Re: What's wrong with C++?

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Wed, 05 Oct 2011 03:53:28 +0200, Peter C. Chapin <PChapin@vtc.vsc.edu>  
a écrit:
> I don't think this is a big deal. It's an interesting theoretical
> observation with little practical significance.
Bad theoretical background is no good (at least, it matters to me, to me,  
it is a base of trustability).

> Nobody is injured by the program
> it didn't create; it's only an inconvenience to the programmer who has to
> adjust the source.
Except the comment which follows the one I quoted, says

> oops, the C++ spec allows implementations to terminate compilesif they  
> recurse too deeply. Nevermind.
That's no good again. After that, a compiler, may produce invalid output.

> C++ isn't alone with this problem either. I understand that Scala's type
> system is also Turing complete.
Did not learned Scala yet (you recalled me to do it a future day, thanks  
for that)

> It is possible, apparently, to write a
> Scala program for which type checking never terminates. Again it's an
> interesting theoretical observation but I don't think anyone really  
> cares.
Really, I do, this really frighten me. I could not trust such a language.

> In our work at VTC on translating some NASA software to SPARK we
> encountered a situation where the SPARK simplifier took an "infinitely"
> long time to execute... well, okay, it only took about an hour. Yes it
> did terminate but it took so long that development was impractical (no
> different, really, than true non-termination). Our response: fix the
> source.
That's not the same. When a Prolog program does not terminates, this  
means: “nothing proved”, “don't known”, “uninterpretable”. If you stop it  
after some time because you don't even know if it gonna ever terminates,  
that's the same, “uninterpretable”. And for you, it did terminates, it did  
not stop after a too much deep recursion, then proudly asserting, “OK  
guys, that's fine, your VC is proved”. Or did it ?

-- 
“Syntactic sugar causes cancer of the semi-colons.”  [Epigrams on  
Programming — Alan J. — P. Yale University]
“Structured Programming supports the law of the excluded muddle.” [Idem]
Java: Write once, Never revisit