A couple of questions

A couple of questions

[Yeric]

Hello,

I am new to ADA95 but not to programming in general, I know a little C/C++,
but have a strong VB background.

I have been trying to move away from VB for a while now, I do not like the
language (my explanations could cover a book, so I will spare you all),
which is bizzare seeing as I know it so well, but then maybe it isnt so
bizzare :)

I have been trying to get to grips with C++ for about 7 months, but have
been struggling. with pointers or more precisely pointers to pointers and
arrays of pointers to arrays of functions, my head feels like it is going to
melt at times.

I am in now way rubbishing C++ I believe that every programming language has
a niche, and fits somewhere, even VB for prototyping and small applications.

I have read a few articles about Design by contract and find the concept
interesting, and wondered how ADA is able to handle this if at all?

I have already had a good read of LAW tutorial and find the whole thing very
interesting, and ADA syntax to be fairly straightforward to follow.

I see there is also good support for interfacing with other applications,
most noticeable COM/DCOM very useful if working in a Windows environment.

I am surprised not to see ADA so widely publicised like so many other well
known programming languages around, I know there is plenty of info on the
net, but not really anywhere else.

What niche does ADA fit into, I notice that it prides itself on embedded
systems, does it have any other special areas apart from what I can see in
military domains, or is it a good all rounder?

Thanks in advance
Yeric

Re: A couple of questions

[James Rogers]

"Yeric" <NOSPAM@NOSPAM.com> wrote in
news:c6usqs$31m$1@sparta.btinternet.com: 

> I have read a few articles about Design by contract and find the
> concept interesting, and wondered how ADA is able to handle this if at
> all? 

Ada handles some parts of design by contract through its ability to
define scalar types, and through strong typing.

type My_Int is range 15..25;

procedure Swap(Left, Right : in out My_Int) is
   Temp : My_Int := Left;
begin
   Left := Right;
   Right := Temp;
end Swap;

Since Left and Right are type My_Int, there is a guarantee that
all values of Left and Right are within the range defined for
My_Int.

> What niche does ADA fit into, I notice that it prides itself on
> embedded systems, does it have any other special areas apart from what
> I can see in military domains, or is it a good all rounder?

Ada is a general purpose language. It fits well in many domains.
Ada has been successfully used for manufacturing control systems,
financial applications, transportation safety and control systems,
robotic control systems, video editing, medical applications,
and scientific calculations.

Jim Rogers

Re: A couple of questions

[Martin Krischik]

Yeric wrote:

> Were does ADA fit into, I notice that it prides itself on embedded
> systems, does it have any other special areas apart from what I can see in
> military domains, or is it a good all rounder?

Ada is a general purpose Language.  Basicly you can do everything with it.

The main focus is secure (error free) programming - the language has been
designed so that most errors are found at compile time.  And for those bugs
not found a compile time Ada checks at run time and throws exceptions.

I find this very handy - For me the time spend with a debugger has been
rededuced to less the 1/10th in comparison to C++.

But unlike other "find the bug while compile" languages every dirty trick is
still open to you. You just have to type long word like
"Unchecked_Convertion" or "Unchecked_Access" and so on.

With Regards

Martin 

-- 
mailto://krischik@users.sourceforge.net
http://www.ada.krischik.com

Re: A couple of questions

[Yeric]

Thank you for your insight.

I have also been looking at a couple of other alternatives, whose names I
shall not mention to avoid a flame war, but suffice to say one language that
prides itself on how easy it is to avoid errors made in C++, choked on a
simple fibonacci example.

I entered a value too large stupidy or not, it did not handle the error very
well and locked my machine, a simple bit of error checking in the code may
have helped, and maybe I am being pedantic, but as a tutorial example I was
less than impressed to say the least.

How well does ADA interface with other languages ?
I know it has capabilities to interface with ADO through COM, what about
.NET, Can ADA do this now, are there any plans for the future ?

I also read that ADA is reviewd every 10 years, so does this mean the
language is going to change/enhance in any way for 2005 ?

One thing that makes me feel a bit uneasy about adopting ADA is that there
seems to be very little activity on web pages for it, and the ADA FAQ is
dated 1997, even some projects that are good now have not changed in over a
year.

Is this becuase the software is so reliable it does not need to be changed ?

To be fair though this is also the same for a couple of other languages I
have looked at, I guess I am used to seeing updates for C/C++ programs
mainly bug fixes :)

How would ADA handle incorrect data types being input apart from exception
handling or lots of messy if then statements ?

I would very much like to know any thoughts advantages/disadvantes of ADA
compared to another language, but I dare not mention the other languages
name to avoid being called a TROLL or starting a debate of this language is
better than that, like a similar post I noted about OO operating systems.

I guess the only way I could really know is to use them both and decide from
there, however learning one language is time consuming but two will be near
impossible.

It is interesting to see that ADA supports range checking, but how about
data type checking, does range checking preclude the need for exception
handling  for a number too large being entered ?

I guess design by contract could be handled using lots of if then statements
and carefully crafted exception handling statements ?

Can ADA interface with OpenGL ? have any games been written in ADA/would ADA
be suited for games programming ?

