Languages
progers@classwide.com               Hard Deadline Schedulability Analysis
(281)648-3165                                 Software Fault Tolerance