Re: Local vs global variables in ADA

[martin.dowie@btopenworld.com (Martin Dowie)]

"Roger" <in@yourdreams.com> wrote in message news:<5Ldx9.3695$151.38236@weber.videotron.net>...
> Yes I'm an Ada newbie and have a questions about local and global variables.
> When exactly is a variable said to be global?

I don't consider Ada to have global variables when used normally (at least
not in the COBOL sense I was brought up with), as even a data item declared
in a package specification, it is still local to that package - as in, you
still have to reference the package name somewhere before using the data
item.

The exception to this is "pragma Export" and "pragma Import". With these
you can do hideously dangerous things and completely remove the need for
context clauses! :-)

e.g.

package body Foo is
   ...
   My_Local : Integer;
   pragma Export (Ada, My_Local, "My_Local");
   ...
end Foo;

...

-- WITHOUT "with Foo;"
--
package body Bar is
   ...
   -- No idea where "My_Local" is actual declared!
   --
   My_Other_Local : Integer;
   pragma Import (Ada, My_Other_Local, "My_Local");
   ...
end Bar;