Are there any GUI designers available for ADA like in VB? even if this is
just designing them and compiling as a resource or exporting as ADA code ?

I have seen a couple of Commercial products for ADA Gnat Pro and GPS, but
there are no published prices for this software.

This menas that either they cost thousands or tens of thousands of pounds or
they are only availble as customised products, and dependent on what your
requiremnts are depends how much it will cost.

While learning ADA I am more than happy with ADAGide and Gnat, and Gwindows
:)

I have bookmarked ADApower.com, any other web sites that may be of interest
?

Regards
Yeric

Re: A couple of questions

[Ed Falis]

On Sat, 1 May 2004 15:12:33 +0000 (UTC), Yeric <NOSPAM@NOSPAM.com> wrote:

> Thank you for your insight.

I'll take a crack at some of these - I'm sure there will be some errors.


> How well does ADA interface with other languages ?

Ada is one of the few languages whose design attended to issues of  
interfacing to other languages.  It does well, particularly with C,  
Fortran, assember, and reasonably well with a lot of others.  There are  
specific capabilities to force calling conventions to match those of other  
languages, and there are specific packages that provide definitions of  
common base types from other languages (eg Interfaces.C,  
Interfaces.Fortran ...).

> I know it has capabilities to interface with ADO through COM, what about
> .NET, Can ADA do this now, are there any plans for the future ?

I believe Martin Carlisle at the USAF Academy and his team have made a  
port of GNAT to .NET.

>
> I also read that ADA is reviewd every 10 years, so does this mean the
> language is going to change/enhance in any way for 2005 ?

There are a number of revision issues being considered at this time, for  
enhancement to the standard in roughly 2005.

>
> One thing that makes me feel a bit uneasy about adopting ADA is that  
> there
> seems to be very little activity on web pages for it, and the ADA FAQ is
> dated 1997, even some projects that are good now have not changed in  
> over a
> year.

Don't know what to tell you.  libre.act-europe.fr is updated on a pretty  
regular basis.

> How would ADA handle incorrect data types being input apart from  
> exception
> handling or lots of messy if then statements ?

Usually by exception handling, though there is a typename'Valid (x)  
attribute available that can be used on input of broader type than  
"typename" to explicitly test.

>
> I would very much like to know any thoughts advantages/disadvantes of ADA
> compared to another language, but I dare not mention the other languages
> name to avoid being called a TROLL or starting a debate of this language  
> is
> better than that, like a similar post I noted about OO operating systems.

Well, you are on comp.lang.ada, so the likelihood of a flameware is less  
(the other posting went to a variety of language newsgroups, so invited it  
a bit more).  It's difficult to state advantages in the abstract.

I've done more than dabbling in quite a few languages, including Java,  
Eiffel, C++, Lisp, ...  The things I most appreciate about Ada are its  
flexibility, its clean syntax, well-defined semantics, and its portability  
(oh yeah, and its helpful compilers).  A nice combination.  Other  
languages I've used are IMO superior in certain areas, but don't bring  
that particular balance that I prefer.

> It is interesting to see that ADA supports range checking, but how about
> data type checking, does range checking preclude the need for exception
> handling  for a number too large being entered ?

Certain type checking can be done at compile time; other checking requires  
run-time checks.  In the latter case, exceptions are the standard way of  
flagging a violation.

>
> I guess design by contract could be handled using lots of if then  
> statements
> and carefully crafted exception handling statements ?

Several compilers provide the implementation-defined pragma Assert, that  
can be used to plant assertions in the code - It provides a lot of DBC,  
though it is not as powerful as what is found in Eiffel.  I believe this  
pragma is being added to the next revision of Ada.  Again, the mechanism  
used to enforce the assertion is an exception.

>
> Can ADA interface with OpenGL ? have any games been written in ADA/would  
> ADA
> be suited for games programming ?

I don't know about games.  The mailing list oglada@niestu.com is all about  
OpenGL bindings and use.

>
> Are there any GUI designers available for ADA like in VB? even if this is
> just designing them and compiling as a resource or exporting as ADA code  
> ?

glade is available for use with GTKAda. ObjectAda has a GUI builder for  
Windows.  There are others, I'm sure.

>
> I have seen a couple of Commercial products for ADA Gnat Pro and GPS, but
> there are no published prices for this software.

Contact sales@gnat.com or sales@act-europe.fr.  These products are mainly  
oriented towards project customers and consultative support (disclaimer: I  
work for AdaCore).  ObjectAda from Aonix has a relatively inexpensive  
version available. RR Software almost certainly does as well.  But most  
hobbiests will use public distributions of GNAT.


> I have bookmarked ADApower.com, any other web sites that may be of  
> interest
> ?

www.adaworld.com, libre.act-europe.fr

- Ed

Re: A couple of questions

[Ludovic Brenta]

"Yeric" writes:
> How well does ADA interface with other languages ?

The Ada standard contains ways to interface to C, FORTRAN and COBOL.
If you can interface to C, you can interface to pretty much any
language.  The Ada capabilities for this are very good, and standard.
On Windows it is possible to load DLLs written in almost any language
(even Visual BASIC) from Ada, or to produce Ada DLLs that can be used
from other languages.

