Learning Ada but missing the basics?

Learning Ada but missing the basics?

[ryan k]

I'm trying to learn Ada because a) I think it's cool to learn new
computer languages and b) it looks like a good one. I've gone the
through a lot of the tutorials but lets say have package MyPackage and
5 subprograms are in the body. Which procedure is run first? Is it
sequential? Is there some sort of equivalent to C's main()? Is a
binary created for every package? I guess I don't understand where
things start and end. Any help or links are greatly appreciated!

Thanks,
Ryan Kaskel

Re: Learning Ada but missing the basics?

[Keith Thompson]

ryan k <ryan@ryankaskel.com> writes:
> I'm trying to learn Ada because a) I think it's cool to learn new
> computer languages and b) it looks like a good one. I've gone the
> through a lot of the tutorials but lets say have package MyPackage and
> 5 subprograms are in the body. Which procedure is run first? Is it
> sequential?

None of them will run unless they're called.

>             Is there some sort of equivalent to C's main()?

Not exactly.  There's no special name for the entry point.  You
specify it when you link the program.

>                                                             Is a
> binary created for every package?

That depends on what you mean by "a binary".  There typically won't be
an executable created for each package.  An Ada package is similar in
some ways to a separately compiled C source file; you can combine
several of them, along with a procedure that's specified to be the
main program, into a single program.  The details of how you do this
are defined by each implementation, not by the language.

>                                   I guess I don't understand where
> things start and end. Any help or links are greatly appreciated!

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Nokia
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

Re: Learning Ada but missing the basics?

[ryan k]

On Jun 30, 4:19 pm, Keith Thompson <ks...@mib.org> wrote:
> ryan k <r...@ryankaskel.com> writes:
> > I'm trying to learn Ada because a) I think it's cool to learn new
> > computer languages and b) it looks like a good one. I've gone the
> > through a lot of the tutorials but lets say have package MyPackage and
> > 5 subprograms are in the body. Which procedure is run first? Is it
> > sequential?
>
> None of them will run unless they're called.
>
> >             Is there some sort of equivalent to C's main()?
>
> Not exactly.  There's no special name for the entry point.  You
> specify it when you link the program.
>
> >                                                             Is a
> > binary created for every package?
>
> That depends on what you mean by "a binary".  There typically won't be
> an executable created for each package.  An Ada package is similar in
> some ways to a separately compiled C source file; you can combine
> several of them, along with a procedure that's specified to be the
> main program, into a single program.  The details of how you do this
> are defined by each implementation, not by the language.
>
> >                                   I guess I don't understand where
> > things start and end. Any help or links are greatly appreciated!
>
> --
> Keith Thompson (The_Other_Keith) ks...@mib.org  <http://www.ghoti.net/~kst>
> Nokia
> "We must do something.  This is something.  Therefore, we must do this."
>     -- Antony Jay and Jonathan Lynn, "Yes Minister"

I use the GNAT compiler. How then do I specify the main procedure?

Thanks.

Re: Learning Ada but missing the basics?

[mockturtle]

On Jun 30, 10:38 pm, ryan k <r...@ryankaskel.com> wrote:
> On Jun 30, 4:19 pm, Keith Thompson <ks...@mib.org> wrote:
>
>
>
> > ryan k <r...@ryankaskel.com> writes:
> > > I'm trying to learn Ada because a) I think it's cool to learn new
> > > computer languages and b) it looks like a good one. I've gone the
> > > through a lot of the tutorials but lets say have package MyPackage and
> > > 5 subprograms are in the body. Which procedure is run first? Is it
> > > sequential?
>
> > None of them will run unless they're called.
>
> > >             Is there some sort of equivalent to C's main()?
>
> > Not exactly.  There's no special name for the entry point.  You
> > specify it when you link the program.
>
> > >                                                             Is a
> > > binary created for every package?
>
> > That depends on what you mean by "a binary".  There typically won't be
> > an executable created for each package.  An Ada package is similar in
> > some ways to a separately compiled C source file; you can combine
> > several of them, along with a procedure that's specified to be the
> > main program, into a single program.  The details of how you do this
> > are defined by each implementation, not by the language.
>
> > >                                   I guess I don't understand where
> > > things start and end. Any help or links are greatly appreciated!
>
> > --
> > Keith Thompson (The_Other_Keith) ks...@mib.org  <http://www.ghoti.net/~kst>
> > Nokia
> > "We must do something.  This is something.  Therefore, we must do this."
> >     -- Antony Jay and Jonathan Lynn, "Yes Minister"
>
> I use the GNAT compiler. How then do I specify the main procedure?
>
> Thanks.

