Re: Visibility and Elaboration

["David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>]

----- Original Message ----- 
From: <And838N@netscape.net>
To: <comp.lang.ada@ada.eu.org>
Sent: June 09, 2003 5:47 AM
Subject: Visibility and Elaboration


> David C. Hoos, Sr. wrote:
> >If you look at your original post (on June 4), there was no "put_line"
> >statement -- hence, the reason for my question
> Ok, your right, there was no put_line statement.  There was only the
> "put" statement.  The compiler would still have complained.

The compiler did _not_ complain when the unneeded "with" of Ada.Text_IO
was removed.

> 
> >GNAT did _not_ tell you it didn't know which one to use.
> Ok, that must be why I wrote "Thus, GNAT's compiler message tells me 
> not that GNAT can't determine which count to use but that I need to 
> specify, for future readers, which count I needed."
> 
> >Using the GNAT compiler, the object file resulting from the
> >compilation of your package would contain a procedure named 
> >my_pkg___elabs. That procedure contains the elaboration code for your 
> >package specification.
> Cool!  I'm going to check that out.  Thank you.
> 
> >Elaboration is nothing at all like the instantiation of a C++ class.
> Ok, elaboration is like the "preparation" of something declared static 
> in C++ or Java? So your saying that all the elaborations in the 
> following code happen before the main procedure is called?
The only elaborations resulting from the following code are from the
Ada standard libraries, viz:
ada__exceptions_E
system__exception_table_E
ada__io_exceptions_E
system__exceptions_E
system__secondary_stack_E
ada__tags_E
ada__streams_E
system__soft_links_E
system__finalization_root_E
system__finalization_implementation_E
ada__finalization_E
ada__finalization__list_controller_E
system__file_control_block_E
system__file_io_E
ada__text_io_E
Yes, they are all performed before exection of the main program.

Build you main program with the command gnatmake -g newelaboration
and look at the file b~newelaboration.adb generated by that process.
> 
> with
> ada.text_io,
> ada.integer_text_io;
> 
> use
> ada.text_io,
> ada.integer_text_io;
> 
> procedure newelaboration is
> 
>     procedure doelaboration(i: integer) is
>         package elo is
>             value: Integer;
>             procedure printvalue;
>         end elo;
> 
>         package body elo is
>             procedure printvalue is
>             begin
>                 put(value);
>             end printvalue;
>         end elo;
>     
>     begin
>         if i < 10 then
>             elo.value := i;
>             doelaboration(i+1);
>             elo.printvalue;
>         end if;
>     end doelaboration;
> 
> begin
> 
> doelaboration(1);
> 
> end newelaboration;
> 
> So using the "new" reserved word is different than an elaboration?
Yes.
> 
> Thanks for the help!
> 
> Andrew
> 
> 
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