Re: basic question on nested packages

["Nasser M. Abbasi" <nma@12000.org>]

On 7/28/2012 12:36 AM, Shark8 wrote:
> On Friday, July 27, 2012 11:27:31 PM UTC-6, Nasser M. Abbasi wrote:
>> On 7/27/2012 10:22 PM, Nasser M. Abbasi wrote:
>>
>>>
>>> What I think would be better is to have ONE lapack package and
>>> with the above packages as nested packages.
>> ref (me)
>>
>> I think may be I need to use 'child packages', not 'nested pacakges',
>> but not sure yet.
>>
>> I am doing a crash course now reading an ada book to learn more
>> the difference between these and which one to use....
>

  
> You could likely use nested packages; though child packages will likely be better
>for maintainability, but if they're short/simple child packages make good sense.
>

Yes, this is what I ended up doing. It was easier that I thought.

Now the lapack client has this:

----------------------------
with Ada.Text_IO; use Ada.Text_IO;
with Interfaces.Fortran; use Interfaces.Fortran;
with lapack, lapack.driver;

procedure mysolve is
     A    : lapack.Fortran_Real_Matrix (1 .. 3, 1 .. 3)
  begin
    lapack.driver.SGESV(...)
    ....
-----------------------

>gnatmake -I../ada mysolve.adb
           -largs
           -L/usr/lib/atlas-base/atlas
           -L/usr/lib/atlas-base/
           -lblas
           -llapack

>./mysolve
-1.31250E+00
  3.50000E+00
  1.12500E+00
>

done!

The only surprise for me, was that I had to WITH the 'driver' which is a
child package of the parent lapack package explicitly to use it from the
client even though I withed the parent package.

I thought, since it is a child package of lapack, then it will be pulled in
automatically by just WITH'ing lapack. But no.

i.e. I thought by inviting the parent in, the children will come along
with the parent and not be left alone outside.

No problem.

I think now the API is much more clean. I rebuild lapack
with this new change and all is well. I think when Lapack binding was made,
child packages did not exist yet in Ada?

I also removed all the pragma linker options that was hard-coded in the
source code. I do not like to see hard-coded values for build in source
code. I think all of this belong to Makefile or gpr and not in source code.

Making more documentations and diagrams and will update all this on
my Ada page soon with a new snapshot tar file in case someone wants to try
it.

--Nasser