I remember I had the same problem when I began... ;-)

Just write a file some_name.adb with a procedure some_name in it.
When you use

        gnatmake some_name

GNAT will take care of all the dependencies and will create
an executable file "some_name".  When you run it, the procedure
some_name will be executed.
(BTW, is not this great? No *#$% Makefiles...)

For example, here it is the typical "Hello World"

-- BEGIN File hello_world.adb
with Text_Io;

procedure Hello_World is
begin
  Text_Io.Put_Line("Hello World!");
end Hello_World;
-- END File hello_world.adb

Disclaimer: I wrote the code above "on the fly" and I did not
check if it compiles, although it should...

Re: Learning Ada but missing the basics?

[Jeffrey R. Carter]

ryan k wrote:
> I'm trying to learn Ada because a) I think it's cool to learn new
> computer languages and b) it looks like a good one. I've gone the
> through a lot of the tutorials but lets say have package MyPackage and
> 5 subprograms are in the body. Which procedure is run first? Is it
> sequential? Is there some sort of equivalent to C's main()? Is a
> binary created for every package? I guess I don't understand where
> things start and end. Any help or links are greatly appreciated!

You've clearly missed something.

Ada is a concurrent language; this answer assumes you haven't created any tasks.

The thread of control in an Ada program is called the environment task. It 
performs elaboration and initialization as needed, calls the main-program 
procedure, and finally performs any finalization that's needed.

The main-program procedure is one that you designate during the building of the 
executable.

Subprograms in packages are only "run" if they're called.

Consider the typical hello-world example:

with Ada.Text_IO;

procedure Hello is
    -- null;
begin -- Hello
    Ada.Text_IO.Put_Line (Item => "Hello, World!");
end Hello;

Here, procedure Hello is the main-program procedure. You indicate that when 
building the executable. For instance, with GNAT you would put it in a file 
named hello.adb and might say

gnatmake -gnato -fstack-check -O1 hello

which will create an executable named hello[.platform-dependent-extension].

Ada.Text_IO is a package which contains a number of subprograms. In this 
example, we call its procedure Put_Line. Put_Line may call other subprograms in 
Ada.Text_IO or in other packages. These are the only subprograms that are "run".

HTH.

-- 
Jeff Carter
"Your mother was a hamster and your father smelt of elderberries."
Monty Python & the Holy Grail
06

Re: Learning Ada but missing the basics?

[ryan k]

On Jun 30, 5:48 pm, "Jeffrey R. Carter"
<spam.jrcarter....@spam.acm.org> wrote:
> ryan k wrote:
> > I'm trying to learn Ada because a) I think it's cool to learn new
> > computer languages and b) it looks like a good one. I've gone the
> > through a lot of the tutorials but lets say have package MyPackage and
> > 5 subprograms are in the body. Which procedure is run first? Is it
> > sequential? Is there some sort of equivalent to C's main()? Is a
> > binary created for every package? I guess I don't understand where
> > things start and end. Any help or links are greatly appreciated!
>
> You've clearly missed something.
>
> Ada is a concurrent language; this answer assumes you haven't created any tasks.
>
> The thread of control in an Ada program is called the environment task. It
> performs elaboration and initialization as needed, calls the main-program
> procedure, and finally performs any finalization that's needed.
>
> The main-program procedure is one that you designate during the building of the
> executable.
>
> Subprograms in packages are only "run" if they're called.
>
> Consider the typical hello-world example:
>
> with Ada.Text_IO;
>
> procedure Hello is
>     -- null;
> begin -- Hello
>     Ada.Text_IO.Put_Line (Item => "Hello, World!");
> end Hello;
>
> Here, procedure Hello is the main-program procedure. You indicate that when
> building the executable. For instance, with GNAT you would put it in a file
> named hello.adb and might say
>
> gnatmake -gnato -fstack-check -O1 hello
>
> which will create an executable named hello[.platform-dependent-extension].
>
> Ada.Text_IO is a package which contains a number of subprograms. In this
> example, we call its procedure Put_Line. Put_Line may call other subprograms in
> Ada.Text_IO or in other packages. These are the only subprograms that are "run".
>
> HTH.
>
> --
> Jeff Carter
> "Your mother was a hamster and your father smelt of elderberries."
> Monty Python & the Holy Grail
> 06

Could anyone point me to an SVN repository for a good, well written
open source Ada application?

Re: Learning Ada but missing the basics?

[Tero Koskinen]

On Mon, 30 Jun 2008 18:15:19 -0700 (PDT) ryan k wrote:
> Could anyone point me to an SVN repository for a good, well written
> open source Ada application?

