Re: Differences between Ada 83 and other revisions

[yoursurrogategod@gmail.com]

On Thursday, February 13, 2014 2:44:47 PM UTC-5, Niklas Holsti wrote:
> On 14-02-13 17:59 , yours.....gmail.com wrote:
> 
> > Hello.  I'm new to Ada, but I would like to get a slightly better
> 
> > understanding of the language.
> 
> 
> 
> Welcome...
> 
> 
> 
> > I like how the Ada compiler is so
> 
> > careful, something I rarely see in other languages.
> 
> 
> 
> Me too.
> 
> 
> 
> > From what I've read and heard, Ada 83 compiler was very strict about
> 
> > what type of code could be compiled and as a result made code that
> 
> > ran as programmed most of the time.
> 
> 
> 
> I have personal experience of this effect, with all versions of Ada. The
> 
> language and compiler are strict, which has two consequences: firstly,
> 
> it encourages you to design and code more carefully and thoughtfully,
> 
> else your code will not pass the compiler; secondly, the compiler will
> 
> really discover some kinds of logical errors at compile time. Both make
> 
> it more likely that the program will actually work as intended, once it
> 
> compiles correctly.
> 
> 
> 
> > However, later revisions have weakened some of these rules for
> 
> > Ada 95 and onward.  Is this true?
> 
> 
> 
> As other posters have noted, Ada 95 relaxed some Ada 83 rules which were
> 
> more "stylistic" than logically necessary. So Ada 95 and later standards
> 
> give more room for different coding styles, while still giving the same
> 
> semantic rigour. I don't believe that this makes Ada programs more
> 
> likely to fail at run time.
> 
> 
> 
> However, Ada 95 and later Ada standards extend the language beyond Ada
> 
> 83 in many ways. Some extensions include new kinds of run-time checks
> 
> for new kinds of run-time errors, which cannot be detected at compile
> 
> time. Ada 83 had a smaller set of run-time checks and errors, so it can
> 
> be argued that programs using the Ada 95 and later extensions have an
> 
> increased risk of failing at run-time even if their compilation succeeds.
> 
> 
> 
> I don't know if this argument is valid; I don't see an increased risk of
> 
> run-time failure in my own programming. But I use the new features
> 
> rather conservatively and sparingly. Moreover, some of the new features
> 
> make it easier to avoid some Ada 83 -level run-time errors -- for
> 
> example, controlled types help to avoid errors in memory allocation and
> 
> deallocation.
> 
> 
> 
> -- 
> 
> Niklas Holsti
> 
> Tidorum Ltd
> 
> niklas holsti tidorum fi
> 
>       .      @       .

So it would be safe to say that the newer versions of Ada have not enabled the creation of less reliable code.  And that the newer versions are overall qualitatively better (hence them being used in things such as Thaly's Bullet and more than a few aerospace projects.

Yes?