Re: An Ada Program Does What It Says?

[agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!zaphod.mps.ohio-state]

In <1993Jan4.082827.11773@hellgate.utah.edu> matwood%peruvian.cs.utah.edu@cs.ut
ah.edu (Mark Atwood) writes:

>In article <9301031530.AA17787@ajpo.sei.cmu.edu>, SAHARBAUGH@ROO.FIT.EDU write
s:
>>I searched B&M's book and noted each example program whose 
>>output is "indeterminate" or "implementation dependent".  I 
>>noted the page number on which the answer appears.  

>(deleted)

>>My warning stands.  Ada code looks deceptively readable.  The 
>>reader must understand the language translator and the 
>>runtime environment to be able to correctly read an Ada 
>>program.

>I just finished reading those books, and yes there do seem to be a lot of
>indeterminate and compiler dependent "thing" in the Ada standard.  A co-
>worker and I discussed it for a while and made the observation that probably
>every language has these "gotcha"'s, they just aren't as well documented
>or understood.

>Stuff like expression ordering, floating point representation, concurency,
>etc, will always be indeterminate.

>Not to trigger yet another C vs Ada flamefest, but this expression in
>C is a classic example...

>  r = (i++ == ++i)

It is also, of course, quite well documented and understood.  You are
correct in stating that just about every language is going to have
syntactically correct constructs which produce undefined or
implementation-defined results.  You are, however, incorrect in your
assumption that Ada is the only language in which these things are
well documented or understood.

[One typically sees a lot more people making mistakes like that above
in C simply because one sees a lot more inadequately or untrained
people working in C than one sees working in Ada -- and we're back to
the 'popularity' issue.]

-- 
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
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Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me.