Check listings at
  http://www.ohloh.net/projects/search?q=ada&x=0&y=0 ,
  http://freshmeat.net/browse/163/ ,
  http://sourceforge.net/search/?type_of_search=soft&words=ada , and
  http://code.google.com/hosting/search?q=label:Ada

for some repositories. Most of the open source Ada projects
are libraries, but if you want an application, you could check
AdaControl (http://www.adalog.fr/adacontrol2.htm, no public
SVN repository available).

-- 
Tero Koskinen - http://iki.fi/tero.koskinen/

Re: Learning Ada but missing the basics?

[Jeffrey R. Carter]

ryan k wrote:
> 
> Could anyone point me to an SVN repository for a good, well written
> open source Ada application?

No. But I could point you to the source for the Mine Detector game:

http://pragmada.home.mchsi.com/mindet.html

-- 
Jeff Carter
"Your mother was a hamster and your father smelt of elderberries."
Monty Python & the Holy Grail
06

Re: Learning Ada but missing the basics?

[DScott]

ryan k wrote:
...
> 
> Could anyone point me to an SVN repository for a good, well written
> open source Ada application?

"Well written" you will have to judge for yourself, but I am glad to give you a copy of a 
small project management tool in Ada if you wish. Is the email address in your posts 
accurate and valid? (Mine in this post is *NOT*!)
-- 
Fui et vidi experiri.
=DSM=

Re: Learning Ada but missing the basics?

[Pascal Obry]

ryan k a �crit :
> Could anyone point me to an SVN repository for a good, well written
> open source Ada application?

Look at AWS and Templates_Parser code. I have put lot of efforts to be 
sure the code is clean, documented and readable. It uses many Ada 
features even some Ada 2005 ones (interfaces, object.method notation, 
anonymous access...).

    https://libre.adacore.com/aws/

If you are adventurous do not hesitate to have a look at the GNAT code 
itself. It is quite large but really clean.

You'll see that on those projects the code quality and style is uniform 
in all the sources. This makes a project easier to maintain by a group 
of people. No one own (by using weird style for example where other 
developers do not feel comfortable) a part of the code. This to say that 
there is no ONE good style but most importantly a style must be 
followed, uniformity is more important to me.

Pascal.

-- 

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

Re: Learning Ada but missing the basics?

[Alex R. Mosteo]

Pascal Obry wrote:

> ryan k a écrit :
>> Could anyone point me to an SVN repository for a good, well written
>> open source Ada application?
> 
> Look at AWS and Templates_Parser code. I have put lot of efforts to be
> sure the code is clean, documented and readable. It uses many Ada
> features even some Ada 2005 ones (interfaces, object.method notation,
> anonymous access...).
> 
>     https://libre.adacore.com/aws/
> 
> If you are adventurous do not hesitate to have a look at the GNAT code
> itself. It is quite large but really clean.
> 
> You'll see that on those projects the code quality and style is uniform
> in all the sources. This makes a project easier to maintain by a group
> of people. No one own (by using weird style for example where other
> developers do not feel comfortable) a part of the code. This to say that
> there is no ONE good style but most importantly a style must be
> followed, uniformity is more important to me.

In this regard, gnat style switches are truly useful. I find I've added quite a
few over time to my defaults.

Re: Learning Ada but missing the basics?

[Georg Bauhaus]

Alex R. Mosteo wrote:
> Pascal Obry wrote:

>> You'll see that on those projects the code quality and style is uniform
>> in all the sources. This makes a project easier to maintain by a group
>> of people. No one own (by using weird style for example where other
>> developers do not feel comfortable) a part of the code. This to say that
>> there is no ONE good style but most importantly a style must be
>> followed, uniformity is more important to me.
> 
> In this regard, gnat style switches are truly useful. I find I've added quite a
> few over time to my defaults.

Which ones of the GNAT style switches do you think have greater
influence on your programs' stability and design? The ones
that criticize typographic qualities, or those that comment
on the qualities of the non-white code?


 -- Georg

Re: Learning Ada but missing the basics?

[Alex R. Mosteo]

Georg Bauhaus wrote:

> Alex R. Mosteo wrote:
>> Pascal Obry wrote:
> 
>>> You'll see that on those projects the code quality and style is uniform
>>> in all the sources. This makes a project easier to maintain by a group
>>> of people. No one own (by using weird style for example where other
>>> developers do not feel comfortable) a part of the code. This to say that
>>> there is no ONE good style but most importantly a style must be
>>> followed, uniformity is more important to me.
>> 
>> In this regard, gnat style switches are truly useful. I find I've added
>> quite a few over time to my defaults.
> 
> Which ones of the GNAT style switches do you think have greater
> influence on your programs' stability and design? The ones
> that criticize typographic qualities, or those that comment
> on the qualities of the non-white code?