> I know it has capabilities to interface with ADO through COM, what about
> .NET, Can ADA do this now, are there any plans for the future ?

Yes. There is an A# project here:

http://www.usafa.af.mil/dfcs/bios/mcc_html/a_sharp.html

> I also read that ADA is reviewd every 10 years, so does this mean the
> language is going to change/enhance in any way for 2005 ?

Yes indeed.  The next ISO standard is expected in Dec 2005.  For more
details, see http://www.ada-auth.org.

> One thing that makes me feel a bit uneasy about adopting ADA is that
> there seems to be very little activity on web pages for it, and the
> ADA FAQ is dated 1997, even some projects that are good now have not
> changed in over a year.
>
> Is this becuase the software is so reliable it does not need to be
> changed ?

In many cases, yes.  There are also many high-profile companies that
use Ada but don't advertise it.  Ada shines in long-lived, real-time,
embedded and safety-critical software, and some people get the
misconception that it is good only in those niches.  This is not true;
Ada is very good for general-purpose programming.

The issue of tha FAQ dating back to 1997 was raised on this newsgroup
recently.  Perhaps someone will volunteer to adopt it.

> To be fair though this is also the same for a couple of other
> languages I have looked at, I guess I am used to seeing updates for
> C/C++ programs mainly bug fixes :)

Yes.  If you look at the constant stream of patches for popular
software, you will see that most of it deals with bug fixes that any
conforming Ada compiler would have caught at compile time.  This is in
particular the case for most buffer overflows, integer overflows, and
associated security holes.

> How would ADA handle incorrect data types being input apart from
> exception handling or lots of messy if then statements ?

I'm not sure what you mean by "incorrect data types being input".  Ada
is a statically-typed language; this means that all type checks are
done at compile time.  Now if you mean checking that values received
from various inputs belong to certain data types, the checks depend on
the particular application at hand.  Ada provides several tools to
help write those checks (e.g. "in", "'Value", "'Valid").  Exceptions,
of course, are one such tool.

> I would very much like to know any thoughts advantages/disadvantes
> of ADA compared to another language, but I dare not mention the
> other languages name to avoid being called a TROLL or starting a
> debate of this language is better than that, like a similar post I
> noted about OO operating systems.

Ada is good for your mental health and for your productivity.  If
helps reduce stress by reducing the number of bugs you write.  You can
also mention other languages here; but Java, C and C++ are especially
prone to attracting flame.  Other languages like Pascal, Eiffel or
Modula-3 are well respected here.

> I guess the only way I could really know is to use them both and
> decide from there, however learning one language is time consuming
> but two will be near impossible.

I have learned and used 12 languages so far, so do not despair.  I
think your idea of writing programs in several languages and compare
the outcome is The Right Way.

> It is interesting to see that ADA supports range checking, but how
> about data type checking, does range checking preclude the need for
> exception handling for a number too large being entered ?

Most of the time, yes, the compiler eliminates run-time checks because
it can statically prove that no exception will ever be raised.  In
other cases such as user or file input, the compiler does insert
run-time checks which can raise Consraint_Error at run time.

> I guess design by contract could be handled using lots of if then
> statements and carefully crafted exception handling statements ?

Ada already provides some support for Design by Contract.  The things
it does not provide are some complex Preconditions, Post-conditions,
and Invariants.  It is possible to program all of these, of course,
possibly using exceptions.

GNAT provides an extension to the language called pragma Assert.  You
can use it at the beginning and end of each subprogram to do design by
contract at run time.  With one compiler option, you can enable and
disable all these checks.

There is also SPARK[1], an annotated subset of Ada with tools that do
full design by contract at compile time.  The SPARK tools look at
specially formatted comments that you add to your source code.  These
comments provide for pre- and postconditions as well as invariants.

[1] http://www.sparkada.com

> Can ADA interface with OpenGL ? have any games been written in
> ADA/would ADA be suited for games programming ?

Yes.  See adaopengl at http://adaopengl.sourceforge.net.

> Are there any GUI designers available for ADA like in VB? even if
> this is just designing them and compiling as a resource or exporting
> as ADA code ?

Yes.  You can write GTK+ programs on various platforms using
GtkAda[1].  The GLADE[2] GUI designer produces XML files that describe
the GUI.  GtkAda can load these files at runtime using libglade, and
also provides gate, a program that generates Ada source code from the
GLADE XML files.

[1] http://libre.act-europe.fr/GtkAda
[2] http://glade.gnome.org

There are also non-free GUI designers for Windows.  One comes with
CLAW[3].

[3] http://www.rrsoftware.com/html/prodinf/claw/claw.htm

> I have seen a couple of Commercial products for ADA Gnat Pro and
> GPS, but there are no published prices for this software.
> 
> This menas that either they cost thousands or tens of thousands of
> pounds or they are only availble as customised products, and
> dependent on what your requiremnts are depends how much it will
> cost.

Both GNAT and GPS are free software; you can download them at no cost,
with source code, from Ada Core Technologies' web site.  See
http://libre.act-europe.fr.

