Re: newbie can't get exceptions to work!

[Brian Rogoff <bpr@shell5.ba.best.com>]

On 13 Apr 2001, Laurent Guerby wrote:
> Brian Rogoff <bpr@shell5.ba.best.com> writes:
> > You should know that nothing is obvious when you're discussing the
> > OCaml type system :-). OK, that's not fair. It is obvious when
> > considered in the context of mathematically sound type systems. If
> > you're not well versed in the theory of such type systems, simple
> > explanations won't be helpful.  Check the caml-list for the mail of
> > the past few weeks titled "The Future of Labels" or somesuch.
> 
> I'm not super-versed in those things (I've read a whole bunch of
> papers and FP conference proeedings over the years but never
> implemented anything), but as I see it, raw labeled arguments
> are a near syntactic feature. Let's say you have:

No, unfortunately they aren't. Remember, this isn't Ada we're taling
about, but a higher order language with type inference and currying. 
The issues are different for Ada. Anyways, here's a pointer to the start
of the most recent discussion 

http://caml.inria.fr/archives/200103/msg00248.html

and here is Jacques' home page from which you can download any of his
publications which interest you 

http://wwwfun.kurims.kyoto-u.ac.jp/~garrigue/

> > Which idiotic platforms?
> 
> All commercial UNIXes (AIX, IRIX, Solaris, OSF1) and VMS, plus NT, all
> with threading correctly supported.

Ah. VMS support is hard to come by for non-mainstream languages. 

> > I believe you made the right decision. It was a brave one too, since
> > I bet there was a strong push for C++. Ada would be my choice too,
> > given what you told me.
> 
> I didn't tell you the major thing ;-), namely that most of the team
> writing the software are not trained software engineers but financial
> and numerical people. C/C++ is just suicide in this environment (no
> array bound checking, pointers all over the place, awful error
> messages and brain-dead syntax...). I spent one whole year of my life
> chasing out of bound access, memory management errors and random hard
> to find crashes in a >500KSLOC of C software with crapping debugging
> technology (Visual C++ released compiled software bugs usually go away
> when you compile in debug mode, I still don't know how people tolerate
> this...), I think this qualifies me for having an opinion on the topic
> ;-).

Well, debugging C is a nightmare. I just don't think that {} vs begin-end
is even a tiny part of why C sucks. Paraphrasing a former President

   It's the semantics, stupid. 

I remember how when I first played with Ada about five years ago I wrote a
smallish test program (between 500 and 1000 LOC) and after I silenced the 
compiler I was prepared to debug... and it worked the first time it ran!

Now, I have been able to get runtime crashes with Ada, and doesn't do
everything, but the difference between C/C++/ObjC and Ada is like night
and day.

> As for the strong push for C++, that was everyone but two people, but
> management did trust us and choosed Ada after three monthes of
> reflexion.  Now the C++ people are all saying C++ is legacy and doing
> Java, and Java people are right now wondering about C#... Needless to
> say their technology opinion is now 0 weighted as far as my management
> is concerned. 

:-)

> The software survived one merger, introduction of distributed
> computations, growth of the team and is greatly satisfying
> to business.

That's great to hear. I love non-defense Ada success stories. I'm not
anti-defense, I think everyone should have a shoulder launched SAM in
their garage (I've got two, and one extra for the wife :), but it's 
nice to hear of success in other industries.

> But even if written in Ada, the code keeps FP-like technique like
> being stateless, having non mutable objects and provably not leaking
> reference counting GC scheme (no cycles can be created with non
> mutable objects).

Well, that's good.

> > I trust the support has been good? 
> 
> Ups and downs, but our bugs do get fixed, our technical questions
> about use of the technology get excellent and timely answer, and the
> GNAT technology is definitely evolving in the right direction over the
> years (new tools, new platforms).

Yes, GNAT is great. I wouldn't have a lot of confidence in the future of
Ada were it not for GNAT.

> Talking about support in the software tool business is kinda tricky,
> for example I know about no other tools used here where users get
> fixes from the vendor at all except at the mandatory update to new
> versions.

Yes indeed, see my answer to your next question. 

> Aren't you worried about lack of formal support for OCaml in your
> company?

A little. The Consortium guarantees that if Projet Cristal folds we
get the rights to the source. I'm fairly confident that it won't fold. 
The compiler code is very understandable, though very sparsely documented. 
I guess I have a vested interest in the popularity of OCaml now. Ada too, 
BTW. I do my best to promote Ada when people aren't shoving their fingers
in their ears :-). I even do a bit of that on the Caml list.

Anyways, I wonder how important formal support *really* is. If you used
some proprietary language X compiler and the company that makes it folds,
where are you then? And, as you mention, most "support" from companies is 
a !@#$ing joke. OCaml source is under CVS web, so I can always get the
latest version, and get up to date bug fixes. So I'm not convinced
that just having some company which supports the software is very 
meaningful. 

Obviously GNAT is safer, since it is free software, but I wonder about
commercial compilers. I think if I were able to get Ada used in house I'd
pay for GNAT. However, it would be nicer if the most up to date version of
GNAT were always available. Even in that case, I'd want to pay, but it 
gives me the warm-fuzzies when lots of people are hacking on it.

-- Brian