I couldn't point to a precise effect, but I like the overall result. In one
hand, nice whitespacing goes a long way into readability. I know people that
dismiss certain kinds of whitespace/comments on the basis that a good editor
highlights what's important, but I'm not totally in this camp.

I have also an itching for the little (many times not useful) details which
borders in obsessiveness, so consistent capitalization (on the fly by the
editor and then checked) saves me a lot of uneasiness and time. Admittedly,
this is a personal problem.

It will not come as a surprise that I like gnatpp a lot.

Re: Learning Ada but missing the basics?

[Simon Wright]

"Alex R. Mosteo" <devnull@mailinator.com> writes:

> In this regard, gnat style switches are truly useful. I find I've
> added quite a few over time to my defaults.

We use -gnaty (in other words, the defaults!). It seemed to me to be
easier to do this than to have perpetual wrangles about which ones are
in, which ones out.

There was a complaint that the default line length (79) is too short,
but this was from a person who believed in long names:

  Message_Processing.Process_The_Message (The_Message_To_Be_Processed : String);

(and that's not the worst instance!)

This was the person who thought the way to get rid of style warnings
was to turn them off.

--S

Re: Learning Ada but missing the basics?

[Pascal Obry]

Simon Wright a �crit :
> This was the person who thought the way to get rid of style warnings
> was to turn them off.

And to avoid out-of-style commit it is quite handy to add checks 
(gnatcheck, gnat -gnaty, ...) on the pre-commit hook of your favorite SCM.

-- 

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

Re: Learning Ada but missing the basics?

[Alex R. Mosteo]

Simon Wright wrote:

> "Alex R. Mosteo" <devnull@mailinator.com> writes:
> 
>> In this regard, gnat style switches are truly useful. I find I've
>> added quite a few over time to my defaults.
> 
> We use -gnaty (in other words, the defaults!). It seemed to me to be
> easier to do this than to have perpetual wrangles about which ones are
> in, which ones out.

This is true, but I use a large code base which would throw thousands of
warnings with this setting. Until I find the time to find a more palatable
solution (possibly separate project files for these offending parts), I've
found this to be the easiest.

In the same vein, in the past I used to hand pick my warning settings, while
nowadays I go with -gnatwa.

> 
> There was a complaint that the default line length (79) is too short,
> but this was from a person who believed in long names:
> 
>   Message_Processing.Process_The_Message (The_Message_To_Be_Processed :
>   String);
> 
> (and that's not the worst instance!)
> 
> This was the person who thought the way to get rid of style warnings
> was to turn them off.

Re: Learning Ada but missing the basics?

[Jean-Pierre Rosen]

Alex R. Mosteo a �crit :
> This is true, but I use a large code base which would throw thousands of
> warnings with this setting. Until I find the time to find a more palatable
> solution (possibly separate project files for these offending parts), I've
> found this to be the easiest.
> 
Maybe AdaControl could provide you with a more finely parameterizable 
and tunable solution... ;-)
-- 
---------------------------------------------------------
            J-P. Rosen (rosen@adalog.fr)
Visit Adalog's web site at http://www.adalog.fr

Re: Learning Ada but missing the basics?

[Gautier]

ryan k:
> Could anyone point me to an SVN repository for a good, well written
> open source Ada application?

Not necessarily well-written, but open-source and with SVN:

http://sf.net/projects/globe3d

Have fun!
Gautier

Re: Learning Ada but missing the basics?

[John McCormick]

On Jun 30, 2:01 pm, ryan k <r...@ryankaskel.com> wrote:
> I'm trying to learn Ada because a) I think it's cool to learn new
> computer languages and b) it looks like a good one. I've gone the
> through a lot of the tutorials but lets say have package MyPackage and
> 5 subprograms are in the body. Which procedure is run first? Is it
> sequential? Is there some sort of equivalent to C's main()? Is a
> binary created for every package? I guess I don't understand where
> things start and end. Any help or links are greatly appreciated!
>
> Thanks,
> Ryan Kaskel


I suggest checking out some of the textbooks available.  There is a
good listing of Ada textbooks at the Ada IC.

http://www.adaic.org/learn/textbook.html

I'm partial, but I think that the Ada Plus Data Structures by Dale,
Weems, and McCormick answers your questions best.

John