The commercial versions are more recent and come with support
contracts.  They are used mostly by the aerospace or other
high-profile industries.  As you suspect, the support contracts are
not for the individual developer.

> While learning ADA I am more than happy with ADAGide and Gnat, and
> Gwindows :)

Good.  You can use GPS too.

> I have bookmarked ADApower.com, any other web sites that may be of
> interest ?

Yes:

http://www.adaic.org
http://www.adaworld.com
http://www.ada-auth.org
http://www.ada-france.org
http://www.ada-belgium.org

PS. I don't know if others told you before, but it is Ada not ADA; see
http://www.adaic.org/AdaWho/byron.html for an explanation why.

-- 
Ludovic Brenta.

Re: A couple of questions

[Dennis Lee Bieber]

On Sat, 1 May 2004 15:12:33 +0000 (UTC), "Yeric" <NOSPAM@NOSPAM.com>
declaimed the following in comp.lang.ada:

> shall not mention to avoid a flame war, but suffice to say one language that

	About the only flame you are likely to trigger is that the
language is called "Ada" -- a formal name (after Augusta Ada Byron,
Countess of Lovelace, a cohort of Charles Babbage), and NOT an acronym. 

	"ADA" is the American Dental Association, or maybe the Americans
with Disabilities Act.

--  
 > ============================================================== <
 >   wlfraed@ix.netcom.com  | Wulfraed  Dennis Lee Bieber  KD6MOG <
 >      wulfraed@dm.net     |       Bestiaria Support Staff       <
 > ============================================================== <
 >           Home Page: <http://www.dm.net/~wulfraed/>            <
 >        Overflow Page: <http://wlfraed.home.netcom.com/>        <

Re: A couple of questions

[Yeric]

> There is A# right now. And other bindings.
>

This is very encouraging :)

> Yes. I've been accompanying the revision process, and I like what I see
very
> much. A number of annoyances in Ada 95 will disapear, and the standard
> library is being updated with lots of really useful stuff. Actually I'm
> using Ada 2005 right now. Ask me how.

Ok I am asking How are you using Ada 2005 :)

> Some things are old, some are new. That's the nature of the Web. There are
a
> lot of projects being updated right now.

True, I got more upto date results from google using Ada95, unfortunately
when I first googled, I did not know much about Ada-83 and Ada95, infact I
only know of Ada because of my academic background, and my old tutor used to
speak very fondly of Ada I think he used to work for M.O.D in UK.

> The latest public version of GNAT, 3.15p, has been around for a lot of
time
> with no serious problem shown.

Ok so the old saying if it aint broke dont fix it

> The bug rate of Ada vs. the other mainstream languages (C, C++, Java) is
in
> the order of 1/10.

This is good to hear, I get very frustrated with C++ at times.

Classes I understand, and inheritence I understand the logic and it makes
sense for reuse, but I wonder how many classes are simply written for a
system specific task and never re-used?

 I can think of only 2 classes I created in C++ that I used regularly, and
only one of them was used to derive a new class and add a few features.

If I understand Ada syntaxt correctly, it does not use the Class notation
but uses notation package with a tagged type ?

> Be ready for the strongly typed language there is. Types are the heart and
> soul of Ada. Once you get the type system right, the procedural code
almost
> writes itself.

Good :)

> Then take a leap of faith, or more likely an informed decision from the
> answers you are getting here.

I did :) I am finding the syntaxt relatively easier to pick up and have
already sussed how code segments are arranged in files, in a nice logical
order, I am still however going to try and learn this other language, and
since it is a well respected language in this group, I will name it as
Eiffel.

Why am I considering both and not just taking the good word of you all ?

This is no disrespect to you people, and if it causes offence then I am
sorry, but I need to keep an open mind and use both, funnily the syntax of
Ada and Eiffel are similar ( Please note I said similar not the same or
better :) )

Then perhaps not decide which one is best, but maybe see how each one can
help me solve problems in the best way.

If it turns out that I can get by using just one ( very doubtful) then I
shall, but I doubt this is likely, I guess understanding more than one tool
will not make me an expert with either tool, but will broaden my knowledge
in the general programming world hopefully.

> For static calls yes. For data coming in from outside, of course you have
to
> check. For dynamic calls, sometimes it's wise to check or handle.

I understand this now, it was design by contract that I misunderstood
thinking that it would handle external calls, but logically it cant I guess,
how can you prempt the unknown, sorry this was my stupidity :)

> Yes. The most impressive graphical stuff I've seen is

This is encouraging also.

> GLADE is your friend.

Ah yes Glade, and AdaGTK, this just gets better :)
>

> There is a public, gratis, GNAT and GPS. If you need professional support
> ask ACT or another consultancy/consultant for the prices.

I am not sure I will need such services yet, but it is also encouraging to
see that it is used commercially.

> Strictly to learn Ada GNAT and a good book suffices. AdaGide, GPS, Emacs,
> Notepad are all good editors. I guess using Gwindows can help practicing,
> but you will not *learn* more *Ada* from there than just from using the
> standard libraries.

I understand this, I was just scoping what is available, for future
references :)

> adaworld.com, adaic.org, ada-auth.org
>
> * * *
>
> I came from C to Ada 95 circa 10 years ago. It improved a lot both the
> quality of my software process, including productivity, and the quality of
> the products. When I was making the shift, I also tried other languages,
> including C++ and Java. I don't have a definite opinion on the quality of
> these languages vs. Ada, because I didn't advance my expertise in them. I
> only know Ada has been serving me well, and from continuing contacts with
> other languages and respective programmers of all level, I still haven't
> found any reason to change.


This is quite interesting, I have taken a similar path, except my background
is VB.

 I also tried Java thought it was the answer to everything, but soon found
this not to be the case, especially with very large Java apps where loading
would be slow and at times unresponsive, and was even worse if trying to run
any other programs at the same time.

However I think Java still serves as a better learning tool than VB for
instance, I have not to my knowledge heard of any educational institution
using Ada as a learning language in the UK.

Thanks everyone for all your answers and help, it is refreshing to post to a
group and receive such useful and qualifying answers.

Thanks also for the tip on the name :) Ada rather than ADA, I just read the
story about Lady Ada and now also understand where the name derives from.

Regards
Yeric

Re: A couple of questions

[Marius Amado Alves]

Yeric <NOSPAM@NOSPAM.com> wrote in message
news:c6usqs$31m$1@sparta.btinternet.com...
> Hello,
>
> I am new to ADA95 but not to programming in general, I know a little
C/C++,
> but have a strong VB background.

Welcome! You can now start writing Ada not ADA as your first rite of passage
:-)

> I have been trying to move away from VB for a while now, I do not like the
> language (my explanations could cover a book, so I will spare you all),
> which is bizzare seeing as I know it so well, but then maybe it isnt so
> bizzare :)

Don't bother :-)

> I have been trying to get to grips with C++ for about 7 months, but have
> been struggling. with pointers or more precisely pointers to pointers and
> arrays of pointers to arrays of functions, my head feels like it is going
to
> melt at times.

A pointerless mind. Good. In Ada you very rarely need to use pointers
(called access types and values in Ada). And when you do she will work hard
to save you from shooting yourself in the foot. Ada 2005 will improve on
this camp further. With the standard container library, you can forget about
pointers entirely. Passing functions will be maximally simplified. Generics
will be more powerfull.

> I am in now way rubbishing C++ I believe that every programming language
has
> a niche, and fits somewhere, even VB for prototyping and small
applications.

Once you have the right environment setup, Ada is good for programming in
the small also. I do all my 'scripting' in Ada.

> I have read a few articles about Design by contract and find the concept
> interesting, and wondered how ADA is able to handle this if at all?

Generic units provide a LOT of contract.

> I have already had a good read of LAW tutorial and find the whole thing
very
> interesting, and ADA syntax to be fairly straightforward to follow.

The syntax is indeed very easy. And most of the language behaves as
expected. In some specific idioms the semantics gets in your way. Stay away
from limited types.

> I see there is also good support for interfacing with other applications,
> most noticeable COM/DCOM very useful if working in a Windows environment.

And there are alternatives. GWindows, JWEL, Claw, GtkAda.

> I am surprised not to see ADA so widely publicised like so many other well
> known programming languages around, I know there is plenty of info on the
> net, but not really anywhere else.

There are books. Good ones BTW.

> What niche does ADA fit into, I notice that it prides itself on embedded
> systems, does it have any other special areas apart from what I can see in
> military domains, or is it a good all rounder?

I use Ada for artificial intelligence, text processing, web systems,
database systems...

(A "couple of questions" uh? :-)

Re: A couple of questions

[Ludovic Brenta]

"Yeric" writes:
> Why am I considering both and not just taking the good word of you
> all ?
> 
> This is no disrespect to you people, and if it causes offence then I
> am sorry, but I need to keep an open mind and use both, funnily the
> syntax of Ada and Eiffel are similar ( Please note I said similar
> not the same or better :) )

People who take the time to gather information before making a
decision deserve respect.  There are few like you who understand that
they will learn even from languages they finally dismiss.

I also evaluated Eiffel, and was impressed with it, before I finally
decided I liked Ada better because Ada does not force object-oriented
formalisms on those who don't need them, has more composition
mechanisms than just inheritance, and provides range checking in the
type system rather than contracts.  YMMV.  Good luck with your
evaluation.

-- 
Ludovic Brenta.

Re: A couple of questions

[Yeric]

> People who take the time to gather information before making a
> decision deserve respect.  There are few like you who understand that
> they will learn even from languages they finally dismiss.

Thank you

>
> I also evaluated Eiffel, and was impressed with it, before I finally
> decided I liked Ada better because Ada does not force object-oriented
> formalisms on those who don't need them, has more composition
> mechanisms than just inheritance, and provides range checking in the
> type system rather than contracts.  YMMV.  Good luck with your
> evaluation.
>
> -- 
> Ludovic Brenta.

YMMV ?

Yes I understand what you are saying about Eiffel, Ada seems to allow mixed
OO & non OO it is the programmers decision, but also makes sure the code is
safer regardles of the style(s) chosen.

I have not fully explored OO, but from my experience with Java, it somtimes
seemed awkward to use OO implementations, where a procedural non OO solution
seemed more natural.

Maybe choice is a good thing, and the programmer is still allowed to take
more control of the program without sacrificing safety.

From what I have seen of Ada and Eiffel syntax, it seems more natural to
write and read certainly more so than Java or C++, not that I am rubbishing
either language, it is just that they seem unatuaral if that makes sense?

There were times when writing in C++, that I could almost translate the
syntax into assembler in my mind while typing it, not that I know a great
deal of assembly language, but we were subjected to 8 weeks of it as part of
our understanding of computers and programming languages. It taught me a lot
but certainly not assembly language :)

Thanks agin for all the replies and help so far, I am in no doubt, that I
will be posting again, when the answers I find on google do not make as much
sense as the answers in this news group.

Yeric

Re: A couple of questions

[Ed Falis]

Yeric,

You've selected a couple of great languages to investigate.  If I had my  
choice of my favorite two to use, it would be Ada and Eiffel.  There are  
different situations in which I would prefer one over the other, but I'd  
be happy with either in most situations.

And yes, I think Bertrand Meyer has acknowledged the influence of Ada on  
his language design.

Would have been interesting to see how the current Ada standard measures  
up in Ian Joyner's "Objects Unencapsulated", don't you think?

- Ed

Re: A couple of questions

[Jeffrey Carter]

Yeric wrote:

> Can ADA interface with OpenGL ? have any games been written in
> ADA/would ADA be suited for games programming ?

You might be interested in the Mine Detector game:

http://home.earthlink.net/~jrcarter010/mindet.html

It may not be exactly what you have in mind when you say "games", but 
it's certainly a game, and certainly written in Ada.

-- 
Jeff Carter
"I've got to stay here, but there's no reason
why you folks shouldn't go out into the lobby
until this thing blows over."
Horse Feathers
50

Re: A couple of questions

[Marius Amado Alves]

> How well does ADA interface with other languages ?

Well enough.

> I know it has capabilities to interface with ADO through COM, what about
> .NET, Can ADA do this now, are there any plans for the future ?

There is A# right now. And other bindings.

> I also read that ADA is reviewd every 10 years, so does this mean the
> language is going to change/enhance in any way for 2005 ?

Yes. I've been accompanying the revision process, and I like what I see very
much. A number of annoyances in Ada 95 will disapear, and the standard
library is being updated with lots of really useful stuff. Actually I'm
using Ada 2005 right now. Ask me how.

> One thing that makes me feel a bit uneasy about adopting ADA is that there
> seems to be very little activity on web pages for it, and the ADA FAQ is
> dated 1997, even some projects that are good now have not changed in over
a
> year.

Some things are old, some are new. That's the nature of the Web. There are a
lot of projects being updated right now.

> Is this becuase the software is so reliable it does not need to be changed
?

The latest public version of GNAT, 3.15p, has been around for a lot of time
with no serious problem shown.

> To be fair though this is also the same for a couple of other languages I
> have looked at, I guess I am used to seeing updates for C/C++ programs
> mainly bug fixes :)

The bug rate of Ada vs. the other mainstream languages (C, C++, Java) is in
the order of 1/10.

> How would ADA handle incorrect data types being input apart from exception
> handling or lots of messy if then statements ?

Be ready for the strongly typed language there is. Types are the heart and
soul of Ada. Once you get the type system right, the procedural code almost
writes itself.

> I would very much like to know any thoughts advantages/disadvantes of ADA
> compared to another language, but I dare not mention the other languages
> name to avoid being called a TROLL or starting a debate of this language
is
> better than that, like a similar post I noted about OO operating systems.

> I guess the only way I could really know is to use them both and decide
from
> there, however learning one language is time consuming but two will be
near
> impossible.

Then take a leap of faith, or more likely an informed decision from the
answers you are getting here.

> It is interesting to see that ADA supports range checking, but how about
> data type checking, does range checking preclude the need for exception
> handling  for a number too large being entered ?

For static calls yes. For data coming in from outside, of course you have to
check. For dynamic calls, sometimes it's wise to check or handle.

> I guess design by contract could be handled using lots of if then
statements
> and carefully crafted exception handling statements ?

No. The contract begins with the types you define, including generics.

> Can ADA interface with OpenGL ? have any games been written in ADA/would
ADA
> be suited for games programming ?

Yes. The most impressive graphical stuff I've seen is

> Are there any GUI designers available for ADA like in VB? even if this is
> just designing them and compiling as a resource or exporting as ADA code ?

GLADE is your friend.

> I have seen a couple of Commercial products for ADA Gnat Pro and GPS, but
> there are no published prices for this software.

There is a public, gratis, GNAT and GPS. If you need professional support
ask ACT or another consultancy/consultant for the prices.

> This menas that either they cost thousands or tens of thousands of pounds
or
> they are only availble as customised products, and dependent on what your
> requiremnts are depends how much it will cost.

Any consultancy will offer you either a standard package or costumized
support. It's your call.

> While learning ADA I am more than happy with ADAGide and Gnat, and
Gwindows

Strictly to learn Ada GNAT and a good book suffices. AdaGide, GPS, Emacs,
Notepad are all good editors. I guess using Gwindows can help practicing,
but you will not *learn* more *Ada* from there than just from using the
standard libraries.

> I have bookmarked ADApower.com, any other web sites that may be of
interest
> ?

adaworld.com, adaic.org, ada-auth.org

* * *

I came from C to Ada 95 circa 10 years ago. It improved a lot both the
quality of my software process, including productivity, and the quality of
the products. When I was making the shift, I also tried other languages,
including C++ and Java. I don't have a definite opinion on the quality of
these languages vs. Ada, because I didn't advance my expertise in them. I
only know Ada has been serving me well, and from continuing contacts with
other languages and respective programmers of all level, I still haven't
found any reason to change.

Re: A couple of questions

[Marius Amado Alves]

"The most impressive graphical stuff I've seen is..."

... a webpage that I cannot pinpoint now. Of course if OpenGL suits you then
you're in the clear. There are bindings. I think that if I needed complex
graphics now I would try OpenGL first.

/*
Some years back a toured the Web for image generation stuff and I distinctly
remember that the most impressive results I found were associated with Ada.
I cannot reproduce that just now. Maybe the pages have moved, maybe they
were the usual OpenGL suspects still out there now and my perception, or
their image, has changed... I seem to remember an horrible acronym, maybe
DJGPP.
*/

Re: A couple of questions

[Marius Amado Alves]

> Ok I am asking How are you using Ada 2005 :)

- using a reference implementation of Ada.Containers

- passing functions at will with 'Unrestricted_Access because I know
something similar will be legal in Ada 2005

- designing for passing generic units to generic units, which will also be
possible in Ada 2005

- ...

> ... I am still however going to try and learn this other language, and
> since it is a well respected language in this group, I will name it as
> Eiffel.

I know Eiffel theoretically and there I find its quality not inferior to
Ada. I'm not sure about support, libraries, open source...

Re: A couple of questions

[Georg Bauhaus]

Yeric <NOSPAM@nospam.com> wrote:
 
: I am still however going to try and learn this other language, and
: since it is a well respected language in this group, I will name it as
: Eiffel.
: 
: Why am I considering both and not just taking the good word of you all ?

Actually there are two ways to use both languages for writing a program.
One is .NET, the other uses the standard mechanisms for calling
external subprograms in either language.

: I understand this now, it was design by contract that I misunderstood
: thinking that it would handle external calls, but logically it cant I guess,

Oh it can. If programmers decide they know the outcome of calling
an external routine, the can say so in the contract.
After all, even without explicit DbC you have to specify the type of the
result and this is a contract item too.

There is an Ada Issue (288) discussing pragmas Pre_Assert,
Classwide_Pre_Assert, and Post_Assert for inclusion in the next
standard. They formalise DbC for future Ada programs.

The names have been changed from Precondition and Postcondition,
unfortunatly, falling short of customary Ada names' quality in my view.


-- Georg

Re: A couple of questions

[Martin Dowie]

"Georg Bauhaus" <sb463ba@l1-hrz.uni-duisburg.de> wrote in message
news:c72d27$cpo$1@a1-hrz.uni-duisburg.de...
> There is an Ada Issue (288) discussing pragmas Pre_Assert,
> Classwide_Pre_Assert, and Post_Assert for inclusion in the next
> standard. They formalise DbC for future Ada programs.
>
> The names have been changed from Precondition and Postcondition,
> unfortunatly, falling short of customary Ada names' quality in my view.

These are not going to be in the next language revision - they are
"No Action". The "Assert" pragma is however going to make it, so
I guess you could make an arguement that the user can mimic pre
and post conditions them selves, with some disapline, e.g.

procedure Foo is
begin
   pragma Assert (<some_pre_condition>);
   -- whatever Foo does
   pragma Assert (<some_post_condition>);
end Foo;

-- Martin

Re: A couple of questions

[Georg Bauhaus]

Martin Dowie <martin.dowie@btopenworld.com> wrote:
:> The names have been changed from Precondition and Postcondition,
:> unfortunatly, falling short of customary Ada names' quality in my view.
: 
: These are not going to be in the next language revision - they are
: "No Action". The "Assert" pragma is however going to make it, so
: I guess you could make an arguement that the user can mimic pre
: and post conditions them selves, with some disapline, e.g.

Ah, yes. I've just taken another look and there seems to be
some hope for DbC fans, expressed in AI-286:

"It anticipates proposals for additional assertion-like
pragmas for subprogram call pre and post conditions, and
type and package oriented invariants. These will be discussed
in separate AIs."

-- Georg

Re: A couple of questions

[Yeric]

> And yes, I think Bertrand Meyer has acknowledged the influence of Ada on
> his language design.

Yes they are similar :)

>
> Would have been interesting to see how the current Ada standard measures
> up in Ian Joyner's "Objects Unencapsulated", don't you think?

I have not read this book, but it is also interesting to see that Ada is not
compared with languages such as C++ Java Smalltalk like Eiffel is.

Reading more about Ada, I am seeing that Ada is a practical language,
allowing the programmer to make his/her informed decisions on how to
implement code.

I like this idea, I am in no way rubbishing OOP, OOP makes sense for most
programming and is indeed a more natural way of programming, however there
are times when defining a class to perform the simplest of things can be
overkill IMHO.

Eiffel does not allow any orphan functions/features or variables to exist,
everything is wrapped in classes, true OO.

Yeric

Re: A couple of questions

[Ed Falis]

On Sun, 2 May 2004 12:00:37 +0000 (UTC), Yeric <NOSPAM@NOSPAM.com> wrote:

>>
>> Would have been interesting to see how the current Ada standard measures
>> up in Ian Joyner's "Objects Unencapsulated", don't you think?
>
> I have not read this book, but it is also interesting to see that Ada is  
> not
> compared with languages such as C++ Java Smalltalk like Eiffel is.

That's easily explained by the fact that Ian is an Eiffel advocate ;-)

- Ed

Re: A couple of questions

[Pascal Obry]

"Yeric" <NOSPAM@NOSPAM.com> writes:

> I am still however going to try and learn this other language, and
> since it is a well respected language in this group, I will name it as
> Eiffel.

Eiffel is a very good language, certainly my second favorite language
after Ada. It is worth learning it I would say. There is a good Open Source
implementation of Eiffel named SmartEiffel. The only minus to Eiffel is that
the community is even smaller than the Ada one, yet you have lot of nice
libraries for OpenGL, XML, GTK, DBMS...

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.org
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595

Re: A couple of questions

[Martin Krischik]

Ed Falis wrote:

>> I have seen a couple of Commercial products for ADA Gnat Pro and GPS, but
>> there are no published prices for this software.
> 
> Contact sales@gnat.com or sales@act-europe.fr.ￜￜTheseￜproductsￜareￜmainly
> oriented towards project customers and consultative support (disclaimer: I
> work for AdaCore).ￜ

I find it very sad that AdaCore does not publish any prices - not even for
the standart platforms Windows and Linux.

With Regards

Martin
-- 
mailto://krischik@users.sourceforge.net
http://www.ada.krischik.com

Re: A couple of questions

[Marius Amado Alves]

> Reading more about Ada, I am seeing that Ada is a practical language,
> allowing the programmer to make his/her informed decisions on how to
> implement code.

That's right. That's called the "building blocks" approach of Ada. Which if
effect makes her multiparadigmatic. The current de rigueur multiparadigm
language is Oz, and in this camp Oz is more complete than Ada, but I find
Ada's combination of features more balanced, and her syntax much much
better.

Re: A couple of questions

[Jeff C,]

"Martin Krischik" <krischik@users.sourceforge.net> wrote in message >
> I find it very sad that AdaCore does not publish any prices - not even for
> the standart platforms Windows and Linux.


It may be sad but it is very typical of vendors that work in this space (not
the Ada market per se but the expensive tools targeted at big company
market).

Re: A couple of questions

[Martin Krischik]

Jeff C, wrote:

> "Martin Krischik"reasonablek@users.sourceforge.net> wrote in message >
>> I find it very sad that AdaCore does not publish any prices - not even
>> for the standart platforms Windows and Linux.

> It may be sad but it is very typical of vendors that work in this space
> (not the Ada market per se but the expensive tools targeted at big company
> market).

Or corse the loose the middle customers. And funnily enough, the loose them
to themself since there are the Open-Source releases.

If there where a boxed version for reasonable price I would consider it.

And let me think a little further: C and C++ support is constantly enhanced
in gps and there is currently no one in the gcc distribution and support
market - at least not as far as I know.

If you want gcc you use the one with your linux distribution or cygwin. But
they can't give you dedicated gcc related support. And they also don't give
you a gps.

Just thinking.

With Regards

Martin

-- 
mailto://krischik@users.sourceforge.net
http://www.ada.krischik.com

Re: A couple of questions

[Hyman Rosen]

Martin Krischik wrote:
> If there where a boxed version for reasonable price I would consider it.

The problem is that the box does not contain a compiler
but a support contract. And what is a reasonable price
for you is a money-losing waste of time for ACT. It's
likely that customers who are able to pay for expensive
support contracts actually use much less support than
would a multitude of people buying cheap ones.

Re: A couple of questions

[Martin Krischik]

Hyman Rosen wrote:

> Martin Krischik wrote:

>> If there where a boxed version for reasonable price I would consider it.
 
> The problem is that the box does not contain a compiler
> but a support contract. And what is a reasonable price
> for you is a money-losing waste of time for ACT. It's
> likely that customers who are able to pay for expensive
> support contracts actually use much less support than
> would a multitude of people buying cheap ones.

True enough.  I guess the "mass market"  for compilers is just not big
enough to make money with after all. 

BTW: With me "reasonable" depend if "Martin" or "Mr. Krischik, BSc" is
making the decision ;-).

With Regards

Martin

-- 
mailto://krischik@users.sourceforge.net
http://www.ada.krischik.com